[PATCH] ecryptfs: fix kernel panic with null dev_name

[Jeffrey Mitchell]

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()

Signed-off-by: Jeffrey Mitchell <jeffrey.mitch...@starlab.io>
---
 fs/ecryptfs/main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index e63259fdef28..b2f6a1937d23 100644
--- 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";
-- 
2.25.1