/*
* Copyright (c) 2004-2020 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
* support for mandatory and extensible security protections. This notice
* is included in support of clause 2.2 (b) of the Apple Public License,
* Version 2.0.
*/
/*
* Kernel Authorization framework: Management of process/thread credentials
* and identity information.
*/
#include <sys/param.h> /* XXX trim includes */
#include <sys/acct.h>
#include <sys/systm.h>
#include <sys/ucred.h>
#include <sys/proc_internal.h>
#include <sys/user.h>
#include <sys/timeb.h>
#include <sys/times.h>
#include <sys/malloc.h>
#include <sys/kauth.h>
#include <sys/kernel.h>
#include <sys/sdt.h>
#include <security/audit/audit.h>
#include <sys/mount.h>
#include <sys/stat.h> /* For manifest constants in posix_cred_access */
#include <sys/sysproto.h>
#include <mach/message.h>
#include <machine/atomic.h>
#include <libkern/OSByteOrder.h>
#include <kern/smr_hash.h>
#include <kern/task.h>
#include <kern/locks.h>
#ifdef MACH_ASSERT
# undef MACH_ASSERT
#endif
#define MACH_ASSERT 1 /* XXX so bogus */
#include <kern/assert.h>
#if CONFIG_MACF
#include <security/mac.h>
#include <security/mac_policy.h>
#include <security/mac_framework.h>
#include <security/_label.h>
#endif
#include <os/hash.h>
#include <IOKit/IOBSD.h>
/* Set to 1 to turn on KAUTH_DEBUG for kern_credential.c */
#if 0
#ifdef KAUTH_DEBUG
#undef KAUTH_DEBUG
#endif
#ifdef K_UUID_FMT
#undef K_UUID_FMT
#endif
#ifdef K_UUID_ARG
#undef K_UUID_ARG
#endif
# define K_UUID_FMT "%08x:%08x:%08x:%08x"
# define K_UUID_ARG(_u) &_u.g_guid_asint[0],&_u.g_guid_asint[1],&_u.g_guid_asint[2],&_u.g_guid_asint[3]
# define KAUTH_DEBUG(fmt, args...) do { printf("%s:%d: " fmt "\n", __PRETTY_FUNCTION__, __LINE__ , ##args); } while (0)
#endif
#if CONFIG_EXT_RESOLVER
/*
* Interface to external identity resolver.
*
* The architecture of the interface is simple; the external resolver calls
* in to get work, then calls back with completed work. It also calls us
* to let us know that it's (re)started, so that we can resubmit work if it
* times out.
*/
static LCK_MTX_DECLARE(kauth_resolver_mtx, &kauth_lck_grp);
#define KAUTH_RESOLVER_LOCK() lck_mtx_lock(&kauth_resolver_mtx);
#define KAUTH_RESOLVER_UNLOCK() lck_mtx_unlock(&kauth_resolver_mtx);
static volatile pid_t kauth_resolver_identity;
static int kauth_identitysvc_has_registered;
static int kauth_resolver_registered;
static uint32_t kauth_resolver_sequence = 31337;
static int kauth_resolver_timeout = 30; /* default: 30 seconds */
struct kauth_resolver_work {
TAILQ_ENTRY(kauth_resolver_work) kr_link;
struct kauth_identity_extlookup kr_work;
uint64_t kr_extend;
uint32_t kr_seqno;
int kr_refs;
int kr_flags;
#define KAUTH_REQUEST_UNSUBMITTED (1<<0)
#define KAUTH_REQUEST_SUBMITTED (1<<1)
#define KAUTH_REQUEST_DONE (1<<2)
int kr_result;
};
TAILQ_HEAD(kauth_resolver_unsubmitted_head, kauth_resolver_work) kauth_resolver_unsubmitted =
TAILQ_HEAD_INITIALIZER(kauth_resolver_unsubmitted);
TAILQ_HEAD(kauth_resolver_submitted_head, kauth_resolver_work) kauth_resolver_submitted =
TAILQ_HEAD_INITIALIZER(kauth_resolver_submitted);
TAILQ_HEAD(kauth_resolver_done_head, kauth_resolver_work) kauth_resolver_done =
TAILQ_HEAD_INITIALIZER(kauth_resolver_done);
/* Number of resolver timeouts between logged complaints */
#define KAUTH_COMPLAINT_INTERVAL 1000
int kauth_resolver_timeout_cnt = 0;
#if DEVELOPMENT || DEBUG
/* Internal builds get different (less ambiguous) breadcrumbs. */
#define KAUTH_RESOLVER_FAILED_ERRCODE EOWNERDEAD
#else
/* But non-Internal builds get errors that are allowed by standards. */
#define KAUTH_RESOLVER_FAILED_ERRCODE EIO
#endif /* DEVELOPMENT || DEBUG */
int kauth_resolver_failed_cnt = 0;
#define RESOLVER_FAILED_MESSAGE(fmt, args...) \
do { \
if (!(kauth_resolver_failed_cnt++ % 100)) { \
printf("%s: " fmt "\n", __PRETTY_FUNCTION__, ##args); \
} \
} while (0)
static int kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data);
static int kauth_resolver_complete(user_addr_t message);
static int kauth_resolver_getwork(user_addr_t message);
static int kauth_resolver_getwork2(user_addr_t message);
static __attribute__((noinline)) int __KERNEL_IS_WAITING_ON_EXTERNAL_CREDENTIAL_RESOLVER__(
struct kauth_resolver_work *);
#define KAUTH_CACHES_MAX_SIZE 10000 /* Max # entries for both groups and id caches */
struct kauth_identity {
TAILQ_ENTRY(kauth_identity) ki_link;
int ki_valid;
uid_t ki_uid;
gid_t ki_gid;
uint32_t ki_supgrpcnt;
gid_t ki_supgrps[NGROUPS];
guid_t ki_guid;
ntsid_t ki_ntsid;
const char *ki_name; /* string name from string cache */
/*
* Expiry times are the earliest time at which we will disregard the
* cached state and go to userland. Before then if the valid bit is
* set, we will return the cached value. If it's not set, we will
* not go to userland to resolve, just assume that there is no answer
* available.
*/
time_t ki_groups_expiry;
time_t ki_guid_expiry;
time_t ki_ntsid_expiry;
};
static TAILQ_HEAD(kauth_identity_head, kauth_identity) kauth_identities =
TAILQ_HEAD_INITIALIZER(kauth_identities);
static LCK_MTX_DECLARE(kauth_identity_mtx, &kauth_lck_grp);
#define KAUTH_IDENTITY_LOCK() lck_mtx_lock(&kauth_identity_mtx);
#define KAUTH_IDENTITY_UNLOCK() lck_mtx_unlock(&kauth_identity_mtx);
#define KAUTH_IDENTITY_CACHEMAX_DEFAULT 100 /* XXX default sizing? */
static int kauth_identity_cachemax = KAUTH_IDENTITY_CACHEMAX_DEFAULT;
static int kauth_identity_count;
static struct kauth_identity *kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry,
ntsid_t *ntsidp, time_t ntsid_expiry, size_t supgrpcnt, gid_t *supgrps, time_t groups_expiry,
const char *name, int nametype);
static void kauth_identity_register_and_free(struct kauth_identity *kip);
static void kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_identity *kip, uint64_t extend_data);
static void kauth_identity_trimcache(int newsize);
static void kauth_identity_lru(struct kauth_identity *kip);
static int kauth_identity_guid_expired(struct kauth_identity *kip);
static int kauth_identity_ntsid_expired(struct kauth_identity *kip);
static int kauth_identity_find_uid(uid_t uid, struct kauth_identity *kir, char *getname);
static int kauth_identity_find_gid(gid_t gid, struct kauth_identity *kir, char *getname);
static int kauth_identity_find_guid(guid_t *guidp, struct kauth_identity *kir, char *getname);
static int kauth_identity_find_ntsid(ntsid_t *ntsid, struct kauth_identity *kir, char *getname);
static int kauth_identity_find_nam(char *name, int valid, struct kauth_identity *kir);
struct kauth_group_membership {
TAILQ_ENTRY(kauth_group_membership) gm_link;
uid_t gm_uid; /* the identity whose membership we're recording */
gid_t gm_gid; /* group of which they are a member */
time_t gm_expiry; /* TTL for the membership, or 0 for persistent entries */
int gm_flags;
#define KAUTH_GROUP_ISMEMBER (1<<0)
};
TAILQ_HEAD(kauth_groups_head, kauth_group_membership) kauth_groups =
TAILQ_HEAD_INITIALIZER(kauth_groups);
static LCK_MTX_DECLARE(kauth_groups_mtx, &kauth_lck_grp);
#define KAUTH_GROUPS_LOCK() lck_mtx_lock(&kauth_groups_mtx);
#define KAUTH_GROUPS_UNLOCK() lck_mtx_unlock(&kauth_groups_mtx);
#define KAUTH_GROUPS_CACHEMAX_DEFAULT 100 /* XXX default sizing? */
static int kauth_groups_cachemax = KAUTH_GROUPS_CACHEMAX_DEFAULT;
static int kauth_groups_count;
static int kauth_groups_expired(struct kauth_group_membership *gm);
static void kauth_groups_lru(struct kauth_group_membership *gm);
static void kauth_groups_updatecache(struct kauth_identity_extlookup *el);
static void kauth_groups_trimcache(int newsize);
/*
* __KERNEL_IS_WAITING_ON_EXTERNAL_CREDENTIAL_RESOLVER__
*
* Description: Waits for the user space daemon to respond to the request
* we made. Function declared non inline to be visible in
* stackshots and spindumps as well as debugging.
*
* Parameters: workp Work queue entry.
*
* Returns: 0 on Success.
* EIO if Resolver is dead.
* EINTR thread interrupted in msleep
* EWOULDBLOCK thread timed out in msleep
* ERESTART returned by msleep.
*
*/
static __attribute__((noinline)) int
__KERNEL_IS_WAITING_ON_EXTERNAL_CREDENTIAL_RESOLVER__(
struct kauth_resolver_work *workp)
{
int error = 0;
struct timespec ts;
for (;;) {
/* we could compute a better timeout here */
ts.tv_sec = kauth_resolver_timeout;
ts.tv_nsec = 0;
error = msleep(workp, &kauth_resolver_mtx, PCATCH, "kr_submit", &ts);
/* request has been completed? */
if ((error == 0) && (workp->kr_flags & KAUTH_REQUEST_DONE)) {
break;
}
/* woken because the resolver has died? */
if (kauth_resolver_identity == 0) {
RESOLVER_FAILED_MESSAGE("kauth external resolver died while while waiting for work to complete");
error = KAUTH_RESOLVER_FAILED_ERRCODE;
break;
}
/* an error? */
if (error != 0) {
break;
}
}
return error;
}
/*
* kauth_resolver_identity_reset
*
* Description: Reset the identity of the external resolver in certain
* controlled circumstances.
*
* Parameters: None.
*
* Returns: Nothing.
*/
void
kauth_resolver_identity_reset(void)
{
KAUTH_RESOLVER_LOCK();
if (kauth_resolver_identity != 0) {
printf("kauth external resolver %d failed to de-register.\n",
kauth_resolver_identity);
kauth_resolver_identity = 0;
kauth_resolver_registered = 0;
}
KAUTH_RESOLVER_UNLOCK();
}
/*
* kauth_resolver_submit
*
* Description: Submit an external credential identity resolution request to
* the user space daemon.
*
* Parameters: lkp A pointer to an external
* lookup request
* extend_data extended data for kr_extend
*
* Returns: 0 Success
* EWOULDBLOCK No resolver registered
* EINTR Operation interrupted (e.g. by
* a signal)
* ENOMEM Could not allocate work item
* copyinstr:EFAULT Bad message from user space
* workp->kr_result:??? An error from the user space
* daemon (includes ENOENT!)
*
* Implicit returns:
* *lkp Modified
*
* Notes: Allocate a work queue entry, submit the work and wait for
* the operation to either complete or time out. Outstanding
* operations may also be cancelled.
*
* Submission is by means of placing the item on a work queue
* which is serviced by an external resolver thread calling
* into the kernel. The caller then sleeps until timeout,
* cancellation, or an external resolver thread calls in with
* a result message to kauth_resolver_complete(). All of these
* events wake the caller back up.
*
* This code is called from either kauth_cred_ismember_gid()
* for a group membership request, or it is called from
* kauth_cred_cache_lookup() when we get a cache miss.
*/
static int
kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data)
{
struct kauth_resolver_work *workp, *killp;
struct timespec ts;
int error, shouldfree;
/* no point actually blocking if the resolver isn't up yet */
if (kauth_resolver_identity == 0) {
/*
* We've already waited an initial <kauth_resolver_timeout>
* seconds with no result.
*
* Sleep on a stack address so no one wakes us before timeout;
* we sleep a half a second in case we are a high priority
* process, so that memberd doesn't starve while we are in a
* tight loop between user and kernel, eating all the CPU.
*/
error = tsleep(&ts, PZERO | PCATCH, "kr_submit", hz / 2);
if (kauth_resolver_identity == 0) {
/*
* if things haven't changed while we were asleep,
* tell the caller we couldn't get an authoritative
* answer.
*/
return EWOULDBLOCK;
}
}
workp = kalloc_type(struct kauth_resolver_work, Z_WAITOK | Z_NOFAIL);
workp->kr_work = *lkp;
workp->kr_extend = extend_data;
workp->kr_refs = 1;
workp->kr_flags = KAUTH_REQUEST_UNSUBMITTED;
workp->kr_result = 0;
/*
* We insert the request onto the unsubmitted queue, the call in from
* the resolver will it to the submitted thread when appropriate.
*/
KAUTH_RESOLVER_LOCK();
workp->kr_seqno = workp->kr_work.el_seqno = kauth_resolver_sequence++;
workp->kr_work.el_result = KAUTH_EXTLOOKUP_INPROG;
/*
* XXX We *MUST NOT* attempt to coalesce identical work items due to
* XXX the inability to ensure order of update of the request item
* XXX extended data vs. the wakeup; instead, we let whoever is waiting
* XXX for each item repeat the update when they wake up.
*/
TAILQ_INSERT_TAIL(&kauth_resolver_unsubmitted, workp, kr_link);
/*
* Wake up an external resolver thread to deal with the new work; one
* may not be available, and if not, then the request will be grabbed
* when a resolver thread comes back into the kernel to request new
* work.
*/
wakeup_one((caddr_t)&kauth_resolver_unsubmitted);
error = __KERNEL_IS_WAITING_ON_EXTERNAL_CREDENTIAL_RESOLVER__(workp);
/* if the request was processed, copy the result */
if (error == 0) {
*lkp = workp->kr_work;
}
if (error == EWOULDBLOCK) {
if ((kauth_resolver_timeout_cnt++ % KAUTH_COMPLAINT_INTERVAL) == 0) {
printf("kauth external resolver timed out (%d timeout(s) of %d seconds).\n",
kauth_resolver_timeout_cnt, kauth_resolver_timeout);
}
if (workp->kr_flags & KAUTH_REQUEST_UNSUBMITTED) {
/*
* If the request timed out and was never collected, the resolver
* is dead and probably not coming back anytime soon. In this
* case we revert to no-resolver behaviour, and punt all the other
* sleeping requests to clear the backlog.
*/
KAUTH_DEBUG("RESOLVER - request timed out without being collected for processing, resolver dead");
/*
* Make the current resolver non-authoritative, and mark it as
* no longer registered to prevent kauth_cred_ismember_gid()
* enqueueing more work until a new one is registered. This
* mitigates the damage a crashing resolver may inflict.
*/
kauth_resolver_identity = 0;
kauth_resolver_registered = 0;
/* kill all the other requestes that are waiting as well */
TAILQ_FOREACH(killp, &kauth_resolver_submitted, kr_link)
wakeup(killp);
TAILQ_FOREACH(killp, &kauth_resolver_unsubmitted, kr_link)
wakeup(killp);
/* Cause all waiting-for-work threads to return EIO */
wakeup((caddr_t)&kauth_resolver_unsubmitted);
}
}
/*
* drop our reference on the work item, and note whether we should
* free it or not
*/
if (--workp->kr_refs <= 0) {
/* work out which list we have to remove it from */
if (workp->kr_flags & KAUTH_REQUEST_DONE) {
TAILQ_REMOVE(&kauth_resolver_done, workp, kr_link);
} else if (workp->kr_flags & KAUTH_REQUEST_SUBMITTED) {
TAILQ_REMOVE(&kauth_resolver_submitted, workp, kr_link);
} else if (workp->kr_flags & KAUTH_REQUEST_UNSUBMITTED) {
TAILQ_REMOVE(&kauth_resolver_unsubmitted, workp, kr_link);
} else {
KAUTH_DEBUG("RESOLVER - completed request has no valid queue");
}
shouldfree = 1;
} else {
/* someone else still has a reference on this request */
shouldfree = 0;
}
/* collect request result */
if (error == 0) {
error = workp->kr_result;
}
KAUTH_RESOLVER_UNLOCK();
/*
* If we dropped the last reference, free the request.
*/
if (shouldfree) {
kfree_type(struct kauth_resolver_work, workp);
}
KAUTH_DEBUG("RESOLVER - returning %d", error);
return error;
}
/*
* identitysvc
*
* Description: System call interface for the external identity resolver.
*
* Parameters: uap->message Message from daemon to kernel
*
* Returns: 0 Successfully became resolver
* EPERM Not the resolver process
* kauth_authorize_generic:EPERM Not root user
* kauth_resolver_complete:EIO
* kauth_resolver_complete:EFAULT
* kauth_resolver_getwork:EINTR
* kauth_resolver_getwork:EFAULT
*
* Notes: This system call blocks until there is work enqueued, at
* which time the kernel wakes it up, and a message from the
* kernel is copied out to the identity resolution daemon, which
* proceed to attempt to resolve it. When the resolution has
* completed (successfully or not), the daemon called back into
* this system call to give the result to the kernel, and wait
* for the next request.
