diff mbox series

[4.14,43/49] NFS: Fix use-after-free in nfs4_init_client()

Message ID 20210614102643.270356884@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

gregkh@linuxfoundation.org June 14, 2021, 10:27 a.m. UTC 
From: Anna Schumaker <Anna.Schumaker@Netapp.com>

commit 476bdb04c501fc64bf3b8464ffddefc8dbe01577 upstream.

KASAN reports a use-after-free when attempting to mount two different
exports through two different NICs that belong to the same server.

Olga was able to hit this with kernels starting somewhere between 5.7
and 5.10, but I traced the patch that introduced the clear_bit() call to
4.13. So something must have changed in the refcounting of the clp
pointer to make this call to nfs_put_client() the very last one.

Fixes: 8dcbec6d20 ("NFSv41: Handle EXCHID4_FLAG_CONFIRMED_R during NFSv4.1 migration")
Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/nfs/nfs4client.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -417,8 +417,8 @@  struct nfs_client *nfs4_init_client(stru
 		 */
 		nfs_mark_client_ready(clp, -EPERM);
 	}
-	nfs_put_client(clp);
 	clear_bit(NFS_CS_TSM_POSSIBLE, &clp->cl_flags);
+	nfs_put_client(clp);
 	return old;
 
 error: