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[PATCH v2 1/7] malloc: Add check for top size corruption.
- From: Istvan Kurucsai <pistukem at gmail dot com>
- To: libc-alpha at sourceware dot org
- Cc: Istvan Kurucsai <pistukem at gmail dot com>
- Date: Tue, 7 Nov 2017 16:27:04 +0100
- Subject: [PATCH v2 1/7] malloc: Add check for top size corruption.
- Authentication-results: sourceware.org; auth=none
- References: <1510068430-27816-1-git-send-email-pistukem@gmail.com>
Ensure that the size of top is below av->system_mem.
* malloc/malloc.c (_int_malloc): Check top size.
---
malloc/malloc.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/malloc/malloc.c b/malloc/malloc.c
index f94d51c..4a30c42 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -4078,6 +4078,10 @@ _int_malloc (mstate av, size_t bytes)
if ((unsigned long) (size) >= (unsigned long) (nb + MINSIZE))
{
+ if (__glibc_unlikely ((unsigned long) (size) >
+ (unsigned long) (av->system_mem)))
+ malloc_printerr("malloc(): corrupted top chunk");
+
remainder_size = size - nb;
remainder = chunk_at_offset (victim, nb);
av->top = remainder;
--
2.7.4