[FFmpeg-cvslog] icodec: correctly check avio_read return value

[Andreas Cadhalpun]

ffmpeg | branch: release/3.2 | Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com> | Tue Nov  8 23:29:28 2016 +0100| [1615d83dcf6ed0401be2f8afbdd8af8d2fc56815] | committer: Andreas Cadhalpun

icodec: correctly check avio_read return value

It can read less than the requested amount, in which case buf contains
uninitialized data, causing problems like segmentation faults later on.

Also make sure that image->size is positive, so that it can't match a
negative error code.

Reviewed-by: Michael Niedermayer <michael at niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
(cherry picked from commit 89eb398c7fc4cb9a15e55bdf2ab6435b5332e377)
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1615d83dcf6ed0401be2f8afbdd8af8d2fc56815
---

 libavformat/icodec.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libavformat/icodec.c b/libavformat/icodec.c
index fa985fb..41a2e4b 100644
--- a/libavformat/icodec.c
+++ b/libavformat/icodec.c
@@ -109,6 +109,10 @@ static int read_header(AVFormatContext *s)
         avio_skip(pb, 5);
 
         ico->images[i].size   = avio_rl32(pb);
+        if (ico->images[i].size <= 0) {
+            av_log(s, AV_LOG_ERROR, "Invalid image size %d\n", ico->images[i].size);
+            return AVERROR_INVALIDDATA;
+        }
         ico->images[i].offset = avio_rl32(pb);
 
         if (avio_seek(pb, ico->images[i].offset, SEEK_SET) < 0)
@@ -174,9 +178,9 @@ static int read_packet(AVFormatContext *s, AVPacket *pkt)
         bytestream_put_le16(&buf, 0);
         bytestream_put_le32(&buf, 0);
 
-        if ((ret = avio_read(pb, buf, image->size)) < 0) {
+        if ((ret = avio_read(pb, buf, image->size)) != image->size) {
             av_packet_unref(pkt);
-            return ret;
+            return ret < 0 ? ret : AVERROR_INVALIDDATA;
         }
 
         st->codecpar->bits_per_coded_sample = AV_RL16(buf + 14);