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Merge pull request #64 from ZNixian/page-boundary-unprotect

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unix: Fix unprotecting memory across a page boundary
This commit is contained in:
Zeex
2021-12-19 14:39:14 +06:00
committed by GitHub
parent 86c102f28f 9d1ba393ae
commit 8de6fdbaca
1 changed files with 8 additions and 3 deletions
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11
subhook_unix.c
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@@ -39,14 +39,19 @@ int subhook_unprotect(void *address, size_t size) {
long pagesize;
pagesize = sysconf(_SC_PAGESIZE);
address = (void *)((long)address & ~(pagesize - 1));
void *aligned_address = (void *)((long)address & ~(pagesize - 1));
int error = mprotect(address, size, SUBHOOK_CODE_PROTECT_FLAGS);
// Fix up the length - since we rounded the start address off, if a jump is right at the
// end of a page we could need to unprotect both.
void *end = address + size;
size_t new_size = end - aligned_address;
int error = mprotect(aligned_address, new_size, SUBHOOK_CODE_PROTECT_FLAGS);
#ifdef SUBHOOK_APPLE
if (-1 == error)
{
/* If mprotect fails, try to use VM_PROT_COPY with vm_protect. */
kern_return_t kret = vm_protect(mach_task_self(), (unsigned long)address, size, 0, SUBHOOK_CODE_PROTECT_FLAGS | VM_PROT_COPY);
kern_return_t kret = vm_protect(mach_task_self(), (unsigned long)aligned_address, new_size, 0, SUBHOOK_CODE_PROTECT_FLAGS | VM_PROT_COPY);
if (kret != KERN_SUCCESS)
{
error = -1;