From 0a4745145840d97619c424961c1b5c625dbf516c Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 4 May 2018 18:16:08 +0200 Subject: avcodec/g2meet: Change order of operations to avoid undefined behavior Fixes: signed integer overflow: 65280 * 196032 cannot be represented in type 'int' Fixes: 7279/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_G2M_fuzzer-5977332473921536 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/g2meet.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'libavcodec') diff --git a/libavcodec/g2meet.c b/libavcodec/g2meet.c index b409dae813..5edfb31560 100644 --- a/libavcodec/g2meet.c +++ b/libavcodec/g2meet.c @@ -1356,14 +1356,16 @@ static void g2m_paint_cursor(G2MContext *c, uint8_t *dst, int stride) } else { dst += x * 3; } - if (y < 0) { + + if (y < 0) h += y; + if (w < 0 || h < 0) + return; + if (y < 0) { cursor += -y * c->cursor_stride; } else { dst += y * stride; } - if (w < 0 || h < 0) - return; for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { -- cgit v1.2.3