[FFmpeg-cvslog] avcodec: fix aac/ac3 parser bitstream buffer size

[Michael Niedermayer]

ffmpeg | branch: release/2.1 | Michael Niedermayer <michaelni at gmx.at> | Fri Aug 22 01:15:57 2014 +0200| [6ab793c2b9bbe1196f9b8af2dd66eef55e631605] | committer: Michael Niedermayer

avcodec: fix aac/ac3 parser bitstream buffer size

Buffers containing copies of the AAC and AC3 header bits were not padded
before parsing, violating init_get_bits() buffer padding requirement,
leading to potential buffer read overflows.
This change adds FF_INPUT_BUFFER_PADDING_SIZE bytes to the bit buffer
for parsing the header in each of aac_parser.c and ac3_parser.c.

Based on patch by: Matt Wolenetz <wolenetz at chromium.org>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit fccd85b9f30525f88692f53134eba41f1f2d90db)

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6ab793c2b9bbe1196f9b8af2dd66eef55e631605
---

 libavcodec/aac_parser.c |    2 +-
 libavcodec/ac3_parser.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/aac_parser.c b/libavcodec/aac_parser.c
index ab6ca4e..cb93ba9 100644
--- a/libavcodec/aac_parser.c
+++ b/libavcodec/aac_parser.c
@@ -34,7 +34,7 @@ static int aac_sync(uint64_t state, AACAC3ParseContext *hdr_info,
     int size;
     union {
         uint64_t u64;
-        uint8_t  u8[8];
+        uint8_t  u8[8 + FF_INPUT_BUFFER_PADDING_SIZE];
     } tmp;
 
     tmp.u64 = av_be2ne64(state);
diff --git a/libavcodec/ac3_parser.c b/libavcodec/ac3_parser.c
index 8dc4c0d..acfbc2e 100644
--- a/libavcodec/ac3_parser.c
+++ b/libavcodec/ac3_parser.c
@@ -147,7 +147,7 @@ static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
     int err;
     union {
         uint64_t u64;
-        uint8_t  u8[8];
+        uint8_t  u8[8 + FF_INPUT_BUFFER_PADDING_SIZE];
     } tmp = { av_be2ne64(state) };
     AC3HeaderInfo hdr;
     GetBitContext gbc;