[FFmpeg-devel] [PATCH 3/3] avcodec/jpegxl_parser: Check get_vlc2()

[Michael Niedermayer]

Fixes: shift exponent -1 is negative
Fixes: 63889/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-6009343056936960

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/jpegxl_parser.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libavcodec/jpegxl_parser.c b/libavcodec/jpegxl_parser.c
index 630fc8a60bf..964f5a9ad5a 100644
--- a/libavcodec/jpegxl_parser.c
+++ b/libavcodec/jpegxl_parser.c
@@ -698,6 +698,10 @@ static int read_vlc_prefix(GetBitContext *gb, JXLEntropyDecoder *dec, JXLSymbolD
     level1_codecounts[0] = hskip;
     for (int i = hskip; i < 18; i++) {
         len = level1_lens[prefix_codelen_map[i]] = get_vlc2(gb, level0_table, 4, 1);
+        if (len < 0) {
+            ret = AVERROR_INVALIDDATA;
+            goto end;
+        }
         level1_codecounts[len]++;
         if (len) {
             total_code += (32 >> len);
@@ -743,6 +747,10 @@ static int read_vlc_prefix(GetBitContext *gb, JXLEntropyDecoder *dec, JXLSymbolD
     total_code = 0;
     for (int i = 0; i < dist->alphabet_size; i++) {
         len = get_vlc2(gb, level1_vlc.table, 5, 1);
+        if (len < 0) {
+            ret = AVERROR_INVALIDDATA;
+            goto end;
+        }
         if (get_bits_left(gb) < 0) {
             ret = AVERROR_BUFFER_TOO_SMALL;
             goto end;
-- 
2.17.1