fmt->index can be controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. Smatch warning: drivers/media/platform/marvell-ccic/mcam-core.c:1323 mcam_vidioc_enum_fmt_vid_cap() warn: potential spectre issue 'mcam_formats' Fix this by sanitizing fmt->index before using it to index mcam_formats. 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/platform/marvell-ccic/mcam-core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/media/platform/marvell-ccic/mcam-core.c b/drivers/media/platform/marvell-ccic/mcam-core.c index 80670ee..0a54dba 100644 --- a/drivers/media/platform/marvell-ccic/mcam-core.c +++ b/drivers/media/platform/marvell-ccic/mcam-core.c @@ -33,6 +33,8 @@ #include "mcam-core.h" +#include <linux/nospec.h> + #ifdef MCAM_MODE_VMALLOC /* * Internal DMA buffer management. Since the controller cannot do S/G I/O, @@ -1318,6 +1320,7 @@ static int mcam_vidioc_enum_fmt_vid_cap(struct file *filp, { if (fmt->index >= N_MCAM_FMTS) return -EINVAL; + fmt->index = array_index_nospec(fmt->index, N_MCAM_FMTS); strlcpy(fmt->description, mcam_formats[fmt->index].desc, sizeof(fmt->description)); fmt->pixelformat = mcam_formats[fmt->index].pixelformat; -- 2.7.4
