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author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2021-03-11 14:09:56 +0000 |
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committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2021-03-26 11:03:06 +0000 |
commit | 8ae909a533b12221c3fd0c2331b13d99d9790718 (patch) | |
tree | 139dd8b6670e894ab1aa576cbbbf5b33d2484df7 | |
parent | 42cc96066b22ba065db11096c78881a55e45def4 (diff) | |
download | glibc-8ae909a533b12221c3fd0c2331b13d99d9790718.tar.gz glibc-8ae909a533b12221c3fd0c2331b13d99d9790718.tar.xz glibc-8ae909a533b12221c3fd0c2331b13d99d9790718.zip |
malloc: Fix a potential realloc issue with memory tagging
At an _int_free call site in realloc the wrong size was used for tag clearing: the chunk header of the next chunk was also cleared which in practice may work, but logically wrong. The tag clearing is moved before the memcpy to save a tag computation, this avoids a chunk2mem. Another chunk2mem is removed because newmem does not have to be recomputed. Whitespaces got fixed too. Reviewed-by: DJ Delorie <dj@redhat.com>
-rw-r--r-- | malloc/malloc.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index 9d9f7b918a..eae000b87e 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -4851,14 +4851,14 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, } else { - void *oldmem = chunk2mem (oldp); + void *oldmem = chunk2rawmem (oldp); + size_t sz = CHUNK_AVAILABLE_SIZE (oldp) - CHUNK_HDR_SZ; + (void) TAG_REGION (oldmem, sz); newmem = TAG_NEW_USABLE (newmem); - memcpy (newmem, oldmem, - CHUNK_AVAILABLE_SIZE (oldp) - CHUNK_HDR_SZ); - (void) TAG_REGION (chunk2rawmem (oldp), oldsize); - _int_free (av, oldp, 1); - check_inuse_chunk (av, newp); - return chunk2mem (newp); + memcpy (newmem, oldmem, sz); + _int_free (av, oldp, 1); + check_inuse_chunk (av, newp); + return newmem; } } } |