*/
int
identitysvc(__unused struct proc *p, struct identitysvc_args *uap, __unused int32_t *retval)
{
int opcode = uap->opcode;
user_addr_t message = uap->message;
struct kauth_resolver_work *workp;
struct kauth_cache_sizes sz_arg = {};
int error;
pid_t new_id;
if (!IOCurrentTaskHasEntitlement(IDENTITYSVC_ENTITLEMENT)) {
KAUTH_DEBUG("RESOLVER - pid %d not entitled to call identitysvc", proc_getpid(current_proc()));
return EPERM;
}
/*
* New server registering itself.
*/
if (opcode == KAUTH_EXTLOOKUP_REGISTER) {
new_id = proc_getpid(current_proc());
if ((error = kauth_authorize_generic(kauth_cred_get(), KAUTH_GENERIC_ISSUSER)) != 0) {
KAUTH_DEBUG("RESOLVER - pid %d refused permission to become identity resolver", new_id);
return error;
}
KAUTH_RESOLVER_LOCK();
if (kauth_resolver_identity != new_id) {
KAUTH_DEBUG("RESOLVER - new resolver %d taking over from old %d", new_id, kauth_resolver_identity);
/*
* We have a new server, so assume that all the old requests have been lost.
*/
while ((workp = TAILQ_LAST(&kauth_resolver_submitted, kauth_resolver_submitted_head)) != NULL) {
TAILQ_REMOVE(&kauth_resolver_submitted, workp, kr_link);
workp->kr_flags &= ~KAUTH_REQUEST_SUBMITTED;
workp->kr_flags |= KAUTH_REQUEST_UNSUBMITTED;
TAILQ_INSERT_HEAD(&kauth_resolver_unsubmitted, workp, kr_link);
}
/*
* Allow user space resolver to override the
* external resolution timeout
*/
if (message > 30 && message < 10000) {
kauth_resolver_timeout = (int)message;
KAUTH_DEBUG("RESOLVER - new resolver changes timeout to %d seconds\n", (int)message);
}
kauth_resolver_identity = new_id;
kauth_resolver_registered = 1;
kauth_identitysvc_has_registered = 1;
wakeup(&kauth_resolver_unsubmitted);
}
KAUTH_RESOLVER_UNLOCK();
return 0;
}
/*
* Beyond this point, we must be the resolver process. We verify this
* by confirming the resolver credential and pid.
*/
if ((kauth_cred_getuid(kauth_cred_get()) != 0) || (proc_getpid(current_proc()) != kauth_resolver_identity)) {
KAUTH_DEBUG("RESOLVER - call from bogus resolver %d\n", proc_getpid(current_proc()));
return EPERM;
}
if (opcode == KAUTH_GET_CACHE_SIZES) {
KAUTH_IDENTITY_LOCK();
sz_arg.kcs_id_size = kauth_identity_cachemax;
KAUTH_IDENTITY_UNLOCK();
KAUTH_GROUPS_LOCK();
sz_arg.kcs_group_size = kauth_groups_cachemax;
KAUTH_GROUPS_UNLOCK();
if ((error = copyout(&sz_arg, uap->message, sizeof(sz_arg))) != 0) {
return error;
}
return 0;
} else if (opcode == KAUTH_SET_CACHE_SIZES) {
if ((error = copyin(uap->message, &sz_arg, sizeof(sz_arg))) != 0) {
return error;
}
if ((sz_arg.kcs_group_size > KAUTH_CACHES_MAX_SIZE) ||
(sz_arg.kcs_id_size > KAUTH_CACHES_MAX_SIZE)) {
return EINVAL;
}
KAUTH_IDENTITY_LOCK();
kauth_identity_cachemax = sz_arg.kcs_id_size;
kauth_identity_trimcache(kauth_identity_cachemax);
KAUTH_IDENTITY_UNLOCK();
KAUTH_GROUPS_LOCK();
kauth_groups_cachemax = sz_arg.kcs_group_size;
kauth_groups_trimcache(kauth_groups_cachemax);
KAUTH_GROUPS_UNLOCK();
return 0;
} else if (opcode == KAUTH_CLEAR_CACHES) {
KAUTH_IDENTITY_LOCK();
kauth_identity_trimcache(0);
KAUTH_IDENTITY_UNLOCK();
KAUTH_GROUPS_LOCK();
kauth_groups_trimcache(0);
KAUTH_GROUPS_UNLOCK();
} else if (opcode == KAUTH_EXTLOOKUP_DEREGISTER) {
/*
* Terminate outstanding requests; without an authoritative
* resolver, we are now back on our own authority.
*/
struct kauth_resolver_work *killp;
KAUTH_RESOLVER_LOCK();
/*
* Clear the identity, but also mark it as unregistered so
* there is no explicit future expectation of us getting a
* new resolver any time soon.
*/
kauth_resolver_identity = 0;
kauth_resolver_registered = 0;
TAILQ_FOREACH(killp, &kauth_resolver_submitted, kr_link)
wakeup(killp);
TAILQ_FOREACH(killp, &kauth_resolver_unsubmitted, kr_link)
wakeup(killp);
/* Cause all waiting-for-work threads to return EIO */
wakeup((caddr_t)&kauth_resolver_unsubmitted);
KAUTH_RESOLVER_UNLOCK();
}
/*
* Got a result returning?
*/
if (opcode & KAUTH_EXTLOOKUP_RESULT) {
if ((error = kauth_resolver_complete(message)) != 0) {
return error;
}
}
/*
* Caller wants to take more work?
*/
if (opcode & KAUTH_EXTLOOKUP_WORKER) {
if ((error = kauth_resolver_getwork(message)) != 0) {
return error;
}
}
return 0;
}
/*
* kauth_resolver_getwork_continue
*
* Description: Continuation for kauth_resolver_getwork
*
* Parameters: result Error code or 0 for the sleep
* that got us to this function
*
* Returns: 0 Success
* EINTR Interrupted (e.g. by signal)
* kauth_resolver_getwork2:EFAULT
*
* Notes: See kauth_resolver_getwork(0 and kauth_resolver_getwork2() for
* more information.
*/
static int
kauth_resolver_getwork_continue(int result)
{
thread_t thread;
struct uthread *ut;
user_addr_t message;
if (result) {
KAUTH_RESOLVER_UNLOCK();
return result;
}
/*
* If we lost a race with another thread/memberd restarting, then we
* need to go back to sleep to look for more work. If it was memberd
* restarting, then the msleep0() will error out here, as our thread
* will already be "dead".
*/
if (TAILQ_FIRST(&kauth_resolver_unsubmitted) == NULL) {
int error;
error = msleep0(&kauth_resolver_unsubmitted, &kauth_resolver_mtx, PCATCH, "GRGetWork", 0, kauth_resolver_getwork_continue);
/*
* If this is a wakeup from another thread in the resolver
* deregistering it, error out the request-for-work thread
*/
if (!kauth_resolver_identity) {
RESOLVER_FAILED_MESSAGE("external resolver died");
error = KAUTH_RESOLVER_FAILED_ERRCODE;
}
KAUTH_RESOLVER_UNLOCK();
return error;
}
thread = current_thread();
ut = get_bsdthread_info(thread);
message = ut->uu_save.uus_kauth.message;
return kauth_resolver_getwork2(message);
}
/*
* kauth_resolver_getwork2
*
* Decription: Common utility function to copy out a identity resolver work
* item from the kernel to user space as part of the user space
* identity resolver requesting work.
*
* Parameters: message message to user space
*
* Returns: 0 Success
* EFAULT Bad user space message address
*
* Notes: This common function exists to permit the use of continuations
* in the identity resolution process. This frees up the stack
* while we are waiting for the user space resolver to complete
* a request. This is specifically used so that our per thread
* cost can be small, and we will therefore be willing to run a
* larger number of threads in the user space identity resolver.
*/
static int
kauth_resolver_getwork2(user_addr_t message)
{
struct kauth_resolver_work *workp;
int error;
/*
* Note: We depend on the caller protecting us from a NULL work item
* queue, since we must have the kauth resolver lock on entry to this
* function.
*/
workp = TAILQ_FIRST(&kauth_resolver_unsubmitted);
/*
* Copy out the external lookup structure for the request, not
* including the el_extend field, which contains the address of the
* external buffer provided by the external resolver into which we
* copy the extension request information.
*/
/* BEFORE FIELD */
if ((error = copyout(&workp->kr_work, message, offsetof(struct kauth_identity_extlookup, el_extend))) != 0) {
KAUTH_DEBUG("RESOLVER - error submitting work to resolve");
goto out;
}
/* AFTER FIELD */
if ((error = copyout(&workp->kr_work.el_info_reserved_1,
message + offsetof(struct kauth_identity_extlookup, el_info_reserved_1),
sizeof(struct kauth_identity_extlookup) - offsetof(struct kauth_identity_extlookup, el_info_reserved_1))) != 0) {
KAUTH_DEBUG("RESOLVER - error submitting work to resolve");
goto out;
}
/*
* Handle extended requests here; if we have a request of a type where
* the kernel wants a translation of extended information, then we need
* to copy it out into the extended buffer, assuming the buffer is
* valid; we only attempt to get the buffer address if we have request
* data to copy into it.
*/
/*
* translate a user@domain string into a uid/gid/whatever
*/
if (workp->kr_work.el_flags & (KAUTH_EXTLOOKUP_VALID_PWNAM | KAUTH_EXTLOOKUP_VALID_GRNAM)) {
uint64_t uaddr;
error = copyin(message + offsetof(struct kauth_identity_extlookup, el_extend), &uaddr, sizeof(uaddr));
if (!error) {
size_t actual; /* not used */
/*
* Use copyoutstr() to reduce the copy size; we let
* this catch a NULL uaddr because we shouldn't be
* asking in that case anyway.
*/
error = copyoutstr(CAST_DOWN(void *, workp->kr_extend), uaddr, MAXPATHLEN, &actual);
}
if (error) {
KAUTH_DEBUG("RESOLVER - error submitting work to resolve");
goto out;
}
}
TAILQ_REMOVE(&kauth_resolver_unsubmitted, workp, kr_link);
workp->kr_flags &= ~KAUTH_REQUEST_UNSUBMITTED;
workp->kr_flags |= KAUTH_REQUEST_SUBMITTED;
TAILQ_INSERT_TAIL(&kauth_resolver_submitted, workp, kr_link);
out:
KAUTH_RESOLVER_UNLOCK();
return error;
}
/*
* kauth_resolver_getwork
*
* Description: Get a work item from the enqueued requests from the kernel and
* give it to the user space daemon.
*
* Parameters: message message to user space
*
* Returns: 0 Success
* EINTR Interrupted (e.g. by signal)
* kauth_resolver_getwork2:EFAULT
*
* Notes: This function blocks in a continuation if there are no work
* items available for processing at the time the user space
* identity resolution daemon makes a request for work. This
* permits a large number of threads to be used by the daemon,
* without using a lot of wired kernel memory when there are no
* actual request outstanding.
*/
static int
kauth_resolver_getwork(user_addr_t message)
{
struct kauth_resolver_work *workp;
int error;
KAUTH_RESOLVER_LOCK();
error = 0;
while ((workp = TAILQ_FIRST(&kauth_resolver_unsubmitted)) == NULL) {
thread_t thread = current_thread();
struct uthread *ut = get_bsdthread_info(thread);
ut->uu_save.uus_kauth.message = message;
error = msleep0(&kauth_resolver_unsubmitted, &kauth_resolver_mtx, PCATCH, "GRGetWork", 0, kauth_resolver_getwork_continue);
KAUTH_RESOLVER_UNLOCK();
/*
* If this is a wakeup from another thread in the resolver
* deregistering it, error out the request-for-work thread
*/
if (!kauth_resolver_identity) {
printf("external resolver died");
error = KAUTH_RESOLVER_FAILED_ERRCODE;
}
return error;
}
return kauth_resolver_getwork2(message);
}
/*
* kauth_resolver_complete
*
* Description: Return a result from userspace.
*
* Parameters: message message from user space
*
* Returns: 0 Success
* EIO The resolver is dead
* copyin:EFAULT Bad message from user space
*/
static int
kauth_resolver_complete(user_addr_t message)
{
struct kauth_identity_extlookup extl;
struct kauth_resolver_work *workp;
struct kauth_resolver_work *killp;
int error, result, want_extend_data;
/*
* Copy in the mesage, including the extension field, since we are
* copying into a local variable.
*/
if ((error = copyin(message, &extl, sizeof(extl))) != 0) {
KAUTH_DEBUG("RESOLVER - error getting completed work\n");
return error;
}
KAUTH_RESOLVER_LOCK();
error = 0;
result = 0;
switch (extl.el_result) {
case KAUTH_EXTLOOKUP_INPROG:
{
static int once = 0;
/* XXX this should go away once memberd is updated */
if (!once) {
printf("kauth_resolver: memberd is not setting valid result codes (assuming always successful)\n");
once = 1;
}
}
OS_FALLTHROUGH;
case KAUTH_EXTLOOKUP_SUCCESS:
break;
case KAUTH_EXTLOOKUP_FATAL:
/* fatal error means the resolver is dead */
KAUTH_DEBUG("RESOLVER - resolver %d died, waiting for a new one", kauth_resolver_identity);
RESOLVER_FAILED_MESSAGE("resolver %d died, waiting for a new one", kauth_resolver_identity);
/*
* Terminate outstanding requests; without an authoritative
* resolver, we are now back on our own authority. Tag the
* resolver unregistered to prevent kauth_cred_ismember_gid()
* enqueueing more work until a new one is registered. This
* mitigates the damage a crashing resolver may inflict.
*/
kauth_resolver_identity = 0;
kauth_resolver_registered = 0;
TAILQ_FOREACH(killp, &kauth_resolver_submitted, kr_link)
wakeup(killp);
TAILQ_FOREACH(killp, &kauth_resolver_unsubmitted, kr_link)
wakeup(killp);
/* Cause all waiting-for-work threads to return EIO */
wakeup((caddr_t)&kauth_resolver_unsubmitted);
/* and return EIO to the caller */
error = KAUTH_RESOLVER_FAILED_ERRCODE;
break;
case KAUTH_EXTLOOKUP_BADRQ:
KAUTH_DEBUG("RESOLVER - resolver reported invalid request %d", extl.el_seqno);
result = EINVAL;
break;
case KAUTH_EXTLOOKUP_FAILURE:
KAUTH_DEBUG("RESOLVER - resolver reported transient failure for request %d", extl.el_seqno);
RESOLVER_FAILED_MESSAGE("resolver reported transient failure for request %d", extl.el_seqno);
result = KAUTH_RESOLVER_FAILED_ERRCODE;
break;
default:
KAUTH_DEBUG("RESOLVER - resolver returned unexpected status %d", extl.el_result);
RESOLVER_FAILED_MESSAGE("resolver returned unexpected status %d", extl.el_result);
result = KAUTH_RESOLVER_FAILED_ERRCODE;
break;
}
/*
* In the case of a fatal error, we assume that the resolver will
* restart quickly and re-collect all of the outstanding requests.
* Thus, we don't complete the request which returned the fatal
* error status.
*/
if (extl.el_result != KAUTH_EXTLOOKUP_FATAL) {
/* scan our list for this request */
TAILQ_FOREACH(workp, &kauth_resolver_submitted, kr_link) {
/* found it? */
if (workp->kr_seqno == extl.el_seqno) {
/*
* Do we want extend_data?
*/
want_extend_data = (workp->kr_work.el_flags & (KAUTH_EXTLOOKUP_WANT_PWNAM | KAUTH_EXTLOOKUP_WANT_GRNAM));
/*
* Get the request of the submitted queue so
* that it is not cleaned up out from under
* us by a timeout.
*/
TAILQ_REMOVE(&kauth_resolver_submitted, workp, kr_link);
workp->kr_flags &= ~KAUTH_REQUEST_SUBMITTED;
workp->kr_flags |= KAUTH_REQUEST_DONE;
workp->kr_result = result;
/* Copy the result message to the work item. */
memcpy(&workp->kr_work, &extl, sizeof(struct kauth_identity_extlookup));
/*
* Check if we have a result in the extension
* field; if we do, then we need to separately
* copy the data from the message el_extend
* into the request buffer that's in the work
* item. We have to do it here because we do
* not want to wake up the waiter until the
* data is in their buffer, and because the
* actual request response may be destroyed
* by the time the requester wakes up, and they
* do not have access to the user space buffer
* address.
*
* It is safe to drop and reacquire the lock
* here because we've already removed the item
* from the submission queue, but have not yet
* moved it to the completion queue. Note that
* near simultaneous requests may result in
* duplication of requests for items in this
* window. This should not be a performance
* issue and is easily detectable by comparing
* time to live on last response vs. time of
* next request in the resolver logs.
*
* A malicious/faulty resolver could overwrite
* part of a user's address space if they return
* flags that mismatch the original request's flags.
*/
if (want_extend_data && (extl.el_flags & (KAUTH_EXTLOOKUP_VALID_PWNAM | KAUTH_EXTLOOKUP_VALID_GRNAM))) {
size_t actual; /* notused */
KAUTH_RESOLVER_UNLOCK();
error = copyinstr(extl.el_extend, CAST_DOWN(void *, workp->kr_extend), MAXPATHLEN, &actual);
KAUTH_DEBUG("RESOLVER - resolver got name :%*s: len = %d\n", (int)actual,
actual ? "null" : (char *)extl.el_extend, actual);
KAUTH_RESOLVER_LOCK();
} else if (extl.el_flags & (KAUTH_EXTLOOKUP_VALID_PWNAM | KAUTH_EXTLOOKUP_VALID_GRNAM)) {
error = EFAULT;
KAUTH_DEBUG("RESOLVER - resolver returned mismatching extension flags (%d), request contained (%d)",
extl.el_flags, want_extend_data);
}
/*
* Move the completed work item to the
* completion queue and wake up requester(s)
*/
TAILQ_INSERT_TAIL(&kauth_resolver_done, workp, kr_link);
wakeup(workp);
break;
}
}
}
/*
* Note that it's OK for us not to find anything; if the request has
* timed out the work record will be gone.
