jmb/hardened_malloc
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Merge 96836f463b into 3ab23f7ebf

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cgzones 2025-01-29 11:58:09 -05:00 • committed by GitHub
commit 6c3a6a3070
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3 changed files with 24 additions and 0 deletions
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5
h_malloc.c
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@ -1295,7 +1295,12 @@ COLD static void init_slow_path(void) {
atomic_store_explicit(&ro.slab_region_end, slab_region_end, memory_order_release);
#if defined(__ANDROID__) && defined(HAS_ARM_MTE)
/* Do not seal to support disabling memory tagging */
if (unlikely(memory_protect_ro(&ro, sizeof(ro)))) {
#else
if (unlikely(memory_protect_seal(&ro, sizeof(ro)))) {
#endif
fatal_error("failed to protect allocator data");
}
memory_set_name(&ro, sizeof(ro), "malloc read-only after init");

18
memory.c
View file

@ -1,6 +1,8 @@
#include <errno.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#ifdef LABEL_MEMORY
#include <sys/prctl.h>
@ -91,6 +93,22 @@ bool memory_protect_rw_metadata(void *ptr, size_t size) {
return memory_protect_prot(ptr, size, PROT_READ|PROT_WRITE, get_metadata_key());
}
COLD bool memory_protect_seal(void *ptr, size_t size) {
#if defined(__linux__) && defined(__NR_mseal)
/* supported since Linux 6.10 */
int ret = syscall(__NR_mseal, ptr, size, 0);
if (ret == 0)
return false;
if (unlikely(errno == ENOMEM))
return true;
if (errno == ENOSYS)
return memory_protect_ro(ptr, size);
fatal_error("non-ENOMEM and non-ENOSYS mseal failure");
#else
return memory_protect_ro(ptr, size);
#endif
}
#ifdef HAVE_COMPATIBLE_MREMAP
bool memory_remap(void *old, size_t old_size, size_t new_size) {
void *ptr = mremap(old, old_size, new_size, 0);

1
memory.h
View file

@ -22,6 +22,7 @@ bool memory_unmap(void *ptr, size_t size);
bool memory_protect_ro(void *ptr, size_t size);
bool memory_protect_rw(void *ptr, size_t size);
bool memory_protect_rw_metadata(void *ptr, size_t size);
bool memory_protect_seal(void *ptr, size_t size);
#ifdef HAVE_COMPATIBLE_MREMAP
bool memory_remap(void *old, size_t old_size, size_t new_size);
bool memory_remap_fixed(void *old, size_t old_size, void *new, size_t new_size);