gma/gma500: fix a memory disclosure bug due to uninitialized bytes

[ Upstream commit 57a25a5f754ce27da2cfa6f413cfd366f878db76 ]

`best_clock` is an object that may be sent out. Object `clock`
contains uninitialized bytes that are copied to `best_clock`,
which leads to memory disclosure and information leak.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191018042953.31099-1-kjlu@umn.edu
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/gma500/cdv_intel_display.c b/drivers/gpu/drm/gma500/cdv_intel_display.c
index f56852a503e8d8d98bebe77889488b47e24ea72b..8b784947ed3b91940af86f96f8f342cfce46b7bc 100644 (file)
--- a/drivers/gpu/drm/gma500/cdv_intel_display.c
+++ b/drivers/gpu/drm/gma500/cdv_intel_display.c
@@ -405,6 +405,8 @@ static bool cdv_intel_find_dp_pll(const struct gma_limit_t *limit,
        struct gma_crtc *gma_crtc = to_gma_crtc(crtc);
        struct gma_clock_t clock;
 
+       memset(&clock, 0, sizeof(clock));
+
        switch (refclk) {
        case 27000:
                if (target < 200000) {