*/
KAUTH_RESOLVER_UNLOCK();
return error;
}
#endif /* CONFIG_EXT_RESOLVER */
/*
* Identity cache.
*/
#define KI_VALID_UID (1<<0) /* UID and GID are mutually exclusive */
#define KI_VALID_GID (1<<1)
#define KI_VALID_GUID (1<<2)
#define KI_VALID_NTSID (1<<3)
#define KI_VALID_PWNAM (1<<4) /* Used for translation */
#define KI_VALID_GRNAM (1<<5) /* Used for translation */
#define KI_VALID_GROUPS (1<<6)
#if CONFIG_EXT_RESOLVER
/*
* kauth_identity_alloc
*
* Description: Allocate and fill out a kauth_identity structure for
* translation between {UID|GID}/GUID/NTSID
*
* Parameters: uid
*
* Returns: NULL Insufficient memory to satisfy
* the request or bad parameters
* !NULL A pointer to the allocated
* structure, filled in
*
* Notes: It is illegal to translate between UID and GID; any given UUID
* or NTSID can only refer to an NTSID or UUID (respectively),
* and *either* a UID *or* a GID, but not both.
*/
static struct kauth_identity *
kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry,
ntsid_t *ntsidp, time_t ntsid_expiry, size_t supgrpcnt, gid_t *supgrps, time_t groups_expiry,
const char *name, int nametype)
{
struct kauth_identity *kip;
/* get and fill in a new identity */
kip = kalloc_type(struct kauth_identity, Z_WAITOK | Z_ZERO | Z_NOFAIL);
if (gid != KAUTH_GID_NONE) {
kip->ki_gid = gid;
kip->ki_valid = KI_VALID_GID;
}
if (uid != KAUTH_UID_NONE) {
if (kip->ki_valid & KI_VALID_GID) {
panic("can't allocate kauth identity with both uid and gid");
}
kip->ki_uid = uid;
kip->ki_valid = KI_VALID_UID;
}
if (supgrpcnt) {
/*
* A malicious/faulty resolver could return bad values
*/
assert(supgrpcnt <= NGROUPS);
assert(supgrps != NULL);
if ((supgrpcnt > NGROUPS) || (supgrps == NULL)) {
return NULL;
}
if (kip->ki_valid & KI_VALID_GID) {
panic("can't allocate kauth identity with both gid and supplementary groups");
}
kip->ki_supgrpcnt = (uint32_t)supgrpcnt;
memcpy(kip->ki_supgrps, supgrps, sizeof(supgrps[0]) * supgrpcnt);
kip->ki_valid |= KI_VALID_GROUPS;
}
kip->ki_groups_expiry = groups_expiry;
if (guidp != NULL) {
kip->ki_guid = *guidp;
kip->ki_valid |= KI_VALID_GUID;
}
kip->ki_guid_expiry = guid_expiry;
if (ntsidp != NULL) {
kip->ki_ntsid = *ntsidp;
kip->ki_valid |= KI_VALID_NTSID;
}
kip->ki_ntsid_expiry = ntsid_expiry;
if (name != NULL) {
kip->ki_name = name;
kip->ki_valid |= nametype;
}
return kip;
}
/*
* kauth_identity_register_and_free
*
* Description: Register an association between identity tokens. The passed
* 'kip' is consumed by this function.
*
* Parameters: kip Pointer to kauth_identity
* structure to register
*
* Returns: (void)
*
* Notes: The memory pointer to by 'kip' is assumed to have been
* previously allocated via kauth_identity_alloc().
*/
static void
kauth_identity_register_and_free(struct kauth_identity *kip)
{
struct kauth_identity *ip;
/*
* We search the cache for the UID listed in the incoming association.
* If we already have an entry, the new information is merged.
*/
ip = NULL;
KAUTH_IDENTITY_LOCK();
if (kip->ki_valid & KI_VALID_UID) {
if (kip->ki_valid & KI_VALID_GID) {
panic("kauth_identity: can't insert record with both UID and GID as key");
}
TAILQ_FOREACH(ip, &kauth_identities, ki_link)
if ((ip->ki_valid & KI_VALID_UID) && (ip->ki_uid == kip->ki_uid)) {
break;
}
} else if (kip->ki_valid & KI_VALID_GID) {
TAILQ_FOREACH(ip, &kauth_identities, ki_link)
if ((ip->ki_valid & KI_VALID_GID) && (ip->ki_gid == kip->ki_gid)) {
break;
}
} else {
panic("kauth_identity: can't insert record without UID or GID as key");
}
if (ip != NULL) {
/* we already have an entry, merge/overwrite */
if (kip->ki_valid & KI_VALID_GUID) {
ip->ki_guid = kip->ki_guid;
ip->ki_valid |= KI_VALID_GUID;
}
ip->ki_guid_expiry = kip->ki_guid_expiry;
if (kip->ki_valid & KI_VALID_NTSID) {
ip->ki_ntsid = kip->ki_ntsid;
ip->ki_valid |= KI_VALID_NTSID;
}
ip->ki_ntsid_expiry = kip->ki_ntsid_expiry;
/* a valid ki_name field overwrites the previous name field */
if (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)) {
/* if there's an old one, discard it */
const char *oname = NULL;
if (ip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)) {
oname = ip->ki_name;
}
ip->ki_name = kip->ki_name;
kip->ki_name = oname;
}
/* and discard the incoming entry */
ip = kip;
} else {
/*
* if we don't have any information on this identity, add it;
* if it pushes us over our limit, discard the oldest one.
*/
TAILQ_INSERT_HEAD(&kauth_identities, kip, ki_link);
if (++kauth_identity_count > kauth_identity_cachemax) {
ip = TAILQ_LAST(&kauth_identities, kauth_identity_head);
TAILQ_REMOVE(&kauth_identities, ip, ki_link);
kauth_identity_count--;
}
}
KAUTH_IDENTITY_UNLOCK();
/* have to drop lock before freeing expired entry (it may be in use) */
if (ip != NULL) {
/* if the ki_name field is used, clear it first */
if (ip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)) {
vfs_removename(ip->ki_name);
}
/* free the expired entry */
kfree_type(struct kauth_identity, ip);
}
}
/*
* kauth_identity_updatecache
*
* Description: Given a lookup result, add any associations that we don't
* currently have; replace ones which have changed.
*
* Parameters: elp External lookup result from
* user space daemon to kernel
* rkip pointer to returned kauth
* identity, or NULL
* extend_data Extended data (can vary)
*
* Returns: (void)
*
* Implicit returns:
* *rkip Modified (if non-NULL)
*
* Notes: For extended information requests, this code relies on the fact
* that elp->el_flags is never used as an rvalue, and is only
* ever bit-tested for valid lookup information we are willing
* to cache.
*
* XXX: We may have to do the same in the case that extended data was
* passed out to user space to ensure that the request string
* gets cached; we may also be able to use the rkip as an
* input to avoid this. The jury is still out.
*
* XXX: This codes performance could be improved for multiple valid
* results by combining the loop iteration in a single loop.
*/
static void
kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_identity *rkip, uint64_t extend_data)
{
struct timeval tv;
struct kauth_identity *kip;
const char *speculative_name = NULL;
microuptime(&tv);
/*
* If there is extended data, and that data represents a name rather
* than something else, speculatively create an entry for it in the
* string cache. We do this to avoid holding the KAUTH_IDENTITY_LOCK
* over the allocation later.
*/
if (elp->el_flags & (KAUTH_EXTLOOKUP_VALID_PWNAM | KAUTH_EXTLOOKUP_VALID_GRNAM)) {
const char *tmp = CAST_DOWN(const char *, extend_data);
speculative_name = vfs_addname(tmp, (uint32_t)strnlen(tmp, MAXPATHLEN - 1), 0, 0);
}
/* user identity? */
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_UID) {
KAUTH_IDENTITY_LOCK();
TAILQ_FOREACH(kip, &kauth_identities, ki_link) {
/* matching record */
if ((kip->ki_valid & KI_VALID_UID) && (kip->ki_uid == elp->el_uid)) {
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) {
assert(elp->el_sup_grp_cnt <= NGROUPS);
if (elp->el_sup_grp_cnt > NGROUPS) {
KAUTH_DEBUG("CACHE - invalid sup_grp_cnt provided (%d), truncating to %d",
elp->el_sup_grp_cnt, NGROUPS);
elp->el_sup_grp_cnt = NGROUPS;
}
kip->ki_supgrpcnt = elp->el_sup_grp_cnt;
memcpy(kip->ki_supgrps, elp->el_sup_groups, sizeof(elp->el_sup_groups[0]) * kip->ki_supgrpcnt);
kip->ki_valid |= KI_VALID_GROUPS;
kip->ki_groups_expiry = (elp->el_member_valid) ? tv.tv_sec + elp->el_member_valid : 0;
}
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_UGUID) {
kip->ki_guid = elp->el_uguid;
kip->ki_valid |= KI_VALID_GUID;
}
kip->ki_guid_expiry = (elp->el_uguid_valid) ? tv.tv_sec + elp->el_uguid_valid : 0;
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_USID) {
kip->ki_ntsid = elp->el_usid;
kip->ki_valid |= KI_VALID_NTSID;
}
kip->ki_ntsid_expiry = (elp->el_usid_valid) ? tv.tv_sec + elp->el_usid_valid : 0;
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_PWNAM) {
const char *oname = kip->ki_name;
kip->ki_name = speculative_name;
speculative_name = NULL;
kip->ki_valid |= KI_VALID_PWNAM;
if (oname) {
/*
* free oname (if any) outside
* the lock
*/
speculative_name = oname;
}
}
kauth_identity_lru(kip);
if (rkip != NULL) {
*rkip = *kip;
}
KAUTH_DEBUG("CACHE - refreshed %d is " K_UUID_FMT, kip->ki_uid, K_UUID_ARG(kip->ki_guid));
break;
}
}
KAUTH_IDENTITY_UNLOCK();
/* not found in cache, add new record */
if (kip == NULL) {
kip = kauth_identity_alloc(elp->el_uid, KAUTH_GID_NONE,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_UGUID) ? &elp->el_uguid : NULL,
(elp->el_uguid_valid) ? tv.tv_sec + elp->el_uguid_valid : 0,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_USID) ? &elp->el_usid : NULL,
(elp->el_usid_valid) ? tv.tv_sec + elp->el_usid_valid : 0,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) ? elp->el_sup_grp_cnt : 0,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) ? elp->el_sup_groups : NULL,
(elp->el_member_valid) ? tv.tv_sec + elp->el_member_valid : 0,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_PWNAM) ? speculative_name : NULL,
KI_VALID_PWNAM);
if (kip != NULL) {
if (rkip != NULL) {
*rkip = *kip;
}
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_PWNAM) {
speculative_name = NULL;
}
KAUTH_DEBUG("CACHE - learned %d is " K_UUID_FMT, kip->ki_uid, K_UUID_ARG(kip->ki_guid));
kauth_identity_register_and_free(kip);
}
}
}
/* group identity? (ignore, if we already processed it as a user) */
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GID && !(elp->el_flags & KAUTH_EXTLOOKUP_VALID_UID)) {
KAUTH_IDENTITY_LOCK();
TAILQ_FOREACH(kip, &kauth_identities, ki_link) {
/* matching record */
if ((kip->ki_valid & KI_VALID_GID) && (kip->ki_gid == elp->el_gid)) {
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GGUID) {
kip->ki_guid = elp->el_gguid;
kip->ki_valid |= KI_VALID_GUID;
}
kip->ki_guid_expiry = (elp->el_gguid_valid) ? tv.tv_sec + elp->el_gguid_valid : 0;
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GSID) {
kip->ki_ntsid = elp->el_gsid;
kip->ki_valid |= KI_VALID_NTSID;
}
kip->ki_ntsid_expiry = (elp->el_gsid_valid) ? tv.tv_sec + elp->el_gsid_valid : 0;
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GRNAM) {
const char *oname = kip->ki_name;
kip->ki_name = speculative_name;
speculative_name = NULL;
kip->ki_valid |= KI_VALID_GRNAM;
if (oname) {
/*
* free oname (if any) outside
* the lock
*/
speculative_name = oname;
}
}
kauth_identity_lru(kip);
if (rkip != NULL) {
*rkip = *kip;
}
KAUTH_DEBUG("CACHE - refreshed %d is " K_UUID_FMT, kip->ki_uid, K_UUID_ARG(kip->ki_guid));
break;
}
}
KAUTH_IDENTITY_UNLOCK();
/* not found in cache, add new record */
if (kip == NULL) {
kip = kauth_identity_alloc(KAUTH_UID_NONE, elp->el_gid,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_GGUID) ? &elp->el_gguid : NULL,
(elp->el_gguid_valid) ? tv.tv_sec + elp->el_gguid_valid : 0,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_GSID) ? &elp->el_gsid : NULL,
(elp->el_gsid_valid) ? tv.tv_sec + elp->el_gsid_valid : 0,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) ? elp->el_sup_grp_cnt : 0,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) ? elp->el_sup_groups : NULL,
(elp->el_member_valid) ? tv.tv_sec + elp->el_member_valid : 0,
(elp->el_flags & KAUTH_EXTLOOKUP_VALID_GRNAM) ? speculative_name : NULL,
KI_VALID_GRNAM);
if (kip != NULL) {
if (rkip != NULL) {
*rkip = *kip;
}
if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GRNAM) {
speculative_name = NULL;
}
KAUTH_DEBUG("CACHE - learned %d is " K_UUID_FMT, kip->ki_uid, K_UUID_ARG(kip->ki_guid));
kauth_identity_register_and_free(kip);
}
}
}
/* If we have a name reference to drop, drop it here */
if (speculative_name != NULL) {
vfs_removename(speculative_name);
}
}
/*
* Trim older entries from the identity cache.
*
* Must be called with the identity cache lock held.
*/
static void
kauth_identity_trimcache(int newsize)
{
struct kauth_identity *kip;
lck_mtx_assert(&kauth_identity_mtx, LCK_MTX_ASSERT_OWNED);
while (kauth_identity_count > newsize) {
kip = TAILQ_LAST(&kauth_identities, kauth_identity_head);
TAILQ_REMOVE(&kauth_identities, kip, ki_link);
kauth_identity_count--;
kfree_type(struct kauth_identity, kip);
}
}
/*
* kauth_identity_lru
*
* Description: Promote the entry to the head of the LRU, assumes the cache
* is locked.
*
* Parameters: kip kauth identity to move to the
* head of the LRU list, if it's
* not already there
*
* Returns: (void)
*
* Notes: This is called even if the entry has expired; typically an
* expired entry that's been looked up is about to be revalidated,
* and having it closer to the head of the LRU means finding it
* quickly again when the revalidation comes through.
*/
static void
kauth_identity_lru(struct kauth_identity *kip)
{
if (kip != TAILQ_FIRST(&kauth_identities)) {
TAILQ_REMOVE(&kauth_identities, kip, ki_link);
TAILQ_INSERT_HEAD(&kauth_identities, kip, ki_link);
}
}
/*
* kauth_identity_guid_expired
*
* Description: Handle lazy expiration of GUID translations.
*
* Parameters: kip kauth identity to check for
* GUID expiration
*
* Returns: 1 Expired
* 0 Not expired
*/
static int
kauth_identity_guid_expired(struct kauth_identity *kip)
{
struct timeval tv;
/*
* Expiration time of 0 means this entry is persistent.
*/
if (kip->ki_guid_expiry == 0) {
return 0;
}
microuptime(&tv);
KAUTH_DEBUG("CACHE - GUID expires @ %ld now %ld", kip->ki_guid_expiry, tv.tv_sec);
return (kip->ki_guid_expiry <= tv.tv_sec) ? 1 : 0;
}
/*
* kauth_identity_ntsid_expired
*
* Description: Handle lazy expiration of NTSID translations.
*
* Parameters: kip kauth identity to check for
* NTSID expiration
*
* Returns: 1 Expired
* 0 Not expired
*/
static int
kauth_identity_ntsid_expired(struct kauth_identity *kip)
{
struct timeval tv;
/*
* Expiration time of 0 means this entry is persistent.
*/
if (kip->ki_ntsid_expiry == 0) {
return 0;
}
microuptime(&tv);
KAUTH_DEBUG("CACHE - NTSID expires @ %ld now %ld", kip->ki_ntsid_expiry, tv.tv_sec);
return (kip->ki_ntsid_expiry <= tv.tv_sec) ? 1 : 0;
}
/*
* kauth_identity_groups_expired
*
* Description: Handle lazy expiration of supplemental group translations.
*
* Parameters: kip kauth identity to check for
* groups expiration
*
* Returns: 1 Expired
* 0 Not expired
*/
static int
kauth_identity_groups_expired(struct kauth_identity *kip)
{
struct timeval tv;
/*
* Expiration time of 0 means this entry is persistent.
