j2k & jpeg2000dec: reset numX/Ytiles if tiles failed allocation

Fixes null pointer dereference

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 2 insertions, 0 deletions

diff --git a/libavcodec/j2kdec.c b/libavcodec/j2kdec.c
index 22bbb2effd..a02b84b820 100644
--- a/libavcodec/j2kdec.c
+++ b/libavcodec/j2kdec.c
@@ -957,6 +957,8 @@ static int decode_codestream(Jpeg2000DecoderContext *s)
         switch (marker){
         case JPEG2000_SIZ:
             ret = get_siz(s);
+            if (!s->tile)
+                s->numXtiles = s->numYtiles = 0;
             break;
         case JPEG2000_COC:
             ret = get_coc(s, codsty, properties);