From 9e6c5b6e865a6b1b9c3a471fc06143f11e69d71b Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 16 Jun 2024 01:51:22 +0200 Subject: [PATCH] swscale/output: alpha can become negative after scaling, use multiply Fixes: left shift of negative value -3245 Fixes: 69047/clusterfuzz-testcase-minimized-ffmpeg_SWS_fuzzer-6571511551950848 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libswscale/output.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/libswscale/output.c b/libswscale/output.c index b234f9c6b9..f9ce43dde8 100644 --- a/libswscale/output.c +++ b/libswscale/output.c @@ -1221,8 +1221,8 @@ yuv2rgba64_1_c_template(SwsContext *c, const int32_t *buf0, Y2 += (1 << 13) - (1 << 29); if (hasAlpha) { - A1 = abuf0[i * 2 ] << 11; - A2 = abuf0[i * 2 + 1] << 11; + A1 = abuf0[i * 2 ] * (1 << 11); + A2 = abuf0[i * 2 + 1] * (1 << 11); A1 += 1 << 13; A2 += 1 << 13; @@ -1267,8 +1267,8 @@ yuv2rgba64_1_c_template(SwsContext *c, const int32_t *buf0, Y2 += (1 << 13) - (1 << 29); if (hasAlpha) { - A1 = abuf0[i * 2 ] << 11; - A2 = abuf0[i * 2 + 1] << 11; + A1 = abuf0[i * 2 ] * (1 << 11); + A2 = abuf0[i * 2 + 1] * (1 << 11); A1 += 1 << 13; A2 += 1 << 13; @@ -1439,7 +1439,7 @@ yuv2rgba64_full_1_c_template(SwsContext *c, const int32_t *buf0, Y += (1 << 13) - (1 << 29); if (hasAlpha) { - A = abuf0[i] << 11; + A = abuf0[i] * (1 << 11); A += 1 << 13; } @@ -1472,7 +1472,7 @@ yuv2rgba64_full_1_c_template(SwsContext *c, const int32_t *buf0, Y += (1 << 13) - (1 << 29); if (hasAlpha) { - A = abuf0[i] << 11; + A = abuf0[i] * (1 << 11); A += 1 << 13; }