smb: client: add NULL check in automount_fullpath

page is checked for null in __build_path_from_dentry_optional_prefix
when tcon->origin_fullpath is not set. However, the check is missing when
it is set.
Add a check to prevent a potential NULL pointer dereference.

Signed-off-by: Ruben Devos <devosruben6@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/namespace.c b/fs/smb/client/namespace.c
index e3f9213..a665580 100644 (file)
--- a/fs/smb/client/namespace.c
+++ b/fs/smb/client/namespace.c
@@ -146,6 +146,9 @@ static char *automount_fullpath(struct dentry *dentry, void *page)
        }
        spin_unlock(&tcon->tc_lock);
 
+       if (unlikely(!page))
+               return ERR_PTR(-ENOMEM);
+
        s = dentry_path_raw(dentry, page, PATH_MAX);
        if (IS_ERR(s))
                return s;