diff options
Diffstat (limited to 'utils/libdislocator')
| -rw-r--r-- | utils/libdislocator/README.md | 2 | ||||
| -rw-r--r-- | utils/libdislocator/libdislocator.so.c | 8 |
2 files changed, 6 insertions, 4 deletions
diff --git a/utils/libdislocator/README.md b/utils/libdislocator/README.md index 1785463e..d0340af0 100644 --- a/utils/libdislocator/README.md +++ b/utils/libdislocator/README.md @@ -1,6 +1,6 @@ # libdislocator, an abusive allocator - (See ../README.md for the general instruction manual.) + (See ../../README.md for the general instruction manual.) This is a companion library that can be used as a drop-in replacement for the libc allocator in the fuzzed binaries. It improves the odds of bumping into diff --git a/utils/libdislocator/libdislocator.so.c b/utils/libdislocator/libdislocator.so.c index 2324e390..c2b200cb 100644 --- a/utils/libdislocator/libdislocator.so.c +++ b/utils/libdislocator/libdislocator.so.c @@ -345,10 +345,10 @@ void free(void *ptr) { len = PTR_L(ptr); total_mem -= len; + u8 * ptr_ = ptr; if (align_allocations && (len & (ALLOC_ALIGN_SIZE - 1))) { - u8 * ptr_ = ptr; size_t rlen = (len & ~(ALLOC_ALIGN_SIZE - 1)) + ALLOC_ALIGN_SIZE; for (; len < rlen; ++len) if (ptr_[len] != TAIL_ALLOC_CANARY) @@ -359,11 +359,13 @@ void free(void *ptr) { /* Protect everything. Note that the extra page at the end is already set as PROT_NONE, so we don't need to touch that. */ - ptr -= PAGE_SIZE * PG_COUNT(len + 8) - len - 8; + ptr_ -= PAGE_SIZE * PG_COUNT(len + 8) - len - 8; - if (mprotect(ptr - 8, PG_COUNT(len + 8) * PAGE_SIZE, PROT_NONE)) + if (mprotect(ptr_ - 8, PG_COUNT(len + 8) * PAGE_SIZE, PROT_NONE)) FATAL("mprotect() failed when freeing memory"); + ptr = ptr_; + /* Keep the mapping; this is wasteful, but prevents ptr reuse. */ } |