| Message ID | YxjpMMUb3WP5Rbu7@work (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Gustavo A. R. Silva |
| Headers | show |
| Series | [next] media: usb: pwc-uncompress: Use flex array destination for memcpy() | expand |
On Wed, Sep 07, 2022 at 07:55:44PM +0100, Gustavo A. R. Silva wrote: > In preparation for FORTIFY_SOURCE performing run-time destination buffer > bounds checking for memcpy(), specify the destination output buffer > explicitly, instead of asking memcpy() to write past the end of what looked > like a fixed-size object. > > Notice that raw_frame is a pointer to a structure that contains > flexible-array member rawframe[]: > > drivers/media/usb/pwc/pwc.h: > 190 struct pwc_raw_frame { > 191 __le16 type; /* type of the webcam */ > 192 __le16 vbandlength; /* Size of 4 lines compressed (used by the > 193 decompressor) */ > 194 __u8 cmd[4]; /* the four byte of the command (in case of > 195 nala, only the first 3 bytes is filled) */ > 196 __u8 rawframe[]; /* frame_size = H / 4 * vbandlength */ > 197 } __packed; > > Link: https://github.com/KSPP/linux/issues/200 > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks! Yeah, this looks very similar to other transformations like this. And this one even had the flex array already! :) Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/drivers/media/usb/pwc/pwc-uncompress.c b/drivers/media/usb/pwc/pwc-uncompress.c index faf44cdeb268..cf2591a9675c 100644 --- a/drivers/media/usb/pwc/pwc-uncompress.c +++ b/drivers/media/usb/pwc/pwc-uncompress.c @@ -39,7 +39,7 @@ int pwc_decompress(struct pwc_device *pdev, struct pwc_frame_buf *fbuf) * first 3 bytes is filled (Nala case). We can * determine this using the type of the webcam */ memcpy(raw_frame->cmd, pdev->cmd_buf, 4); - memcpy(raw_frame+1, yuv, pdev->frame_size); + memcpy(raw_frame->rawframe, yuv, pdev->frame_size); vb2_set_plane_payload(&fbuf->vb.vb2_buf, 0, struct_size(raw_frame, rawframe, pdev->frame_size)); return 0;
In preparation for FORTIFY_SOURCE performing run-time destination buffer bounds checking for memcpy(), specify the destination output buffer explicitly, instead of asking memcpy() to write past the end of what looked like a fixed-size object. Notice that raw_frame is a pointer to a structure that contains flexible-array member rawframe[]: drivers/media/usb/pwc/pwc.h: 190 struct pwc_raw_frame { 191 __le16 type; /* type of the webcam */ 192 __le16 vbandlength; /* Size of 4 lines compressed (used by the 193 decompressor) */ 194 __u8 cmd[4]; /* the four byte of the command (in case of 195 nala, only the first 3 bytes is filled) */ 196 __u8 rawframe[]; /* frame_size = H / 4 * vbandlength */ 197 } __packed; Link: https://github.com/KSPP/linux/issues/200 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- drivers/media/usb/pwc/pwc-uncompress.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)