4.19-stable review patch. If anyone has any objections, please let me know.
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From: Ricardo Ribalda ribalda@chromium.org
[ Upstream commit c8931ef55bd325052ec496f242aea7f6de47dc9c ]
Struct uvc_frame and interval (u32*) are packaged together on streaming->formats on a single contiguous allocation.
Right now they are allocated right after uvc_format, without taking into consideration their required alignment.
This is working fine because both structures have a field with a pointer, but it will stop working when the sizeof() of any of those structs is not a multiple of the sizeof(void*).
Enforce that alignment during the allocation.
Signed-off-by: Ricardo Ribalda ribalda@chromium.org Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Link: https://lore.kernel.org/r/20240404-uvc-align-v2-1-9e104b0ecfbd@chromium.org Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/usb/uvc/uvc_driver.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index 775d67720648..6367ee9c0066 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -860,16 +860,26 @@ static int uvc_parse_streaming(struct uvc_device *dev, goto error; }
- size = nformats * sizeof(*format) + nframes * sizeof(*frame) + /* + * Allocate memory for the formats, the frames and the intervals, + * plus any required padding to guarantee that everything has the + * correct alignment. + */ + size = nformats * sizeof(*format); + size = ALIGN(size, __alignof__(*frame)) + nframes * sizeof(*frame); + size = ALIGN(size, __alignof__(*interval)) + nintervals * sizeof(*interval); + format = kzalloc(size, GFP_KERNEL); - if (format == NULL) { + if (!format) { ret = -ENOMEM; goto error; }
- frame = (struct uvc_frame *)&format[nformats]; - interval = (u32 *)&frame[nframes]; + frame = (void *)format + nformats * sizeof(*format); + frame = PTR_ALIGN(frame, __alignof__(*frame)); + interval = (void *)frame + nframes * sizeof(*frame); + interval = PTR_ALIGN(interval, __alignof__(*interval));
streaming->format = format; streaming->nformats = nformats;