/*
* Copyright (c) 2018-2020 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@
*/
#include <sys/errno.h>
#include <mach/mach_types.h>
#include <mach/mach_traps.h>
#include <mach/host_priv.h>
#include <mach/kern_return.h>
#include <mach/memory_object_control.h>
#include <mach/memory_object_types.h>
#include <mach/port.h>
#include <mach/policy.h>
#include <mach/upl.h>
#include <mach/thread_act.h>
#include <mach/mach_vm.h>
#include <kern/host.h>
#include <kern/kalloc.h>
#include <kern/queue.h>
#include <kern/thread.h>
#include <kern/ipc_kobject.h>
#include <ipc/ipc_port.h>
#include <ipc/ipc_space.h>
#include <vm/memory_object_internal.h>
#include <vm/vm_kern.h>
#include <vm/vm_fault_internal.h>
#include <vm/vm_map.h>
#include <vm/vm_pageout_xnu.h>
#include <vm/vm_protos_internal.h>
#include <vm/vm_shared_region_internal.h>
#include <vm/vm_ubc.h>
#include <vm/vm_page_internal.h>
#include <vm/vm_object_internal.h>
#include <sys/kdebug_triage.h>
#include <sys/random.h>
#if __has_feature(ptrauth_calls)
#include <ptrauth.h>
extern boolean_t diversify_user_jop;
#endif /* __has_feature(ptrauth_calls) */
/*
* SHARED REGION MEMORY PAGER
*
* This external memory manager (EMM) handles mappings of a dyld shared cache
* in shared regions, applying any necessary modifications (sliding,
* pointer signing, ...).
*
* It mostly handles page-in requests (from memory_object_data_request()) by
* getting the original data from its backing VM object, itself backed by
* the dyld shared cache file, modifying it if needed and providing it to VM.
*
* The modified pages will never be dirtied, so the memory manager doesn't
* need to handle page-out requests (from memory_object_data_return()). The
* pages need to be mapped copy-on-write, so that the originals stay clean.
*
* We don't expect to have to handle a large number of shared cache files,
* so the data structures are very simple (simple linked list) for now.
*/
/* forward declarations */
void shared_region_pager_reference(memory_object_t mem_obj);
void shared_region_pager_deallocate(memory_object_t mem_obj);
kern_return_t shared_region_pager_init(memory_object_t mem_obj,
memory_object_control_t control,
memory_object_cluster_size_t pg_size);
kern_return_t shared_region_pager_terminate(memory_object_t mem_obj);
kern_return_t shared_region_pager_data_request(memory_object_t mem_obj,
memory_object_offset_t offset,
memory_object_cluster_size_t length,
vm_prot_t protection_required,
memory_object_fault_info_t fault_info);
kern_return_t shared_region_pager_data_return(memory_object_t mem_obj,
memory_object_offset_t offset,
memory_object_cluster_size_t data_cnt,
memory_object_offset_t *resid_offset,
int *io_error,
boolean_t dirty,
boolean_t kernel_copy,
int upl_flags);
kern_return_t shared_region_pager_data_initialize(memory_object_t mem_obj,
memory_object_offset_t offset,
memory_object_cluster_size_t data_cnt);
kern_return_t shared_region_pager_map(memory_object_t mem_obj,
vm_prot_t prot);
kern_return_t shared_region_pager_last_unmap(memory_object_t mem_obj);
boolean_t shared_region_pager_backing_object(
memory_object_t mem_obj,
memory_object_offset_t mem_obj_offset,
vm_object_t *backing_object,
vm_object_offset_t *backing_offset);
/*
* Vector of VM operations for this EMM.
* These routines are invoked by VM via the memory_object_*() interfaces.
*/
const struct memory_object_pager_ops shared_region_pager_ops = {
.memory_object_reference = shared_region_pager_reference,
.memory_object_deallocate = shared_region_pager_deallocate,
.memory_object_init = shared_region_pager_init,
.memory_object_terminate = shared_region_pager_terminate,
.memory_object_data_request = shared_region_pager_data_request,
.memory_object_data_return = shared_region_pager_data_return,
.memory_object_data_initialize = shared_region_pager_data_initialize,
.memory_object_map = shared_region_pager_map,
.memory_object_last_unmap = shared_region_pager_last_unmap,
.memory_object_backing_object = shared_region_pager_backing_object,
.memory_object_pager_name = "shared_region"
};
#if __has_feature(ptrauth_calls)
/*
* Track mappings between shared_region_id and the key used to sign
* authenticated pointers.
*/
typedef struct shared_region_jop_key_map {
queue_chain_t srk_queue;
char *srk_shared_region_id;
uint64_t srk_jop_key;
os_refcnt_t srk_ref_count; /* count of tasks active with this shared_region_id */
} *shared_region_jop_key_map_t;
os_refgrp_decl(static, srk_refgrp, "shared region key ref cnts", NULL);
/*
* The list is protected by the "shared_region_key_map" lock.
*/
int shared_region_key_count = 0; /* number of active shared_region_id keys */
queue_head_t shared_region_jop_key_queue = QUEUE_HEAD_INITIALIZER(shared_region_jop_key_queue);
LCK_GRP_DECLARE(shared_region_jop_key_lck_grp, "shared_region_jop_key");
LCK_MTX_DECLARE(shared_region_jop_key_lock, &shared_region_jop_key_lck_grp);
#if __has_feature(ptrauth_calls)
/*
* Generate a random pointer signing key that isn't 0.
*/
uint64_t
generate_jop_key(void)
{
uint64_t key;
do {
read_random(&key, sizeof key);
} while (key == 0);
return key;
}
#endif /* __has_feature(ptrauth_calls) */
/*
* Find the pointer signing key for the give shared_region_id.
*/
uint64_t
shared_region_find_key(char *shared_region_id)
{
shared_region_jop_key_map_t region;
uint64_t key;
lck_mtx_lock(&shared_region_jop_key_lock);
queue_iterate(&shared_region_jop_key_queue, region, shared_region_jop_key_map_t, srk_queue) {
if (strcmp(region->srk_shared_region_id, shared_region_id) == 0) {
goto found;
}
}
panic("shared_region_find_key() no key for region '%s'", shared_region_id);
found:
key = region->srk_jop_key;
lck_mtx_unlock(&shared_region_jop_key_lock);
return key;
}
/*
* Return a authentication key to use for the given shared_region_id.
* If inherit is TRUE, then the key must match inherited_key.
* Creates an additional reference when successful.
*/
void
shared_region_key_alloc(char *shared_region_id, bool inherit, uint64_t inherited_key)
{
shared_region_jop_key_map_t region;
shared_region_jop_key_map_t new = NULL;
assert(shared_region_id != NULL);
again:
lck_mtx_lock(&shared_region_jop_key_lock);
queue_iterate(&shared_region_jop_key_queue, region, shared_region_jop_key_map_t, srk_queue) {
if (strcmp(region->srk_shared_region_id, shared_region_id) == 0) {
os_ref_retain_locked(®ion->srk_ref_count);
goto done;
}
}
/*
* ID was not found, if first time, allocate a new one and redo the lookup.
*/
if (new == NULL) {
lck_mtx_unlock(&shared_region_jop_key_lock);
new = kalloc_type(struct shared_region_jop_key_map, Z_WAITOK);
uint_t len = strlen(shared_region_id) + 1;
new->srk_shared_region_id = kalloc_data(len, Z_WAITOK);
strlcpy(new->srk_shared_region_id, shared_region_id, len);
os_ref_init(&new->srk_ref_count, &srk_refgrp);
if (diversify_user_jop && inherit) {
new->srk_jop_key = inherited_key;
} else if (diversify_user_jop && strlen(shared_region_id) > 0) {
new->srk_jop_key = generate_jop_key();
} else {
new->srk_jop_key = ml_default_jop_pid();
}
goto again;
}
/*
* Use the newly allocated entry
*/
++shared_region_key_count;
queue_enter_first(&shared_region_jop_key_queue, new, shared_region_jop_key_map_t, srk_queue);
region = new;
new = NULL;
done:
if (inherit && inherited_key != region->srk_jop_key) {
panic("shared_region_key_alloc() inherited key mismatch");
}
lck_mtx_unlock(&shared_region_jop_key_lock);
/*
* free any unused new entry
*/
if (new != NULL) {
kfree_data(new->srk_shared_region_id,
strlen(new->srk_shared_region_id) + 1);
kfree_type(struct shared_region_jop_key_map, new);
}
}
/*
* Mark the end of using a shared_region_id's key
*/
extern void
shared_region_key_dealloc(char *shared_region_id)
{
shared_region_jop_key_map_t region;
assert(shared_region_id != NULL);
lck_mtx_lock(&shared_region_jop_key_lock);
queue_iterate(&shared_region_jop_key_queue, region, shared_region_jop_key_map_t, srk_queue) {
if (strcmp(region->srk_shared_region_id, shared_region_id) == 0) {
goto done;
}
}
panic("shared_region_key_dealloc() Shared region ID '%s' not found", shared_region_id);
done:
if (os_ref_release_locked(®ion->srk_ref_count) == 0) {
queue_remove(&shared_region_jop_key_queue, region, shared_region_jop_key_map_t, srk_queue);
--shared_region_key_count;
} else {
region = NULL;
}
lck_mtx_unlock(&shared_region_jop_key_lock);
if (region != NULL) {
kfree_data(region->srk_shared_region_id,
strlen(region->srk_shared_region_id) + 1);
kfree_type(struct shared_region_jop_key_map, region);
}
}
#endif /* __has_feature(ptrauth_calls) */
/*
* The "shared_region_pager" describes a memory object backed by
* the "shared_region" EMM.
*/
typedef struct shared_region_pager {
struct memory_object srp_header; /* mandatory generic header */
/* pager-specific data */
queue_chain_t srp_queue; /* next & prev pagers */
#if MEMORY_OBJECT_HAS_REFCOUNT
#define srp_ref_count srp_header.mo_ref
#else
os_ref_atomic_t srp_ref_count; /* active uses */
#endif
bool srp_is_mapped; /* has active mappings */
bool srp_is_ready; /* is this pager ready? */
vm_object_t srp_backing_object; /* VM object for shared cache */
vm_object_offset_t srp_backing_offset;
vm_shared_region_slide_info_t srp_slide_info;
#if __has_feature(ptrauth_calls)
uint64_t srp_jop_key; /* zero if used for arm64 */
#endif /* __has_feature(ptrauth_calls) */
} *shared_region_pager_t;
#define SHARED_REGION_PAGER_NULL ((shared_region_pager_t) NULL)
/*
* List of memory objects managed by this EMM.
* The list is protected by the "shared_region_pager_lock" lock.
*/
int shared_region_pager_count = 0; /* number of pagers */
int shared_region_pager_count_mapped = 0; /* number of unmapped pagers */
queue_head_t shared_region_pager_queue = QUEUE_HEAD_INITIALIZER(shared_region_pager_queue);
LCK_GRP_DECLARE(shared_region_pager_lck_grp, "shared_region_pager");
LCK_MTX_DECLARE(shared_region_pager_lock, &shared_region_pager_lck_grp);
/*
* Maximum number of unmapped pagers we're willing to keep around.
*/
int shared_region_pager_cache_limit = 0;
/*
* Statistics & counters.
