From: Karina Yankevich Date: Wed, 21 Aug 2024 11:31:34 +0000 (+0300) Subject: media: v4l2-dv-timings: prevent possible overflow in v4l2_detect_gtf() X-Git-Tag: v6.15-rc1~174^2~18 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3edd1fc48d2c045e8259561797c89fe78f01717e;p=thirdparty%2Fkernel%2Flinux.git media: v4l2-dv-timings: prevent possible overflow in v4l2_detect_gtf() In v4l2_detect_gtf(), it seems safer to cast the 32-bit image_width variable to the 64-bit type u64 before multiplying to avoid a possible overflow. The resulting object code even seems to look better, at least on x86_64. Found by Linux Verification Center (linuxtesting.org) with Svace. [Sergey: rewrote the patch subject/descripition] Fixes: c9bc9f50753d ("[media] v4l2-dv-timings: fix overflow in gtf timings calculation") Cc: stable@vger.kernel.org Signed-off-by: Karina Yankevich Signed-off-by: Sergey Shtylyov Signed-off-by: Hans Verkuil --- diff --git a/drivers/media/v4l2-core/v4l2-dv-timings.c b/drivers/media/v4l2-core/v4l2-dv-timings.c index 6361e11d2be7c..7710cb26bea00 100644 --- a/drivers/media/v4l2-core/v4l2-dv-timings.c +++ b/drivers/media/v4l2-core/v4l2-dv-timings.c @@ -764,7 +764,7 @@ bool v4l2_detect_gtf(unsigned int frame_height, u64 num; u32 den; - num = ((image_width * GTF_D_C_PRIME * (u64)hfreq) - + num = (((u64)image_width * GTF_D_C_PRIME * hfreq) - ((u64)image_width * GTF_D_M_PRIME * 1000)); den = (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000) * (2 * GTF_CELL_GRAN); @@ -774,7 +774,7 @@ bool v4l2_detect_gtf(unsigned int frame_height, u64 num; u32 den; - num = ((image_width * GTF_S_C_PRIME * (u64)hfreq) - + num = (((u64)image_width * GTF_S_C_PRIME * hfreq) - ((u64)image_width * GTF_S_M_PRIME * 1000)); den = (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000) * (2 * GTF_CELL_GRAN);