From: Kieran Kunhya via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Cc: michaelni <code@ffmpeg.org>, Kieran Kunhya <kieran618@googlemail.com>
Subject: [FFmpeg-devel] Re: [PATCH] swscale/output: Fix unsigned cast position in yuv2* (PR #20698)
Date: Mon, 13 Oct 2025 17:20:55 +0100
Message-ID: <CABGuwEmni6hv6mxjN+57AEmnPbVKDG+SHOyErMObAjTF=ek0BQ@mail.gmail.com> (raw)
In-Reply-To: <176036206413.25.15905318861432080946@bf907ddaa564>
On Mon, 13 Oct 2025, 14:28 michaelni via ffmpeg-devel, <
ffmpeg-devel@ffmpeg.org> wrote:
> PR #20698 opened by michaelni
> URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20698
> Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20698.patch
>
>
> >From 93794583405909cfe8e7abffdd84c2454959ff18 Mon Sep 17 00:00:00 2001
> From: Michael Niedermayer <michael@niedermayer.cc>
> Date: Mon, 13 Oct 2025 14:32:45 +0200
> Subject: [PATCH 1/2] swscale/output: Fix integer overflow in
> yuv2ya16_X_c_template()
>
> Found-by: colod colod <colodcolod7@gmail.com>
>
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
> libswscale/output.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libswscale/output.c b/libswscale/output.c
> index b873276c00..cb6630bd73 100644
> --- a/libswscale/output.c
> +++ b/libswscale/output.c
> @@ -1028,7 +1028,7 @@ yuv2ya16_X_c_template(SwsInternal *c, const int16_t
> *lumFilter,
> int A = 0xffff;
>
> for (j = 0; j < lumFilterSize; j++)
> - Y += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> + Y += lumSrc[j][i] * (unsigned)lumFilter[j];
>
> Y >>= 15;
> Y += (1<<3) + 0x8000;
> @@ -1037,7 +1037,7 @@ yuv2ya16_X_c_template(SwsInternal *c, const int16_t
> *lumFilter,
> if (hasAlpha) {
> A = -0x40000000 + (1<<14);
> for (j = 0; j < lumFilterSize; j++)
> - A += (unsigned)(alpSrc[j][i] * lumFilter[j]);
> + A += alpSrc[j][i] * (unsigned)lumFilter[j];
>
> A >>= 15;
> A += 0x8000;
> --
> 2.49.1
>
>
> >From 9d0761453e5ecaa1344d63e2fcc9bd3cc6d4d0f6 Mon Sep 17 00:00:00 2001
> From: Michael Niedermayer <michael@niedermayer.cc>
> Date: Mon, 13 Oct 2025 14:46:16 +0200
> Subject: [PATCH 2/2] swscale/output: Fix unsigned cast position in yuv2*
>
> Fixes: signed overflow
>
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
> libswscale/output.c | 90 ++++++++++++++++++++++-----------------------
> 1 file changed, 45 insertions(+), 45 deletions(-)
>
> diff --git a/libswscale/output.c b/libswscale/output.c
> index cb6630bd73..877db04f36 100644
> --- a/libswscale/output.c
> +++ b/libswscale/output.c
> @@ -503,8 +503,8 @@ static void yuv2nv12cX_c(enum AVPixelFormat dstFormat,
> const uint8_t *chrDither,
> int v = chrDither[(i + 3) & 7] << 12;
> int j;
> for (j=0; j<chrFilterSize; j++) {
> - u += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - v += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + u += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + v += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
>
> dest[2*i]= av_clip_uint8(u>>19);
> @@ -516,8 +516,8 @@ static void yuv2nv12cX_c(enum AVPixelFormat dstFormat,
> const uint8_t *chrDither,
> int v = chrDither[(i + 3) & 7] << 12;
> int j;
> for (j=0; j<chrFilterSize; j++) {
> - u += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - v += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + u += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + v += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
>
> dest[2*i]= av_clip_uint8(v>>19);
> @@ -577,8 +577,8 @@ static void yuv2p01xcX_c(int big_endian, const uint8_t
> *chrDither,
> int v = 1 << (shift - 1);
>
> for (j = 0; j < chrFilterSize; j++) {