*/
if (kip->ki_groups_expiry == 0) {
return 0;
}
microuptime(&tv);
KAUTH_DEBUG("CACHE - GROUPS expires @ %ld now %ld\n", kip->ki_groups_expiry, tv.tv_sec);
return (kip->ki_groups_expiry <= tv.tv_sec) ? 1 : 0;
}
/*
* kauth_identity_find_uid
*
* Description: Search for an entry by UID
*
* Parameters: uid UID to find
* kir Pointer to return area
* getname Name buffer, if ki_name wanted
*
* Returns: 0 Found
* ENOENT Not found
*
* Implicit returns:
* *klr Modified, if found
*/
static int
kauth_identity_find_uid(uid_t uid, struct kauth_identity *kir, char *getname)
{
struct kauth_identity *kip;
KAUTH_IDENTITY_LOCK();
TAILQ_FOREACH(kip, &kauth_identities, ki_link) {
if ((kip->ki_valid & KI_VALID_UID) && (uid == kip->ki_uid)) {
kauth_identity_lru(kip);
/* Copy via structure assignment */
*kir = *kip;
/* If a name is wanted and one exists, copy it out */
if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))) {
strlcpy(getname, kip->ki_name, MAXPATHLEN);
}
break;
}
}
KAUTH_IDENTITY_UNLOCK();
return (kip == NULL) ? ENOENT : 0;
}
/*
* kauth_identity_find_gid
*
* Description: Search for an entry by GID
*
* Parameters: gid GID to find
* kir Pointer to return area
* getname Name buffer, if ki_name wanted
*
* Returns: 0 Found
* ENOENT Not found
*
* Implicit returns:
* *klr Modified, if found
*/
static int
kauth_identity_find_gid(uid_t gid, struct kauth_identity *kir, char *getname)
{
struct kauth_identity *kip;
KAUTH_IDENTITY_LOCK();
TAILQ_FOREACH(kip, &kauth_identities, ki_link) {
if ((kip->ki_valid & KI_VALID_GID) && (gid == kip->ki_gid)) {
kauth_identity_lru(kip);
/* Copy via structure assignment */
*kir = *kip;
/* If a name is wanted and one exists, copy it out */
if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))) {
strlcpy(getname, kip->ki_name, MAXPATHLEN);
}
break;
}
}
KAUTH_IDENTITY_UNLOCK();
return (kip == NULL) ? ENOENT : 0;
}
/*
* kauth_identity_find_guid
*
* Description: Search for an entry by GUID
*
* Parameters: guidp Pointer to GUID to find
* kir Pointer to return area
* getname Name buffer, if ki_name wanted
*
* Returns: 0 Found
* ENOENT Not found
*
* Implicit returns:
* *klr Modified, if found
*
* Note: The association may be expired, in which case the caller
* may elect to call out to userland to revalidate.
*/
static int
kauth_identity_find_guid(guid_t *guidp, struct kauth_identity *kir, char *getname)
{
struct kauth_identity *kip;
KAUTH_IDENTITY_LOCK();
TAILQ_FOREACH(kip, &kauth_identities, ki_link) {
if ((kip->ki_valid & KI_VALID_GUID) && (kauth_guid_equal(guidp, &kip->ki_guid))) {
kauth_identity_lru(kip);
/* Copy via structure assignment */
*kir = *kip;
/* If a name is wanted and one exists, copy it out */
if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))) {
strlcpy(getname, kip->ki_name, MAXPATHLEN);
}
break;
}
}
KAUTH_IDENTITY_UNLOCK();
return (kip == NULL) ? ENOENT : 0;
}
/*
* kauth_identity_find_nam
*
* Description: Search for an entry by name
*
* Parameters: name Pointer to name to find
* valid KI_VALID_PWNAM or KI_VALID_GRNAM
* kir Pointer to return area
*
* Returns: 0 Found
* ENOENT Not found
*
* Implicit returns:
* *klr Modified, if found
*/
static int
kauth_identity_find_nam(char *name, int valid, struct kauth_identity *kir)
{
struct kauth_identity *kip;
KAUTH_IDENTITY_LOCK();
TAILQ_FOREACH(kip, &kauth_identities, ki_link) {
if ((kip->ki_valid & valid) && !strcmp(name, kip->ki_name)) {
kauth_identity_lru(kip);
/* Copy via structure assignment */
*kir = *kip;
break;
}
}
KAUTH_IDENTITY_UNLOCK();
return (kip == NULL) ? ENOENT : 0;
}
/*
* kauth_identity_find_ntsid
*
* Description: Search for an entry by NTSID
*
* Parameters: ntsid Pointer to NTSID to find
* kir Pointer to return area
* getname Name buffer, if ki_name wanted
*
* Returns: 0 Found
* ENOENT Not found
*
* Implicit returns:
* *klr Modified, if found
*
* Note: The association may be expired, in which case the caller
* may elect to call out to userland to revalidate.
*/
static int
kauth_identity_find_ntsid(ntsid_t *ntsid, struct kauth_identity *kir, char *getname)
{
struct kauth_identity *kip;
KAUTH_IDENTITY_LOCK();
TAILQ_FOREACH(kip, &kauth_identities, ki_link) {
if ((kip->ki_valid & KI_VALID_NTSID) && (kauth_ntsid_equal(ntsid, &kip->ki_ntsid))) {
kauth_identity_lru(kip);
/* Copy via structure assignment */
*kir = *kip;
/* If a name is wanted and one exists, copy it out */
if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))) {
strlcpy(getname, kip->ki_name, MAXPATHLEN);
}
break;
}
}
KAUTH_IDENTITY_UNLOCK();
return (kip == NULL) ? ENOENT : 0;
}
#endif /* CONFIG_EXT_RESOLVER */
/*
* GUID handling.
*/
guid_t kauth_null_guid;
/*
* kauth_guid_equal
*
* Description: Determine the equality of two GUIDs
*
* Parameters: guid1 Pointer to first GUID
* guid2 Pointer to second GUID
*
* Returns: 0 If GUIDs are unequal
* !0 If GUIDs are equal
*/
int
kauth_guid_equal(guid_t *guid1, guid_t *guid2)
{
return bcmp(guid1, guid2, sizeof(*guid1)) == 0;
}
/*
* kauth_wellknown_guid
*
* Description: Determine if a GUID is a well-known GUID
*
* Parameters: guid Pointer to GUID to check
*
* Returns: KAUTH_WKG_NOT Not a well known GUID
* KAUTH_WKG_EVERYBODY "Everybody"
* KAUTH_WKG_NOBODY "Nobody"
* KAUTH_WKG_OWNER "Other"
* KAUTH_WKG_GROUP "Group"
*/
int
kauth_wellknown_guid(guid_t *guid)
{
static char fingerprint[] = {0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef};
uint32_t code;
/*
* All WKGs begin with the same 12 bytes.
*/
if (bcmp((void *)guid, fingerprint, 12) == 0) {
/*
* The final 4 bytes are our code (in network byte order).
*/
code = OSSwapHostToBigInt32(*(uint32_t *)&guid->g_guid[12]);
switch (code) {
case 0x0000000c:
return KAUTH_WKG_EVERYBODY;
case 0xfffffffe:
return KAUTH_WKG_NOBODY;
case 0x0000000a:
return KAUTH_WKG_OWNER;
case 0x00000010:
return KAUTH_WKG_GROUP;
}
}
return KAUTH_WKG_NOT;
}
/*
* kauth_ntsid_equal
*
* Description: Determine the equality of two NTSIDs (NT Security Identifiers)
*
* Parameters: sid1 Pointer to first NTSID
* sid2 Pointer to second NTSID
*
* Returns: 0 If GUIDs are unequal
* !0 If GUIDs are equal
*/
int
kauth_ntsid_equal(ntsid_t *sid1, ntsid_t *sid2)
{
/* check sizes for equality, also sanity-check size while we're at it */
if ((KAUTH_NTSID_SIZE(sid1) == KAUTH_NTSID_SIZE(sid2)) &&
(KAUTH_NTSID_SIZE(sid1) <= sizeof(*sid1)) &&
bcmp(sid1, sid2, KAUTH_NTSID_SIZE(sid1)) == 0) {
return 1;
}
return 0;
}
/*
* Identity KPI
*
* We support four tokens representing identity:
* - Credential reference
* - UID
* - GUID
* - NT security identifier
*
* Of these, the UID is the ubiquitous identifier; cross-referencing should
* be done using it.
*/
/*
* kauth_cred_change_egid
*
* Description: Set EGID by changing the first element of cr_groups for the
* passed credential; if the new EGID exists in the list of
* groups already, then rotate the old EGID into its position,
* otherwise replace it
*
* Parameters: cred Pointer to the credential to modify
* new_egid The new EGID to set
*
* Returns: 0 The egid did not displace a member of
* the supplementary group list
* 1 The egid being set displaced a member
* of the supplementary groups list
*
* Note: Utility function; internal use only because of locking.
*
* This function operates on the credential passed; the caller
* must operate either on a newly allocated credential (one for
* which there is no hash cache reference and no externally
* visible pointer reference), or a template credential.
*/
static int
kauth_cred_change_egid(kauth_cred_t cred, gid_t new_egid)
{
int i;
int displaced = 1;
#if radar_4600026
int is_member;
#endif /* radar_4600026 */
gid_t old_egid = kauth_cred_getgid(cred);
posix_cred_t pcred = posix_cred_get(cred);
/* Ignoring the first entry, scan for a match for the new egid */
for (i = 1; i < pcred->cr_ngroups; i++) {
/*
* If we find a match, swap them so we don't lose overall
* group information
*/
if (pcred->cr_groups[i] == new_egid) {
pcred->cr_groups[i] = old_egid;
displaced = 0;
break;
}
}
#if radar_4600026
#error Fix radar 4600026 first!!!
/*
* This is correct for memberd behaviour, but incorrect for POSIX; to address
* this, we would need to automatically opt-out any SUID/SGID binary, and force
* it to use initgroups to opt back in. We take the approach of considering it
* opt'ed out in any group of 16 displacement instead, since it's a much more
* conservative approach (i.e. less likely to cause things to break).
*/
/*
* If we displaced a member of the supplementary groups list of the
* credential, and we have not opted out of memberd, then if memberd
* says that the credential is a member of the group, then it has not
* actually been displaced.
*
* NB: This is typically a cold code path.
*/
if (displaced && !(pcred->cr_flags & CRF_NOMEMBERD) &&
kauth_cred_ismember_gid(cred, new_egid, &is_member) == 0 &&
is_member) {
displaced = 0;
}
#endif /* radar_4600026 */
/* set the new EGID into the old spot */
pcred->cr_groups[0] = new_egid;
return displaced;
}
uid_t
kauth_cred_getuid(kauth_cred_t cred)
{
return posix_cred_get(cred)->cr_uid;
}
uid_t
kauth_cred_getruid(kauth_cred_t cred)
{
return posix_cred_get(cred)->cr_ruid;
}
uid_t
kauth_cred_getsvuid(kauth_cred_t cred)
{
return posix_cred_get(cred)->cr_svuid;
}
gid_t
kauth_cred_getgid(kauth_cred_t cred)
{
return posix_cred_get(cred)->cr_gid;
}
gid_t
kauth_cred_getrgid(kauth_cred_t cred)
{
return posix_cred_get(cred)->cr_rgid;
}
gid_t
kauth_cred_getsvgid(kauth_cred_t cred)
{
return posix_cred_get(cred)->cr_svgid;
}
static int kauth_cred_cache_lookup(int from, int to, void *src, void *dst);
#if CONFIG_EXT_RESOLVER == 0
/*
* If there's no resolver, only support a subset of the kauth_cred_x2y() lookups.
*/
static __inline int
kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
{
/* NB: These must match the definitions used by Libinfo's mbr_identifier_translate(). */
static const uuid_t _user_compat_prefix = {0xff, 0xff, 0xee, 0xee, 0xdd, 0xdd, 0xcc, 0xcc, 0xbb, 0xbb, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00};
static const uuid_t _group_compat_prefix = {0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0x00, 0x00, 0x00, 0x00};
#define COMPAT_PREFIX_LEN (sizeof(uuid_t) - sizeof(id_t))
assert(from != to);
switch (from) {
case KI_VALID_UID: {
id_t uid = htonl(*(id_t *)src);
if (to == KI_VALID_GUID) {
uint8_t *uu = dst;
memcpy(uu, _user_compat_prefix, sizeof(_user_compat_prefix));
memcpy(&uu[COMPAT_PREFIX_LEN], &uid, sizeof(uid));
return 0;
}
break;
}
case KI_VALID_GID: {
id_t gid = htonl(*(id_t *)src);
if (to == KI_VALID_GUID) {
uint8_t *uu = dst;
memcpy(uu, _group_compat_prefix, sizeof(_group_compat_prefix));
memcpy(&uu[COMPAT_PREFIX_LEN], &gid, sizeof(gid));
return 0;
}
break;
}
case KI_VALID_GUID: {
const uint8_t *uu = src;
if (to == KI_VALID_UID) {
if (memcmp(uu, _user_compat_prefix, COMPAT_PREFIX_LEN) == 0) {
id_t uid;
memcpy(&uid, &uu[COMPAT_PREFIX_LEN], sizeof(uid));
*(id_t *)dst = ntohl(uid);
return 0;
}
} else if (to == KI_VALID_GID) {
if (memcmp(uu, _group_compat_prefix, COMPAT_PREFIX_LEN) == 0) {
id_t gid;
memcpy(&gid, &uu[COMPAT_PREFIX_LEN], sizeof(gid));
*(id_t *)dst = ntohl(gid);
return 0;
}
}
break;
}
default:
/* NOT IMPLEMENTED */
break;
}
return ENOENT;
}
#endif
#if defined(CONFIG_EXT_RESOLVER) && (CONFIG_EXT_RESOLVER)
/*
* Structure to hold supplemental groups. Used for impedance matching with
* kauth_cred_cache_lookup below.
*/
struct supgroups {
size_t *count;
gid_t *groups;
};
/*
* kauth_cred_uid2groups
*
* Description: Fetch supplemental GROUPS from UID
*
* Parameters: uid UID to examine
* groups pointer to an array of gid_ts
* gcount pointer to the number of groups wanted/returned
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *groups Modified, if successful
* *gcount Modified, if successful
*
*/
static int
kauth_cred_uid2groups(uid_t *uid, gid_t *groups, size_t *gcount)
{
int rv;
struct supgroups supgroups;
supgroups.count = gcount;
supgroups.groups = groups;
rv = kauth_cred_cache_lookup(KI_VALID_UID, KI_VALID_GROUPS, uid, &supgroups);
return rv;
}
#endif
/*
* kauth_cred_guid2pwnam
*
* Description: Fetch PWNAM from GUID
*
* Parameters: guidp Pointer to GUID to examine
* pwnam Pointer to user@domain buffer
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *pwnam Modified, if successful
*
* Notes: pwnam is assumed to point to a buffer of MAXPATHLEN in size
*/
int
kauth_cred_guid2pwnam(guid_t *guidp, char *pwnam)
{
return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_PWNAM, guidp, pwnam);
}
/*
* kauth_cred_guid2grnam
*
* Description: Fetch GRNAM from GUID
*
* Parameters: guidp Pointer to GUID to examine
* grnam Pointer to group@domain buffer
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *grnam Modified, if successful
*
* Notes: grnam is assumed to point to a buffer of MAXPATHLEN in size
*/
int
kauth_cred_guid2grnam(guid_t *guidp, char *grnam)
{
return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_GRNAM, guidp, grnam);
}
/*
* kauth_cred_pwnam2guid
*
* Description: Fetch PWNAM from GUID
*
* Parameters: pwnam String containing user@domain
* guidp Pointer to buffer for GUID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *guidp Modified, if successful
*
* Notes: pwnam should not point to a request larger than MAXPATHLEN
* bytes in size, including the NUL termination of the string.
*/
int
kauth_cred_pwnam2guid(char *pwnam, guid_t *guidp)
{
return kauth_cred_cache_lookup(KI_VALID_PWNAM, KI_VALID_GUID, pwnam, guidp);
}
/*
* kauth_cred_grnam2guid
*
* Description: Fetch GRNAM from GUID
*
* Parameters: grnam String containing group@domain
* guidp Pointer to buffer for GUID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *guidp Modified, if successful
*
* Notes: grnam should not point to a request larger than MAXPATHLEN
* bytes in size, including the NUL termination of the string.
