cifs: fix potential double free during failed mount

commit 8378a51e3f8140f60901fb27208cc7a6e47047b5 upstream.

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2088799

Cc: stable@vger.kernel.org
Signed-off-by: Roberto Bergantinos <rbergant@redhat.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 2b1a1c029c75ec19376a7250fb806b516e59ad03..6d150bb87aaf8ce8892bc5287dd236e156de9fa9 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -836,7 +836,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
              int flags, struct smb3_fs_context *old_ctx)
 {
        int rc;
-       struct super_block *sb;
+       struct super_block *sb = NULL;
        struct cifs_sb_info *cifs_sb = NULL;
        struct cifs_mnt_data mnt_data;
        struct dentry *root;
@@ -932,9 +932,11 @@ out_super:
        return root;
 out:
        if (cifs_sb) {
-               kfree(cifs_sb->prepath);
-               smb3_cleanup_fs_context(cifs_sb->ctx);
-               kfree(cifs_sb);
+               if (!sb || IS_ERR(sb)) {  /* otherwise kill_sb will handle */
+                       kfree(cifs_sb->prepath);
+                       smb3_cleanup_fs_context(cifs_sb->ctx);
+                       kfree(cifs_sb);
+               }
        }
        return root;
 }