2019-10-18 22:27:52

by Kangjie Lu

Subject: [PATCH] drm/gma500: fix memory disclosures due to uninitialized bytes

"clock" may be copied to "best_clock". Initializing best_clock
is not sufficient. The fix initializes clock as well to avoid
memory disclosures and informaiton leaks.

Signed-off-by: Kangjie Lu <[email protected]>
---
drivers/gpu/drm/gma500/oaktrail_crtc.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/gma500/oaktrail_crtc.c b/drivers/gpu/drm/gma500/oaktrail_crtc.c
index 167c10767dd4..900e5499249d 100644
--- a/drivers/gpu/drm/gma500/oaktrail_crtc.c
+++ b/drivers/gpu/drm/gma500/oaktrail_crtc.c
@@ -129,6 +129,7 @@ static bool mrst_sdvo_find_best_pll(const struct gma_limit_t *limit,
s32 freq_error, min_error = 100000;

memset(best_clock, 0, sizeof(*best_clock));
+ memset(&clock, 0, sizeof(clock));

for (clock.m = limit->m.min; clock.m <= limit->m.max; clock.m++) {
for (clock.n = limit->n.min; clock.n <= limit->n.max;
@@ -185,6 +186,7 @@ static bool mrst_lvds_find_best_pll(const struct gma_limit_t *limit,
int err = target;

memset(best_clock, 0, sizeof(*best_clock));
+ memset(&clock, 0, sizeof(clock));

for (clock.m = limit->m.min; clock.m <= limit->m.max; clock.m++) {
for (clock.p1 = limit->p1.min; clock.p1 <= limit->p1.max;
--
2.17.1

2019-10-22 12:19:55

by Daniel Vetter

Subject: Re: [PATCH] drm/gma500: fix memory disclosures due to uninitialized bytes

On Thu, Oct 17, 2019 at 11:41:50PM -0500, Kangjie Lu wrote:
> "clock" may be copied to "best_clock". Initializing best_clock
> is not sufficient. The fix initializes clock as well to avoid
> memory disclosures and informaiton leaks.
>
> Signed-off-by: Kangjie Lu <[email protected]>

Again no leak here, but also doesn't hurt, so applied.
-Daniel

> ---
> drivers/gpu/drm/gma500/oaktrail_crtc.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/gma500/oaktrail_crtc.c b/drivers/gpu/drm/gma500/oaktrail_crtc.c
> index 167c10767dd4..900e5499249d 100644
> --- a/drivers/gpu/drm/gma500/oaktrail_crtc.c
> +++ b/drivers/gpu/drm/gma500/oaktrail_crtc.c
> @@ -129,6 +129,7 @@ static bool mrst_sdvo_find_best_pll(const struct gma_limit_t *limit,
> s32 freq_error, min_error = 100000;
>
> memset(best_clock, 0, sizeof(*best_clock));
> + memset(&clock, 0, sizeof(clock));
>
> for (clock.m = limit->m.min; clock.m <= limit->m.max; clock.m++) {
> for (clock.n = limit->n.min; clock.n <= limit->n.max;
> @@ -185,6 +186,7 @@ static bool mrst_lvds_find_best_pll(const struct gma_limit_t *limit,
> int err = target;
>
> memset(best_clock, 0, sizeof(*best_clock));
> + memset(&clock, 0, sizeof(clock));
>
> for (clock.m = limit->m.min; clock.m <= limit->m.max; clock.m++) {
> for (clock.p1 = limit->p1.min; clock.p1 <= limit->p1.max;
> --
> 2.17.1
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch