/*
* Copyright (c) 2009-2020 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 <mach_assert.h>
#include <sys/errno.h>
#include <i386/param.h>
#include <i386/misc_protos.h>
#include <i386/cpu_data.h>
#include <i386/machine_cpu.h>
#include <i386/machine_routines.h>
#include <i386/cpuid.h>
#include <i386/vmx.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_fault.h>
#include <san/kasan.h>
#include <sys/kdebug.h>
#include <kern/copyout_shim.h>
#include <kern/zalloc_internal.h>
#undef copyin
#undef copyout
static int copyio(int, user_addr_t, char *, vm_size_t, vm_size_t *, int);
static int copyio_phys(addr64_t, addr64_t, vm_size_t, int);
/*
* Copy sizes bigger than this value will cause a kernel panic.
*
* Yes, this is an arbitrary fixed limit, but it's almost certainly
* a programming error to be copying more than this amount between
* user and wired kernel memory in a single invocation on this
* platform.
*/
const int copysize_limit_panic = (64 * MB);
/*
* The copy engine has the following characteristics
* - copyio() handles copies to/from user or kernel space
* - copypv() deals with physical or virtual addresses
*
* Readers familiar with the 32-bit kernel will expect Joe's thesis at this
* point describing the full glory of the copy window implementation. In K64,
* however, there is no need for windowing. Thanks to the vast shared address
* space, the kernel has direct access to userspace and to physical memory.
*
* User virtual addresses are accessible provided the user's cr3 is loaded.
* Physical addresses are accessible via the direct map and the PHYSMAP_PTOV()
* translation.
*
* Copyin/out variants all boil done to just these 2 routines in locore.s which
* provide fault-recoverable copying:
*/
extern int _bcopy(const void *, void *, vm_size_t);
extern int _bcopystr(const void *, void *, vm_size_t, vm_size_t *);
extern int _copyin_atomic32(const char *src, uint32_t *dst);
extern int _copyin_atomic64(const char *src, uint64_t *dst);
extern int _copyout_atomic32(const uint32_t *u32, char *src);
extern int _copyout_atomic64(const uint64_t *u64, char *src);
/*
* Types of copies:
*/
#define COPYIN 0 /* from user virtual to kernel virtual */
#define COPYOUT 1 /* from kernel virtual to user virtual */
#define COPYINSTR 2 /* string variant of copyout */
#define COPYINPHYS 3 /* from user virtual to kernel physical */
#define COPYOUTPHYS 4 /* from kernel physical to user virtual */
#define COPYINATOMIC32 5 /* from user virtual to kernel virtual */
#define COPYINATOMIC64 6 /* from user virtual to kernel virtual */
#define COPYOUTATOMIC32 7 /* from user virtual to kernel virtual */
#define COPYOUTATOMIC64 8 /* from user virtual to kernel virtual */
#if ENABLE_SMAPLOG
typedef struct {
uint64_t timestamp;
thread_t thread;
uintptr_t cr4;
uint8_t cpuid;
uint8_t smap_state;
uint8_t copyio_active;
} smaplog_entry_t;
#define SMAPLOG_BUFFER_SIZE (50)
static smaplog_entry_t smaplog_cbuf[SMAPLOG_BUFFER_SIZE];
static uint32_t smaplog_head = 0;
static void
smaplog_add_entry(boolean_t enabling)
{
uint32_t index = 0;
thread_t thread = current_thread();
do {
index = smaplog_head;
} while (!OSCompareAndSwap(index, (index + 1) % SMAPLOG_BUFFER_SIZE, &smaplog_head));
assert(index < SMAPLOG_BUFFER_SIZE);
assert(smaplog_head < SMAPLOG_BUFFER_SIZE);
assert(thread);
smaplog_cbuf[index].timestamp = mach_absolute_time();
smaplog_cbuf[index].thread = thread;
smaplog_cbuf[index].cpuid = cpu_number();
smaplog_cbuf[index].cr4 = get_cr4();
smaplog_cbuf[index].smap_state = enabling;
smaplog_cbuf[index].copyio_active = (thread->machine.specFlags & CopyIOActive) ? 1 : 0;
}
#endif /* ENABLE_SMAPLOG */
extern boolean_t pmap_smap_enabled;
static inline void
user_access_enable(void)
{
if (pmap_smap_enabled) {
stac();
#if ENABLE_SMAPLOG
smaplog_add_entry(TRUE);
#endif
}
}
static inline void
user_access_disable(void)
{
if (pmap_smap_enabled) {
clac();
#if ENABLE_SMAPLOG
smaplog_add_entry(FALSE);
#endif
}
}
#if COPYIO_TRACE_ENABLED
#define COPYIO_TRACE(x, a, b, c, d, e) KERNEL_DEBUG_CONSTANT(x, a, b, c, d, e)
#else
#define COPYIO_TRACE(x, a, b, c, d, e) do { } while(0)
#endif
static int
copyio(int copy_type, user_addr_t user_addr, char *kernel_addr,
vm_size_t nbytes, vm_size_t *lencopied, int use_kernel_map)
{
thread_t thread = current_thread();
pmap_t pmap;
vm_size_t bytes_copied;
int error = 0;
boolean_t istate = FALSE;
boolean_t recursive_CopyIOActive;
#if COPYIO_TRACE_ENABLED
int debug_type = 0xeff70010;
debug_type += (copy_type << 2);
#endif
if (__improbable(nbytes > copysize_limit_panic)) {
panic("%s(%p, %p, %lu) - transfer too large", __func__,
(void *)user_addr, (void *)kernel_addr, nbytes);
}
COPYIO_TRACE(debug_type | DBG_FUNC_START,
user_addr, kernel_addr, nbytes, use_kernel_map, 0);
if (__improbable(nbytes == 0)) {
goto out;
}
pmap = thread->map->pmap;
boolean_t nopagezero = thread->map->pmap->pagezero_accessible;
if ((copy_type != COPYINPHYS) && (copy_type != COPYOUTPHYS)) {
if (__improbable((vm_offset_t)kernel_addr < VM_MIN_KERNEL_AND_KEXT_ADDRESS)) {
panic("Invalid copy parameter, copy type: %d, kernel address: %p", copy_type, kernel_addr);
}
zone_element_bounds_check((vm_offset_t)kernel_addr, nbytes);
}
/* Sanity and security check for addresses to/from a user */
if (__improbable(((pmap != kernel_pmap) && (use_kernel_map == 0)) &&
((nbytes && (user_addr + nbytes <= user_addr)) || ((user_addr + nbytes) > vm_map_max(thread->map))))) {
error = EFAULT;
goto out;
}
if (copy_type >= COPYINATOMIC32 && copy_type <= COPYOUTATOMIC64) {
if (__improbable(pmap == kernel_pmap)) {
error = EFAULT;
goto out;
}
}
#if KASAN
switch (copy_type) {
case COPYIN:
case COPYINSTR:
case COPYINATOMIC32:
case COPYINATOMIC64:
__asan_storeN((uptr)kernel_addr, nbytes);
break;
case COPYOUT:
case COPYOUTATOMIC32:
case COPYOUTATOMIC64:
__asan_loadN((uptr)kernel_addr, nbytes);
break;
}
#endif
/*
* If the no_shared_cr3 boot-arg is set (true), the kernel runs on
* its own pmap and cr3 rather than the user's -- so that wild accesses
* from kernel or kexts can be trapped. So, during copyin and copyout,
* we need to switch back to the user's map/cr3. The thread is flagged
* "CopyIOActive" at this time so that if the thread is pre-empted,
* we will later restore the correct cr3.
*/
recursive_CopyIOActive = thread->machine.specFlags & CopyIOActive;
boolean_t pdswitch = no_shared_cr3 || nopagezero;
if (__improbable(pdswitch)) {
istate = ml_set_interrupts_enabled(FALSE);
if (nopagezero && pmap_pcid_ncpus) {
pmap_pcid_activate(pmap, cpu_number(), TRUE, TRUE);
} else if (get_cr3_base() != pmap->pm_cr3) {
set_cr3_raw(pmap->pm_cr3);
}
thread->machine.specFlags |= CopyIOActive;
} else {
thread->machine.specFlags |= CopyIOActive;
}
user_access_enable();
#if DEVELOPMENT || DEBUG
/*
* Ensure that we're running on the target thread's cr3.
