ecryptfs: fix kernel panic with null dev_name

When mounting eCryptfs, a null "dev_name" argument to ecryptfs_mount()
causes a kernel panic if the parsed options are valid. The easiest way to
reproduce this is to call mount() from userspace with an existing
eCryptfs mount's options and a "source" argument of 0.

Error out if "dev_name" is null in ecryptfs_mount()

Fixes: 237fead61998 ("[PATCH] ecryptfs: fs/Makefile and fs/Kconfig")
Cc: stable@vger.kernel.org
Signed-off-by: Jeffrey Mitchell <jeffrey.mitchell@starlab.io>
Signed-off-by: Tyler Hicks <code@tyhicks.com>

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 77b96737b1ffbdeea6d22294530e85ce05464dde..d66bbd2df191e5cf69310243a711dd341e3822c7 100644 (file)
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -492,6 +492,12 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
                goto out;
        }
 
+       if (!dev_name) {
+               rc = -EINVAL;
+               err = "Device name cannot be null";
+               goto out;
+       }
+
        rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
        if (rc) {
                err = "Error parsing options";