Patch "media: uvcvideo: Don't expose unsupported formats to userspace" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    media: uvcvideo: Don't expose unsupported formats to userspace

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     media-uvcvideo-don-t-expose-unsupported-formats-to-u.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 18b568da34a66c2485bce4d7f56e4e5700a51b34
Author: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Date:   Thu Apr 20 10:45:59 2023 +0100

    media: uvcvideo: Don't expose unsupported formats to userspace
    
    [ Upstream commit 81f3affa19d6ab0c32aef46b053838219eef7e71 ]
    
    When the uvcvideo driver encounters a format descriptor with an unknown
    format GUID, it creates a corresponding struct uvc_format instance with
    the fcc field set to 0. Since commit 50459f103edf ("media: uvcvideo:
    Remove format descriptions"), the driver relies on the V4L2 core to
    provide the format description string, which the V4L2 core can't do
    without a valid 4CC. This triggers a WARN_ON.
    
    As a format with a zero 4CC can't be selected, it is unusable for
    applications. Ignore the format completely without creating a uvc_format
    instance, which fixes the warning.
    
    Link: https://bugzilla.kernel.org/show_bug.cgi?id=217252
    Link: https://bugzilla.redhat.com/show_bug.cgi?id=2180107
    
    Fixes: 50459f103edf ("media: uvcvideo: Remove format descriptions")
    Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
    Reviewed-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
    Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 2e7df1de0af9a..b19c75a6f5952 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -530,14 +530,17 @@ static int uvc_parse_format(struct uvc_device *dev,
 		/* Find the format descriptor from its GUID. */
 		fmtdesc = uvc_format_by_guid(&buffer[5]);
 
-		if (fmtdesc != NULL) {
-			format->fcc = fmtdesc->fcc;
-		} else {
+		if (!fmtdesc) {
+			/*
+			 * Unknown video formats are not fatal errors, the
+			 * caller will skip this descriptor.
+			 */
 			dev_info(&streaming->intf->dev,
 				 "Unknown video format %pUl\n", &buffer[5]);
-			format->fcc = 0;
+			return 0;
 		}
 
+		format->fcc = fmtdesc->fcc;
 		format->bpp = buffer[21];
 
 		/* Some devices report a format that doesn't match what they
@@ -945,7 +948,7 @@ static int uvc_parse_streaming(struct uvc_device *dev,
 	interval = (u32 *)&frame[nframes];
 
 	streaming->format = format;
-	streaming->nformats = nformats;
+	streaming->nformats = 0;
 
 	/* Parse the format descriptors. */
 	while (buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE) {
@@ -959,7 +962,10 @@ static int uvc_parse_streaming(struct uvc_device *dev,
 				&interval, buffer, buflen);
 			if (ret < 0)
 				goto error;
+			if (!ret)
+				break;
 
+			streaming->nformats++;
 			frame += format->nframes;
 			format++;