avcodec/qdrw: fix decoding of odd sized images for 8bpp

Signed-off-by: Paul B Mahol <onemda@gmail.com>
8 years ago · 1dcf91f2d3
parent dc78696ea4
commit 1dcf91f2d3
1 changed files with 6 additions and 8 deletions
--- a/libavcodec/qdrw.c
+++ b/libavcodec/qdrw.c
@ -231,26 +231,24 @@ static int decode_rle(AVCodecContext *avctx, AVFrame *p, GetByteContext *gbc,
            if (code & 0x80 ) { /* run */
                pix = bytestream2_get_byte(gbc);
                for (j = 0; j < 257 - code; j++) {
-                    out[pos] = pix;
+                    if (pos < offset)
+                        out[pos] = pix;
                    pos += step;
-                    if (pos >= offset) {
+                    if (pos >= offset && step > 1) {
                        pos -= offset;
                        pos++;
                    }
-                    if (pos >= offset)
-                        return AVERROR_INVALIDDATA;
                }
                left  -= 2;
            } else { /* copy */
                for (j = 0; j < code + 1; j++) {
-                    out[pos] = bytestream2_get_byte(gbc);
+                    if (pos < offset)
+                        out[pos] = bytestream2_get_byte(gbc);
                    pos += step;
-                    if (pos >= offset) {
+                    if (pos >= offset && step > 1) {
                        pos -= offset;
                        pos++;
                    }
-                    if (pos >= offset)
-                        return AVERROR_INVALIDDATA;
                }
                left  -= 2 + code;
            }