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 7d47b3d5cc0d0be41258c71f4e81b3840be88a2d..54d554d72000451f86e2187ed8f26bf3856c831d 100644 (file)
--- a/drivers/gpu/drm/gma500/cdv_intel_display.c
+++ b/drivers/gpu/drm/gma500/cdv_intel_display.c
@@ -415,6 +415,8 @@ 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) {