From 1a10d7fdb6d0e235e9d230916244cc2769d3f170 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 17 Jun 2021 14:33:29 +0200 Subject: [PATCH] media: uvc: don't do DMA on stack As warned by smatch: drivers/media/usb/uvc/uvc_v4l2.c:911 uvc_ioctl_g_input() error: doing dma on the stack (&i) drivers/media/usb/uvc/uvc_v4l2.c:943 uvc_ioctl_s_input() error: doing dma on the stack (&i) those two functions call uvc_query_ctrl passing a pointer to a data at the DMA stack. those are used to send URBs via usb_control_msg(). Using DMA stack is not supported and should not work anymore on modern Linux versions. So, use a kmalloc'ed buffer. Cc: stable@vger.kernel.org # Kernel 4.9 and upper Reviewed-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/uvc/uvc_v4l2.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index 252136cc885c..6acb8013de08 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -899,8 +899,8 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input) { struct uvc_fh *handle = fh; struct uvc_video_chain *chain = handle->chain; + u8 *buf; int ret; - u8 i; if (chain->selector == NULL || (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) { @@ -908,22 +908,27 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input) return 0; } + buf = kmalloc(1, GFP_KERNEL); + if (!buf) + return -ENOMEM; + ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, chain->selector->id, chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, - &i, 1); - if (ret < 0) - return ret; + buf, 1); + if (!ret) + *input = *buf - 1; - *input = i - 1; - return 0; + kfree(buf); + + return ret; } static int uvc_ioctl_s_input(struct file *file, void *fh, unsigned int input) { struct uvc_fh *handle = fh; struct uvc_video_chain *chain = handle->chain; + u8 *buf; int ret; - u32 i; ret = uvc_acquire_privileges(handle); if (ret < 0) @@ -939,10 +944,17 @@ static int uvc_ioctl_s_input(struct file *file, void *fh, unsigned int input) if (input >= chain->selector->bNrInPins) return -EINVAL; - i = input + 1; - return uvc_query_ctrl(chain->dev, UVC_SET_CUR, chain->selector->id, - chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, - &i, 1); + buf = kmalloc(1, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + *buf = input + 1; + ret = uvc_query_ctrl(chain->dev, UVC_SET_CUR, chain->selector->id, + chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, + buf, 1); + kfree(buf); + + return ret; } static int uvc_ioctl_queryctrl(struct file *file, void *fh, -- 2.11.0