omap2fb: Fix stack memory disclosure

commit a01421e4484327fe44f8e126793ed5a48a221e24 upstream.

Using [1] for static analysis I found that the OMAPFB_QUERY_PLANE,
OMAPFB_GET_COLOR_KEY, OMAPFB_GET_DISPLAY_INFO, and OMAPFB_GET_VRAM_INFO
cases could all leak uninitialized stack memory--either due to
uninitialized padding or 'reserved' fields.

Fix them by clearing the shared union used to store copied out data.

[1] https://github.com/vlad902/kernel-uninitialized-memory-checker

Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Fixes: b39a982ddecf ("OMAP: DSS2: omapfb driver")
Cc: security@kernel.org
[b.zolnierkie: prefix patch subject with "omap2fb: "]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c b/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c
index a3edb20..a846d32 100644 (file)
--- a/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c
+++ b/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c
@@ -609,6 +609,8 @@ int omapfb_ioctl(struct fb_info *fbi, unsigned int cmd, unsigned long arg)
 
        int r = 0;
 
+       memset(&p, 0, sizeof(p));
+
        switch (cmd) {
        case OMAPFB_SYNC_GFX:
                DBG("ioctl SYNC_GFX\n");