From: Benjamin Randazzo <benjamin@xxxxxxxxxxx> This patch has been added to the 3.18 stable tree. If you have any objections, please let us know. =============== [ Upstream commit 33afeac21b9cb79ad8fc5caf239af89c79e25e1e ] commit b6878d9e03043695dbf3fa1caa6dfc09db225b16 upstream. In drivers/md/md.c get_bitmap_file() uses kmalloc() for creating a mdu_bitmap_file_t called "file". 5769 file = kmalloc(sizeof(*file), GFP_NOIO); 5770 if (!file) 5771 return -ENOMEM; This structure is copied to user space at the end of the function. 5786 if (err == 0 && 5787 copy_to_user(arg, file, sizeof(*file))) 5788 err = -EFAULT But if bitmap is disabled only the first byte of "file" is initialized with zero, so it's possible to read some bytes (up to 4095) of kernel space memory from user space. This is an information leak. 5775 /* bitmap disabled, zero the first byte and copy out */ 5776 if (!mddev->bitmap_info.file) 5777 file->pathname[0] = '\0'; Signed-off-by: Benjamin Randazzo <benjamin@xxxxxxxxxxx> Signed-off-by: NeilBrown <neilb@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> --- drivers/md/md.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 4339035..dd7a370 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5432,8 +5432,7 @@ static int get_bitmap_file(struct mddev *mddev, void __user * arg) char *ptr, *buf = NULL; int err = -ENOMEM; - file = kmalloc(sizeof(*file), GFP_NOIO); - + file = kzalloc(sizeof(*file), GFP_NOIO); if (!file) goto out; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html