Handle palette underflows, fill remaining space with black (zero) data.

Patch by Sebastian Vater <cdgs basty googlemail com>.

Originally committed as revision 23111 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 2 insertions, 4 deletions

diff --git a/libavcodec/iff.c b/libavcodec/iff.c
index 2b3648bc8a..019af4dbfe 100644
--- a/libavcodec/iff.c
+++ b/libavcodec/iff.c
@@ -123,10 +123,8 @@ int ff_cmap_read_palette(AVCodecContext *avctx, uint32_t *pal)
     }
 
     count = 1 << avctx->bits_per_coded_sample;
-    if (avctx->extradata_size < count * 3) {
-        av_log(avctx, AV_LOG_ERROR, "palette data underflow\n");
-        return AVERROR_INVALIDDATA;
-    }
+    // If extradata is smaller than actually needed, fill the remaining with black.
+    count = FFMIN(avctx->extradata_size / 3, count);
     for (i=0; i < count; i++) {
         pal[i] = 0xFF000000 | AV_RB24( avctx->extradata + i*3 );
     }