From: Chuck Lever Date: Thu, 20 Apr 2023 17:56:24 +0000 (-0400) Subject: SUNRPC: Support TLS handshake in the server-side TCP socket code X-Git-Tag: v6.6-pxa1908~1323^2~1 X-Git-Url: https://git.dujemihanovic.xyz/?a=commitdiff_plain;h=b3cbf98e2fdf3cb147a95161560cd25987284330;p=linux.git SUNRPC: Support TLS handshake in the server-side TCP socket code 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 --- 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 5a3bb42e1f50..31bc7025cb44 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -1857,7 +1857,10 @@ 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( @@ -1990,6 +1993,17 @@ 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 #include #include -#define RPCDBG_FACILITY RPCDBG_AUTH +#include +#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 c5b74f523fc4..a51c9b989d58 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -44,9 +44,11 @@ #include #include #include +#include #include #include #include +#include #include #include @@ -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); @@ -359,6 +367,8 @@ 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); } @@ -396,6 +406,88 @@ 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 */ @@ -1257,6 +1349,7 @@ 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 = { @@ -1580,10 +1673,12 @@ 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); }