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author | Zeex <zeex@rocketmail.com> | 2021-12-19 14:39:14 +0600 |
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committer | GitHub <noreply@github.com> | 2021-12-19 14:39:14 +0600 |
commit | 8de6fdbaca68eb5f0adfbb560498481d511bdaee (patch) | |
tree | 4574b7aae5e2dda9e9f9e8b76ca219b59a12690e | |
parent | 86c102f28fb7f3b396f6879bd6ee8f8bb0199c9e (diff) | |
parent | 9d1ba393ae200bb7a4286997d4f6bddc014616b0 (diff) | |
download | subhook-8de6fdbaca68eb5f0adfbb560498481d511bdaee.zip subhook-8de6fdbaca68eb5f0adfbb560498481d511bdaee.tar.gz subhook-8de6fdbaca68eb5f0adfbb560498481d511bdaee.tar.bz2 |
Merge pull request #64 from ZNixian/page-boundary-unprotect
unix: Fix unprotecting memory across a page boundary
-rw-r--r-- | subhook_unix.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/subhook_unix.c b/subhook_unix.c index 4d9c03a..697974d 100644 --- a/subhook_unix.c +++ b/subhook_unix.c @@ -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; |