*/
int shared_region_pager_count_max = 0;
int shared_region_pager_count_unmapped_max = 0;
int shared_region_pager_num_trim_max = 0;
int shared_region_pager_num_trim_total = 0;
uint64_t shared_region_pager_copied = 0;
uint64_t shared_region_pager_slid = 0;
uint64_t shared_region_pager_slid_error = 0;
uint64_t shared_region_pager_reclaimed = 0;
/* internal prototypes */
shared_region_pager_t shared_region_pager_lookup(memory_object_t mem_obj);
void shared_region_pager_dequeue(shared_region_pager_t pager);
void shared_region_pager_deallocate_internal(shared_region_pager_t pager,
boolean_t locked);
void shared_region_pager_terminate_internal(shared_region_pager_t pager);
void shared_region_pager_trim(void);
#if DEBUG
int shared_region_pagerdebug = 0;
#define PAGER_ALL 0xffffffff
#define PAGER_INIT 0x00000001
#define PAGER_PAGEIN 0x00000002
#define PAGER_DEBUG(LEVEL, A) \
MACRO_BEGIN \
if ((shared_region_pagerdebug & (LEVEL)) == (LEVEL)) { \
printf A; \
} \
MACRO_END
#else
#define PAGER_DEBUG(LEVEL, A)
#endif
/*
* shared_region_pager_init()
*
* Initialize the memory object and makes it ready to be used and mapped.
*/
kern_return_t
shared_region_pager_init(
memory_object_t mem_obj,
memory_object_control_t control,
#if !DEBUG
__unused
#endif
memory_object_cluster_size_t pg_size)
{
shared_region_pager_t pager;
kern_return_t kr;
memory_object_attr_info_data_t attributes;
PAGER_DEBUG(PAGER_ALL,
("shared_region_pager_init: %p, %p, %x\n",
mem_obj, control, pg_size));
if (control == MEMORY_OBJECT_CONTROL_NULL) {
return KERN_INVALID_ARGUMENT;
}
pager = shared_region_pager_lookup(mem_obj);
memory_object_control_reference(control);
pager->srp_header.mo_control = control;
attributes.copy_strategy = MEMORY_OBJECT_COPY_DELAY;
/* attributes.cluster_size = (1 << (CLUSTER_SHIFT + PAGE_SHIFT));*/
attributes.cluster_size = (1 << (PAGE_SHIFT));
attributes.may_cache_object = FALSE;
attributes.temporary = TRUE;
kr = memory_object_change_attributes(
control,
MEMORY_OBJECT_ATTRIBUTE_INFO,
(memory_object_info_t) &attributes,
MEMORY_OBJECT_ATTR_INFO_COUNT);
if (kr != KERN_SUCCESS) {
panic("shared_region_pager_init: "
"memory_object_change_attributes() failed");
}
#if CONFIG_SECLUDED_MEMORY
if (secluded_for_filecache) {
#if 00
/*
* XXX FBDP do we want this in the secluded pool?
* Ideally, we'd want the shared region used by Camera to
* NOT be in the secluded pool, but all other shared regions
* in the secluded pool...
*/
memory_object_mark_eligible_for_secluded(control, TRUE);
#endif /* 00 */
}
#endif /* CONFIG_SECLUDED_MEMORY */
return KERN_SUCCESS;
}
/*
* shared_region_data_return()
*
* Handles page-out requests from VM. This should never happen since
* the pages provided by this EMM are not supposed to be dirty or dirtied
* and VM should simply discard the contents and reclaim the pages if it
* needs to.
*/
kern_return_t
shared_region_pager_data_return(
__unused memory_object_t mem_obj,
__unused memory_object_offset_t offset,
__unused memory_object_cluster_size_t data_cnt,
__unused memory_object_offset_t *resid_offset,
__unused int *io_error,
__unused boolean_t dirty,
__unused boolean_t kernel_copy,
__unused int upl_flags)
{
panic("shared_region_pager_data_return: should never get called");
return KERN_FAILURE;
}
kern_return_t
shared_region_pager_data_initialize(
__unused memory_object_t mem_obj,
__unused memory_object_offset_t offset,
__unused memory_object_cluster_size_t data_cnt)
{
panic("shared_region_pager_data_initialize: should never get called");
return KERN_FAILURE;
}
/*
* shared_region_pager_data_request()
*
* Handles page-in requests from VM.
*/
int shared_region_pager_data_request_debug = 0;
kern_return_t
shared_region_pager_data_request(
memory_object_t mem_obj,
memory_object_offset_t offset,
memory_object_cluster_size_t length,
#if !DEBUG
__unused
#endif
vm_prot_t protection_required,
memory_object_fault_info_t mo_fault_info)
{
shared_region_pager_t pager;
memory_object_control_t mo_control;
upl_t upl;
int upl_flags;
upl_size_t upl_size;
upl_page_info_t *upl_pl;
unsigned int pl_count;
vm_object_t src_top_object, src_page_object, dst_object;
kern_return_t kr, retval;
vm_offset_t src_vaddr, dst_vaddr;
vm_offset_t cur_offset;
vm_offset_t offset_in_page;
kern_return_t error_code;
vm_prot_t prot;
vm_page_t src_page, top_page;
int interruptible;
struct vm_object_fault_info fault_info;
mach_vm_offset_t slide_start_address;
u_int32_t slide_info_page_size;
PAGER_DEBUG(PAGER_ALL, ("shared_region_pager_data_request: %p, %llx, %x, %x\n", mem_obj, offset, length, protection_required));
retval = KERN_SUCCESS;
src_top_object = VM_OBJECT_NULL;
src_page_object = VM_OBJECT_NULL;
upl = NULL;
upl_pl = NULL;
fault_info = *((struct vm_object_fault_info *)(uintptr_t)mo_fault_info);
fault_info.stealth = TRUE;
fault_info.io_sync = FALSE;
fault_info.mark_zf_absent = FALSE;
fault_info.batch_pmap_op = FALSE;
interruptible = fault_info.interruptible;
pager = shared_region_pager_lookup(mem_obj);
assert(pager->srp_is_ready);
assert(os_ref_get_count_raw(&pager->srp_ref_count) > 1); /* pager is alive */
assert(pager->srp_is_mapped); /* pager is mapped */
PAGER_DEBUG(PAGER_PAGEIN, ("shared_region_pager_data_request: %p, %llx, %x, %x, pager %p\n", mem_obj, offset, length, protection_required, pager));
/*
* Gather in a UPL all the VM pages requested by VM.
*/
mo_control = pager->srp_header.mo_control;
upl_size = length;
upl_flags =
UPL_RET_ONLY_ABSENT |
UPL_SET_LITE |
UPL_NO_SYNC |
UPL_CLEAN_IN_PLACE | /* triggers UPL_CLEAR_DIRTY */
UPL_SET_INTERNAL;
pl_count = 0;
kr = memory_object_upl_request(mo_control,
offset, upl_size,
&upl, NULL, NULL, upl_flags, VM_KERN_MEMORY_SECURITY);
if (kr != KERN_SUCCESS) {
ktriage_record(thread_tid(current_thread()), KDBG_TRIAGE_EVENTID(KDBG_TRIAGE_SUBSYS_SHARED_REGION, KDBG_TRIAGE_RESERVED, KDBG_TRIAGE_SHARED_REGION_NO_UPL), 0 /* arg */);
retval = kr;
goto done;
}
dst_object = memory_object_control_to_vm_object(mo_control);
assert(dst_object != VM_OBJECT_NULL);
/*
* We'll map the original data in the kernel address space from the
* backing VM object (itself backed by the shared cache file via
* the vnode pager).
*/
src_top_object = pager->srp_backing_object;
assert(src_top_object != VM_OBJECT_NULL);
vm_object_reference(src_top_object); /* keep the source object alive */
slide_start_address = pager->srp_slide_info->si_slid_address;
slide_info_page_size = pager->srp_slide_info->si_slide_info_entry->version == 1 ? PAGE_SIZE_FOR_SR_SLIDE : pager->srp_slide_info->si_slide_info_entry->page_size;
fault_info.lo_offset += pager->srp_backing_offset;
fault_info.hi_offset += pager->srp_backing_offset;
/*
* Fill in the contents of the pages requested by VM.
*/
upl_pl = UPL_GET_INTERNAL_PAGE_LIST(upl);
pl_count = length / PAGE_SIZE;
for (cur_offset = 0;
retval == KERN_SUCCESS && cur_offset < length;
cur_offset += PAGE_SIZE) {
ppnum_t dst_pnum;
if (!upl_page_present(upl_pl, (int)(cur_offset / PAGE_SIZE))) {
/* this page is not in the UPL: skip it */
continue;
}
/*
* Map the source (dyld shared cache) page in the kernel's
* virtual address space.
* We already hold a reference on the src_top_object.
*/
retry_src_fault:
vm_object_lock(src_top_object);
vm_object_paging_begin(src_top_object);
error_code = 0;
prot = VM_PROT_READ;
src_page = VM_PAGE_NULL;
kr = vm_fault_page(src_top_object,
pager->srp_backing_offset + offset + cur_offset,
VM_PROT_READ,
FALSE,
FALSE, /* src_page not looked up */
&prot,
&src_page,
&top_page,
NULL,
&error_code,
FALSE,
&fault_info);
switch (kr) {
case VM_FAULT_SUCCESS:
break;
case VM_FAULT_RETRY:
goto retry_src_fault;
case VM_FAULT_MEMORY_SHORTAGE:
if (vm_page_wait(interruptible)) {
goto retry_src_fault;
}
ktriage_record(thread_tid(current_thread()), KDBG_TRIAGE_EVENTID(KDBG_TRIAGE_SUBSYS_SHARED_REGION, KDBG_TRIAGE_RESERVED, KDBG_TRIAGE_SHARED_REGION_PAGER_MEMORY_SHORTAGE), 0 /* arg */);
OS_FALLTHROUGH;
case VM_FAULT_INTERRUPTED:
retval = MACH_SEND_INTERRUPTED;
goto done;
case VM_FAULT_SUCCESS_NO_VM_PAGE:
/* success but no VM page: fail */
vm_object_paging_end(src_top_object);
vm_object_unlock(src_top_object);
OS_FALLTHROUGH;
case VM_FAULT_MEMORY_ERROR:
/* the page is not there ! */
if (error_code) {
retval = error_code;
} else {
retval = KERN_MEMORY_ERROR;
}
goto done;
default:
panic("shared_region_pager_data_request: "
"vm_fault_page() unexpected error 0x%x\n",
kr);
}
assert(src_page != VM_PAGE_NULL);
assert(src_page->vmp_busy);
if (src_page->vmp_q_state != VM_PAGE_ON_SPECULATIVE_Q) {
vm_page_lockspin_queues();
if (src_page->vmp_q_state != VM_PAGE_ON_SPECULATIVE_Q) {
vm_page_speculate(src_page, FALSE);
}
vm_page_unlock_queues();
}
/*
* Establish pointers to the source
* and destination physical pages.
*/
dst_pnum = (ppnum_t)
upl_phys_page(upl_pl, (int)(cur_offset / PAGE_SIZE));
assert(dst_pnum != 0);
src_vaddr = (vm_map_offset_t)
phystokv((pmap_paddr_t)VM_PAGE_GET_PHYS_PAGE(src_page)
<< PAGE_SHIFT);
dst_vaddr = (vm_map_offset_t)
phystokv((pmap_paddr_t)dst_pnum << PAGE_SHIFT);
src_page_object = VM_PAGE_OBJECT(src_page);
/*
* Validate the original page...
*/
if (src_page_object->code_signed) {
vm_page_validate_cs_mapped(
src_page, PAGE_SIZE, 0,
(const void *) src_vaddr);
}
/*
* ... and transfer the results to the destination page.
*/
UPL_SET_CS_VALIDATED(upl_pl, cur_offset / PAGE_SIZE,
src_page->vmp_cs_validated);
UPL_SET_CS_TAINTED(upl_pl, cur_offset / PAGE_SIZE,
src_page->vmp_cs_tainted);
UPL_SET_CS_NX(upl_pl, cur_offset / PAGE_SIZE,
src_page->vmp_cs_nx);
/*
* The page provider might access a mapped file, so let's
* release the object lock for the source page to avoid a
* potential deadlock.
* The source page is kept busy and we have a
* "paging_in_progress" reference on its object, so it's safe
* to unlock the object here.
