From: Chuck Lever <chuck.lever@xxxxxxxxxx>
This patch adds opportunitistic RPC-with-TLS to the Linux in-kernel
NFS server. If the client requests RPC-with-TLS and the user space
handshake agent is running, the server will set up a TLS session.
There are no policy settings yet. For example, the server cannot
yet require the use of RPC-with-TLS to access its data.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/svc_xprt.h | 5 ++
include/linux/sunrpc/svcsock.h | 2 +
include/trace/events/sunrpc.h | 16 ++++++
net/sunrpc/svc_xprt.c | 5 ++
net/sunrpc/svcauth_unix.c | 11 +++-
net/sunrpc/svcsock.c | 101 ++++++++++++++++++++++++++++++++++++++-
6 files changed, 132 insertions(+), 8 deletions(-)
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 775368802762..867479204840 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -27,7 +27,7 @@ struct svc_xprt_ops {
void (*xpo_detach)(struct svc_xprt *);
void (*xpo_free)(struct svc_xprt *);
void (*xpo_kill_temp_xprt)(struct svc_xprt *);
- void (*xpo_start_tls)(struct svc_xprt *);
+ void (*xpo_handshake)(struct svc_xprt *xprt);
};
struct svc_xprt_class {
@@ -70,6 +70,9 @@ struct svc_xprt {
#define XPT_LOCAL 12 /* connection from loopback interface */
#define XPT_KILL_TEMP 13 /* call xpo_kill_temp_xprt before closing */
#define XPT_CONG_CTRL 14 /* has congestion control */
+#define XPT_HANDSHAKE 15 /* xprt requests a handshake */
+#define XPT_TLS_SESSION 16 /* transport-layer security established */
+#define XPT_PEER_AUTH 17 /* peer has been authenticated */
struct svc_serv *xpt_server; /* service for transport */
atomic_t xpt_reserved; /* space on outq that is rsvd */
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index dd73fa174af5..d16ae621782c 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -38,6 +38,8 @@ struct svc_sock {
/* Number of queued send requests */
atomic_t sk_sendqlen;
+ struct completion sk_handshake_done;
+
struct page * sk_pages[RPCSVC_MAXPAGES]; /* received data */
};
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 030c7ff6862b..88ef5537c49e 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -1870,7 +1870,10 @@ TRACE_EVENT(svc_stats_latency,
{ BIT(XPT_CACHE_AUTH), "CACHE_AUTH" }, \
{ BIT(XPT_LOCAL), "LOCAL" }, \
{ BIT(XPT_KILL_TEMP), "KILL_TEMP" }, \
- { BIT(XPT_CONG_CTRL), "CONG_CTRL" })
+ { BIT(XPT_CONG_CTRL), "CONG_CTRL" }, \
+ { BIT(XPT_HANDSHAKE), "HANDSHAKE" }, \
+ { BIT(XPT_TLS_SESSION), "TLS_SESSION" }, \
+ { BIT(XPT_PEER_AUTH), "PEER_AUTH" })
TRACE_EVENT(svc_xprt_create_err,
TP_PROTO(
@@ -2003,6 +2006,17 @@ DEFINE_SVC_XPRT_EVENT(close);
DEFINE_SVC_XPRT_EVENT(detach);
DEFINE_SVC_XPRT_EVENT(free);
+#define DEFINE_SVC_TLS_EVENT(name) \
+ DEFINE_EVENT(svc_xprt_event, svc_tls_##name, \
+ TP_PROTO(const struct svc_xprt *xprt), \
+ TP_ARGS(xprt))
+
+DEFINE_SVC_TLS_EVENT(start);
+DEFINE_SVC_TLS_EVENT(upcall);
+DEFINE_SVC_TLS_EVENT(unavailable);
+DEFINE_SVC_TLS_EVENT(not_started);
+DEFINE_SVC_TLS_EVENT(timed_out);
+
TRACE_EVENT(svc_xprt_accept,
TP_PROTO(
const struct svc_xprt *xprt,
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 3b9708b39e35..84e5d7d31481 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -427,7 +427,7 @@ static bool svc_xprt_ready(struct svc_xprt *xprt)
if (xpt_flags & BIT(XPT_BUSY))
return false;
- if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE)))
