From: Kees Cook Date: Fri, 6 Jan 2023 06:17:04 +0000 (-0800) Subject: media: uvcvideo: Silence memcpy() run-time false positive warnings X-Git-Tag: v6.6.7~3400^2~51^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b839212988575c701aab4d3d9ca15e44c87e383c;p=platform%2Fkernel%2Flinux-starfive.git media: uvcvideo: Silence memcpy() run-time false positive warnings The memcpy() in uvc_video_decode_meta() intentionally copies across the length and flags members and into the trailing buf flexible array. Split the copy so that the compiler can better reason about (the lack of) buffer overflows here. Avoid the run-time false positive warning: memcpy: detected field-spanning write (size 12) of single field "&meta->length" at drivers/media/usb/uvc/uvc_video.c:1355 (size 1) Additionally fix a typo in the documentation for struct uvc_meta_buf. Reported-by: ionut_n2001@yahoo.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=216810 Signed-off-by: Kees Cook Reviewed-by: Laurent Pinchart Signed-off-by: Laurent Pinchart --- diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index 98d34d2..d4b023d4 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -1356,7 +1356,9 @@ static void uvc_video_decode_meta(struct uvc_streaming *stream, if (has_scr) memcpy(stream->clock.last_scr, scr, 6); - memcpy(&meta->length, mem, length); + meta->length = mem[0]; + meta->flags = mem[1]; + memcpy(meta->buf, &mem[2], length - 2); meta_buf->bytesused += length + sizeof(meta->ns) + sizeof(meta->sof); uvc_dbg(stream->dev, FRAME, diff --git a/include/uapi/linux/uvcvideo.h b/include/uapi/linux/uvcvideo.h index d45d0c2..f8618545 100644 --- a/include/uapi/linux/uvcvideo.h +++ b/include/uapi/linux/uvcvideo.h @@ -88,7 +88,7 @@ struct uvc_xu_control_query { * struct. The first two fields are added by the driver, they can be used for * clock synchronisation. The rest is an exact copy of a UVC payload header. * Only complete objects with complete buffers are included. Therefore it's - * always sizeof(meta->ts) + sizeof(meta->sof) + meta->length bytes large. + * always sizeof(meta->ns) + sizeof(meta->sof) + meta->length bytes large. */ struct uvc_meta_buf { __u64 ns;