> - u += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - v += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + u += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + v += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
>
> output_pixel(&dest[2*i] , u);
> @@ -678,8 +678,8 @@ yuv2mono_X_c_template(SwsInternal *c, const int16_t
> *lumFilter,
> int Y2 = 1 << 18;
>
> for (j = 0; j < lumFilterSize; j++) {
> - Y1 += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> - Y2 += (unsigned)(lumSrc[j][i+1] * lumFilter[j]);
> + Y1 += lumSrc[j][i] * (unsigned)lumFilter[j];
> + Y2 += lumSrc[j][i+1] * (unsigned)lumFilter[j];
> }
> Y1 >>= 19;
> Y2 >>= 19;
> @@ -896,12 +896,12 @@ yuv2422_X_c_template(SwsInternal *c, const int16_t
> *lumFilter,
> int V = 1 << 18;
>
> for (j = 0; j < lumFilterSize; j++) {
> - Y1 += (unsigned)(lumSrc[j][i * 2] * lumFilter[j]);
> - Y2 += (unsigned)(lumSrc[j][i * 2 + 1] * lumFilter[j]);
> + Y1 += lumSrc[j][i * 2] * (unsigned)lumFilter[j];
> + Y2 += lumSrc[j][i * 2 + 1] * (unsigned)lumFilter[j];
> }
> for (j = 0; j < chrFilterSize; j++) {
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
> Y1 >>= 19;
> Y2 >>= 19;
> @@ -1802,12 +1802,12 @@ yuv2rgb_X_c_template(SwsInternal *c, const int16_t
> *lumFilter,
> const void *r, *g, *b;
>
> for (j = 0; j < lumFilterSize; j++) {
> - Y1 += (unsigned)(lumSrc[j][i * 2] * lumFilter[j]);
> - Y2 += (unsigned)(lumSrc[j][i * 2 + 1] * lumFilter[j]);
> + Y1 += lumSrc[j][i * 2] * (unsigned)lumFilter[j];
> + Y2 += lumSrc[j][i * 2 + 1] * (unsigned)lumFilter[j];
> }
> for (j = 0; j < chrFilterSize; j++) {
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
> Y1 >>= 19;
> Y2 >>= 19;
> @@ -1817,8 +1817,8 @@ yuv2rgb_X_c_template(SwsInternal *c, const int16_t
> *lumFilter,
> A1 = 1 << 18;
> A2 = 1 << 18;
> for (j = 0; j < lumFilterSize; j++) {
> - A1 += (unsigned)(alpSrc[j][i * 2 ] * lumFilter[j]);
> - A2 += (unsigned)(alpSrc[j][i * 2 + 1] * lumFilter[j]);
> + A1 += alpSrc[j][i * 2 ] * (unsigned)lumFilter[j];
> + A2 += alpSrc[j][i * 2 + 1] * (unsigned)lumFilter[j];
> }
> A1 >>= 19;
> A2 >>= 19;
> @@ -2179,11 +2179,11 @@ yuv2rgb_full_X_c_template(SwsInternal *c, const
> int16_t *lumFilter,
> int V = (1<<9)-(128 << 19);
>
> for (j = 0; j < lumFilterSize; j++) {
> - Y += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> + Y += lumSrc[j][i] * (unsigned)lumFilter[j];
> }
> for (j = 0; j < chrFilterSize; j++) {
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
> Y >>= 10;
> U >>= 10;
> @@ -2191,7 +2191,7 @@ yuv2rgb_full_X_c_template(SwsInternal *c, const
> int16_t *lumFilter,
> if (hasAlpha) {
> A = 1 << 18;
> for (j = 0; j < lumFilterSize; j++) {
> - A += (unsigned)(alpSrc[j][i] * lumFilter[j]);
> + A += alpSrc[j][i] * (unsigned)lumFilter[j];
> }
> A >>= 19;
> if (A & 0x100)
> @@ -2360,11 +2360,11 @@ yuv2gbrp_full_X_c(SwsInternal *c, const int16_t
> *lumFilter,
> int R, G, B;
>
> for (j = 0; j < lumFilterSize; j++)
> - Y += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> + Y += lumSrc[j][i] * (unsigned)lumFilter[j];
>
> for (j = 0; j < chrFilterSize; j++) {
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
>
> Y >>= 10;
> @@ -2375,7 +2375,7 @@ yuv2gbrp_full_X_c(SwsInternal *c, const int16_t
> *lumFilter,
> A = 1 << 18;
>
> for (j = 0; j < lumFilterSize; j++)
> - A += (unsigned)(alpSrc[j][i] * lumFilter[j]);
> + A += alpSrc[j][i] * (unsigned)lumFilter[j];
>
> if (A & 0xF8000000)
> A = av_clip_uintp2(A, 27);
> @@ -2679,7 +2679,7 @@ yuv2ya8_X_c(SwsInternal *c, const int16_t *lumFilter,
> int Y = 1 << 18, A = 1 << 18;
>
> for (j = 0; j < lumFilterSize; j++)
