[PATCH 4.7 096/141] NFS: Dont drop CB requests with invalid principals

From: Greg Kroah-Hartman
Date: Thu Oct 06 2016 - 04:43:31 EST


4.7-stable review patch. If anyone has any objections, please let me know.

------------------

From: Chuck Lever <chuck.lever@xxxxxxxxxx>

commit a4e187d83d88eeaba6252aac0a2ffe5eaa73a818 upstream.

Before commit 778be232a207 ("NFS do not find client in NFSv4
pg_authenticate"), the Linux callback server replied with
RPC_AUTH_ERROR / RPC_AUTH_BADCRED, instead of dropping the CB
request. Let's restore that behavior so the server has a chance to
do something useful about it, and provide a warning that helps
admins correct the problem.

Fixes: 778be232a207 ("NFS do not find client in NFSv4 ...")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Tested-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/nfs/callback_xdr.c | 6 +++++-
net/sunrpc/svc.c | 5 +++++
2 files changed, 10 insertions(+), 1 deletion(-)

--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -925,7 +925,7 @@ static __be32 nfs4_callback_compound(str
if (hdr_arg.minorversion == 0) {
cps.clp = nfs4_find_client_ident(SVC_NET(rqstp), hdr_arg.cb_ident);
if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
- return rpc_drop_reply;
+ goto out_invalidcred;
}

cps.minorversion = hdr_arg.minorversion;
@@ -953,6 +953,10 @@ static __be32 nfs4_callback_compound(str
nfs_put_client(cps.clp);
dprintk("%s: done, status = %u\n", __func__, ntohl(status));
return rpc_success;
+
+out_invalidcred:
+ pr_warn_ratelimited("NFS: NFSv4 callback contains invalid cred\n");
+ return rpc_autherr_badcred;
}

/*
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1194,6 +1194,11 @@ svc_process_common(struct svc_rqst *rqst
procp->pc_release(rqstp, NULL, rqstp->rq_resp);
goto dropit;
}
+ if (*statp == rpc_autherr_badcred) {
+ if (procp->pc_release)
+ procp->pc_release(rqstp, NULL, rqstp->rq_resp);
+ goto err_bad_auth;
+ }
if (*statp == rpc_success &&
(xdr = procp->pc_encode) &&
!xdr(rqstp, resv->iov_base+resv->iov_len, rqstp->rq_resp)) {