NFS: Fix use-after-free in nfs4_init_client()

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>
This commit is contained in:
Anna Schumaker 2021-06-02 14:31:20 -04:00 committed by Trond Myklebust
parent 0b4f132b15
commit 476bdb04c5

View File

@ -435,8 +435,8 @@ struct nfs_client *nfs4_init_client(struct nfs_client *clp,
*/
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: