[FFmpeg-cvslog] avcodec/tiff: Check palette shift

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Mar 14 01:34:14 2017 +0100| [cfa10e11be4c17fdff0c77cba7c0b3d6ea99acea] | committer: Michael Niedermayer

avcodec/tiff: Check palette shift

Fixes multiple  runtime error: shift exponent 792 is too large for 32-bit type 'unsigned int'

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=cfa10e11be4c17fdff0c77cba7c0b3d6ea99acea
---

 libavcodec/tiff.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index 456da51..0be7be7 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -996,6 +996,11 @@ static int tiff_decode_tag(TiffContext *s, AVFrame *frame)
         bytestream2_skip(&pal_gb[2], count / 3 * off * 2);
 
         off = (type_sizes[type] - 1) << 3;
+        if (off > 31U) {
+            av_log(s->avctx, AV_LOG_ERROR, "palette shift %d is out of range\n", off);
+            return AVERROR_INVALIDDATA;
+        }
+
         for (i = 0; i < count / 3; i++) {
             uint32_t p = 0xFF000000;
             p |= (ff_tget(&pal_gb[0], type, s->le) >> off) << 16;