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 <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2024-06-16 01:51:22 +02:00
parent c22488f718
commit 9e6c5b6e86
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@ -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;
}