*/
int
kauth_cred_grnam2guid(char *grnam, guid_t *guidp)
{
return kauth_cred_cache_lookup(KI_VALID_GRNAM, KI_VALID_GUID, grnam, guidp);
}
/*
* kauth_cred_guid2uid
*
* Description: Fetch UID from GUID
*
* Parameters: guidp Pointer to GUID to examine
* uidp Pointer to buffer for UID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *uidp Modified, if successful
*/
int
kauth_cred_guid2uid(guid_t *guidp, uid_t *uidp)
{
return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_UID, guidp, uidp);
}
/*
* kauth_cred_guid2gid
*
* Description: Fetch GID from GUID
*
* Parameters: guidp Pointer to GUID to examine
* gidp Pointer to buffer for GID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *gidp Modified, if successful
*/
int
kauth_cred_guid2gid(guid_t *guidp, gid_t *gidp)
{
return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_GID, guidp, gidp);
}
/*
* kauth_cred_nfs4domain2dsnode
*
* Description: Fetch dsnode from nfs4domain
*
* Parameters: nfs4domain Pointer to a string nfs4 domain
* dsnode Pointer to buffer for dsnode
*
* Returns: 0 Success
* ENOENT For now just a stub that always fails
*
* Implicit returns:
* *dsnode Modified, if successuful
*/
int
kauth_cred_nfs4domain2dsnode(__unused char *nfs4domain, __unused char *dsnode)
{
return ENOENT;
}
/*
* kauth_cred_dsnode2nfs4domain
*
* Description: Fetch nfs4domain from dsnode
*
* Parameters: nfs4domain Pointer to string dsnode
* dsnode Pointer to buffer for nfs4domain
*
* Returns: 0 Success
* ENOENT For now just a stub that always fails
*
* Implicit returns:
* *nfs4domain Modified, if successuful
*/
int
kauth_cred_dsnode2nfs4domain(__unused char *dsnode, __unused char *nfs4domain)
{
return ENOENT;
}
/*
* kauth_cred_ntsid2uid
*
* Description: Fetch UID from NTSID
*
* Parameters: sidp Pointer to NTSID to examine
* uidp Pointer to buffer for UID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *uidp Modified, if successful
*/
int
kauth_cred_ntsid2uid(ntsid_t *sidp, uid_t *uidp)
{
return kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_UID, sidp, uidp);
}
/*
* kauth_cred_ntsid2gid
*
* Description: Fetch GID from NTSID
*
* Parameters: sidp Pointer to NTSID to examine
* gidp Pointer to buffer for GID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *gidp Modified, if successful
*/
int
kauth_cred_ntsid2gid(ntsid_t *sidp, gid_t *gidp)
{
return kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_GID, sidp, gidp);
}
/*
* kauth_cred_ntsid2guid
*
* Description: Fetch GUID from NTSID
*
* Parameters: sidp Pointer to NTSID to examine
* guidp Pointer to buffer for GUID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *guidp Modified, if successful
*/
int
kauth_cred_ntsid2guid(ntsid_t *sidp, guid_t *guidp)
{
return kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_GUID, sidp, guidp);
}
/*
* kauth_cred_uid2guid
*
* Description: Fetch GUID from UID
*
* Parameters: uid UID to examine
* guidp Pointer to buffer for GUID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *guidp Modified, if successful
*/
int
kauth_cred_uid2guid(uid_t uid, guid_t *guidp)
{
return kauth_cred_cache_lookup(KI_VALID_UID, KI_VALID_GUID, &uid, guidp);
}
/*
* kauth_cred_getguid
*
* Description: Fetch GUID from credential
*
* Parameters: cred Credential to examine
* guidp Pointer to buffer for GUID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *guidp Modified, if successful
*/
int
kauth_cred_getguid(kauth_cred_t cred, guid_t *guidp)
{
return kauth_cred_uid2guid(kauth_cred_getuid(cred), guidp);
}
/*
* kauth_cred_getguid
*
* Description: Fetch GUID from GID
*
* Parameters: gid GID to examine
* guidp Pointer to buffer for GUID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *guidp Modified, if successful
*/
int
kauth_cred_gid2guid(gid_t gid, guid_t *guidp)
{
return kauth_cred_cache_lookup(KI_VALID_GID, KI_VALID_GUID, &gid, guidp);
}
/*
* kauth_cred_uid2ntsid
*
* Description: Fetch NTSID from UID
*
* Parameters: uid UID to examine
* sidp Pointer to buffer for NTSID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *sidp Modified, if successful
*/
int
kauth_cred_uid2ntsid(uid_t uid, ntsid_t *sidp)
{
return kauth_cred_cache_lookup(KI_VALID_UID, KI_VALID_NTSID, &uid, sidp);
}
/*
* kauth_cred_getntsid
*
* Description: Fetch NTSID from credential
*
* Parameters: cred Credential to examine
* sidp Pointer to buffer for NTSID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *sidp Modified, if successful
*/
int
kauth_cred_getntsid(kauth_cred_t cred, ntsid_t *sidp)
{
return kauth_cred_uid2ntsid(kauth_cred_getuid(cred), sidp);
}
/*
* kauth_cred_gid2ntsid
*
* Description: Fetch NTSID from GID
*
* Parameters: gid GID to examine
* sidp Pointer to buffer for NTSID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *sidp Modified, if successful
*/
int
kauth_cred_gid2ntsid(gid_t gid, ntsid_t *sidp)
{
return kauth_cred_cache_lookup(KI_VALID_GID, KI_VALID_NTSID, &gid, sidp);
}
/*
* kauth_cred_guid2ntsid
*
* Description: Fetch NTSID from GUID
*
* Parameters: guidp Pointer to GUID to examine
* sidp Pointer to buffer for NTSID
*
* Returns: 0 Success
* kauth_cred_cache_lookup:EINVAL
*
* Implicit returns:
* *sidp Modified, if successful
*/
int
kauth_cred_guid2ntsid(guid_t *guidp, ntsid_t *sidp)
{
return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_NTSID, guidp, sidp);
}
/*
* kauth_cred_cache_lookup
*
* Description: Lookup a translation in the cache; if one is not found, and
* the attempt was not fatal, submit the request to the resolver
* instead, and wait for it to complete or be aborted.
*
* Parameters: from Identity information we have
* to Identity information we want
* src Pointer to buffer containing
* the source identity
* dst Pointer to buffer to receive
* the target identity
*
* Returns: 0 Success
* EINVAL Unknown source identity type
*/
#if CONFIG_EXT_RESOLVER
static int
kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
{
struct kauth_identity ki;
struct kauth_identity_extlookup el;
int error;
uint64_t extend_data = 0ULL;
int (* expired)(struct kauth_identity *kip);
char *namebuf = NULL;
KAUTH_DEBUG("CACHE - translate %d to %d", from, to);
/*
* Look for an existing cache entry for this association.
* If the entry has not expired, return the cached information.
* We do not cache user@domain translations here; they use too
* much memory to hold onto forever, and can not be updated
* atomically.
*/
if (to == KI_VALID_PWNAM || to == KI_VALID_GRNAM) {
if (dst == NULL) {
return EINVAL;
}
namebuf = dst;
*namebuf = '\0';
}
ki.ki_valid = 0;
switch (from) {
case KI_VALID_UID:
error = kauth_identity_find_uid(*(uid_t *)src, &ki, namebuf);
break;
case KI_VALID_GID:
error = kauth_identity_find_gid(*(gid_t *)src, &ki, namebuf);
break;
case KI_VALID_GUID:
error = kauth_identity_find_guid((guid_t *)src, &ki, namebuf);
break;
case KI_VALID_NTSID:
error = kauth_identity_find_ntsid((ntsid_t *)src, &ki, namebuf);
break;
case KI_VALID_PWNAM:
case KI_VALID_GRNAM:
/* Names are unique in their 'from' space */
error = kauth_identity_find_nam((char *)src, from, &ki);
break;
default:
return EINVAL;
}
/* If we didn't get what we're asking for. Call the resolver */
if (!error && !(to & ki.ki_valid)) {
error = ENOENT;
}
/* lookup failure or error */
if (error != 0) {
/* any other error is fatal */
if (error != ENOENT) {
/* XXX bogus check - this is not possible */
KAUTH_DEBUG("CACHE - cache search error %d", error);
return error;
}
} else {
/* found a valid cached entry, check expiry */
switch (to) {
case KI_VALID_GUID:
expired = kauth_identity_guid_expired;
break;
case KI_VALID_NTSID:
expired = kauth_identity_ntsid_expired;
break;
case KI_VALID_GROUPS:
expired = kauth_identity_groups_expired;
break;
default:
switch (from) {
case KI_VALID_GUID:
expired = kauth_identity_guid_expired;
break;
case KI_VALID_NTSID:
expired = kauth_identity_ntsid_expired;
break;
default:
expired = NULL;
}
}
/*
* If no expiry function, or not expired, we have found
* a hit.
*/
if (expired) {
if (!expired(&ki)) {
KAUTH_DEBUG("CACHE - entry valid, unexpired");
expired = NULL; /* must clear it is used as a flag */
} else {
/*
* We leave ki_valid set here; it contains a
* translation but the TTL has expired. If we can't
* get a result from the resolver, we will use it as
* a better-than nothing alternative.
*/
KAUTH_DEBUG("CACHE - expired entry found");
}
} else {
KAUTH_DEBUG("CACHE - no expiry function");
}
if (!expired) {
/* do we have a translation? */
if (ki.ki_valid & to) {
KAUTH_DEBUG("CACHE - found matching entry with valid 0x%08x", ki.ki_valid);
DTRACE_PROC4(kauth__identity__cache__hit, int, from, int, to, void *, src, void *, dst);
goto found;
} else {
/*
* GUIDs and NTSIDs map to either a UID or a GID, but not both.
* If we went looking for a translation from GUID or NTSID and
* found a translation that wasn't for our desired type, then
* don't bother calling the resolver. We know that this
* GUID/NTSID can't translate to our desired type.
*/
switch (from) {
case KI_VALID_GUID:
case KI_VALID_NTSID:
switch (to) {
case KI_VALID_GID:
if ((ki.ki_valid & KI_VALID_UID)) {
KAUTH_DEBUG("CACHE - unexpected entry 0x%08x & %x", ki.ki_valid, KI_VALID_GID);
return ENOENT;
}
break;
case KI_VALID_UID:
if ((ki.ki_valid & KI_VALID_GID)) {
KAUTH_DEBUG("CACHE - unexpected entry 0x%08x & %x", ki.ki_valid, KI_VALID_UID);
return ENOENT;
}
break;
}
break;
}
}
}
}
/*
* We failed to find a cache entry; call the resolver.
*
* Note: We ask for as much non-extended data as we can get,
* and only provide (or ask for) extended information if
* we have a 'from' (or 'to') which requires it. This
* way we don't pay for the extra transfer overhead for
* data we don't need.
*/
bzero(&el, sizeof(el));
el.el_info_pid = proc_getpid(current_proc());
switch (from) {
case KI_VALID_UID:
el.el_flags = KAUTH_EXTLOOKUP_VALID_UID;
el.el_uid = *(uid_t *)src;
break;
case KI_VALID_GID:
el.el_flags = KAUTH_EXTLOOKUP_VALID_GID;
el.el_gid = *(gid_t *)src;
break;
case KI_VALID_GUID:
el.el_flags = KAUTH_EXTLOOKUP_VALID_UGUID | KAUTH_EXTLOOKUP_VALID_GGUID;
el.el_uguid = *(guid_t *)src;
el.el_gguid = *(guid_t *)src;
break;
case KI_VALID_NTSID:
el.el_flags = KAUTH_EXTLOOKUP_VALID_USID | KAUTH_EXTLOOKUP_VALID_GSID;
el.el_usid = *(ntsid_t *)src;
el.el_gsid = *(ntsid_t *)src;
break;
case KI_VALID_PWNAM:
/* extra overhead */
el.el_flags = KAUTH_EXTLOOKUP_VALID_PWNAM;
extend_data = CAST_USER_ADDR_T(src);
break;
case KI_VALID_GRNAM:
/* extra overhead */
el.el_flags = KAUTH_EXTLOOKUP_VALID_GRNAM;
extend_data = CAST_USER_ADDR_T(src);
break;
default:
return EINVAL;
}
/*
* Here we ask for everything all at once, to avoid having to work
* out what we really want now, or might want soon.
*
* Asking for SID translations when we don't know we need them right
* now is going to cause excess work to be done if we're connected
* to a network that thinks it can translate them. This list needs
* to get smaller/smarter.
*/
el.el_flags |= KAUTH_EXTLOOKUP_WANT_UID | KAUTH_EXTLOOKUP_WANT_GID |
KAUTH_EXTLOOKUP_WANT_UGUID | KAUTH_EXTLOOKUP_WANT_GGUID |
KAUTH_EXTLOOKUP_WANT_USID | KAUTH_EXTLOOKUP_WANT_GSID;
if (to == KI_VALID_PWNAM) {
/* extra overhead */
el.el_flags |= KAUTH_EXTLOOKUP_WANT_PWNAM;
extend_data = CAST_USER_ADDR_T(dst);
}
if (to == KI_VALID_GRNAM) {
/* extra overhead */
el.el_flags |= KAUTH_EXTLOOKUP_WANT_GRNAM;
extend_data = CAST_USER_ADDR_T(dst);
}
if (to == KI_VALID_GROUPS) {
/* Expensive and only useful for an NFS client not using kerberos */
el.el_flags |= KAUTH_EXTLOOKUP_WANT_SUPGRPS;
if (ki.ki_valid & KI_VALID_GROUPS) {
/*
* Copy the current supplemental groups for the resolver.
* The resolver should check these groups first and if
* the user (uid) is still a member it should endeavor to
* keep them in the list. Otherwise NFS clients could get
* changing access to server file system objects on each
* expiration.
*/
if (ki.ki_supgrpcnt > NGROUPS) {
panic("kauth data structure corrupted. kauth identity 0x%p with %u groups, greater than max of %d",
&ki, ki.ki_supgrpcnt, NGROUPS);
}
el.el_sup_grp_cnt = (uint32_t)ki.ki_supgrpcnt;
memcpy(el.el_sup_groups, ki.ki_supgrps, sizeof(el.el_sup_groups[0]) * ki.ki_supgrpcnt);
/* Let the resolver know these were the previous valid groups */
el.el_flags |= KAUTH_EXTLOOKUP_VALID_SUPGRPS;
KAUTH_DEBUG("GROUPS: Sending previously valid GROUPS");
} else {
KAUTH_DEBUG("GROUPS: no valid groups to send");
}
}
/* Call resolver */
KAUTH_DEBUG("CACHE - calling resolver for %x", el.el_flags);
DTRACE_PROC3(kauth__id__resolver__submitted, int, from, int, to, uintptr_t, src);
error = kauth_resolver_submit(&el, extend_data);
DTRACE_PROC2(kauth__id__resolver__returned, int, error, struct kauth_identity_extlookup *, &el)
KAUTH_DEBUG("CACHE - resolver returned %d", error);
/* was the external lookup successful? */
if (error == 0) {
/*
* Save the results from the lookup - we may have other
* information, even if we didn't get a guid or the
* extended data.
*
* If we came from a name, we know the extend_data is valid.
*/
if (from == KI_VALID_PWNAM) {
el.el_flags |= KAUTH_EXTLOOKUP_VALID_PWNAM;
} else if (from == KI_VALID_GRNAM) {
el.el_flags |= KAUTH_EXTLOOKUP_VALID_GRNAM;
}
kauth_identity_updatecache(&el, &ki, extend_data);
/*
* Check to see if we have a valid cache entry
* originating from the result.
*/
if (!(ki.ki_valid & to)) {
error = ENOENT;
}
}
if (error) {
return error;
}
found:
/*
* Copy from the appropriate struct kauth_identity cache entry
* structure into the destination buffer area.
*/
switch (to) {
case KI_VALID_UID:
*(uid_t *)dst = ki.ki_uid;
break;
case KI_VALID_GID:
*(gid_t *)dst = ki.ki_gid;
break;
case KI_VALID_GUID:
*(guid_t *)dst = ki.ki_guid;
break;
case KI_VALID_NTSID:
*(ntsid_t *)dst = ki.ki_ntsid;
break;
case KI_VALID_GROUPS: {
struct supgroups *gp = (struct supgroups *)dst;
size_t limit = ki.ki_supgrpcnt;
if (gp->count) {
limit = MIN(ki.ki_supgrpcnt, *gp->count);
*gp->count = limit;
}
memcpy(gp->groups, ki.ki_supgrps, sizeof(gid_t) * limit);
}
break;
case KI_VALID_PWNAM:
case KI_VALID_GRNAM:
/* handled in kauth_resolver_complete() */
break;
default:
return EINVAL;
}
KAUTH_DEBUG("CACHE - returned successfully");
return 0;
}
/*
* Group membership cache.
*
* XXX the linked-list implementation here needs to be optimized.
*/
/*
* kauth_groups_expired
*
* Description: Handle lazy expiration of group membership cache entries
*
* Parameters: gm group membership entry to
* check for expiration
*
* Returns: 1 Expired
* 0 Not expired
*/
static int
kauth_groups_expired(struct kauth_group_membership *gm)
{
struct timeval tv;
/*
* Expiration time of 0 means this entry is persistent.
*/
if (gm->gm_expiry == 0) {
return 0;
}
microuptime(&tv);
return (gm->gm_expiry <= tv.tv_sec) ? 1 : 0;
}
/*
* kauth_groups_lru
*
* Description: Promote the entry to the head of the LRU, assumes the cache
* is locked.
*
* Parameters: kip group membership entry to move
* to the head of the LRU list,
* if it's not already there
*
* Returns: (void)
*
* Notes: This is called even if the entry has expired; typically an
* expired entry that's been looked up is about to be revalidated,
* and having it closer to the head of the LRU means finding it
* quickly again when the revalidation comes through.
*/
static void
kauth_groups_lru(struct kauth_group_membership *gm)
{
if (gm != TAILQ_FIRST(&kauth_groups)) {
TAILQ_REMOVE(&kauth_groups, gm, gm_link);
TAILQ_INSERT_HEAD(&kauth_groups, gm, gm_link);
}
}
/*
* kauth_groups_updatecache
*
* Description: Given a lookup result, add any group cache associations that
* we don't currently have.
*
* Parameters: elp External lookup result from
* user space daemon to kernel
* rkip pointer to returned kauth
* identity, or NULL
*
* Returns: (void)
*/
static void
kauth_groups_updatecache(struct kauth_identity_extlookup *el)
{
struct kauth_group_membership *gm;
struct timeval tv;
/* need a valid response if we are to cache anything */
if ((el->el_flags &
(KAUTH_EXTLOOKUP_VALID_UID | KAUTH_EXTLOOKUP_VALID_GID | KAUTH_EXTLOOKUP_VALID_MEMBERSHIP)) !=
(KAUTH_EXTLOOKUP_VALID_UID | KAUTH_EXTLOOKUP_VALID_GID | KAUTH_EXTLOOKUP_VALID_MEMBERSHIP)) {
return;
}
microuptime(&tv);
/*
* Search for an existing record for this association before inserting
* a new one; if we find one, update it instead of creating a new one
*/
KAUTH_GROUPS_LOCK();
TAILQ_FOREACH(gm, &kauth_groups, gm_link) {
if ((el->el_uid == gm->gm_uid) &&
(el->el_gid == gm->gm_gid)) {
if (el->el_flags & KAUTH_EXTLOOKUP_ISMEMBER) {
gm->gm_flags |= KAUTH_GROUP_ISMEMBER;
} else {
gm->gm_flags &= ~KAUTH_GROUP_ISMEMBER;
}
gm->gm_expiry = (el->el_member_valid) ? el->el_member_valid + tv.tv_sec : 0;
kauth_groups_lru(gm);
break;
}
}
KAUTH_GROUPS_UNLOCK();
/* if we found an entry to update, stop here */
if (gm != NULL) {
return;
}
/* allocate a new record */
gm = kalloc_type(struct kauth_group_membership, Z_WAITOK | Z_NOFAIL);
gm->gm_uid = el->el_uid;
gm->gm_gid = el->el_gid;
if (el->el_flags & KAUTH_EXTLOOKUP_ISMEMBER) {
gm->gm_flags |= KAUTH_GROUP_ISMEMBER;
} else {
gm->gm_flags &= ~KAUTH_GROUP_ISMEMBER;
}
gm->gm_expiry = (el->el_member_valid) ? el->el_member_valid + tv.tv_sec : 0;
/*
* Insert the new entry. Note that it's possible to race ourselves
* here and end up with duplicate entries in the list. Wasteful, but
* harmless since the first into the list will never be looked up,
* and thus will eventually just fall off the end.
*/
KAUTH_GROUPS_LOCK();
TAILQ_INSERT_HEAD(&kauth_groups, gm, gm_link);
if (++kauth_groups_count > kauth_groups_cachemax) {
gm = TAILQ_LAST(&kauth_groups, kauth_groups_head);
TAILQ_REMOVE(&kauth_groups, gm, gm_link);
kauth_groups_count--;
} else {
gm = NULL;
}
KAUTH_GROUPS_UNLOCK();
/* free expired cache entry */
kfree_type(struct kauth_group_membership, gm);
}
/*
* Trim older entries from the group membership cache.
*
* Must be called with the group cache lock held.
*/
static void
kauth_groups_trimcache(int new_size)
{
struct kauth_group_membership *gm;
lck_mtx_assert(&kauth_groups_mtx, LCK_MTX_ASSERT_OWNED);
while (kauth_groups_count > new_size) {
gm = TAILQ_LAST(&kauth_groups, kauth_groups_head);
TAILQ_REMOVE(&kauth_groups, gm, gm_link);
kauth_groups_count--;
kfree_type(struct kauth_group_membership, gm);
}
}
#endif /* CONFIG_EXT_RESOLVER */
/*
* Group membership KPI
*/
/*
* kauth_cred_ismember_gid
*
* Description: Given a credential and a GID, determine if the GID is a member
* of one of the supplementary groups associated with the given
* credential
*
* Parameters: cred Credential to check in
* gid GID to check for membership
* resultp Pointer to int to contain the
* result of the call
*
* Returns: 0 Success
* ENOENT Could not perform lookup
* kauth_resolver_submit:EWOULDBLOCK
* kauth_resolver_submit:EINTR
* kauth_resolver_submit:ENOMEM
* kauth_resolver_submit:ENOENT User space daemon did not vend
* this credential.
* kauth_resolver_submit:??? Unlikely error from user space
*
* Implicit returns:
* *resultp (modified) 1 Is member
* 0 Is not member
*
* Notes: This function guarantees not to modify resultp when returning
* an error.
*
* This function effectively checks the EGID as well, since the
* EGID is cr_groups[0] as an implementation detail.
*/
int
kauth_cred_ismember_gid(kauth_cred_t cred, gid_t gid, int *resultp)
{
posix_cred_t pcred = posix_cred_get(cred);
int i;
/*
* Check the per-credential list of override groups.
*
* We can conditionalise this on cred->cr_gmuid == KAUTH_UID_NONE since
* the cache should be used for that case.
*/
for (i = 0; i < pcred->cr_ngroups; i++) {
if (gid == pcred->cr_groups[i]) {
*resultp = 1;
return 0;
}
}
/*
* If we don't have a UID for group membership checks, the in-cred list
* was authoritative and we can stop here.
*/
if (pcred->cr_gmuid == KAUTH_UID_NONE) {
*resultp = 0;
return 0;
}
#if CONFIG_EXT_RESOLVER
struct kauth_group_membership *gm;
struct kauth_identity_extlookup el;
int error;
/*
* If the resolver hasn't checked in yet, we are early in the boot
* phase and the local group list is complete and authoritative.
*/
if (!kauth_resolver_registered) {
*resultp = 0;
return 0;
}
/* TODO: */
/* XXX check supplementary groups */
/* XXX check whiteout groups */
/* XXX nesting of supplementary/whiteout groups? */
/*
* Check the group cache.
*/
KAUTH_GROUPS_LOCK();
TAILQ_FOREACH(gm, &kauth_groups, gm_link) {
if ((gm->gm_uid == pcred->cr_gmuid) && (gm->gm_gid == gid) && !kauth_groups_expired(gm)) {
kauth_groups_lru(gm);
break;
}
}
/* did we find a membership entry? */
if (gm != NULL) {
*resultp = (gm->gm_flags & KAUTH_GROUP_ISMEMBER) ? 1 : 0;
}
KAUTH_GROUPS_UNLOCK();
/* if we did, we can return now */
if (gm != NULL) {
DTRACE_PROC2(kauth__group__cache__hit, int, pcred->cr_gmuid, int, gid);
return 0;
}
/* nothing in the cache, need to go to userland */
bzero(&el, sizeof(el));
el.el_info_pid = proc_getpid(current_proc());
el.el_flags = KAUTH_EXTLOOKUP_VALID_UID | KAUTH_EXTLOOKUP_VALID_GID | KAUTH_EXTLOOKUP_WANT_MEMBERSHIP;
el.el_uid = pcred->cr_gmuid;
el.el_gid = gid;
el.el_member_valid = 0; /* XXX set by resolver? */
DTRACE_PROC2(kauth__group__resolver__submitted, int, el.el_uid, int, el.el_gid);
error = kauth_resolver_submit(&el, 0ULL);
DTRACE_PROC2(kauth__group__resolver__returned, int, error, int, el.el_flags);
if (error != 0) {
return error;
}
/* save the results from the lookup */
kauth_groups_updatecache(&el);
/* if we successfully ascertained membership, report */
if (el.el_flags & KAUTH_EXTLOOKUP_VALID_MEMBERSHIP) {
*resultp = (el.el_flags & KAUTH_EXTLOOKUP_ISMEMBER) ? 1 : 0;
return 0;
}
return ENOENT;
#else
*resultp = 0;
return 0;
#endif
}
/*
* kauth_cred_ismember_guid
*
* Description: Determine whether the supplied credential is a member of the
* group nominated by GUID.
*
* Parameters: cred Credential to check in
* guidp Pointer to GUID whose group
* we are testing for membership
* resultp Pointer to int to contain the
* result of the call
*
* Returns: 0 Success
* kauth_cred_guid2gid:EINVAL
* kauth_cred_ismember_gid:ENOENT
* kauth_resolver_submit:ENOENT User space daemon did not vend
* this credential.
* kauth_cred_ismember_gid:EWOULDBLOCK
* kauth_cred_ismember_gid:EINTR
* kauth_cred_ismember_gid:ENOMEM
* kauth_cred_ismember_gid:??? Unlikely error from user space
*
* Implicit returns:
* *resultp (modified) 1 Is member
* 0 Is not member
*/
int
kauth_cred_ismember_guid(__unused kauth_cred_t cred, guid_t *guidp, int *resultp)
{
int error = 0;
switch (kauth_wellknown_guid(guidp)) {
case KAUTH_WKG_NOBODY:
*resultp = 0;
break;
case KAUTH_WKG_EVERYBODY:
*resultp = 1;
break;
default:
{
gid_t gid;
#if CONFIG_EXT_RESOLVER
struct kauth_identity ki;
/*
* Grovel the identity cache looking for this GUID.
* If we find it, and it is for a user record, return
* false because it's not a group.
*
* This is necessary because we don't have -ve caching
* of group memberships, and we really want to avoid
* calling out to the resolver if at all possible.
*
* Because we're called by the ACL evaluator, and the
* ACL evaluator is likely to encounter ACEs for users,
* this is expected to be a common case.
*/
ki.ki_valid = 0;
if ((error = kauth_identity_find_guid(guidp, &ki, NULL)) == 0 &&
!kauth_identity_guid_expired(&ki)) {
if (ki.ki_valid & KI_VALID_GID) {
/* It's a group after all... */
gid = ki.ki_gid;
goto do_check;
}
if (ki.ki_valid & KI_VALID_UID) {
*resultp = 0;
return 0;
}
}
#endif /* CONFIG_EXT_RESOLVER */
/*
* Attempt to translate the GUID to a GID. Even if
* this fails, we will have primed the cache if it is
* a user record and we'll see it above the next time
* we're asked.
*/
if ((error = kauth_cred_guid2gid(guidp, &gid)) != 0) {
/*
* If we have no guid -> gid translation, it's not a group and
* thus the cred can't be a member.
*/
if (error == ENOENT) {
*resultp = 0;
error = 0;
}
} else {
#if CONFIG_EXT_RESOLVER
do_check:
#endif /* CONFIG_EXT_RESOLVER */
error = kauth_cred_ismember_gid(cred, gid, resultp);
}
}
break;
}
return error;
}
/*
* kauth_cred_gid_subset
*
* Description: Given two credentials, determine if all GIDs associated with
* the first are also associated with the second
*
* Parameters: cred1 Credential to check for
* cred2 Credential to check in
* resultp Pointer to int to contain the
* result of the call
*
* Returns: 0 Success
* non-zero See kauth_cred_ismember_gid for
* error codes
*
* Implicit returns:
* *resultp (modified) 1 Is subset
* 0 Is not subset
*
* Notes: This function guarantees not to modify resultp when returning
* an error.
*/
int
kauth_cred_gid_subset(kauth_cred_t cred1, kauth_cred_t cred2, int *resultp)
{
int i, err, res = 1;
gid_t gid;
posix_cred_t pcred1 = posix_cred_get(cred1);
posix_cred_t pcred2 = posix_cred_get(cred2);
/* First, check the local list of groups */
for (i = 0; i < pcred1->cr_ngroups; i++) {
gid = pcred1->cr_groups[i];
if ((err = kauth_cred_ismember_gid(cred2, gid, &res)) != 0) {
return err;
}
if (!res && gid != pcred2->cr_rgid && gid != pcred2->cr_svgid) {
*resultp = 0;
return 0;
}
}
/* Check real gid */
if ((err = kauth_cred_ismember_gid(cred2, pcred1->cr_rgid, &res)) != 0) {
return err;
}
if (!res && pcred1->cr_rgid != pcred2->cr_rgid &&
pcred1->cr_rgid != pcred2->cr_svgid) {
*resultp = 0;
return 0;
}
/* Finally, check saved gid */
if ((err = kauth_cred_ismember_gid(cred2, pcred1->cr_svgid, &res)) != 0) {
return err;
}
if (!res && pcred1->cr_svgid != pcred2->cr_rgid &&
pcred1->cr_svgid != pcred2->cr_svgid) {
*resultp = 0;
return 0;
}
*resultp = 1;
return 0;
}
/*
* kauth_cred_issuser
*
* Description: Fast replacement for issuser()
*
* Parameters: cred Credential to check for super
* user privileges
*
* Returns: 0 Not super user
* !0 Is super user
*
* Notes: This function uses a magic number which is not a manifest
* constant; this is bad practice.
*/
int
kauth_cred_issuser(kauth_cred_t cred)
{
return kauth_cred_getuid(cred) == 0;
}
/*
* Credential KPI
*/
static smrh_key_t kauth_cred_key(kauth_cred_t cred);
static uint32_t kauth_cred_key_hash(smrh_key_t key, uint32_t seed);
static bool kauth_cred_key_equ(smrh_key_t k1, smrh_key_t k2);
static uint32_t kauth_cred_obj_hash(const struct smrq_slink *, uint32_t seed);
static bool kauth_cred_obj_equ(const struct smrq_slink *, smrh_key_t);
static bool kauth_cred_obj_try_get(void *);
struct ucred_rw {
os_ref_atomic_t crw_weak_ref;
struct ucred *crw_cred;
struct smrq_slink crw_link;
struct smr_node crw_node;
};
#define KAUTH_CRED_REF_MAX 0x0ffffffful
ZONE_DEFINE_ID(ZONE_ID_KAUTH_CRED, "cred", struct ucred, ZC_READONLY | ZC_ZFREE_CLEARMEM);
static KALLOC_TYPE_DEFINE(ucred_rw_zone, struct ucred_rw, KT_DEFAULT);
os_refgrp_decl(static, ucred_ref_grp, "ucred_rw", NULL);
SMRH_TRAITS_DEFINE(kauth_cred_traits, struct ucred_rw, crw_link,
.domain = &smr_proc_task,
.key_hash = kauth_cred_key_hash,
.key_equ = kauth_cred_key_equ,
.obj_hash = kauth_cred_obj_hash,
.obj_equ = kauth_cred_obj_equ,
.obj_try_get = kauth_cred_obj_try_get);
static struct smr_shash kauth_cred_hash;
static inline void
ucred_rw_ref(struct ucred_rw *rw)
{
os_ref_retain_raw(&rw->crw_weak_ref, &ucred_ref_grp);
}
static inline bool
ucred_rw_tryref(struct ucred_rw *rw)
{
return os_ref_retain_try_raw(&rw->crw_weak_ref, &ucred_ref_grp);
}
static inline os_ref_count_t
ucred_rw_unref(struct ucred_rw *rw)
{
return os_ref_release_raw(&rw->crw_weak_ref, &ucred_ref_grp);
}
static inline void
ucred_rw_unref_live(struct ucred_rw *rw)
{
os_ref_release_live_raw(&rw->crw_weak_ref, &ucred_ref_grp);
}
__abortlike
static void
kauth_cred_panic_over_released(kauth_cred_t cred)
{
panic("kauth_cred_unref: cred %p over-released", cred);
}
__abortlike
static void
kauth_cred_panic_over_retain(kauth_cred_t cred)
{
panic("kauth_cred_ref: cred %p over-retained", cred);
}
static void
kauth_cred_hold(kauth_cred_t cred)
{
unsigned long ref;
ref = zalloc_ro_update_field_atomic(ZONE_ID_KAUTH_CRED,
cred, cr_ref, ZRO_ATOMIC_ADD_LONG, 1);
if (ref >= KAUTH_CRED_REF_MAX) {
kauth_cred_panic_over_retain(cred);
}
}
static void
kauth_cred_drop(kauth_cred_t cred)
{
unsigned long ref;
ref = zalloc_ro_update_field_atomic(ZONE_ID_KAUTH_CRED,
cred, cr_ref, ZRO_ATOMIC_ADD_LONG, -1);
if (__improbable(ref == 0 || ref > KAUTH_CRED_REF_MAX)) {
kauth_cred_panic_over_released(cred);
}
}
/*
* kauth_cred_init
*
* Description: Initialize the credential hash cache
*
* Parameters: (void)
*
* Returns: (void)
*
* Notes: Intialize the credential hash cache for use; the credential
* hash cache is used convert duplicate credentials into a
* single reference counted credential in order to save wired
* kernel memory. In practice, this generally means a desktop
* system runs with a few tens of credentials, instead of one
* per process, one per thread, one per vnode cache entry, and
* so on. This generally results in savings of 200K or more
* (potentially much more on server systems).
*
* We also create the kernel and init creds before lockdown
* so that vfs_context0 and initcred pointers can be made constant.
*
* We do this in the "ZALLOC" stage because we need
* the kauth_cred_hash_mtx to be initialized,
* and to allocate the kernel cred.
*/
__startup_func
static void
kauth_cred_init(void)
{
struct posix_cred kernel_cred_template = {
.cr_ngroups = 1,
.cr_flags = CRF_NOMEMBERD,
};
smr_shash_init(&kauth_cred_hash, SMRSH_BALANCED, maxproc / 4);
vfs_context0.vc_ucred = posix_cred_create(&kernel_cred_template);
}
STARTUP(ZALLOC, STARTUP_RANK_LAST, kauth_cred_init);
uid_t
kauth_getuid(void)
{
return kauth_cred_getuid(kauth_cred_get());
}
uid_t
kauth_getruid(void)
{
return kauth_cred_getruid(kauth_cred_get());
}
gid_t
kauth_getgid(void)
{
return kauth_cred_getgid(kauth_cred_get());
}
gid_t
kauth_getrgid(void)
{
return kauth_cred_getrgid(kauth_cred_get());
}
kauth_cred_t
kauth_cred_get(void)
{
return current_thread_ro()->tro_cred;
}
intptr_t
current_thread_cred_label_get(int slot)
{
#if CONFIG_MACF
return mac_label_get(kauth_cred_get()->cr_label, slot);
#else
return 0;
#endif
}
__abortlike
static void
current_cached_proc_cred_panic(proc_t p)
{
panic("current_cached_proc_cred(%p) called but current_proc() is %p",
p, current_proc());
}
kauth_cred_t
current_cached_proc_cred(proc_t p)
{
thread_ro_t tro = current_thread_ro();
if (tro->tro_proc != p && p != PROC_NULL) {
current_cached_proc_cred_panic(p);
}
return tro->tro_realcred;
}
intptr_t
current_cached_proc_label_get(int slot)
{
#if CONFIG_MACF
return mac_label_get(current_cached_proc_cred(PROC_NULL)->cr_label, slot);
#else
return 0;
#endif
}
kauth_cred_t
current_cached_proc_cred_ref(proc_t p)
{
kauth_cred_t cred = current_cached_proc_cred(p);
kauth_cred_ref(cred);
return cred;
}
__attribute__((noinline))
static void
kauth_cred_thread_update_slow(thread_ro_t tro, proc_t proc)
{
struct ucred *cred = kauth_cred_proc_ref(proc);
struct thread_ro_creds my_creds = tro->tro_creds;
if (my_creds.tro_realcred != cred) {
if (my_creds.tro_realcred == my_creds.tro_cred) {
kauth_cred_set(&my_creds.tro_cred, cred);
}
kauth_cred_set(&my_creds.tro_realcred, cred);
zalloc_ro_update_field(ZONE_ID_THREAD_RO,
tro, tro_creds, &my_creds);
}
kauth_cred_unref(&cred);
}
/*
* current_cached_proc_cred_update
*
* Notes: This code is common code called from system call or trap entry
* in the case that the process thread may have been changed
* since the last time the thread entered the kernel.
