From: Anna Schumaker <Anna.Schumaker@Netapp.com>
Date: Wed, 2 Jun 2021 14:31:20 -0400
Subject: [PATCH] NFS: Fix use-after-free in nfs4_init_client()
Git-commit: 476bdb04c501fc64bf3b8464ffddefc8dbe01577
Patch-mainline: v5.13-rc6
References: git-fixes
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>
Acked-by: NeilBrown <neilb@suse.com>
---
fs/nfs/nfs4client.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -435,8 +435,8 @@ 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: