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From 0d6085cb1b4330b835ad08a3ec8f80b30f0cadb4 Mon Sep 17 00:00:00 2001
From: mancha <mancha1@hush.com>
Date: Wed, 11 Sep 2013
Subject: CVE-2013-4332
malloc: Check for integer overflow in pvalloc, valloc, and memalign.
A large bytes parameter to pvalloc, valloc, or memalign could cause
an integer overflow and corrupt allocator internals. Check the
overflow does not occur before continuing with the allocation.
Note: This is a backport to glibc 2.17 of the following three commits:
* https://sourceware.org/git/?p=glibc.git;a=commit;h=1159a193696a
* https://sourceware.org/git/?p=glibc.git;a=commit;h=55e17aadc1ef
* https://sourceware.org/git/?p=glibc.git;a=commit;h=b73ed247781d
---
malloc.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3020,6 +3020,13 @@ __libc_memalign(size_t alignment, size_t
/* Otherwise, ensure that it is at least a minimum chunk size */
if (alignment < MINSIZE) alignment = MINSIZE;
+ /* Check for overflow. */
+ if (bytes > SIZE_MAX - alignment - MINSIZE)
+ {
+ __set_errno (ENOMEM);
+ return 0;
+ }
+
arena_get(ar_ptr, bytes + alignment + MINSIZE);
if(!ar_ptr)
return 0;
@@ -3051,6 +3058,13 @@ __libc_valloc(size_t bytes)
size_t pagesz = GLRO(dl_pagesize);
+ /* Check for overflow. */
+ if (bytes > SIZE_MAX - pagesz - MINSIZE)
+ {
+ __set_errno (ENOMEM);
+ return 0;
+ }
+
__malloc_ptr_t (*hook) __MALLOC_PMT ((size_t, size_t,
const __malloc_ptr_t)) =
force_reg (__memalign_hook);
@@ -3088,6 +3102,13 @@ __libc_pvalloc(size_t bytes)
size_t page_mask = GLRO(dl_pagesize) - 1;
size_t rounded_bytes = (bytes + page_mask) & ~(page_mask);
+ /* Check for overflow. */
+ if (bytes > SIZE_MAX - 2*pagesz - MINSIZE)
+ {
+ __set_errno (ENOMEM);
+ return 0;
+ }
+
__malloc_ptr_t (*hook) __MALLOC_PMT ((size_t, size_t,
const __malloc_ptr_t)) =
force_reg (__memalign_hook);
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