*/
__attribute__((always_inline))
void
current_cached_proc_cred_update(void)
{
thread_ro_t tro = current_thread_ro();
proc_t proc = tro->tro_proc;
if (__improbable(tro->tro_task != kernel_task &&
tro->tro_realcred != proc_ucred_unsafe(proc))) {
kauth_cred_thread_update_slow(tro, proc);
}
}
kauth_cred_t
kauth_cred_get_with_ref(void)
{
struct ucred *ucred = kauth_cred_get();
kauth_cred_ref(ucred);
return ucred;
}
__abortlike
static void
kauth_cred_verify_panic(kauth_cred_t cred, struct ucred_rw *cred_rw)
{
panic("kauth_cred_t backref mismatch: cred:%p cred->cr_rw:%p "
"cred_rw:%p", cred, cred->cr_rw, cred_rw);
}
__pure2
static struct ucred_rw *
kauth_cred_rw(kauth_cred_t cred)
{
struct ucred_rw *rw = kauth_cred_require(cred)->cr_rw;
if (__improbable(rw->crw_cred != cred)) {
kauth_cred_verify_panic(cred, rw);
}
return rw;
}
kauth_cred_t
kauth_cred_proc_ref(proc_t procp)
{
kauth_cred_t cred;
smr_proc_task_enter();
cred = proc_ucred_smr(procp);
if (!ucred_rw_tryref(kauth_cred_rw(cred))) {
cred = NOCRED;
}
smr_proc_task_leave();
if (__improbable(cred == NOCRED)) {
proc_ucred_lock(procp);
cred = proc_ucred_locked(procp);
kauth_cred_ref(cred);
proc_ucred_unlock(procp);
}
return cred;
}
static kauth_cred_t
__kauth_cred_proc_ref_for_pidversion_slow(pid_t pid, uint32_t pidvers, bool dovers)
{
kauth_cred_t cred = NOCRED;
proc_t procp;
procp = proc_find(pid);
if (procp == PROC_NULL) {
return NOCRED;
}
if (dovers && proc_get_ro(procp)->p_idversion != pidvers) {
proc_rele(procp);
return NOCRED;
}
cred = kauth_cred_proc_ref(procp);
proc_rele(procp);
return cred;
}
static inline kauth_cred_t
__kauth_cred_proc_ref_for_pidversion(pid_t pid, uint32_t pidvers, bool dovers)
{
kauth_cred_t cred = NOCRED;
struct proc_ro *pro;
proc_t procp;
int err;
smr_proc_task_enter();
procp = proc_find_noref_smr(pid);
if (procp == PROC_NULL) {
err = ESRCH;
} else {
pro = proc_get_ro(procp);
cred = proc_ucred_smr(procp);
if (dovers && pro->p_idversion != pidvers) {
err = ESRCH;
} else if (!ucred_rw_tryref(kauth_cred_rw(cred))) {
err = EAGAIN;
} else {
err = 0;
}
}
smr_proc_task_leave();
if (__probable(err == 0)) {
return cred;
}
if (err == EAGAIN) {
return __kauth_cred_proc_ref_for_pidversion_slow(pid, pidvers, dovers);
}
return NOCRED;
}
kauth_cred_t
kauth_cred_proc_ref_for_pid(pid_t pid)
{
return __kauth_cred_proc_ref_for_pidversion(pid, 0, false);
}
kauth_cred_t
kauth_cred_proc_ref_for_pidversion(pid_t pid, uint32_t pidvers)
{
return __kauth_cred_proc_ref_for_pidversion(pid, pidvers, true);
}
/*
* kauth_cred_alloc
*
* Description: Create a deduplicated credential optionally derived
* from a parent credential, according to the specified template.
*
* Parameters: parent_cred the parent cred the model is
* derived from (or NOCRED for
* a creation)
*
* model_cred the (mutable) template of the
* cred to add to the hash table.
*
* Returns: (kauth_thread_t) The inserted cred, or the
* collision that was found.
*/
static kauth_cred_t
kauth_cred_alloc(kauth_cred_t parent_cred, kauth_cred_t model_cred)
{
struct ucred_rw *found_rw;
struct ucred_rw *new_rw;
struct ucred *newcred;
/*
* Step 1: find if there's a duplicate entry
*/
found_rw = smr_shash_get(&kauth_cred_hash, kauth_cred_key(model_cred),
&kauth_cred_traits);
if (found_rw) {
/* found a duplicate, free the label if the model owned it */
#if CONFIG_MACF
if (!parent_cred || model_cred->cr_label != parent_cred->cr_label) {
mac_cred_label_destroy(model_cred);
}
#endif
/* smr_hash_get() already did a kauth_cred_ro() */
return found_rw->crw_cred;
}
/*
* Step 2: create a fresh new kauth_cred.
*
* give it ownership of the label and audit session,
* if it doesn't have it already.
*/
#if CONFIG_MACF
if (parent_cred && model_cred->cr_label == parent_cred->cr_label) {
mac_cred_label_init(model_cred);
mac_cred_label_associate(parent_cred, model_cred);
}
mac_cred_label_seal(model_cred);
#else
(void)parent_cred;
#endif
AUDIT_SESSION_REF(model_cred);
new_rw = zalloc_flags(ucred_rw_zone, Z_WAITOK | Z_ZERO | Z_NOFAIL);
os_ref_init_raw(&new_rw->crw_weak_ref, &ucred_ref_grp);
model_cred->cr_rw = new_rw;
model_cred->cr_unused = NULL;
model_cred->cr_ref = 0;
newcred = zalloc_ro(ZONE_ID_KAUTH_CRED, Z_WAITOK | Z_ZERO | Z_NOFAIL);
new_rw->crw_cred = newcred;
#if HAS_APPLE_PAC
{
void *naked_ptr = model_cred->cr_label;
void *signed_ptr;
signed_ptr = ptrauth_sign_unauthenticated(naked_ptr,
ptrauth_key_process_independent_data,
ptrauth_blend_discriminator(&newcred->cr_label,
OS_PTRAUTH_DISCRIMINATOR("ucred.cr_label")));
memcpy((void *)&model_cred->cr_label, &signed_ptr, sizeof(void *));
}
#endif
zalloc_ro_update_elem(ZONE_ID_KAUTH_CRED, newcred, model_cred);
/*
* Step 3: try to insert in the hash table,
* and deal someone else racing us.
*/
found_rw = smr_shash_get_or_insert(&kauth_cred_hash,
kauth_cred_key(newcred), &new_rw->crw_link, &kauth_cred_traits);
if (__probable(!found_rw)) {
return newcred;
}
#if CONFIG_MACF
mac_cred_label_free(newcred->cr_label);
#endif
AUDIT_SESSION_UNREF(newcred);
zfree(ucred_rw_zone, new_rw);
zfree_ro(ZONE_ID_KAUTH_CRED, newcred);
/* smr_shash_get_or_insert() already did a kauth_cred_ro() */
return found_rw->crw_cred;
}
kauth_cred_t
kauth_cred_require(kauth_cred_t cred)
{
zone_require_ro(ZONE_ID_KAUTH_CRED, sizeof(struct ucred), cred);
return cred;
}
__abortlike
static void
kauth_cred_rw_verify_panic(const struct ucred_rw *cred_rw, kauth_cred_t cred)
{
panic("ucred_rw backref mismatch: cred_rw:%p cred_rw->crw_cred:%p "
"cred: %p", cred_rw, cred_rw->crw_cred, cred);
}
__pure2
static kauth_cred_t
kauth_cred_ro(const struct ucred_rw *cred_rw)
{
kauth_cred_t cred = kauth_cred_require(cred_rw->crw_cred);
if (__improbable(cred->cr_rw != cred_rw)) {
kauth_cred_rw_verify_panic(cred_rw, cred);
}
return cred;
}
__attribute__((noinline))
static void
kauth_cred_free(struct smr_node *node)
{
struct ucred_rw *rw = __container_of(node, struct ucred_rw, crw_node);
struct ucred *cred = kauth_cred_ro(rw);
if (cred == vfs_context0.vc_ucred) {
panic("Over-release of the kernel credentials");
}
if (os_atomic_load(&cred->cr_ref, relaxed) != 0) {
panic("%s: freeing credential with active long-term ref", __func__);
}
#if CONFIG_MACF
mac_cred_label_free(cred->cr_label);
#endif
zfree(ucred_rw_zone, rw);
zfree_ro(ZONE_ID_KAUTH_CRED, cred);
}
__attribute__((noinline))
static void
kauth_cred_retire(struct ucred_rw *rw, struct ucred *cred __unused)
{
vm_size_t size = sizeof(struct ucred_rw) +
#if CONFIG_MACF
sizeof(struct label) +
#endif
sizeof(struct ucred);
smr_shash_remove(&kauth_cred_hash, &rw->crw_link, &kauth_cred_traits);
AUDIT_SESSION_UNREF(cred); /* uses SMR, safe to do immediately */
smr_call(&smr_proc_task, &rw->crw_node, size, kauth_cred_free);
}
static kauth_cred_t
posix_cred_create_internal(posix_cred_t pcred, struct au_session audit)
{
struct ucred model = {
.cr_posix = *pcred,
.cr_label = NULL,
.cr_audit = audit,
};
int is_member = 0;
pcred = posix_cred_get(&model);
if (pcred->cr_ngroups < 1) {
return NOCRED;
}
if (pcred->cr_flags & CRF_NOMEMBERD) {
pcred->cr_gmuid = KAUTH_UID_NONE;
} else {
/*
* If the template credential is not opting out of external
* group membership resolution, then we need to check that
* the UID we will be using is resolvable by the external
* resolver. If it's not, then we opt it out anyway, since
* all future external resolution requests will be failing
* anyway, and potentially taking a long time to do it. We
* use gid 0 because we always know it will exist and not
* trigger additional lookups. This is OK, because we end up
* precatching the information here as a result.
*/
if (!kauth_cred_ismember_gid(&model, 0, &is_member)) {
/*
* It's a recognized value; we don't really care about
* the answer, so long as it's something the external
* resolver could have vended.
*/
pcred->cr_gmuid = pcred->cr_uid;
} else {
/*
* It's not something the external resolver could
* have vended, so we don't want to ask it more
* questions about the credential in the future. This
* speeds up future lookups, as long as the caller
* caches results; otherwise, it the same recurring
* cost. Since most credentials are used multiple
* times, we still get some performance win from this.
*/
pcred->cr_gmuid = KAUTH_UID_NONE;
pcred->cr_flags |= CRF_NOMEMBERD;
}
}
mac_cred_label_init(&model);
return kauth_cred_alloc(NOCRED, &model);
}
/*
* kauth_cred_create
*
* Description: Obsolete function that is unfortunately exported,
* but that no one should use directly.
*
* Parameters: cred Template for credential to
* be created
*
* Returns: (kauth_cred_t) The credential that was found
* in the hash or created
* NULL kauth_cred_add() failed, or
* there was not an egid specified
*
* Notes: The gmuid is hard-defaulted to the UID specified. Since we
* maintain this field, we can't expect callers to know how it
* needs to be set. Callers should be prepared for this field
* to be overwritten.
*/
kauth_cred_t
kauth_cred_create(kauth_cred_t cred)
{
return posix_cred_create_internal(&cred->cr_posix, cred->cr_audit);
}
kauth_cred_t
kauth_cred_derive(kauth_cred_t cred, kauth_cred_derive_t derive_fn)
{
struct ucred model = {
.cr_posix = cred->cr_posix,
.cr_label = cred->cr_label,
.cr_audit = cred->cr_audit,
};
if (derive_fn(cred, &model)) {
return kauth_cred_alloc(cred, &model);
}
kauth_cred_ref(cred);
return cred;
}
bool
kauth_cred_proc_update(
proc_t p,
proc_settoken_t action,
kauth_cred_derive_t derive_fn)
{
kauth_cred_t cur_cred, free_cred, new_cred;
cur_cred = kauth_cred_proc_ref(p);
for (;;) {
new_cred = kauth_cred_derive(cur_cred, derive_fn);
if (new_cred == cur_cred) {
if (action == PROC_SETTOKEN_ALWAYS) {
set_security_token(p, cur_cred);
}
kauth_cred_unref(&new_cred);
kauth_cred_unref(&cur_cred);
return false;
}
proc_ucred_lock(p);
if (__probable(proc_ucred_locked(p) == cur_cred)) {
kauth_cred_ref(new_cred);
kauth_cred_hold(new_cred);
zalloc_ro_mut(ZONE_ID_PROC_RO, proc_get_ro(p),
offsetof(struct proc_ro, p_ucred),
&new_cred, sizeof(struct ucred *));
kauth_cred_drop(cur_cred);
ucred_rw_unref_live(cur_cred->cr_rw);
proc_update_creds_onproc(p, new_cred);
proc_ucred_unlock(p);
if (action == PROC_SETTOKEN_SETUGID) {
OSBitOrAtomic(P_SUGID, &p->p_flag);
}
if (action != PROC_SETTOKEN_NONE) {
set_security_token(p, new_cred);
}
kauth_cred_unref(&new_cred);
kauth_cred_unref(&cur_cred);
return true;
}
free_cred = cur_cred;
cur_cred = proc_ucred_locked(p);
kauth_cred_ref(cur_cred);
proc_ucred_unlock(p);
kauth_cred_unref(&free_cred);
kauth_cred_unref(&new_cred);
}
}
/*
* kauth_cred_model_setresuid
*
* Description: Update the given credential using the UID arguments. The given
* UIDs are used to set the effective UID, real UID, saved UID,
* and GMUID (used for group membership checking).
*
* Parameters: model The model credential
* ruid The new real UID
* euid The new effective UID
* svuid The new saved UID
* gmuid KAUTH_UID_NONE -or- the new
* group membership UID
*
* Returns: (kauth_cred_t) The updated credential
*
* Note: gmuid is different in that a KAUTH_UID_NONE is a valid
* setting, so if you don't want it to change, pass it the
* previous value, explicitly.
*/
bool
kauth_cred_model_setresuid(
kauth_cred_t model,
uid_t ruid,
uid_t euid,
uid_t svuid,
uid_t gmuid)
{
posix_cred_t pcred = posix_cred_get(model);
bool updated = false;
/*
* We don't need to do anything if the UIDs we are changing are
* already the same as the UIDs passed in
*/
if (euid != KAUTH_UID_NONE && pcred->cr_uid != euid) {
pcred->cr_uid = euid;
updated = true;
}
if (ruid != KAUTH_UID_NONE && pcred->cr_ruid != ruid) {
pcred->cr_ruid = ruid;
updated = true;
}
if (svuid != KAUTH_UID_NONE && pcred->cr_svuid != svuid) {
pcred->cr_svuid = svuid;
updated = true;
}
if (pcred->cr_gmuid != gmuid) {
/*
* If we are setting the gmuid to KAUTH_UID_NONE, then we want
* to opt out of participation in external group resolution,
* unless we explicitly opt back in later.
*/
pcred->cr_gmuid = gmuid;
if (gmuid == KAUTH_UID_NONE) {
pcred->cr_flags |= CRF_NOMEMBERD;
}
updated = true;
}
return updated;
}
/*
* kauth_cred_model_setresgid
*
* Description: Update the given credential using the GID arguments. The given
* GIDs are used to set the effective GID, real GID, and saved
* GID.
*
* Parameters: model The model credential
* rgid The new real GID
* egid The new effective GID
* svgid The new saved GID
*
* Returns: (kauth_cred_t) The updated credential
*/
bool
kauth_cred_model_setresgid(
kauth_cred_t model,
gid_t rgid,
gid_t egid,
gid_t svgid)
{
posix_cred_t pcred = posix_cred_get(model);
bool updated = false;
if (egid != KAUTH_GID_NONE && pcred->cr_gid != egid) {
if (kauth_cred_change_egid(model, egid)) {
pcred->cr_flags |= CRF_NOMEMBERD;
pcred->cr_gmuid = KAUTH_UID_NONE;
}
updated = true;
}
if (rgid != KAUTH_GID_NONE && pcred->cr_rgid != rgid) {
pcred->cr_rgid = rgid;
updated = true;
}
if (svgid != KAUTH_GID_NONE && pcred->cr_svgid != svgid) {
pcred->cr_svgid = svgid;
updated = true;
}
return updated;
}
/*
* Update the given credential with the given groups. We only allocate a new
* credential when the given gid actually results in changes to the existing
* credential.
* The gmuid argument supplies a new uid (or KAUTH_UID_NONE to opt out)
* which will be used for group membership checking.
*/
/*
* kauth_cred_model_setgroups
*
* Description: Update the given credential using the provide supplementary
* group list and group membership UID
*
* Parameters: cred The model credential
* groups Pointer to gid_t array which
* contains the new group list
* groupcount The count of valid groups which
* are contained in 'groups'
* gmuid KAUTH_UID_NONE -or- the new
* group membership UID
*
* Returns: (kauth_cred_t) The updated credential
*
* Note: gmuid is different in that a KAUTH_UID_NONE is a valid
* setting, so if you don't want it to change, pass it the
* previous value, explicitly.
*
* XXX: Changes are determined in ordinal order - if the caller passes
* in the same groups list that is already present in the
* credential, but the members are in a different order, even if
* the EGID is not modified (i.e. cr_groups[0] is the same), it
* is considered a modification to the credential, and a new
* credential is created.
*
* This should perhaps be better optimized, but it is considered
* to be the caller's problem.
*/
bool
kauth_cred_model_setgroups(
kauth_cred_t model,
gid_t *groups,
size_t groupcount,
uid_t gmuid)
{
posix_cred_t pcred = posix_cred_get(model);
assert(groupcount <= NGROUPS);
groupcount = MIN(groupcount, NGROUPS);
/*
* We don't need to do anything if the given list of groups does not
* change.
