[FFmpeg-devel] [PATCH 1/3] swscale/swscale: Do not crash on floats

[FFmpeg-devel] [PATCH 1/3] swscale/swscale: Do not crash on floats

[Michael Niedermayer]

Fixes: shift exponent 32 is too large for 32-bit type 'unsigned int'
Fixes: division by zero
Fixes: 391981061/clusterfuzz-testcase-minimized-ffmpeg_SWS_fuzzer-6691017763389440
Fixes: 392929028/clusterfuzz-testcase-minimized-ffmpeg_SWS_fuzzer-5142088307507200

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

diff --git a/libswscale/swscale.c b/libswscale/swscale.c
index 98f94d029fb..38b1e198239 100644
--- a/libswscale/swscale.c
+++ b/libswscale/swscale.c
@@ -623,7 +623,7 @@ av_cold void ff_sws_init_range_convert(SwsInternal *c)
 {
     c->lumConvertRange = NULL;
     c->chrConvertRange = NULL;
-    if (c->opts.src_range != c->opts.dst_range && !isAnyRGB(c->opts.dst_format)) {
+    if (c->opts.src_range != c->opts.dst_range && !isAnyRGB(c->opts.dst_format) && c->dstBpc < 32) {
         init_range_convert_constants(c);
         if (c->dstBpc <= 14) {
             if (c->opts.src_range) {
-- 
2.48.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

[FFmpeg-devel] [PATCH 2/3] swscale/output: Fix integer overflow in yuv2gbrp_full_X_c()

[Michael Niedermayer]

Fixes: signed integer overflow: 1966895953 + 210305024 cannot be represented in type 'int'
Fixes: 391921975/clusterfuzz-testcase-minimized-ffmpeg_SWS_fuzzer-5916798905548800

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libswscale/output.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libswscale/output.c b/libswscale/output.c
index 21c3bdc3076..084727edfe0 100644
--- a/libswscale/output.c
+++ b/libswscale/output.c
@@ -2316,9 +2316,9 @@ yuv2gbrp_full_X_c(SwsInternal *c, const int16_t *lumFilter,
         Y -= c->yuv2rgb_y_offset;
         Y *= c->yuv2rgb_y_coeff;
         Y += 1 << (SH-1);
-        R = Y + V * c->yuv2rgb_v2r_coeff;
-        G = Y + V * c->yuv2rgb_v2g_coeff + U * c->yuv2rgb_u2g_coeff;
-        B = Y +                            U * c->yuv2rgb_u2b_coeff;
+        R = Y + V * (unsigned)c->yuv2rgb_v2r_coeff;
+        G = Y + V * (unsigned)c->yuv2rgb_v2g_coeff + U * (unsigned)c->yuv2rgb_u2g_coeff;
+        B = Y +                                      U * (unsigned)c->yuv2rgb_u2b_coeff;
 
         if ((R | G | B) & 0xC0000000) {
             R = av_clip_uintp2(R, 30);
-- 
2.48.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

[FFmpeg-devel] [PATCH 3/3] avcodec/osq: avoid undefined negation

[Michael Niedermayer]

Fixes: negation of -2147483648 cannot be represented in type 'int32_t' (aka 'int'); cast to an unsigned type to negate this value to itself
Fixes: 390646659/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_OSQ_fuzzer-5040277374435328

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

diff --git a/libavcodec/osq.c b/libavcodec/osq.c
index 83b4a9d618d..5c7826778dc 100644
--- a/libavcodec/osq.c
+++ b/libavcodec/osq.c
@@ -190,7 +190,7 @@ static uint32_t get_urice(GetBitContext *gb, int k)
 
 static int32_t get_srice(GetBitContext *gb, int x)
 {
-    int32_t y = get_urice(gb, x);
+    uint32_t y = get_urice(gb, x);
     return get_bits1(gb) ? -y : y;
 }
 
-- 
2.48.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Re: [FFmpeg-devel] [PATCH 3/3] avcodec/osq: avoid undefined negation

[James Almer]

[-- Attachment #1.1.1: Type: text/plain, Size: 1032 bytes --]

On 2/3/2025 11:58 PM, Michael Niedermayer wrote:
> Fixes: negation of -2147483648 cannot be represented in type 'int32_t' (aka 'int'); cast to an unsigned type to negate this value to itself
> Fixes: 390646659/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_OSQ_fuzzer-5040277374435328
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>   libavcodec/osq.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavcodec/osq.c b/libavcodec/osq.c
> index 83b4a9d618d..5c7826778dc 100644
> --- a/libavcodec/osq.c
> +++ b/libavcodec/osq.c
> @@ -190,7 +190,7 @@ static uint32_t get_urice(GetBitContext *gb, int k)
>   
>   static int32_t get_srice(GetBitContext *gb, int x)
>   {
> -    int32_t y = get_urice(gb, x);
> +    uint32_t y = get_urice(gb, x);
>       return get_bits1(gb) ? -y : y;

Does -y here work as intended now that y is unsigned?

>   }
>   


[-- Attachment #1.2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 495 bytes --]

[-- Attachment #2: Type: text/plain, Size: 251 bytes --]

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Re: [FFmpeg-devel] [PATCH 3/3] avcodec/osq: avoid undefined negation

[Michael Niedermayer]

[-- Attachment #1.1: Type: text/plain, Size: 1398 bytes --]

On Tue, Feb 04, 2025 at 12:16:59AM -0300, James Almer wrote:
> On 2/3/2025 11:58 PM, Michael Niedermayer wrote:
> > Fixes: negation of -2147483648 cannot be represented in type 'int32_t' (aka 'int'); cast to an unsigned type to negate this value to itself
> > Fixes: 390646659/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_OSQ_fuzzer-5040277374435328
> > 
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >   libavcodec/osq.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/libavcodec/osq.c b/libavcodec/osq.c
> > index 83b4a9d618d..5c7826778dc 100644
> > --- a/libavcodec/osq.c
> > +++ b/libavcodec/osq.c
> > @@ -190,7 +190,7 @@ static uint32_t get_urice(GetBitContext *gb, int k)
> >   static int32_t get_srice(GetBitContext *gb, int x)
> >   {
> > -    int32_t y = get_urice(gb, x);
> > +    uint32_t y = get_urice(gb, x);
> >       return get_bits1(gb) ? -y : y;
> 
> Does -y here work as intended now that y is unsigned?

why would it not ?

subtraction is the same operation for signed (twos complement) and unsigned

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The worst form of inequality is to try to make unequal things equal.
-- Aristotle

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]

[-- Attachment #2: Type: text/plain, Size: 251 bytes --]

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".