+ if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE)))
return true;
if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
@@ -828,6 +828,9 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
module_put(xprt->xpt_class->xcl_owner);
}
svc_xprt_received(xprt);
+ } else if (test_bit(XPT_HANDSHAKE, &xprt->xpt_flags)) {
+ xprt->xpt_ops->xpo_handshake(xprt);
+ svc_xprt_received(xprt);
} else if (svc_xprt_reserve_slot(rqstp, xprt)) {
/* XPT_DATA|XPT_DEFERRED case: */
dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 4485088ce27b..174783f804fa 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -17,8 +17,9 @@
#include <net/ipv6.h>
#include <linux/kernel.h>
#include <linux/user_namespace.h>
-#define RPCDBG_FACILITY RPCDBG_AUTH
+#include <trace/events/sunrpc.h>
+#define RPCDBG_FACILITY RPCDBG_AUTH
#include "netns.h"
@@ -832,6 +833,7 @@ svcauth_tls_accept(struct svc_rqst *rqstp)
{
struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct svc_cred *cred = &rqstp->rq_cred;
+ struct svc_xprt *xprt = rqstp->rq_xprt;
u32 flavor, len;
void *body;
__be32 *p;
@@ -865,14 +867,19 @@ svcauth_tls_accept(struct svc_rqst *rqstp)
if (cred->cr_group_info == NULL)
return SVC_CLOSE;
- if (rqstp->rq_xprt->xpt_ops->xpo_start_tls) {
+ if (xprt->xpt_ops->xpo_handshake) {
p = xdr_reserve_space(&rqstp->rq_res_stream, XDR_UNIT * 2 + 8);
if (!p)
return SVC_CLOSE;
+ trace_svc_tls_start(xprt);
*p++ = rpc_auth_null;
*p++ = cpu_to_be32(8);
memcpy(p, "STARTTLS", 8);
+
+ set_bit(XPT_HANDSHAKE, &xprt->xpt_flags);
+ svc_xprt_enqueue(xprt);
} else {
+ trace_svc_tls_unavailable(xprt);
if (xdr_stream_encode_opaque_auth(&rqstp->rq_res_stream,
RPC_AUTH_NULL, NULL, 0) < 0)
return SVC_CLOSE;
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index f4a7d99360e8..4e50c6187c63 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -44,9 +44,11 @@
#include <net/tcp.h>
#include <net/tcp_states.h>
#include <net/tls.h>
+#include <net/handshake.h>
#include <linux/uaccess.h>
#include <linux/highmem.h>
#include <asm/ioctls.h>
+#include <linux/key.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/clnt.h>
@@ -64,6 +66,12 @@
#define RPCDBG_FACILITY RPCDBG_SVCXPRT
+/* To-do: to avoid tying up an nfsd thread while waiting for a
+ * handshake request, the request could instead be deferred.
+ */
+enum {
+ SVC_HANDSHAKE_TO = 5U * HZ
+};
static struct svc_sock *svc_setup_socket(struct svc_serv *, struct socket *,
int flags);
@@ -360,6 +368,8 @@ static void svc_data_ready(struct sock *sk)
rmb();
svsk->sk_odata(sk);
trace_svcsock_data_ready(&svsk->sk_xprt, 0);
+ if (test_bit(XPT_HANDSHAKE, &svsk->sk_xprt.xpt_flags))
+ return;
if (!test_and_set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags))
svc_xprt_enqueue(&svsk->sk_xprt);
}
@@ -397,6 +407,88 @@ static void svc_tcp_kill_temp_xprt(struct svc_xprt *xprt)
sock_no_linger(svsk->sk_sock->sk);
}
+/**
+ * svc_tcp_handshake_done - Handshake completion handler
+ * @data: address of xprt to wake
+ * @status: status of handshake
+ * @peerid: serial number of key containing the remote peer's identity
+ *
+ * If a security policy is specified as an export option, we don't
+ * have a specific export here to check. So we set a "TLS session
+ * is present" flag on the xprt and let an upper layer enforce local
+ * security policy.