*/
if ((pmap != kernel_pmap) && !use_kernel_map &&
(get_cr3_base() != pmap->pm_cr3)) {
panic("copyio(%d,%p,%p,%ld,%p,%d) cr3 is %p expects %p",
copy_type, (void *)user_addr, kernel_addr, nbytes, lencopied, use_kernel_map,
(void *) get_cr3_raw(), (void *) pmap->pm_cr3);
}
#endif
if (__improbable(pdswitch)) {
(void) ml_set_interrupts_enabled(istate);
}
COPYIO_TRACE(0xeff70044 | DBG_FUNC_NONE, user_addr,
kernel_addr, nbytes, 0, 0);
switch (copy_type) {
case COPYIN:
error = _bcopy((const void *) user_addr,
kernel_addr,
nbytes);
break;
case COPYOUT:
error = _bcopy(kernel_addr,
(void *) user_addr,
nbytes);
break;
case COPYINPHYS:
error = _bcopy((const void *) user_addr,
PHYSMAP_PTOV(kernel_addr),
nbytes);
break;
case COPYOUTPHYS:
error = _bcopy((const void *) PHYSMAP_PTOV(kernel_addr),
(void *) user_addr,
nbytes);
break;
case COPYINATOMIC32:
error = _copyin_atomic32((const void *) user_addr,
(void *) kernel_addr);
break;
case COPYINATOMIC64:
error = _copyin_atomic64((const void *) user_addr,
(void *) kernel_addr);
break;
case COPYOUTATOMIC32:
error = _copyout_atomic32((const void *) kernel_addr,
(void *) user_addr);
break;
case COPYOUTATOMIC64:
error = _copyout_atomic64((const void *) kernel_addr,
(void *) user_addr);
break;
case COPYINSTR:
error = _bcopystr((const void *) user_addr,
kernel_addr,
(int) nbytes,
&bytes_copied);
/*
* lencopied should be updated on success
* or ENAMETOOLONG... but not EFAULT
*/
if (error != EFAULT) {
*lencopied = bytes_copied;
}
if (error) {
#if KDEBUG
nbytes = *lencopied;
#endif
break;
}
if (*(kernel_addr + bytes_copied - 1) == 0) {
/*
* we found a NULL terminator... we're done
*/
#if KDEBUG
nbytes = *lencopied;
#endif
break;
} else {
/*
* no more room in the buffer and we haven't
* yet come across a NULL terminator
*/
#if KDEBUG
nbytes = *lencopied;
#endif
error = ENAMETOOLONG;
break;
}
}
user_access_disable();
if (__improbable(pdswitch)) {
istate = ml_set_interrupts_enabled(FALSE);
if (!recursive_CopyIOActive && (get_cr3_raw() != kernel_pmap->pm_cr3)) {
if (nopagezero && pmap_pcid_ncpus) {
pmap_pcid_activate(pmap, cpu_number(), TRUE, FALSE);
} else {
set_cr3_raw(kernel_pmap->pm_cr3);
}
}
if (!recursive_CopyIOActive) {
thread->machine.specFlags &= ~CopyIOActive;
}
(void) ml_set_interrupts_enabled(istate);
} else if (!recursive_CopyIOActive) {
thread->machine.specFlags &= ~CopyIOActive;
}
out:
COPYIO_TRACE(debug_type | DBG_FUNC_END, user_addr, kernel_addr, nbytes, error, 0);
return error;
}
static int
copyio_phys(addr64_t source, addr64_t sink, vm_size_t csize, int which)
{
char *paddr;
user_addr_t vaddr;
int ctype;
if (which & cppvPsnk) {
paddr = (char *)sink;
vaddr = (user_addr_t)source;
ctype = COPYINPHYS;
} else {
paddr = (char *)source;
vaddr = (user_addr_t)sink;
ctype = COPYOUTPHYS;
CALL_COPYOUT_SHIM_PHYS((void *)PHYSMAP_PTOV(source), sink, csize)
}
return copyio(ctype, vaddr, paddr, csize, NULL, which & cppvKmap);
}
int
copyinmsg(const user_addr_t user_addr, char *kernel_addr, mach_msg_size_t nbytes)
{
return copyio(COPYIN, user_addr, kernel_addr, nbytes, NULL, 0);
}
int
copyin(const user_addr_t user_addr, void *kernel_addr, vm_size_t nbytes)
{
return copyio(COPYIN, user_addr, kernel_addr, nbytes, NULL, 0);
}
/*
* copy{in,out}_atomic{32,64}
* Read or store an aligned value from userspace as a single memory transaction.
