avcodec/mjpegdec: Check number of components for JPEG-LS

Fixes out of array accesses
Fixes: asan_heap-oob_1c1a4ea_1242_cov_2274415971_TESTcmyk.jpg
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Gbp-Pq: Name CVE-2015-1872.patch

diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 7aedd2a14ff5b61f32397d8b5e2c762a8788caf9..3f3f81ad6f173914037feaa70a35c23b1d293143 100644 (file)
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -375,8 +375,12 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
         return AVERROR_PATCHWELCOME;
     }
     if (s->ls) {
-        if (s->nb_components > 1)
+        if (s->nb_components == 3) {
             s->avctx->pix_fmt = AV_PIX_FMT_RGB24;
+        } else if (s->nb_components != 1) {
+            av_log(s->avctx, AV_LOG_ERROR, "Unsupported number of components %d\n", s->nb_components);
+            return AVERROR_PATCHWELCOME;
+        }
         else if (s->bits <= 8)
             s->avctx->pix_fmt = AV_PIX_FMT_GRAY8;
         else