| Message ID | 20230420100750.10463-1-laurent.pinchart@ideasonboard.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | media: uvcvideo: Don't expose unsupported formats to userspace | expand |
Hi Laurent I agree with the intent of the patch but am not sure that this will work. Regards! On Thu, 20 Apr 2023 at 12:07, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > > 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. > > Fixes: 50459f103edf ("media: uvcvideo: Remove format descriptions") > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > --- > drivers/media/usb/uvc/uvc_driver.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > index de64c9d789fd..25b8199f4e82 100644 > --- a/drivers/media/usb/uvc/uvc_driver.c > +++ b/drivers/media/usb/uvc/uvc_driver.c > @@ -251,14 +251,17 @@ 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]; > > /* > @@ -689,6 +692,8 @@ static int uvc_parse_streaming(struct uvc_device *dev, > &interval, buffer, buflen); For devices with unknown formats streaming->nformats will not be valid, it will be higher than the actual formats on streaming->formats. > if (ret < 0) > goto error; > + if (!ret) > + break; > > frame += format->nframes; > format++; > -- > Regards, > > Laurent Pinchart >
Hi Ricardo, On Mon, May 01, 2023 at 01:44:11PM +0200, Ricardo Ribalda wrote: > Hi Laurent > > I agree with the intent of the patch but am not sure that this will work. > > Regards! > > On Thu, 20 Apr 2023 at 12:07, Laurent Pinchart wrote: > > > > 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. > > > > Fixes: 50459f103edf ("media: uvcvideo: Remove format descriptions") > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > --- > > drivers/media/usb/uvc/uvc_driver.c | 13 +++++++++---- > > 1 file changed, 9 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > index de64c9d789fd..25b8199f4e82 100644 > > --- a/drivers/media/usb/uvc/uvc_driver.c > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > @@ -251,14 +251,17 @@ 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]; > > > > /* > > @@ -689,6 +692,8 @@ static int uvc_parse_streaming(struct uvc_device *dev, > > &interval, buffer, buflen); > > For devices with unknown formats streaming->nformats will not be > valid, it will be higher than the actual formats on > streaming->formats. Indeed. I think this could be handled quite simply: diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index d966d003632b..cc6608eb3ab9 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -679,7 +679,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, interval = (u32 *)&frame[nframes]; streaming->formats = format; - streaming->nformats = nformats; + streaming->nformats = 0; /* Parse the format descriptors. */ while (buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE) { @@ -695,6 +695,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, if (!ret) break; + streaming->nformats++; frame += format->nframes; format++; What do you think ? I can submit a v2 with this change. > > if (ret < 0) > > goto error; > > + if (!ret) > > + break; > > > > frame += format->nframes; > > format++;
Hi Laurent On Mon, 1 May 2023 at 14:01, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > > Hi Ricardo, > > On Mon, May 01, 2023 at 01:44:11PM +0200, Ricardo Ribalda wrote: > > Hi Laurent > > > > I agree with the intent of the patch but am not sure that this will work. > > > > Regards! > > > > On Thu, 20 Apr 2023 at 12:07, Laurent Pinchart wrote: > > > > > > 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. > > > > > > Fixes: 50459f103edf ("media: uvcvideo: Remove format descriptions") > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > > --- > > > drivers/media/usb/uvc/uvc_driver.c | 13 +++++++++---- > > > 1 file changed, 9 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > > index de64c9d789fd..25b8199f4e82 100644 > > > --- a/drivers/media/usb/uvc/uvc_driver.c > > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > > @@ -251,14 +251,17 @@ 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]; > > > > > > /* > > > @@ -689,6 +692,8 @@ static int uvc_parse_streaming(struct uvc_device *dev, > > > &interval, buffer, buflen); > > > > For devices with unknown formats streaming->nformats will not be > > valid, it will be higher than the actual formats on > > streaming->formats. > > Indeed. I think this could be handled quite