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| author | Florian Weimer <fw@deneb.enyo.de> | 2018-12-31 22:04:36 +0100 |
|---|---|---|
| committer | Florian Weimer <fw@deneb.enyo.de> | 2018-12-31 22:09:37 +0100 |
| commit | b50dd3bc8cbb1efe85399b03d7e6c0310c2ead84 (patch) | |
| tree | 817ec49386ef014ba0a02926c08579408e9c71ce /malloc | |
| parent | 0b9c84906f653978fb8768c7ebd0ee14a47e662e (diff) | |
| download | glibc-b50dd3bc8cbb1efe85399b03d7e6c0310c2ead84.zip glibc-b50dd3bc8cbb1efe85399b03d7e6c0310c2ead84.tar.gz glibc-b50dd3bc8cbb1efe85399b03d7e6c0310c2ead84.tar.bz2 | |
malloc: Always call memcpy in _int_realloc [BZ #24027]
This commit removes the custom memcpy implementation from _int_realloc
for small chunk sizes. The ncopies variable has the wrong type, and
an integer wraparound could cause the existing code to copy too few
elements (leaving the new memory region mostly uninitialized).
Therefore, removing this code fixes bug 24027.
Diffstat (limited to 'malloc')
| -rw-r--r-- | malloc/malloc.c | 43 |
1 files changed, 1 insertions, 42 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index c33709e..0a20a60 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -4581,11 +4581,6 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, mchunkptr remainder; /* extra space at end of newp */ unsigned long remainder_size; /* its size */ - unsigned long copysize; /* bytes to copy */ - unsigned int ncopies; /* INTERNAL_SIZE_T words to copy */ - INTERNAL_SIZE_T* s; /* copy source */ - INTERNAL_SIZE_T* d; /* copy destination */ - /* oldmem size */ if (__builtin_expect (chunksize_nomask (oldp) <= 2 * SIZE_SZ, 0) || __builtin_expect (oldsize >= av->system_mem, 0)) @@ -4653,43 +4648,7 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, } else { - /* - Unroll copy of <= 36 bytes (72 if 8byte sizes) - We know that contents have an odd number of - INTERNAL_SIZE_T-sized words; minimally 3. - */ - - copysize = oldsize - SIZE_SZ; - s = (INTERNAL_SIZE_T *) (chunk2mem (oldp)); - d = (INTERNAL_SIZE_T *) (newmem); - ncopies = copysize / sizeof (INTERNAL_SIZE_T); - assert (ncopies >= 3); - - if (ncopies > 9) - memcpy (d, s, copysize); - - else - { - *(d + 0) = *(s + 0); - *(d + 1) = *(s + 1); - *(d + 2) = *(s + 2); - if (ncopies > 4) - { - *(d + 3) = *(s + 3); - *(d + 4) = *(s + 4); - if (ncopies > 6) - { - *(d + 5) = *(s + 5); - *(d + 6) = *(s + 6); - if (ncopies > 8) - { - *(d + 7) = *(s + 7); - *(d + 8) = *(s + 8); - } - } - } - } - + memcpy (newmem, chunk2mem (oldp), oldsize - SIZE_SZ); _int_free (av, oldp, 1); check_inuse_chunk (av, newp); return chunk2mem (newp); |