[FFmpeg-devel] [PR] swscale/rgb2rgb_template: fix signed shift into sign bit (PR #21750)

[FFmpeg-devel] [PR] swscale/rgb2rgb_template: fix signed shift into sign bit (PR #21750)

[michaelni via ffmpeg-devel]

PR #21750 opened by michaelni
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21750
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21750.patch

Fixes: left shift of 255 by 24 places cannot be represented in type 'int'
Fixes: 471591904/clusterfuzz-testcase-minimized-ffmpeg_SWS_fuzzer-5141341165387776

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>


>From 0939c34f0df3a3886974be3c186ddbe853f52bd9 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Fri, 13 Feb 2026 23:40:38 +0100
Subject: [PATCH] swscale/rgb2rgb_template: fix signed shift into sign bit

Fixes: left shift of 255 by 24 places cannot be represented in type 'int'
Fixes: 471591904/clusterfuzz-testcase-minimized-ffmpeg_SWS_fuzzer-5141341165387776

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libswscale/rgb2rgb_template.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libswscale/rgb2rgb_template.c b/libswscale/rgb2rgb_template.c
index 47a1bb8368..7d4a605043 100644
--- a/libswscale/rgb2rgb_template.c
+++ b/libswscale/rgb2rgb_template.c
@@ -470,11 +470,11 @@ static inline void yuvPlanartouyvy_c(const uint8_t *ysrc, const uint8_t *usrc,
 
         for (i = 0; i < chromWidth; i++) {
 #if HAVE_BIGENDIAN
-            *idst++ = (uc[0] << 24) + (yc[0] << 16) +
+            *idst++ = ((unsigned)uc[0] << 24) + (yc[0] << 16) +
                       (vc[0] <<  8) + (yc[1] <<  0);
 #else
             *idst++ = uc[0] + (yc[0] << 8) +
-                      (vc[0] << 16) + (yc[1] << 24);
+                      (vc[0] << 16) + ((unsigned)yc[1] << 24);
 #endif
             yc += 2;
             uc++;
-- 
2.52.0

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