simply: We will still be overallocating. I guess it is not a big deal... But what about a helper function. I think it will be less hacky diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index 7aefa76a42b3..b49c2b911d03 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -483,6 +483,33 @@ static int uvc_parse_format(struct uvc_device *dev, return buffer - start; } +static bool is_valid_format(unsigned char *buffer, unsigned int buflen) +{ + if (buflen < 2) + return false; + + switch (buffer[2]) { + case UVC_VS_FORMAT_UNCOMPRESSED: + case UVC_VS_FORMAT_MJPEG: + case UVC_VS_FORMAT_DV: + case UVC_VS_FORMAT_FRAME_BASED: + { + const struct uvc_format_desc *fmtdesc; + + if (buflen < 6) + return false; + fmtdesc = uvc_format_by_guid(&buffer[5]); + if (!fmtdesc) + return false; + return true; + } + default: + break; + } + + return false; +} + static int uvc_parse_streaming(struct uvc_device *dev, struct usb_interface *intf) { @@ -613,19 +640,15 @@ static int uvc_parse_streaming(struct uvc_device *dev, /* Count the format and frame descriptors. */ while (_buflen > 2 && _buffer[1] == USB_DT_CS_INTERFACE) { - switch (_buffer[2]) { - case UVC_VS_FORMAT_UNCOMPRESSED: - case UVC_VS_FORMAT_MJPEG: - case UVC_VS_FORMAT_FRAME_BASED: + if (is_valid_format(_buffer, _buflen)) nformats++; - break; + switch (_buffer[2]) { case UVC_VS_FORMAT_DV: /* * DV format has no frame descriptor. We will create a * dummy frame descriptor with a dummy frame interval. */ - nformats++; nframes++; nintervals++; break; @@ -679,11 +702,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, /* Parse the format descriptors. */ while (buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE) { - switch (buffer[2]) { - case UVC_VS_FORMAT_UNCOMPRESSED: - case UVC_VS_FORMAT_MJPEG: - case UVC_VS_FORMAT_DV: - case UVC_VS_FORMAT_FRAME_BASED: + if (!is_valid_format(buffer, buflen)) { format->frame = frame; ret = uvc_parse_format(dev, streaming, format, &interval, buffer, buflen); @@ -692,13 +711,6 @@ static int uvc_parse_streaming(struct uvc_device *dev, frame += format->nframes; format++; - - buflen -= ret; - buffer += ret; - continue; - - default: - break; } buflen -= buffer[0]; > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > index d966d003632b..cc6608eb3ab9 100644 > --- a/drivers/media/usb/uvc/uvc_driver.c > +++ b/drivers/media/usb/uvc/uvc_driver.c > @@ -679,7 +679,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, > interval = (u32 *)&frame[nframes]; > > streaming->formats = format; > - streaming->nformats = nformats; > + streaming->nformats = 0; > > /* Parse the format descriptors. */ > while (buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE) { > @@ -695,6 +695,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, > if (!ret) > break; > > + streaming->nformats++; > frame += format->nframes; > format++; > > What do you think ? I can submit a v2 with this change. > > > > if (ret < 0) > > > goto error; > > > + if (!ret) > > > + break; > > > > > > frame += format->nframes; > > > format++; > > -- > Regards, > > Laurent Pinchart -- Ricardo Ribalda
Hi Ricardo, On Mon, May 01, 2023 at 03:22:16PM +0200, Ricardo Ribalda wrote: > On Mon, 1 May 2023 at 14:01, Laurent Pinchart wrote: > > On Mon, May 01, 2023 at 01:44:11PM +0200, Ricardo Ribalda wrote: > > > Hi Laurent > > > > > > I agree with the intent of the patch but am not sure that this will work. > > > > > > Regards! > > > > > > On Thu, 20 Apr 2023 at 12:07, Laurent Pinchart wrote: > > > > > > > > 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. > > > > > > > > Fixes: 50459f103edf ("media: uvcvideo: Remove format descriptions") > > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > > > --- > > > > drivers/media/usb/uvc/uvc_driver.c | 13 +++++++++---- > > > > 1 file changed, 9 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > > > index de64c9d789fd..25b8199f4e82 100644 > > > > --- a/drivers/media/usb/uvc/uvc_driver.c > > > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > > > @@ -251,14 +251,17 @@ 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]; > > > > > > > > /* > > > > @@ -689,6 +692,8 @@ static int uvc_parse_streaming(struct uvc_device *dev, > > > > &interval, buffer, buflen); > > > > > > For devices with unknown formats streaming->nformats will not be > > > valid, it will be higher than the actual formats on > > > streaming->formats. > > > > Indeed. I