Thread (4 messages) 4 messages, 3 authors, 2019-01-11

Re: [PATCH] Fix stack memory disclosure

From: Kees Cook <hidden>
Date: 2019-01-08 23:41:38
Also in: lkml

On Sat, Jan 5, 2019 at 11:51 PM Vlad Tsyrklevich [off-list ref] wrote:
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 <redacted>
Reviewed-by: Kees Cook <redacted>
Fixes: b39a982ddecf ("OMAP: DSS2: omapfb driver")

Since this driver is orphaned (according to MAINTAINERS), I think this
fix should go via Bart's tree. Bart, can you take this?

-Kees
quoted hunk ↗ jump to hunk
Cc: security@kernel.org

---
 drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c | 2 ++
 1 file changed, 2 insertions(+)
diff --git a/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c b/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c
index 53f93616c..8e23160ec 100644
--- 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");
--
2.17.0

-- 
Kees Cook
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