File libelf-check-compression-before-allocate-output-buffer.patch of Package elfutils.8903
[PATCH] libelf: Check compression ratio before trying to allocate output buffer.
From: Mark Wielaard <mark at klomp dot org>
To: elfutils-devel at sourceware dot org
Cc: Mark Wielaard <mark at klomp dot org>
Date: Fri, 24 Mar 2017 15:06:04 +0100
Subject: [PATCH] libelf: Check compression ratio before trying to allocate
output buffer.
Reference: bnc#1033086
The maximum compression factor (http://www.zlib.net/zlib_tech.html) is
1032:1. Add a sanity check for that before trying to allocate lots of
memory and trying to decompress lots of bogus data.
https://sourceware.org/bugzilla/show_bug.cgi?id=21301
elfutils packaging edits:
- changelog hunk removed from original patch to avoid conflict
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
libelf/ChangeLog | 5 +++++
libelf/elf_compress.c | 9 +++++++++
2 files changed, 14 insertions(+)
diff --git a/libelf/elf_compress.c b/libelf/elf_compress.c
index dac0ac6..711be59 100644
--- a/libelf/elf_compress.c
+++ b/libelf/elf_compress.c
@@ -211,6 +211,15 @@ void *
internal_function
__libelf_decompress (void *buf_in, size_t size_in, size_t size_out)
{
+ /* Catch highly unlikely compression ratios so we don't allocate
+ some giant amount of memory for nothing. The max compression
+ factor 1032:1 comes from http://www.zlib.net/zlib_tech.html */
+ if (unlikely (size_out / 1032 > size_in))
+ {
+ __libelf_seterrno (ELF_E_INVALID_DATA);
+ return NULL;
+ }
+
void *buf_out = malloc (size_out);
if (unlikely (buf_out == NULL))
{
--
1.8.3.1