* These functions support userspace synchronization features
*/
int
copyin_atomic32(const user_addr_t user_addr, uint32_t *kernel_addr)
{
/* Test alignment */
if (user_addr & 3) {
return EINVAL;
}
return copyio(COPYINATOMIC32, user_addr, (char *)(uintptr_t)kernel_addr, 4, NULL, 0);
}
int
copyin_atomic32_wait_if_equals(const user_addr_t user_addr, uint32_t value)
{
uint32_t u32;
int result = copyin_atomic32(user_addr, &u32);
if (__improbable(result)) {
return result;
}
if (u32 != value) {
return ESTALE;
}
cpu_pause();
return 0;
}
int
copyin_atomic64(const user_addr_t user_addr, uint64_t *kernel_addr)
{
/* Test alignment */
if (user_addr & 7) {
return EINVAL;
}
return copyio(COPYINATOMIC64, user_addr, (char *)(uintptr_t)kernel_addr, 8, NULL, 0);
}
int
copyout_atomic32(uint32_t value, user_addr_t user_addr)
{
/* Test alignment */
if (user_addr & 3) {
return EINVAL;
}
return copyio(COPYOUTATOMIC32, user_addr, (char *)&value, 4, NULL, 0);
}
int
copyout_atomic64(uint64_t value, user_addr_t user_addr)
{
/* Test alignment */
if (user_addr & 7) {
return EINVAL;
}
return copyio(COPYOUTATOMIC64, user_addr, (char *)&value, 8, NULL, 0);
}
int
copyinstr(const user_addr_t user_addr, char *kernel_addr, vm_size_t nbytes, vm_size_t *lencopied)
{
*lencopied = 0;
return copyio(COPYINSTR, user_addr, kernel_addr, nbytes, lencopied, 0);
}
int
copyoutmsg(const char *kernel_addr, user_addr_t user_addr, mach_msg_size_t nbytes)
{
CALL_COPYOUT_SHIM_MSG(kernel_addr, user_addr, (vm_size_t)nbytes)
return copyio(COPYOUT, user_addr, (char *)(uintptr_t)kernel_addr, nbytes, NULL, 0);
}
int
copyout(const void *kernel_addr, user_addr_t user_addr, vm_size_t nbytes)
{
CALL_COPYOUT_SHIM_NRML(kernel_addr, user_addr, nbytes)
return copyio(COPYOUT, user_addr, (char *)(uintptr_t)kernel_addr, nbytes, NULL, 0);
}
#if (DEBUG || DEVELOPMENT)
int
verify_write(const void *source, void *dst, size_t size)
{
int rc;
disable_preemption();
rc = _bcopy((const char*)source, (char*)dst, size);
enable_preemption();
return rc;
}
#endif
kern_return_t
copypv(addr64_t src64, addr64_t snk64, unsigned int size, int which)
{
unsigned int lop, csize;
int bothphys = 0;
KERNEL_DEBUG(0xeff7004c | DBG_FUNC_START, (unsigned)src64,
(unsigned)snk64, size, which, 0);
if ((which & (cppvPsrc | cppvPsnk)) == 0) { /* Make sure that only one is virtual */
panic("copypv: no more than 1 parameter may be virtual"); /* Not allowed */
}
if ((which & (cppvPsrc | cppvPsnk)) == (cppvPsrc | cppvPsnk)) {
bothphys = 1; /* both are physical */
}
while (size) {
if (bothphys) {
lop = (unsigned int)(PAGE_SIZE - (snk64 & (PAGE_SIZE - 1))); /* Assume sink smallest */
if (lop > (unsigned int)(PAGE_SIZE - (src64 & (PAGE_SIZE - 1)))) {
lop = (unsigned int)(PAGE_SIZE - (src64 & (PAGE_SIZE - 1))); /* No, source is smaller */
}
} else {
/*
* only need to compute the resid for the physical page
* address... we don't care about where we start/finish in
* the virtual since we just call the normal copyin/copyout
*/
if (which & cppvPsrc) {
lop = (unsigned int)(PAGE_SIZE - (src64 & (PAGE_SIZE - 1)));
} else {
lop = (unsigned int)(PAGE_SIZE - (snk64 & (PAGE_SIZE - 1)));
}
}
csize = size; /* Assume we can copy it all */
if (lop < size) {
csize = lop; /* Nope, we can't do it all */
}
#if 0
/*
* flush_dcache64 is currently a nop on the i386...
* it's used when copying to non-system memory such
* as video capture cards... on PPC there was a need
* to flush due to how we mapped this memory... not
* sure if it's needed on i386.
*/
if (which & cppvFsrc) {
flush_dcache64(src64, csize, 1); /* If requested, flush source before move */
}
if (which & cppvFsnk) {
flush_dcache64(snk64, csize, 1); /* If requested, flush sink before move */
}
#endif
if (bothphys) {
bcopy_phys(src64, snk64, csize); /* Do a physical copy, virtually */
} else {
if (copyio_phys(src64, snk64, csize, which)) {
return KERN_FAILURE;
}
}
#if 0
if (which & cppvFsrc) {
flush_dcache64(src64, csize, 1); /* If requested, flush source after move */
}
if (which & cppvFsnk) {
flush_dcache64(snk64, csize, 1); /* If requested, flush sink after move */
}
#endif
size -= csize; /* Calculate what is left */
snk64 += csize; /* Bump sink to next physical address */
src64 += csize; /* Bump source to next physical address */
}
KERNEL_DEBUG(0xeff7004c | DBG_FUNC_END, (unsigned)src64,
(unsigned)snk64, size, which, 0);
return KERN_SUCCESS;
}