*/
if (pcred->cr_gmuid == gmuid &&
pcred->cr_ngroups == groupcount &&
memcmp(pcred->cr_groups, groups, groupcount * sizeof(gid_t)) == 0) {
return false;
}
pcred->cr_gmuid = gmuid;
pcred->cr_ngroups = (short)groupcount;
memcpy(pcred->cr_groups, groups, groupcount * sizeof(gid_t));
if (gmuid == KAUTH_UID_NONE) {
pcred->cr_flags |= CRF_NOMEMBERD;
} else {
pcred->cr_flags &= ~CRF_NOMEMBERD;
}
return true;
}
/*
* Notes: The return value exists to account for the possibility of a
* kauth_cred_t without a POSIX label. This will be the case in
* the future (see posix_cred_get() below, for more details).
*/
#if CONFIG_EXT_RESOLVER
int kauth_external_supplementary_groups_supported = 1;
SYSCTL_INT(_kern, OID_AUTO, ds_supgroups_supported, CTLFLAG_RW | CTLFLAG_LOCKED, &kauth_external_supplementary_groups_supported, 0, "");
#endif
int
kauth_cred_getgroups(kauth_cred_t cred, gid_t *grouplist, size_t *countp)
{
size_t limit = NGROUPS;
posix_cred_t pcred;
if (cred == NULL) {
KAUTH_DEBUG("kauth_cred_getgroups got NULL credential");
return EINVAL;
}
if (grouplist == NULL) {
KAUTH_DEBUG("kauth_cred_getgroups got NULL group list");
return EINVAL;
}
pcred = posix_cred_get(cred);
#if CONFIG_EXT_RESOLVER
/*
* If we've not opted out of using the resolver, then convert the cred to a list
* of supplemental groups. We do this only if there has been a resolver to talk to,
* since we may be too early in boot, or in an environment that isn't using DS.
*/
if (kauth_identitysvc_has_registered && kauth_external_supplementary_groups_supported && (pcred->cr_flags & CRF_NOMEMBERD) == 0) {
uid_t uid = kauth_cred_getuid(cred);
int err;
err = kauth_cred_uid2groups(&uid, grouplist, countp);
if (!err) {
return 0;
}
/* On error just fall through */
KAUTH_DEBUG("kauth_cred_getgroups failed %d\n", err);
}
#endif /* CONFIG_EXT_RESOLVER */
/*
* If they just want a copy of the groups list, they may not care
* about the actual count. If they specify an input count, however,
* treat it as an indicator of the buffer size available in grouplist,
* and limit the returned list to that size.
*/
if (countp) {
limit = MIN(*countp, pcred->cr_ngroups);
*countp = limit;
}
memcpy(grouplist, pcred->cr_groups, sizeof(gid_t) * limit);
return 0;
}
/*
* kauth_cred_model_setuidgid
*
* Description: Update the given credential using the UID and GID arguments.
* The given UID is used to set the effective UID, real UID, and
* saved UID. The given GID is used to set the effective GID,
* real GID, and saved GID.
*
* Parameters: model The model credential
* uid The new UID to use
* gid The new GID to use
*
* Returns: (kauth_cred_t) The updated credential
*
* Notes: We set the gmuid to uid if the credential we are inheriting
* from has not opted out of memberd participation; otherwise
* we set it to KAUTH_UID_NONE
*
* This code is only ever called from the per-thread credential
* code path in the "set per thread credential" case; and in
* posix_spawn() in the case that the POSIX_SPAWN_RESETIDS
* flag is set.
*/
bool
kauth_cred_model_setuidgid(kauth_cred_t model, uid_t uid, gid_t gid)
{
struct posix_cred pcred = {
.cr_uid = uid,
.cr_ruid = uid,
.cr_svuid = uid,
.cr_ngroups = 1,
.cr_gid = gid,
.cr_rgid = gid,
.cr_svgid = gid,
.cr_flags = model->cr_posix.cr_flags,
};
/* inherit the opt-out of memberd */
if (pcred.cr_flags & CRF_NOMEMBERD) {
pcred.cr_gmuid = KAUTH_UID_NONE;
} else {
pcred.cr_gmuid = uid;
}
if (memcmp(&model->cr_posix, &pcred, sizeof(struct posix_cred)) != 0) {
model->cr_posix = pcred;
return true;
}
return false;
}
/*
* kauth_cred_model_setauditinfo
*
* Description: Update the given credential using the given au_session_t.
*
* Parameters: model The model credential
* auditinfo_p Pointer to ne audit information
*
* Returns: (kauth_cred_t) The updated credential
*/
bool
kauth_cred_model_setauditinfo(kauth_cred_t model, au_session_t *auditinfo_p)
{
if (memcmp(&model->cr_audit, auditinfo_p, sizeof(model->cr_audit)) != 0) {
model->cr_audit = *auditinfo_p;
return true;
}
return false;
}
#if CONFIG_MACF
kauth_cred_t
kauth_cred_label_update(kauth_cred_t cred, struct label *label)
{
kauth_cred_t new_cred;
new_cred = kauth_cred_derive(cred,
^bool (kauth_cred_t parent, kauth_cred_t model) {
mac_cred_label_init(model);
mac_cred_label_associate(parent, model);
mac_cred_label_update(model, label);
return true;
});
kauth_cred_unref(&cred);
return new_cred;
}
int
kauth_proc_label_update(struct proc *p, struct label *label)
{
kauth_cred_proc_update(p, PROC_SETTOKEN_NONE,
^bool (kauth_cred_t parent, kauth_cred_t model) {
mac_cred_label_init(model);
mac_cred_label_associate(parent, model);
mac_cred_label_update(model, label);
return true;
});
return 0;
}
/*
* kauth_proc_label_update_execve
*
* Description: Update the label inside the credential associated with the
* process as part of a transitioning execve. The label will
* be updated by the policies as part of this processing, not
* provided up front.
*
* Parameters: p The process to modify
* ctx The context of the exec
* vp The vnode being exec'ed
* scriptl The script MAC label
* execl The executable MAC label
* lupdateerror The error place holder for MAC label authority
* to update about possible termination
*
* Returns: 0 Label update did not make credential
* disjoint
* 1 Label update caused credential to be
* disjoint
*
* Notes: The credential associated with the process WILL change as a
* result of this call. The caller should not assume the process
* reference to the old credential still exists.
*/
void
kauth_proc_label_update_execve(struct proc *p, vfs_context_t ctx,
struct vnode *vp, off_t offset, struct vnode *scriptvp, struct label *scriptl,
struct label *execl, unsigned int *csflags, void *macextensions, int *disjoint, int *update_return)
{
kauth_cred_proc_update(p, PROC_SETTOKEN_NONE,
^bool (kauth_cred_t parent, kauth_cred_t model) {
mac_cred_label_init(model);
mac_cred_label_associate(parent, model);
mac_cred_label_update_execve(ctx, model,
vp, offset, scriptvp, scriptl, execl, csflags,
macextensions, disjoint, update_return);
return true;
});
}
#else
kauth_cred_t
kauth_cred_label_update(__unused kauth_cred_t cred, __unused struct label *label)
{
return NULL;
}
int
kauth_proc_label_update(__unused struct proc *p, __unused struct label *label)
{
return 0;
}
#endif
void
kauth_cred_ref(kauth_cred_t cred)
{
ucred_rw_ref(kauth_cred_rw(cred));
}
void
(kauth_cred_unref)(kauth_cred_t * credp)
{
struct ucred *cred = *credp;
struct ucred_rw *rw = kauth_cred_rw(cred);
*credp = NOCRED;
if (ucred_rw_unref(rw) == 0) {
kauth_cred_retire(rw, cred);
}
}
/*
* kauth_cred_set
*
* Description: Store a long-term credential reference to a credential pointer,
* dropping the long-term reference on any previous credential held
* at the address.
*
* Parameters: credp Pointer to the credential
* storage field. If *credp points
* to a valid credential before
* this call, its long-term
* reference will be dropped.
* new_cred The new credential to take a
* long-term reference to and
* assign to *credp. May be
* NOCRED.
*
* Returns: (void)
*
* Notes: Taking/dropping a long-term reference is costly in terms of
* performance.
*/
void
(kauth_cred_set)(kauth_cred_t * credp, kauth_cred_t new_cred)
{
kauth_cred_t old_cred = *credp;
if (old_cred != new_cred) {
if (IS_VALID_CRED(new_cred)) {
kauth_cred_ref(new_cred);
kauth_cred_hold(new_cred);
}
*credp = new_cred;
if (IS_VALID_CRED(old_cred)) {
kauth_cred_drop(old_cred);
kauth_cred_unref(&old_cred);
}
}
}
/*
* kauth_cred_copy_real
*
* Description: Returns a credential based on the passed credential but which
* reflects the real rather than effective UID and GID.
*
* Parameters: cred The credential from which to
* derive the new credential
*
* Returns: (kauth_cred_t) The copied credential
*
* IMPORTANT: This function DOES NOT utilize kauth_cred_update(); as a
* result, the caller is responsible for dropping BOTH the
* additional reference on the passed cred (if any), and the
* credential returned by this function. The drop should be
* via the kauth_cred_unref() KPI.
*/
kauth_cred_t
kauth_cred_copy_real(kauth_cred_t cred)
{
kauth_cred_derive_t fn = ^bool (kauth_cred_t parent __unused, kauth_cred_t model) {
posix_cred_t pcred = posix_cred_get(model);
/* if the credential is already 'real', just take a reference */
if ((pcred->cr_ruid == pcred->cr_uid) &&
(pcred->cr_rgid == pcred->cr_gid)) {
return false;
}
pcred->cr_uid = pcred->cr_ruid;
/* displacing a supplementary group opts us out of memberd */
if (kauth_cred_change_egid(model, pcred->cr_rgid)) {
pcred->cr_flags |= CRF_NOMEMBERD;
pcred->cr_gmuid = KAUTH_UID_NONE;
}
/*
* If the cred is not opted out, make sure we are using the r/euid
* for group checks
*/
if (pcred->cr_gmuid != KAUTH_UID_NONE) {
pcred->cr_gmuid = pcred->cr_ruid;
}
return true;
};
return kauth_cred_derive(cred, fn);
}
/*
* Hash table traits methods
*/
static smrh_key_t
kauth_cred_key(kauth_cred_t cred)
{
return (smrh_key_t){ .smrk_opaque = cred };
}
static uint32_t
kauth_cred_ro_hash(const struct ucred *cred, uint32_t seed)
{
uint32_t hash = seed;
hash = os_hash_jenkins_update(&cred->cr_posix,
sizeof(struct posix_cred), hash);
hash = os_hash_jenkins_update(&cred->cr_audit,
sizeof(struct au_session), hash);
#if CONFIG_MACF
if (cred->cr_posix.cr_flags & CRF_MAC_ENFORCE) {
hash = mac_cred_label_hash_update(cred->cr_label, hash);
}
#endif /* CONFIG_MACF */
return hash;
}
static uint32_t
kauth_cred_key_hash(smrh_key_t key, uint32_t seed)
{
return kauth_cred_ro_hash(key.smrk_opaque, seed);
}
static uint32_t
kauth_cred_obj_hash(const struct smrq_slink *link, uint32_t seed)
{
const struct ucred_rw *rw;
rw = __container_of(link, struct ucred_rw, crw_link);
/* this is used during rehash, re-auth the objects as we do */
return kauth_cred_ro_hash(kauth_cred_ro(rw), seed);
}
static bool
kauth_cred_key_equ(smrh_key_t k1, smrh_key_t k2)
{
const struct ucred *cred1 = k1.smrk_opaque;
const struct ucred *cred2 = k2.smrk_opaque;
const struct posix_cred *pcred1 = &cred1->cr_posix;
const struct posix_cred *pcred2 = &cred2->cr_posix;
/*
* don't worry about the label unless the flags in
* either credential tell us to.
*/
if (memcmp(pcred1, pcred2, sizeof(*pcred1))) {
return false;
}
if (memcmp(&cred1->cr_audit, &cred2->cr_audit, sizeof(cred1->cr_audit))) {
return false;
}
#if CONFIG_MACF
/* Note: we know the flags are equal, so we only need to test one */
if (pcred1->cr_flags & CRF_MAC_ENFORCE) {
if (!mac_cred_label_is_equal(cred1->cr_label, cred2->cr_label)) {
return false;
}
}
#endif
return true;
}
static bool
kauth_cred_obj_equ(const struct smrq_slink *link, smrh_key_t key)
{
const struct ucred_rw *rw;
rw = __container_of(link, struct ucred_rw, crw_link);
/* only do the kauth_cred_ro() check in try_get() */
return kauth_cred_key_equ(kauth_cred_key(rw->crw_cred), key);
}
static bool
kauth_cred_obj_try_get(void *obj)
{
struct ucred_rw *rw = obj;
kauth_cred_t cred = kauth_cred_require(rw->crw_cred);
if (__improbable(cred->cr_rw != rw)) {
kauth_cred_rw_verify_panic(rw, cred);
}
return ucred_rw_tryref(rw);
}
/*
**********************************************************************
* The following routines will be moved to a policy_posix.c module at
* some future point.
**********************************************************************
*/
/*
* posix_cred_create
*
* Description: Helper function to create a kauth_cred_t credential that is
* initally labelled with a specific POSIX credential label
*
* Parameters: pcred The posix_cred_t to use as the initial
* label value
*
* Returns: (kauth_cred_t) The credential that was found in the
* hash or creates
* NULL kauth_cred_make() failed, or there was
* no egid specified, or we failed to
* attach a label to the new credential
*
* Notes: The gmuid is hard-defaulted to the UID specified. Since we
* maintain this field, we can't expect callers to know how it
* needs to be set. Callers should be prepared for this field
* to be overwritten.
*/
kauth_cred_t
posix_cred_create(posix_cred_t pcred)
{
struct au_session audit = {
.as_aia_p = audit_default_aia_p,
};
return posix_cred_create_internal(pcred, audit);
}
/*
* posix_cred_get
*
* Description: Given a kauth_cred_t, return the POSIX credential label, if
* any, which is associated with it.
*
* Parameters: cred The credential to obtain the label from
*
* Returns: posix_cred_t The POSIX credential label
*
* Notes: In the event that the policy_posix MACF module IS NOT loaded,
* this function will return a pointer to a posix_cred_t which
* GRANTS all access (effectively, a "root" credential). This is
* necessary to support legacy code which insists on tightly
* integrating POSIX credentials into its APIs, including, but
* not limited to, System V IPC mechanisms, POSIX IPC mechanisms,
* NFSv3, signals, dtrace, and a large number of kauth routines
* used to implement POSIX permissions related system calls.
*
* In the event that the policy_posix MACF module IS loaded, and
* there is no POSIX label on the kauth_cred_t credential, this
* function will return a pointer to a posix_cred_t which DENIES
* all access (effectively, a "deny rights granted by POSIX"
* credential). This is necessary to support the concept of a
* transiently loaded POSIX policy, or kauth_cred_t credentials
* which can not be used in conjunctions with POSIX permissions
* checks.
*
* This function currently returns the address of the cr_posix
* field of the supplied kauth_cred_t credential, and as such
* currently can not fail. In the future, this will not be the
* case.
*/
posix_cred_t
posix_cred_get(kauth_cred_t cred)
{
return &cred->cr_posix;
}
/*
* posix_cred_access
*
* Description: Perform a POSIX access check for a protected object
*
* Parameters: cred The credential to check
* object_uid The POSIX UID of the protected object
* object_gid The POSIX GID of the protected object
* object_mode The POSIX mode of the protected object
* mode_req The requested POSIX access rights
*
* Returns 0 Access is granted
* EACCES Access is denied
*
* Notes: This code optimizes the case where the world and group rights
* would both grant the requested rights to avoid making a group
* membership query. This is a big performance win in the case
* where this is true.
*/
int
posix_cred_access(kauth_cred_t cred, id_t object_uid, id_t object_gid, mode_t object_mode, mode_t mode_req)
{
int is_member;
mode_t mode_owner = (object_mode & S_IRWXU);
mode_t mode_group = (mode_t)((object_mode & S_IRWXG) << 3);
mode_t mode_world = (mode_t)((object_mode & S_IRWXO) << 6);
/*
* Check first for owner rights
*/
if (kauth_cred_getuid(cred) == object_uid && (mode_req & mode_owner) == mode_req) {
return 0;
}
/*
* Combined group and world rights check, if we don't have owner rights
*
* OPTIMIZED: If group and world rights would grant the same bits, and
* they set of requested bits is in both, then we can simply check the
* world rights, avoiding a group membership check, which is expensive.
*/
if ((mode_req & mode_group & mode_world) == mode_req) {
return 0;
} else {
/*
* NON-OPTIMIZED: requires group membership check.
*/
if ((mode_req & mode_group) != mode_req) {
/*
* exclusion group : treat errors as "is a member"
*
* NON-OPTIMIZED: +group would deny; must check group
*/
if (!kauth_cred_ismember_gid(cred, object_gid, &is_member) && is_member) {
/*
* DENY: +group denies
*/
return EACCES;
} else {
if ((mode_req & mode_world) != mode_req) {
/*
* DENY: both -group & world would deny
*/
return EACCES;
} else {
/*
* ALLOW: allowed by -group and +world
*/
return 0;
}
}
} else {
/*
* inclusion group; treat errors as "not a member"
*
* NON-OPTIMIZED: +group allows, world denies; must
* check group
*/
if (!kauth_cred_ismember_gid(cred, object_gid, &is_member) && is_member) {
/*
* ALLOW: allowed by +group
*/
return 0;
} else {
if ((mode_req & mode_world) != mode_req) {
/*
* DENY: both -group & world would deny
*/
return EACCES;
} else {
/*
* ALLOW: allowed by -group and +world
*/
return 0;
}
}
}
}
}