ffmpeg | branch: release/3.2 | Dale Curtis <dalecur...@chromium.org> | Fri Nov 17 16:05:30 2017 -0800| [13763f71926057e57ddd75b7c8ff93e6ab23f8ab] | committer: Michael Niedermayer
Fix undefined shift on assumed 8-bit input. decode_user_data() attempts to create an integer |build| value with 8 bits of spacing for 3 components. However each component is an int32_t, so shifting each component is undefined for values outside of the 8 bit range. This patch simply clamps input to 8-bits per component and prints out a warning that the values were clamped. Signed-off-by: Dale Curtis <dalecur...@chromium.org> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> (cherry picked from commit 7010dd98b575d2e39fca947e609b85be7490b269) Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=13763f71926057e57ddd75b7c8ff93e6ab23f8ab --- libavcodec/mpeg4videodec.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c index 02b87b3376..eff59578dd 100644 --- a/libavcodec/mpeg4videodec.c +++ b/libavcodec/mpeg4videodec.c @@ -2149,8 +2149,15 @@ static int decode_user_data(Mpeg4DecContext *ctx, GetBitContext *gb) e = sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build); if (e != 4) { e = sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3) + 1; - if (e > 1) - build = (ver << 16) + (ver2 << 8) + ver3; + if (e > 1) { + if (ver > 0xFF || ver2 > 0xFF || ver3 > 0xFF) { + av_log(s->avctx, AV_LOG_WARNING, + "Unknown Lavc version string encountered, %d.%d.%d; " + "clamping sub-version values to 8-bits.\n", + ver, ver2, ver3); + } + build = ((ver & 0xFF) << 16) + ((ver2 & 0xFF) << 8) + (ver3 & 0xFF); + } } if (e != 4) { if (strcmp(buf, "ffmpeg") == 0) _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog
