[PATCH v3 resend] media: davinci/vpbe: array underflow in vpbe_enum_outputs()

Dan Carpenter
2019-04-24T09:46:27Z

In vpbe_enum_outputs() we check if (temp_index >= cfg->num_outputs) but
the problem is that "temp_index" can be negative. This patch changes
the types to unsigned to address this array underflow bug.

Fixes: 66715cdc3224 ("[media] davinci vpbe: VPBE display driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
---
I sent this patch last May but somehow the spam filters on the lists
must have eaten it. I didn't get a copy from the kernel-janitors list.
The only trace I have of my original patch is that the maintainer Acked
it. Resending.

v2: In the first version, I clamped output->index to 0-INT_MAX for every
driver. In v2, I only changed the vpbe.h driver header file.
v3: In v3 I changed the header and the .c file (All three versions of
patch "worked", they just had philosophical and style issues).

drivers/media/platform/davinci/vpbe.c | 2 +-
include/media/davinci/vpbe.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/davinci/vpbe.c b/drivers/media/platform/davinci/vpbe.c
index 8339163a5231..4e24f5d781f4 100644
--- a/drivers/media/platform/davinci/vpbe.c
+++ b/drivers/media/platform/davinci/vpbe.c
@@ -104,7 +104,7 @@ static int vpbe_enum_outputs(struct vpbe_device *vpbe_dev,
struct v4l2_output *output)
{
struct vpbe_config *cfg = vpbe_dev->cfg;
- int temp_index = output->index;
+ unsigned int temp_index = output->index;

if (temp_index >= cfg->num_outputs)
return -EINVAL;
diff --git a/include/media/davinci/vpbe.h b/include/media/davinci/vpbe.h
index 5c31a7682492..f76d2f25a824 100644
--- a/include/media/davinci/vpbe.h
+++ b/include/media/davinci/vpbe.h
@@ -92,7 +92,7 @@ struct vpbe_config {
struct encoder_config_info *ext_encoders;
/* amplifier information goes here */
struct amp_config_info *amp;
- int num_outputs;
+ unsigned int num_outputs;
/* Order is venc outputs followed by LCD and then external encoders */
struct vpbe_output *outputs;
};
--
2.18.0