avcodec/jpeg2000dec: add some sanity checking on newpasses

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

libavcodec/jpeg2000.h

@@ -71,6 +71,8 @@ enum Jpeg2000Quantsty { // quantization style
 #define JPEG2000_MAX_DECLEVELS 32
 #define JPEG2000_MAX_RESLEVELS (JPEG2000_MAX_DECLEVELS + 1)
 
+#define JPEG2000_MAX_PASSES 100
+
 // T1 flags
 // flags determining significance of neighbor coefficients
 #define JPEG2000_T1_SIG_N  0x0001

libavcodec/jpeg2000dec.c

@@ -805,6 +805,11 @@ static int jpeg2000_decode_packet(Jpeg2000DecoderContext *s,
             }
             if ((newpasses = getnpasses(s)) < 0)
                 return newpasses;
+            av_assert2(newpasses > 0);
+            if (cblk->npasses + newpasses >= JPEG2000_MAX_PASSES) {
+                avpriv_request_sample(s->avctx, "Too many passes\n");
+                return AVERROR_PATCHWELCOME;
+            }
             if ((llen = getlblockinc(s)) < 0)
                 return llen;
             if (cblk->lblock + llen + av_log2(newpasses) > 16) {