think this could be handled quite simply: > > We will still be overallocating. I guess it is not a big deal... > > But what about a helper function. I think it will be less hacky > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c > b/drivers/media/usb/uvc/uvc_driver.c > index 7aefa76a42b3..b49c2b911d03 100644 > --- a/drivers/media/usb/uvc/uvc_driver.c > +++ b/drivers/media/usb/uvc/uvc_driver.c > @@ -483,6 +483,33 @@ static int uvc_parse_format(struct uvc_device *dev, > return buffer - start; > } > > +static bool is_valid_format(unsigned char *buffer, unsigned int buflen) > +{ > + if (buflen < 2) > + return false; > + > + switch (buffer[2]) { > + case UVC_VS_FORMAT_UNCOMPRESSED: > + case UVC_VS_FORMAT_MJPEG: > + case UVC_VS_FORMAT_DV: > + case UVC_VS_FORMAT_FRAME_BASED: > + { > + const struct uvc_format_desc *fmtdesc; > + > + if (buflen < 6) Not the right length. > + return false; > + fmtdesc = uvc_format_by_guid(&buffer[5]); This isn't quite right for MJPEG and DV. Honestly, I'm not sure I would bother. We're overallocating only for devices that expose non-supported formats. That's a very small minority of devices, the extra memory is quite small, and we should instead add support for those formats anyway. > + if (!fmtdesc) > + return false; > + return true; > + } > + default: > + break; > + } > + > + return false; > +} > + > static int uvc_parse_streaming(struct uvc_device *dev, > struct usb_interface *intf) > { > @@ -613,19 +640,15 @@ static int uvc_parse_streaming(struct uvc_device *dev, > > /* Count the format and frame descriptors. */ > while (_buflen > 2 && _buffer[1] == USB_DT_CS_INTERFACE) { > - switch (_buffer[2]) { > - case UVC_VS_FORMAT_UNCOMPRESSED: > - case UVC_VS_FORMAT_MJPEG: > - case UVC_VS_FORMAT_FRAME_BASED: > + if (is_valid_format(_buffer, _buflen)) > nformats++; > - break; > > + switch (_buffer[2]) { > case UVC_VS_FORMAT_DV: > /* > * DV format has no frame descriptor. We will create a > * dummy frame descriptor with a dummy frame interval. > */ > - nformats++; > nframes++; > nintervals++; > break; > @@ -679,11 +702,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, > > /* Parse the format descriptors. */ > while (buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE) { > - switch (buffer[2]) { > - case UVC_VS_FORMAT_UNCOMPRESSED: > - case UVC_VS_FORMAT_MJPEG: > - case UVC_VS_FORMAT_DV: > - case UVC_VS_FORMAT_FRAME_BASED: > + if (!is_valid_format(buffer, buflen)) { > format->frame = frame; > ret = uvc_parse_format(dev, streaming, format, > &interval, buffer, buflen); > @@ -692,13 +711,6 @@ static int uvc_parse_streaming(struct uvc_device *dev, > > frame += format->nframes; > format++; > - > - buflen -= ret; > - buffer += ret; > - continue; > - > - default: > - break; > } > > buflen -= buffer[0]; > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > index d966d003632b..cc6608eb3ab9 100644 > > --- a/drivers/media/usb/uvc/uvc_driver.c > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > @@ -679,7 +679,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, > > interval = (u32 *)&frame[nframes]; > > > > streaming->formats = format; > > - streaming->nformats = nformats; > > + streaming->nformats = 0; > > > > /* Parse the format descriptors. */ > > while (buflen > 2 && buffer[1] == USB_DT_CS_INTERFACE) { > > @@ -695,6 +695,7 @@ static int uvc_parse_streaming(struct uvc_device *dev, > > if (!ret) > > break; > > > > + streaming->nformats++; > > frame += format->nframes; > > format++; > > > > What do you think ? I can submit a v2 with this change. > > > > > > if (ret < 0) > > > > goto error; > > > > + if (!ret) > > > > + break; > > > > > > > > frame += format->nframes; > > > > format++;
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index de64c9d789fd..25b8199f4e82 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -251,14 +251,17 @@ 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]; /* @@ -689,6 +692,8 @@ static int uvc_parse_streaming(struct uvc_device *dev, &interval, buffer, buflen); if (ret < 0) goto error; + if (!ret) + break; frame += format->nframes; format++;
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. Fixes: 50459f103edf ("media: uvcvideo: Remove format descriptions") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> --- drivers/media/usb/uvc/uvc_driver.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)