[FFmpeg-devel] [PATCH 2/4] avcodec/jpeg2000dec: Fixes invalid shifts in jpeg2000_decode_packets_po_iteration()

Michael Niedermayer michael at niedermayer.cc
Mon Jul 2 21:45:09 EEST 2018


Fixes: shift exponent 47 is too large for 32-bit type 'int'
Fixes: 9163/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5661750182543360

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/jpeg2000dec.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index 4071b5ce53..96dab8e176 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -1254,10 +1254,10 @@ static int jpeg2000_decode_packets_po_iteration(Jpeg2000DecoderContext *s, Jpeg2
                         if (reslevelno >= codsty->nreslevels)
                             continue;
 
-                        if (yc % (1 << (rlevel->log2_prec_height + reducedresno)) && y != tile->coord[1][0]) //FIXME this is a subset of the check
+                        if (yc % (1LL << (rlevel->log2_prec_height + reducedresno)) && y != tile->coord[1][0]) //FIXME this is a subset of the check
                             continue;
 
-                        if (xc % (1 << (rlevel->log2_prec_width + reducedresno)) && x != tile->coord[0][0]) //FIXME this is a subset of the check
+                        if (xc % (1LL << (rlevel->log2_prec_width + reducedresno)) && x != tile->coord[0][0]) //FIXME this is a subset of the check
                             continue;
 
                         // check if a precinct exists
@@ -1325,10 +1325,10 @@ static int jpeg2000_decode_packets_po_iteration(Jpeg2000DecoderContext *s, Jpeg2
                         uint8_t reducedresno = codsty->nreslevels - 1 -reslevelno; //  ==> N_L - r
                         Jpeg2000ResLevel *rlevel = comp->reslevel + reslevelno;
 
-                        if (yc % (1 << (rlevel->log2_prec_height + reducedresno)) && y != tile->coord[1][0]) //FIXME this is a subset of the check
+                        if (yc % (1LL << (rlevel->log2_prec_height + reducedresno)) && y != tile->coord[1][0]) //FIXME this is a subset of the check
                             continue;
 
-                        if (xc % (1 << (rlevel->log2_prec_width + reducedresno)) && x != tile->coord[0][0]) //FIXME this is a subset of the check
+                        if (xc % (1LL << (rlevel->log2_prec_width + reducedresno)) && x != tile->coord[0][0]) //FIXME this is a subset of the check
                             continue;
 
                         // check if a precinct exists
-- 
2.18.0



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