+ */
+static void svc_tcp_handshake_done(void *data, int status, key_serial_t peerid)
+{
+ struct svc_xprt *xprt = data;
+ struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+
+ if (!status) {
+ if (peerid != TLS_NO_PEERID)
+ set_bit(XPT_PEER_AUTH, &xprt->xpt_flags);
+ set_bit(XPT_TLS_SESSION, &xprt->xpt_flags);
+ }
+ clear_bit(XPT_HANDSHAKE, &xprt->xpt_flags);
+ complete_all(&svsk->sk_handshake_done);
+}
+
+/**
+ * svc_tcp_handshake - Perform a transport-layer security handshake
+ * @xprt: connected transport endpoint
+ *
+ */
+static void svc_tcp_handshake(struct svc_xprt *xprt)
+{
+ struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+ struct sock *sk = svsk->sk_sock->sk;
+ struct tls_handshake_args args = {
+ .ta_sock = svsk->sk_sock,
+ .ta_done = svc_tcp_handshake_done,
+ .ta_data = xprt,
+ };
+ int ret;
+
+ trace_svc_tls_upcall(xprt);
+
+ clear_bit(XPT_TLS_SESSION, &xprt->xpt_flags);
+ init_completion(&svsk->sk_handshake_done);
+
+ ret = tls_server_hello_x509(&args, GFP_KERNEL);
+ if (ret) {
+ trace_svc_tls_not_started(xprt);
+ goto out_failed;
+ }
+
+ ret = wait_for_completion_interruptible_timeout(&svsk->sk_handshake_done,
+ SVC_HANDSHAKE_TO);
+ if (ret <= 0) {
+ if (tls_handshake_cancel(sk)) {
+ trace_svc_tls_timed_out(xprt);
+ goto out_close;
+ }
+ }
+
+ if (!test_bit(XPT_TLS_SESSION, &xprt->xpt_flags)) {
+ trace_svc_tls_unavailable(xprt);
+ goto out_close;
+ }
+
+ /* Mark the transport ready in case the remote sent RPC
+ * traffic before the kernel received the handshake
+ * completion downcall.
+ */
+ set_bit(XPT_DATA, &xprt->xpt_flags);
+ svc_xprt_enqueue(xprt);
+ return;
+
+out_close:
+ set_bit(XPT_CLOSE, &xprt->xpt_flags);
+out_failed:
+ clear_bit(XPT_HANDSHAKE, &xprt->xpt_flags);
+ set_bit(XPT_DATA, &xprt->xpt_flags);
+ svc_xprt_enqueue(xprt);
+}
+
/*
* See net/ipv6/ip_sockglue.c : ip_cmsg_recv_pktinfo
*/
@@ -1258,6 +1350,7 @@ static const struct svc_xprt_ops svc_tcp_ops = {
.xpo_has_wspace = svc_tcp_has_wspace,
.xpo_accept = svc_tcp_accept,
.xpo_kill_temp_xprt = svc_tcp_kill_temp_xprt,
+ .xpo_handshake = svc_tcp_handshake,
};
static struct svc_xprt_class svc_tcp_class = {
@@ -1581,10 +1674,12 @@ static void svc_tcp_sock_detach(struct svc_xprt *xprt)
static void svc_sock_free(struct svc_xprt *xprt)
{
struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+ struct socket *sock = svsk->sk_sock;
- if (svsk->sk_sock->file)
- sockfd_put(svsk->sk_sock);
+ tls_handshake_cancel(sock->sk);
+ if (sock->file)
+ sockfd_put(sock);
else
- sock_release(svsk->sk_sock);
+ sock_release(sock);
kfree(svsk);
}
