f->index can be controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. Smatch warning: drivers/media/usb/tm6000/tm6000-video.c:879 vidioc_enum_fmt_vid_cap() warn: potential spectre issue 'format' Fix this by sanitizing f->index before using it to index array _format_ Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@xxxxxxxxxxxxxxx Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> --- drivers/media/usb/tm6000/tm6000-video.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/usb/tm6000/tm6000-video.c b/drivers/media/usb/tm6000/tm6000-video.c index b2399d4..d701027 100644 --- a/drivers/media/usb/tm6000/tm6000-video.c +++ b/drivers/media/usb/tm6000/tm6000-video.c @@ -26,6 +26,7 @@ #include <linux/kthread.h> #include <linux/highmem.h> #include <linux/freezer.h> +#include <linux/nospec.h> #include "tm6000-regs.h" #include "tm6000.h" @@ -875,6 +876,7 @@ static int vidioc_enum_fmt_vid_cap(struct file *file, void *priv, if (f->index >= ARRAY_SIZE(format)) return -EINVAL; + f->index = array_index_nospec(f->index, ARRAY_SIZE(format)); strlcpy(f->description, format[f->index].name, sizeof(f->description)); f->pixelformat = format[f->index].fourcc; return 0; -- 2.7.4
