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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2021-02-25 14:49:58 +0000
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2021-03-26 10:43:51 +0000
commit42cc96066b22ba065db11096c78881a55e45def4 (patch)
tree806136a0e5fe76b6e811810f6626a11753260dca
parent7759be2593b689cb1eafc0f52ee7f59c639e5d2f (diff)
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malloc: Fix a realloc crash with heap tagging [BZ 27468]
_int_free must be called with a chunk that has its tag reset. This was
missing in a rare case that could crash when heap tagging is enabled:
when in a multi-threaded process the current arena runs out of memory
during realloc, but another arena still has space to finish the realloc
then _int_free was called without clearing the user allocation tags.

Fixes bug 27468.

Reviewed-by: DJ Delorie <dj@redhat.com>
-rw-r--r--malloc/malloc.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 530c792997..9d9f7b918a 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3446,7 +3446,9 @@ __libc_realloc (void *oldmem, size_t bytes)
       newp = __libc_malloc (bytes);
       if (newp != NULL)
         {
-          memcpy (newp, oldmem, oldsize - SIZE_SZ);
+	  size_t sz = CHUNK_AVAILABLE_SIZE (oldp) - CHUNK_HDR_SZ;
+	  memcpy (newp, oldmem, sz);
+	  (void) TAG_REGION (chunk2rawmem (oldp), sz);
           _int_free (ar_ptr, oldp, 0);
         }
     }