*/
assert(src_page->vmp_busy);
assert(src_page_object->paging_in_progress > 0);
vm_object_unlock(src_page_object);
/*
* Process the original contents of the source page
* into the destination page.
*/
for (offset_in_page = 0;
offset_in_page < PAGE_SIZE;
offset_in_page += slide_info_page_size) {
vm_object_offset_t chunk_offset;
vm_object_offset_t offset_in_backing_object;
vm_object_offset_t offset_in_sliding_range;
chunk_offset = offset + cur_offset + offset_in_page;
bcopy((const char *)(src_vaddr +
offset_in_page),
(char *)(dst_vaddr + offset_in_page),
slide_info_page_size);
offset_in_backing_object = (chunk_offset +
pager->srp_backing_offset);
if ((offset_in_backing_object < pager->srp_slide_info->si_start) ||
(offset_in_backing_object >= pager->srp_slide_info->si_end)) {
/* chunk is outside of sliding range: done */
shared_region_pager_copied++;
continue;
}
offset_in_sliding_range = offset_in_backing_object - pager->srp_slide_info->si_start;
kr = vm_shared_region_slide_page(pager->srp_slide_info,
dst_vaddr + offset_in_page,
(mach_vm_offset_t) (offset_in_sliding_range + slide_start_address),
(uint32_t) (offset_in_sliding_range / slide_info_page_size),
#if __has_feature(ptrauth_calls)
pager->srp_slide_info->si_ptrauth ? pager->srp_jop_key : 0
#else /* __has_feature(ptrauth_calls) */
0
#endif /* __has_feature(ptrauth_calls) */
);
if (shared_region_pager_data_request_debug) {
printf("shared_region_data_request"
"(%p,0x%llx+0x%llx+0x%04llx): 0x%llx "
"in sliding range [0x%llx:0x%llx]: "
"SLIDE offset 0x%llx="
"(0x%llx+0x%llx+0x%llx+0x%04llx)"
"[0x%016llx 0x%016llx] "
"code_signed=%d "
"cs_validated=%d "
"cs_tainted=%d "
"cs_nx=%d "
"kr=0x%x\n",
pager,
offset,
(uint64_t) cur_offset,
(uint64_t) offset_in_page,
chunk_offset,
pager->srp_slide_info->si_start,
pager->srp_slide_info->si_end,
(pager->srp_backing_offset +
offset +
cur_offset +
offset_in_page),
pager->srp_backing_offset,
offset,
(uint64_t) cur_offset,
(uint64_t) offset_in_page,
*(uint64_t *)(dst_vaddr + offset_in_page),
*(uint64_t *)(dst_vaddr + offset_in_page + 8),
src_page_object->code_signed,
src_page->vmp_cs_validated,
src_page->vmp_cs_tainted,
src_page->vmp_cs_nx,
kr);
}
if (kr != KERN_SUCCESS) {
ktriage_record(thread_tid(current_thread()), KDBG_TRIAGE_EVENTID(KDBG_TRIAGE_SUBSYS_SHARED_REGION, KDBG_TRIAGE_RESERVED, KDBG_TRIAGE_SHARED_REGION_SLIDE_ERROR), 0 /* arg */);
shared_region_pager_slid_error++;
retval = KERN_MEMORY_ERROR;
break;
}
shared_region_pager_slid++;
}
assert(VM_PAGE_OBJECT(src_page) == src_page_object);
assert(src_page->vmp_busy);
assert(src_page_object->paging_in_progress > 0);
vm_object_lock(src_page_object);
/*
* Cleanup the result of vm_fault_page() of the source page.
*/
vm_page_wakeup_done(src_page_object, src_page);
src_page = VM_PAGE_NULL;
vm_object_paging_end(src_page_object);
vm_object_unlock(src_page_object);
if (top_page != VM_PAGE_NULL) {
assert(VM_PAGE_OBJECT(top_page) == src_top_object);
vm_object_lock(src_top_object);
VM_PAGE_FREE(top_page);
vm_object_paging_end(src_top_object);
vm_object_unlock(src_top_object);
}
}
done:
if (upl != NULL) {
/* clean up the UPL */
/*
* The pages are currently dirty because we've just been
* writing on them, but as far as we're concerned, they're
* clean since they contain their "original" contents as
* provided by us, the pager.
* Tell the UPL to mark them "clean".
*/
upl_clear_dirty(upl, TRUE);
/* abort or commit the UPL */
if (retval != KERN_SUCCESS) {
upl_abort(upl, 0);
} else {
boolean_t empty;
assertf(page_aligned(upl->u_offset) && page_aligned(upl->u_size),
"upl %p offset 0x%llx size 0x%x\n",
upl, upl->u_offset, upl->u_size);
upl_commit_range(upl, 0, upl->u_size,
UPL_COMMIT_CS_VALIDATED | UPL_COMMIT_WRITTEN_BY_KERNEL,
upl_pl, pl_count, &empty);
}
/* and deallocate the UPL */
upl_deallocate(upl);
upl = NULL;
}
if (src_top_object != VM_OBJECT_NULL) {
vm_object_deallocate(src_top_object);
}
return retval;
}
/*
* shared_region_pager_reference()
*
* Get a reference on this memory object.
* For external usage only. Assumes that the initial reference count is not 0,
* i.e one should not "revive" a dead pager this way.
*/
void
shared_region_pager_reference(
memory_object_t mem_obj)
{
shared_region_pager_t pager;
pager = shared_region_pager_lookup(mem_obj);
lck_mtx_lock(&shared_region_pager_lock);
os_ref_retain_locked_raw(&pager->srp_ref_count, NULL);
lck_mtx_unlock(&shared_region_pager_lock);
}
/*
* shared_region_pager_dequeue:
*
* Removes a pager from the list of pagers.
*
* The caller must hold "shared_region_pager_lock".
