[FFmpeg-cvslog] avcodec/vmnc: Check that rectangles are within the picture

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Mon Jan 20 18:08:18 2014 +0100| [6ba02602aa7fc7d38db582e75b8b093fb3c1608d] | committer: Michael Niedermayer

avcodec/vmnc: Check  that rectangles are within the picture

Prevents out of array accesses with CODEC_FLAG_EMU_EDGE

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6ba02602aa7fc7d38db582e75b8b093fb3c1608d
---

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

diff --git a/libavcodec/vmnc.c b/libavcodec/vmnc.c
index 5f91ab1..46bd52e 100644
--- a/libavcodec/vmnc.c
+++ b/libavcodec/vmnc.c
@@ -291,6 +291,11 @@ static int decode_hextile(VmncContext *c, uint8_t* dst, GetByteContext *gb,
                         fg = vmnc_get_pixel(gb, bpp, c->bigendian);
                     xy = bytestream2_get_byte(gb);
                     wh = bytestream2_get_byte(gb);
+                    if (   (xy >> 4) + (wh >> 4) + 1 > w - i
+                        || (xy & 0xF) + (wh & 0xF)+1 > h - j) {
+                        av_log(c->avctx, AV_LOG_ERROR, "Rectangle outside picture\n");
+                        return AVERROR_INVALIDDATA;
+                    }
                     paint_rect(dst2, xy >> 4, xy & 0xF,
                                (wh>>4)+1, (wh & 0xF)+1, fg, bpp, stride);
                 }