[FFmpeg-cvslog] Check for out of bound writes in the QDM2 decoder.

[Laurent Aimar]

ffmpeg | branch: release/0.6 | Laurent Aimar <fenrir at videolan.org> | Sat Oct  1 00:45:05 2011 +0200| [0f7bf1786e43d05c4ec1667a1457df7b22b05561] | committer: Reinhard Tartler

Check for out of bound writes in the QDM2 decoder.

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
Signed-off-by: Justin Ruggles <justin.ruggles at gmail.com>
(cherry picked from commit 291d74a46d32183653db07818c7b3407fd50a288)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>
(cherry picked from commit a31ccacb1a9b2abc0e140a812fb0ffca6f7c2591)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0f7bf1786e43d05c4ec1667a1457df7b22b05561
---

 libavcodec/qdm2.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/libavcodec/qdm2.c b/libavcodec/qdm2.c
index 6451fbe..3273dd1 100644
--- a/libavcodec/qdm2.c
+++ b/libavcodec/qdm2.c
@@ -75,6 +75,7 @@ do { \
 #define SAMPLES_NEEDED_2(why) \
      av_log (NULL,AV_LOG_INFO,"This file triggers some missing code. Please contact the developers.\nPosition: %s\n",why);
 
+#define QDM2_MAX_FRAME_SIZE 512
 
 typedef int8_t sb_int8_array[2][30][64];
 
@@ -167,7 +168,7 @@ typedef struct {
     /// I/O data
     const uint8_t *compressed_data;
     int compressed_size;
-    float output_buffer[1024];
+    float output_buffer[QDM2_MAX_FRAME_SIZE * 2];
 
     /// Synthesis filter
     DECLARE_ALIGNED(16, MPA_INT, synth_buf)[MPA_MAX_CHANNELS][512*2];
@@ -1799,6 +1800,8 @@ static av_cold int qdm2_decode_init(AVCodecContext *avctx)
 
     avctx->channels = s->nb_channels = s->channels = AV_RB32(extradata);
     extradata += 4;
+    if (s->channels > MPA_MAX_CHANNELS)
+        return AVERROR_INVALIDDATA;
 
     avctx->sample_rate = AV_RB32(extradata);
     extradata += 4;
@@ -1820,6 +1823,8 @@ static av_cold int qdm2_decode_init(AVCodecContext *avctx)
     // something like max decodable tones
     s->group_order = av_log2(s->group_size) + 1;
     s->frame_size = s->group_size / 16; // 16 iterations per super block
+    if (s->frame_size > QDM2_MAX_FRAME_SIZE)
+        return AVERROR_INVALIDDATA;
 
     s->sub_sampling = s->fft_order - 7;
     s->frequency_range = 255 / (1 << (2 - s->sub_sampling));