*/
void
shared_region_pager_dequeue(
shared_region_pager_t pager)
{
assert(!pager->srp_is_mapped);
queue_remove(&shared_region_pager_queue,
pager,
shared_region_pager_t,
srp_queue);
pager->srp_queue.next = NULL;
pager->srp_queue.prev = NULL;
shared_region_pager_count--;
}
/*
* shared_region_pager_terminate_internal:
*
* Trigger the asynchronous termination of the memory object associated
* with this pager.
* When the memory object is terminated, there will be one more call
* to memory_object_deallocate() (i.e. shared_region_pager_deallocate())
* to finish the clean up.
*
* "shared_region_pager_lock" should not be held by the caller.
* We don't need the lock because the pager has already been removed from
* the pagers' list and is now ours exclusively.
*/
void
shared_region_pager_terminate_internal(
shared_region_pager_t pager)
{
assert(pager->srp_is_ready);
assert(!pager->srp_is_mapped);
assert(os_ref_get_count_raw(&pager->srp_ref_count) == 1);
if (pager->srp_backing_object != VM_OBJECT_NULL) {
vm_object_deallocate(pager->srp_backing_object);
pager->srp_backing_object = VM_OBJECT_NULL;
}
/* trigger the destruction of the memory object */
memory_object_destroy(pager->srp_header.mo_control, VM_OBJECT_DESTROY_PAGER);
}
/*
* shared_region_pager_deallocate_internal()
*
* Release a reference on this pager and free it when the last reference goes away.
* Can be called with shared_region_pager_lock held or not, but always returns
* with it unlocked.
*/
void
shared_region_pager_deallocate_internal(
shared_region_pager_t pager,
boolean_t locked)
{
boolean_t needs_trimming;
int count_unmapped;
os_ref_count_t ref_count;
if (!locked) {
lck_mtx_lock(&shared_region_pager_lock);
}
/* if we have too many unmapped pagers, trim some */
count_unmapped = shared_region_pager_count - shared_region_pager_count_mapped;
needs_trimming = (count_unmapped > shared_region_pager_cache_limit);
/* drop a reference on this pager */
ref_count = os_ref_release_locked_raw(&pager->srp_ref_count, NULL);
if (ref_count == 1) {
/*
* Only the "named" reference is left, which means that
* no one is really holding on to this pager anymore.
* Terminate it.
*/
shared_region_pager_dequeue(pager);
/* the pager is all ours: no need for the lock now */
lck_mtx_unlock(&shared_region_pager_lock);
shared_region_pager_terminate_internal(pager);
} else if (ref_count == 0) {
/*
* Dropped the existence reference; the memory object has
* been terminated. Do some final cleanup and release the
* pager structure.
*/
lck_mtx_unlock(&shared_region_pager_lock);
vm_shared_region_slide_info_t si = pager->srp_slide_info;
#if __has_feature(ptrauth_calls)
/*
* The slide_info for auth sections lives in the shared region.
* Just deallocate() on the shared region and clear the field.
*/
if (si != NULL) {
if (si->si_shared_region != NULL) {
assert(si->si_ptrauth);
vm_shared_region_deallocate(si->si_shared_region);
pager->srp_slide_info = NULL;
si = NULL;
}
}
#endif /* __has_feature(ptrauth_calls) */
if (si != NULL) {
vm_object_deallocate(si->si_slide_object);
/* free the slide_info_entry */
kfree_data(si->si_slide_info_entry,
si->si_slide_info_size);
kfree_type(struct vm_shared_region_slide_info, si);
pager->srp_slide_info = NULL;
}
if (pager->srp_header.mo_control != MEMORY_OBJECT_CONTROL_NULL) {
memory_object_control_deallocate(pager->srp_header.mo_control);
pager->srp_header.mo_control = MEMORY_OBJECT_CONTROL_NULL;
}
kfree_type(struct shared_region_pager, pager);
pager = SHARED_REGION_PAGER_NULL;
} else {
/* there are still plenty of references: keep going... */
lck_mtx_unlock(&shared_region_pager_lock);
}
if (needs_trimming) {
shared_region_pager_trim();
}
/* caution: lock is not held on return... */
}
/*
* shared_region_pager_deallocate()
*
* Release a reference on this pager and free it when the last
* reference goes away.
*/
void
shared_region_pager_deallocate(
memory_object_t mem_obj)
{
shared_region_pager_t pager;
PAGER_DEBUG(PAGER_ALL, ("shared_region_pager_deallocate: %p\n", mem_obj));
pager = shared_region_pager_lookup(mem_obj);
shared_region_pager_deallocate_internal(pager, FALSE);
}
/*
*
*/
kern_return_t
shared_region_pager_terminate(
#if !DEBUG
__unused
#endif
memory_object_t mem_obj)
{
PAGER_DEBUG(PAGER_ALL, ("shared_region_pager_terminate: %p\n", mem_obj));
return KERN_SUCCESS;
}
/*
* shared_region_pager_map()
*
* This allows VM to let us, the EMM, know that this memory object
* is currently mapped one or more times. This is called by VM each time
* the memory object gets mapped, but we only take one extra reference the
* first time it is called.
*/
kern_return_t
shared_region_pager_map(
memory_object_t mem_obj,
__unused vm_prot_t prot)
{
shared_region_pager_t pager;
PAGER_DEBUG(PAGER_ALL, ("shared_region_pager_map: %p\n", mem_obj));
pager = shared_region_pager_lookup(mem_obj);
lck_mtx_lock(&shared_region_pager_lock);
assert(pager->srp_is_ready);
assert(os_ref_get_count_raw(&pager->srp_ref_count) > 0); /* pager is alive */
if (!pager->srp_is_mapped) {
pager->srp_is_mapped = TRUE;
os_ref_retain_locked_raw(&pager->srp_ref_count, NULL);
shared_region_pager_count_mapped++;
}
lck_mtx_unlock(&shared_region_pager_lock);
return KERN_SUCCESS;
}
/*
* shared_region_pager_last_unmap()
*
* This is called by VM when this memory object is no longer mapped anywhere.