> - Y += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> + Y += lumSrc[j][i] * (unsigned)lumFilter[j];
>
> Y >>= 19;
> if (Y & 0x100)
> @@ -2687,7 +2687,7 @@ yuv2ya8_X_c(SwsInternal *c, const int16_t *lumFilter,
>
> if (hasAlpha) {
> for (j = 0; j < lumFilterSize; j++)
> - A += (unsigned)(alpSrc[j][i] * lumFilter[j]);
> + A += alpSrc[j][i] * (unsigned)lumFilter[j];
>
> A >>= 19;
>
> @@ -2793,11 +2793,11 @@ yuv2v30_X_c_template(SwsInternal *c, const int16_t
> *lumFilter,
> int j;
>
> for (j = 0; j < lumFilterSize; j++)
> - Y += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> + Y += lumSrc[j][i] * (unsigned)lumFilter[j];
>
> for (j = 0; j < chrFilterSize; j++) {
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
>
> Y = av_clip_uintp2(Y >> 17, 10);
> @@ -2847,11 +2847,11 @@ yuv2xv36_X_c(SwsInternal *c, const int16_t
> *lumFilter,
> int j;
>
> for (j = 0; j < lumFilterSize; j++)
> - Y += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> + Y += lumSrc[j][i] * (unsigned)lumFilter[j];
>
> for (j = 0; j < chrFilterSize; j++) {
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
> }
>
> output_pixels(dest + 8 * i + 2, Y, 15, 12, 4)
> @@ -3011,13 +3011,13 @@ yuv2ayuv_X_c_template(SwsInternal *c, const
> int16_t *lumFilter,
> int V = 1 << 18, A = 255;
>
> for (j = 0; j < lumFilterSize; j++)
> - Y += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> + Y += lumSrc[j][i] * (unsigned)lumFilter[j];
>
> for (j = 0; j < chrFilterSize; j++)
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
>
> for (j = 0; j < chrFilterSize; j++)
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
>
> Y >>= 19;
> U >>= 19;
> @@ -3034,7 +3034,7 @@ yuv2ayuv_X_c_template(SwsInternal *c, const int16_t
> *lumFilter,
> A = 1 << 18;
>
> for (j = 0; j < lumFilterSize; j++)
> - A += (unsigned)(alpSrc[j][i] * lumFilter[j]);
> + A += alpSrc[j][i] * (unsigned)lumFilter[j];
>
> A >>= 19;
>
> @@ -3105,13 +3105,13 @@ AYUVPACKEDWRAPPER(uyva, AV_PIX_FMT_UYVA)
> int U = 1 << (shift - 1), V = 1 << (shift - 1); \
> \
> for (j = 0; j < lumFilterSize; j++) { \
> - Y1 += (unsigned)(lumSrc[j][i * 2] * lumFilter[j]);
> \
> - Y2 += (unsigned)(lumSrc[j][i * 2 + 1] * lumFilter[j]);
> \
> + Y1 += lumSrc[j][i * 2] * (unsigned)lumFilter[j];
> \
> + Y2 += lumSrc[j][i * 2 + 1] * (unsigned)lumFilter[j];
> \
> } \
> \
> for (j = 0; j < chrFilterSize; j++) { \
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> \
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> \
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
> \
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
> \
> } \
> \
> output_pixel(dest + 8 * i + 0, Y1, bits); \
> @@ -3259,13 +3259,13 @@ yuv2vyu444_X_c(SwsInternal *c, const int16_t
> *lumFilter,
> int V = 1 << 18;
>
> for (j = 0; j < lumFilterSize; j++)
> - Y += (unsigned)(lumSrc[j][i] * lumFilter[j]);
> + Y += lumSrc[j][i] * (unsigned)lumFilter[j];
>
> for (j = 0; j < chrFilterSize; j++)
> - U += (unsigned)(chrUSrc[j][i] * chrFilter[j]);
> + U += chrUSrc[j][i] * (unsigned)chrFilter[j];
>
> for (j = 0; j < chrFilterSize; j++)
> - V += (unsigned)(chrVSrc[j][i] * chrFilter[j]);
> + V += chrVSrc[j][i] * (unsigned)chrFilter[j];
>
> Y >>= 19;
> U >>= 19;
> --
> 2.49.1
>
Seems fine
>
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next prev parent reply other threads:[~2025-10-13 16:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-13 13:27 [FFmpeg-devel] " michaelni via ffmpeg-devel
2025-10-13 16:20 ` Kieran Kunhya via ffmpeg-devel [this message]
2025-10-14 19:13 ` [FFmpeg-devel] " Michael Niedermayer via ffmpeg-devel
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