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| author | Istvan Kurucsai <pistukem@gmail.com> | 2018-12-21 00:13:01 -0500 |
|---|---|---|
| committer | DJ Delorie <dj@delorie.com> | 2018-12-21 00:15:28 -0500 |
| commit | c0e82f117357a941e4d40fcc08babbd6a3c3a1b5 (patch) | |
| tree | e3a3be7a006a17335f648af7b08b8f14f9fca90a | |
| parent | ebe544bf6e8eec35e754fd49efb027c6f161b6cb (diff) | |
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malloc: Check the alignment of mmapped chunks before unmapping.
* malloc/malloc.c (munmap_chunk): Verify chunk alignment.
| -rw-r--r-- | ChangeLog | 4 | ||||
| -rw-r--r-- | malloc/malloc.c | 5 |
2 files changed, 8 insertions, 1 deletions
@@ -1,3 +1,7 @@ +2018-12-21 Istvan Kurucsai <pistukem@gmail.com> + + * malloc/malloc.c (munmap_chunk): Verify chunk alignment. + 2018-12-20 Istvan Kurucsai <pistukem@gmail.com> * malloc/malloc.c (mremap_chunk): Additional checks. diff --git a/malloc/malloc.c b/malloc/malloc.c index 32d47f083c..c33709e966 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -2889,6 +2889,7 @@ systrim (size_t pad, mstate av) static void munmap_chunk (mchunkptr p) { + size_t pagesize = GLRO (dl_pagesize); INTERNAL_SIZE_T size = chunksize (p); assert (chunk_is_mmapped (p)); @@ -2898,6 +2899,7 @@ munmap_chunk (mchunkptr p) if (DUMPED_MAIN_ARENA_CHUNK (p)) return; + uintptr_t mem = (uintptr_t) chunk2mem (p); uintptr_t block = (uintptr_t) p - prev_size (p); size_t total_size = prev_size (p) + size; /* Unfortunately we have to do the compilers job by hand here. Normally @@ -2905,7 +2907,8 @@ munmap_chunk (mchunkptr p) page size. But gcc does not recognize the optimization possibility (in the moment at least) so we combine the two values into one before the bit test. */ - if (__builtin_expect (((block | total_size) & (GLRO (dl_pagesize) - 1)) != 0, 0)) + if (__glibc_unlikely ((block | total_size) & (pagesize - 1)) != 0 + || __glibc_unlikely (!powerof2 (mem & (pagesize - 1)))) malloc_printerr ("munmap_chunk(): invalid pointer"); atomic_decrement (&mp_.n_mmaps); |