generic-library/ffmpeg
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

qdm2: clip array indices returned by qdm2_get_vlc().

Browse Source 
Prevents subsequent overreads when these numbers are used as indices
in arrays.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org

Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>
(cherry picked from commit 64953f67f98da2e787aeb45cc7f504390fa32a69)
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

Conflicts:

	libavcodec/qdm2.c
This commit is contained in:
Ronald S. Bultje 2012-05-02 16:12:46 +00:00 committed by Derek Buitenhuis
parent 07bff95176
commit 4bccd5a36b
1 changed files with 13 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
libavcodec/qdm2.c
View File

@ -883,9 +883,13 @@ static void synthfilt_build_sb_samples (QDM2Context *q, GetBitContext *gb, int l
break; break;
case 30: case 30:
if (BITS_LEFT(length,gb) >= 4) if (BITS_LEFT(length,gb) >= 4) {
samples[0] = type30_dequant[qdm2_get_vlc(gb, &vlc_tab_type30, 0, 1)]; unsigned index = qdm2_get_vlc(gb, &vlc_tab_type30, 0, 1);
else if (index < FF_ARRAY_ELEMS(type30_dequant)) {
samples[0] = type30_dequant[index];
} else
samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx);
} else
samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx); samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx);
run = 1; run = 1;
@ -899,8 +903,12 @@ static void synthfilt_build_sb_samples (QDM2Context *q, GetBitContext *gb, int l
type34_predictor = samples[0]; type34_predictor = samples[0];
type34_first = 0; type34_first = 0;
} else { } else {
samples[0] = type34_delta[qdm2_get_vlc(gb, &vlc_tab_type34, 0, 1)] / type34_div + type34_predictor; unsigned index = qdm2_get_vlc(gb, &vlc_tab_type34, 0, 1);
type34_predictor = samples[0]; if (index < FF_ARRAY_ELEMS(type34_delta)) {
samples[0] = type34_delta[index] / type34_div + type34_predictor;
type34_predictor = samples[0];
} else
samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx);
} }
} else { } else {
samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx); samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx);