[PATCH] dm ioctl: prevent stack leak in dm ioctl call

[Adrian Salido <salidoa@xxxxxxxxxx>]

Struct dm_ioctl has some padding/data that is not explicitly cleared
before copying to user. This can cause kernel stack contents to be
leaked to user space.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Adrian Salido <salidoa@xxxxxxxxxx>
---
 drivers/md/dm-ioctl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 4da6fc6b1ffd..07627062faae 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1835,6 +1835,7 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
 		return -ENOTTY;
 	}
 
+	memset(&param_kernel, 0, sizeof(param_kernel));
 	/*
 	 * Copy the parameters into kernel space.
 	 */
-- 
2.13.0.rc0.306.g87b477812d-goog

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