*/
kern_return_t
shared_region_pager_last_unmap(
memory_object_t mem_obj)
{
shared_region_pager_t pager;
int count_unmapped;
PAGER_DEBUG(PAGER_ALL,
("shared_region_pager_last_unmap: %p\n", mem_obj));
pager = shared_region_pager_lookup(mem_obj);
lck_mtx_lock(&shared_region_pager_lock);
if (pager->srp_is_mapped) {
/*
* All the mappings are gone, so let go of the one extra
* reference that represents all the mappings of this pager.
*/
shared_region_pager_count_mapped--;
count_unmapped = (shared_region_pager_count - shared_region_pager_count_mapped);
if (count_unmapped > shared_region_pager_count_unmapped_max) {
shared_region_pager_count_unmapped_max = count_unmapped;
}
pager->srp_is_mapped = FALSE;
shared_region_pager_deallocate_internal(pager, TRUE);
/* caution: deallocate_internal() released the lock ! */
} else {
lck_mtx_unlock(&shared_region_pager_lock);
}
return KERN_SUCCESS;
}
boolean_t
shared_region_pager_backing_object(
memory_object_t mem_obj,
memory_object_offset_t offset,
vm_object_t *backing_object,
vm_object_offset_t *backing_offset)
{
shared_region_pager_t pager;
PAGER_DEBUG(PAGER_ALL,
("shared_region_pager_backing_object: %p\n", mem_obj));
pager = shared_region_pager_lookup(mem_obj);
*backing_object = pager->srp_backing_object;
*backing_offset = pager->srp_backing_offset + offset;
return TRUE;
}
/*
*
*/
shared_region_pager_t
shared_region_pager_lookup(
memory_object_t mem_obj)
{
shared_region_pager_t pager;
assert(mem_obj->mo_pager_ops == &shared_region_pager_ops);
pager = (shared_region_pager_t)(uintptr_t) mem_obj;
assert(os_ref_get_count_raw(&pager->srp_ref_count) > 0);
return pager;
}
/*
* Create and return a pager for the given object with the
* given slide information.
*/
static shared_region_pager_t
shared_region_pager_create(
vm_object_t backing_object,
vm_object_offset_t backing_offset,
struct vm_shared_region_slide_info *slide_info,
#if !__has_feature(ptrauth_calls)
__unused
#endif /* !__has_feature(ptrauth_calls) */
uint64_t jop_key)
{
shared_region_pager_t pager;
memory_object_control_t control;
kern_return_t kr;
vm_object_t object;
pager = kalloc_type(struct shared_region_pager, Z_WAITOK);
if (pager == SHARED_REGION_PAGER_NULL) {
return SHARED_REGION_PAGER_NULL;
}
/*
* The vm_map call takes both named entry ports and raw memory
* objects in the same parameter. We need to make sure that
* vm_map does not see this object as a named entry port. So,
* we reserve the first word in the object for a fake ip_kotype
* setting - that will tell vm_map to use it as a memory object.
*/
pager->srp_header.mo_ikot = IKOT_MEMORY_OBJECT;
pager->srp_header.mo_pager_ops = &shared_region_pager_ops;
pager->srp_header.mo_control = MEMORY_OBJECT_CONTROL_NULL;
pager->srp_is_ready = FALSE;/* not ready until it has a "name" */
/* existence reference (for the cache) + 1 for the caller */
os_ref_init_count_raw(&pager->srp_ref_count, NULL, 2);
pager->srp_is_mapped = FALSE;
pager->srp_backing_object = backing_object;
pager->srp_backing_offset = backing_offset;
pager->srp_slide_info = slide_info;
#if __has_feature(ptrauth_calls)
pager->srp_jop_key = jop_key;
/*
* If we're getting slide_info from the shared_region,
* take a reference, so it can't disappear from under us.
*/
if (slide_info->si_shared_region) {
assert(slide_info->si_ptrauth);
vm_shared_region_reference(slide_info->si_shared_region);
}
#endif /* __has_feature(ptrauth_calls) */
vm_object_reference(backing_object);
lck_mtx_lock(&shared_region_pager_lock);
/* enter new pager at the head of our list of pagers */
queue_enter_first(&shared_region_pager_queue,
pager,
shared_region_pager_t,
srp_queue);
shared_region_pager_count++;
if (shared_region_pager_count > shared_region_pager_count_max) {
shared_region_pager_count_max = shared_region_pager_count;
}
lck_mtx_unlock(&shared_region_pager_lock);
kr = memory_object_create_named((memory_object_t) pager,
0,
&control);
assert(kr == KERN_SUCCESS);
memory_object_mark_trusted(control);
lck_mtx_lock(&shared_region_pager_lock);
/* the new pager is now ready to be used */
pager->srp_is_ready = TRUE;
object = memory_object_to_vm_object((memory_object_t) pager);
assert(object);
/*
* No one knows about this object and so we get away without the object lock.
* This object is _eventually_ backed by the dyld shared cache and so we want
* to benefit from the lock priority boosting.
*/
object->object_is_shared_cache = TRUE;
lck_mtx_unlock(&shared_region_pager_lock);
/* wakeup anyone waiting for this pager to be ready */
thread_wakeup(&pager->srp_is_ready);
return pager;
}
/*
* shared_region_pager_setup()
*
* Provide the caller with a memory object backed by the provided
* "backing_object" VM object.
*/
memory_object_t
shared_region_pager_setup(
vm_object_t backing_object,
vm_object_offset_t backing_offset,
struct vm_shared_region_slide_info *slide_info,
uint64_t jop_key)
{
shared_region_pager_t pager;
/* create new pager */
pager = shared_region_pager_create(backing_object,
backing_offset, slide_info, jop_key);
if (pager == SHARED_REGION_PAGER_NULL) {
/* could not create a new pager */
return MEMORY_OBJECT_NULL;
}
lck_mtx_lock(&shared_region_pager_lock);
while (!pager->srp_is_ready) {
lck_mtx_sleep(&shared_region_pager_lock,
LCK_SLEEP_DEFAULT,
&pager->srp_is_ready,
THREAD_UNINT);
}
lck_mtx_unlock(&shared_region_pager_lock);
return (memory_object_t) pager;
}
#if __has_feature(ptrauth_calls)
/*
* shared_region_pager_match()
*
* Provide the caller with a memory object backed by the provided
* "backing_object" VM object.
*/
memory_object_t
shared_region_pager_match(
vm_object_t backing_object,
vm_object_offset_t backing_offset,
vm_shared_region_slide_info_t slide_info,
uint64_t jop_key)
{
shared_region_pager_t pager;
vm_shared_region_slide_info_t si;
lck_mtx_lock(&shared_region_pager_lock);
queue_iterate(&shared_region_pager_queue, pager, shared_region_pager_t, srp_queue) {
if (pager->srp_backing_object != backing_object->vo_copy) {
continue;
}
if (pager->srp_backing_offset != backing_offset) {
continue;
}
si = pager->srp_slide_info;
/* If there's no AUTH section then it can't match (slide_info is always !NULL) */
if (!si->si_ptrauth) {
continue;
}
if (pager->srp_jop_key != jop_key) {
continue;
}
if (si->si_slide != slide_info->si_slide) {
continue;
}
if (si->si_start != slide_info->si_start) {
continue;
}
if (si->si_end != slide_info->si_end) {
continue;
}
if (si->si_slide_object != slide_info->si_slide_object) {
continue;
}
if (si->si_slide_info_size != slide_info->si_slide_info_size) {
continue;
}
if (memcmp(si->si_slide_info_entry, slide_info->si_slide_info_entry, si->si_slide_info_size) != 0) {
continue;
}
/* the caller expects a reference on this */
os_ref_retain_locked_raw(&pager->srp_ref_count, NULL);
lck_mtx_unlock(&shared_region_pager_lock);
return (memory_object_t)pager;
}
/*
* We didn't find a pre-existing pager, so create one.
*
* Note slight race condition here since we drop the lock. This could lead to more than one
* thread calling setup with the same arguments here. That shouldn't break anything, just
* waste a little memory.
*/
lck_mtx_unlock(&shared_region_pager_lock);
return shared_region_pager_setup(backing_object->vo_copy, backing_offset, slide_info, jop_key);
}
void
shared_region_pager_match_task_key(memory_object_t memobj, __unused task_t task)
{
__unused shared_region_pager_t pager = (shared_region_pager_t)memobj;
assert(pager->srp_jop_key == task->jop_pid);
}
#endif /* __has_feature(ptrauth_calls) */
void
shared_region_pager_trim(void)
{
shared_region_pager_t pager, prev_pager;
queue_head_t trim_queue;
int num_trim;
int count_unmapped;
lck_mtx_lock(&shared_region_pager_lock);
/*
* We have too many pagers, try and trim some unused ones,
* starting with the oldest pager at the end of the queue.
*/
queue_init(&trim_queue);
num_trim = 0;
for (pager = (shared_region_pager_t)queue_last(&shared_region_pager_queue);
!queue_end(&shared_region_pager_queue, (queue_entry_t) pager);
pager = prev_pager) {
/* get prev elt before we dequeue */
prev_pager = (shared_region_pager_t)queue_prev(&pager->srp_queue);
if (os_ref_get_count_raw(&pager->srp_ref_count) == 2 &&
pager->srp_is_ready &&
!pager->srp_is_mapped) {
/* this pager can be trimmed */
num_trim++;
/* remove this pager from the main list ... */
shared_region_pager_dequeue(pager);
/* ... and add it to our trim queue */
queue_enter_first(&trim_queue,
pager,
shared_region_pager_t,
srp_queue);
/* do we have enough pagers to trim? */
count_unmapped = (shared_region_pager_count - shared_region_pager_count_mapped);
if (count_unmapped <= shared_region_pager_cache_limit) {
break;
}
}
}
if (num_trim > shared_region_pager_num_trim_max) {
shared_region_pager_num_trim_max = num_trim;
}
shared_region_pager_num_trim_total += num_trim;
lck_mtx_unlock(&shared_region_pager_lock);
/* terminate the trimmed pagers */
while (!queue_empty(&trim_queue)) {
queue_remove_first(&trim_queue,
pager,
shared_region_pager_t,
srp_queue);
pager->srp_queue.next = NULL;
pager->srp_queue.prev = NULL;
assert(os_ref_get_count_raw(&pager->srp_ref_count) == 2);
/*
* We can't call deallocate_internal() because the pager
* has already been dequeued, but we still need to remove
* a reference.
*/
(void)os_ref_release_locked_raw(&pager->srp_ref_count, NULL);
shared_region_pager_terminate_internal(pager);
}
}
static uint64_t
shared_region_pager_purge(
shared_region_pager_t pager)
{
uint64_t pages_purged;
vm_object_t object;
pages_purged = 0;
object = memory_object_to_vm_object((memory_object_t) pager);
assert(object != VM_OBJECT_NULL);
vm_object_lock(object);
pages_purged = object->resident_page_count;
vm_object_reap_pages(object, REAP_DATA_FLUSH);
pages_purged -= object->resident_page_count;
// printf(" %s:%d pager %p object %p purged %llu left %d\n", __FUNCTION__, __LINE__, pager, object, pages_purged, object->resident_page_count);
vm_object_unlock(object);
return pages_purged;
}
uint64_t
shared_region_pager_purge_all(void)
{
uint64_t pages_purged;
shared_region_pager_t pager;
pages_purged = 0;
lck_mtx_lock(&shared_region_pager_lock);
queue_iterate(&shared_region_pager_queue, pager, shared_region_pager_t, srp_queue) {
pages_purged += shared_region_pager_purge(pager);
}
lck_mtx_unlock(&shared_region_pager_lock);
#if DEVELOPMENT || DEBUG
printf(" %s:%d pages purged: %llu\n", __FUNCTION__, __LINE__, pages_purged);
#endif /* DEVELOPMENT || DEBUG */
return pages_purged;
}