[PATCH 5.17 030/772] cifs: fix potential double free during failed mount

Greg Kroah-Hartman
2022-06-07T20:18:54Z

From: Ronnie Sahlberg <lsahlber@redhat.com>

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>
---
fs/cifs/cifsfs.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -836,7 +836,7 @@ cifs_smb3_do_mount(struct file_system_ty
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;
}