From de458e5d3fa4d79859db3da21d50092a34f28cfc Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 30 Sep 2023 19:48:17 +0200 Subject: [PATCH] avformat/jacosubdec: avoid signed integer overflows in get_shift() Fixes: signed integer overflow: 22014562800 * 934633746 cannot be represented in type 'long' Fixes: 51896/clusterfuzz-testcase-minimized-ffmpeg_dem_JACOSUB_fuzzer-5189603246866432 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 32447b149fb61eb48436eddbbb1adf91b70ec5e4) Signed-off-by: Michael Niedermayer --- libavformat/jacosubdec.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/libavformat/jacosubdec.c b/libavformat/jacosubdec.c index 42c201f93a..41216081ee 100644 --- a/libavformat/jacosubdec.c +++ b/libavformat/jacosubdec.c @@ -124,7 +124,7 @@ shift_and_ret: return buf + len; } -static int get_shift(int timeres, const char *buf) +static int get_shift(unsigned timeres, const char *buf) { int sign = 1; int a = 0, b = 0, c = 0, d = 0; @@ -148,7 +148,11 @@ static int get_shift(int timeres, const char *buf) case 3: d = c; c = b; b = a; a = 0; } - ret = sign * (((int64_t)a*3600 + (int64_t)b*60 + c) * timeres + d); + ret = (int64_t)a*3600 + (int64_t)b*60 + c; + if (FFABS(ret) > (INT64_MAX - FFABS(d)) / timeres) + return 0; + ret = sign * (ret * timeres + d); + if ((int)ret != ret) ret = 0;