On 7/9/24 2:34 PM, Sean McGovern wrote:
For even small values of 'asrc', shifting them by 24 bits or more
will cause arithmetic overflow and be caught by
GCC's undefined behaviour sanitizer.
Ensure the values do not overflow by up-casting the bracketed
expressions involving 'asrc' to int32_t.
---
libswscale/yuv2rgb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/libswscale/yuv2rgb.c b/libswscale/yuv2rgb.c
index 977eb3a7dd..ac0b811f61 100644
--- a/libswscale/yuv2rgb.c
+++ b/libswscale/yuv2rgb.c
@@ -100,9 +100,9 @@ const int *sws_getCoefficients(int colorspace)
#define PUTRGBA(dst, ysrc, asrc, i, abase) \
Y = ysrc[2 * i]; \
- dst[2 * i] = r[Y] + g[Y] + b[Y] + (asrc[2 * i] << abase); \
+ dst[2 * i] = r[Y] + g[Y] + b[Y] + ((int32_t)(asrc[2 * i]) <<
abase); \
Y = ysrc[2 * i + 1]; \
- dst[2 * i + 1] = r[Y] + g[Y] + b[Y] + (asrc[2 * i + 1] << abase);
+ dst[2 * i + 1] = r[Y] + g[Y] + b[Y] + ((int32_t)(asrc[2 * i + 1]) <<
abase);
#define PUTRGB48(dst, src, asrc, i, abase) \
Y = src[ 2 * i]; \
Are these able to be negative? If not, it may be wise to cast to
uint32_t instead as left shifting a negative integer is UB.
- Leo Izen (Traneptora)
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