diff mbox series

[v2,10/15] SUNRPC: Capture cmsg metadata on client-side receive

Message ID 165452709314.1496.1821426681306661216.stgit@oracle-102.nfsv4.dev (mailing list archive)
State New, archived
Headers show
Series RPC-with-TLS client side | expand

Commit Message

Chuck Lever June 6, 2022, 2:51 p.m. UTC
kTLS sockets use cmsg to report decryption errors and the need
for session re-keying. An "application data" message contains a ULP
payload, and that is passed along to the RPC client. An "alert"
message triggers connection reset. Everything else is discarded.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/net/tls.h             |    2 ++
 include/trace/events/sunrpc.h |   40 +++++++++++++++++++++++++++++++++
 net/sunrpc/xprtsock.c         |   49 +++++++++++++++++++++++++++++++++++++++--
 3 files changed, 89 insertions(+), 2 deletions(-)

Comments

Jeff Layton July 18, 2022, 7:53 p.m. UTC | #1
On Mon, 2022-06-06 at 10:51 -0400, Chuck Lever wrote:
> kTLS sockets use cmsg to report decryption errors and the need
> for session re-keying. An "application data" message contains a ULP
> payload, and that is passed along to the RPC client. An "alert"
> message triggers connection reset. Everything else is discarded.
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  include/net/tls.h             |    2 ++
>  include/trace/events/sunrpc.h |   40 +++++++++++++++++++++++++++++++++
>  net/sunrpc/xprtsock.c         |   49 +++++++++++++++++++++++++++++++++++++++--
>  3 files changed, 89 insertions(+), 2 deletions(-)
> 
> diff --git a/include/net/tls.h b/include/net/tls.h
> index 6b1bf46daa34..54bccb2e4014 100644
> --- a/include/net/tls.h
> +++ b/include/net/tls.h
> @@ -71,6 +71,8 @@ static inline struct tlsh_sock *tlsh_sk(struct sock *sk)
>  
>  #define TLS_CRYPTO_INFO_READY(info)	((info)->cipher_type)
>  
> +#define TLS_RECORD_TYPE_ALERT		0x15
> +#define TLS_RECORD_TYPE_HANDSHAKE	0x16
>  #define TLS_RECORD_TYPE_DATA		0x17
>  
>  #define TLS_AAD_SPACE_SIZE		13
> diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
> index 986e135e314f..d7d07f3b850e 100644
> --- a/include/trace/events/sunrpc.h
> +++ b/include/trace/events/sunrpc.h
> @@ -1319,6 +1319,46 @@ TRACE_EVENT(xs_data_ready,
>  	TP_printk("peer=[%s]:%s", __get_str(addr), __get_str(port))
>  );
>  
> +/*
> + * From https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml
> + *
> + * Captured March 2022. Other values are unassigned or reserved.
> + */
> +#define rpc_show_tls_content_type(type) \
> +	__print_symbolic(type, \
> +		{ 20,		"change cipher spec" }, \
> +		{ 21,		"alert" }, \
> +		{ 22,		"handshake" }, \
> +		{ 23,		"application data" }, \
> +		{ 24,		"heartbeat" }, \
> +		{ 25,		"tls12_cid" }, \
> +		{ 26,		"ACK" })
> +
> +TRACE_EVENT(xs_tls_contenttype,
> +	TP_PROTO(
> +		const struct rpc_xprt *xprt,
> +		unsigned char ctype
> +	),
> +
> +	TP_ARGS(xprt, ctype),
> +
> +	TP_STRUCT__entry(
> +		__string(addr, xprt->address_strings[RPC_DISPLAY_ADDR])
> +		__string(port, xprt->address_strings[RPC_DISPLAY_PORT])
> +		__field(unsigned long, ctype)
> +	),
> +
> +	TP_fast_assign(
> +		__assign_str(addr, xprt->address_strings[RPC_DISPLAY_ADDR]);
> +		__assign_str(port, xprt->address_strings[RPC_DISPLAY_PORT]);
> +		__entry->ctype = ctype;
> +	),
> +
> +	TP_printk("peer=[%s]:%s: %s", __get_str(addr), __get_str(port),
> +		rpc_show_tls_content_type(__entry->ctype)
> +	)
> +);
> +
>  TRACE_EVENT(xs_stream_read_data,
>  	TP_PROTO(struct rpc_xprt *xprt, ssize_t err, size_t total),
>  
> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
> index 0a521aee0b2f..c73af8f1c3d4 100644
> --- a/net/sunrpc/xprtsock.c
> +++ b/net/sunrpc/xprtsock.c
> @@ -47,6 +47,8 @@
>  #include <net/checksum.h>
>  #include <net/udp.h>
>  #include <net/tcp.h>
> +#include <net/tls.h>
> +
>  #include <linux/bvec.h>
>  #include <linux/highmem.h>
>  #include <linux/uio.h>
> @@ -350,13 +352,56 @@ xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp)
>  	return want;
>  }
>  
> +static int
> +xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg,
> +		     struct cmsghdr *cmsg, int ret)
> +{
> +	if (cmsg->cmsg_level == SOL_TLS &&
> +	    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
> +		u8 content_type = *((u8 *)CMSG_DATA(cmsg));
> +
> +		trace_xs_tls_contenttype(xprt_from_sock(sock->sk), content_type);
> +		switch (content_type) {
> +		case TLS_RECORD_TYPE_DATA:
> +			/* TLS sets EOR at the end of each application data
> +			 * record, even though there might be more frames
> +			 * waiting to be decrypted. */
> +			msg->msg_flags &= ~MSG_EOR;
> +			break;
> +		case TLS_RECORD_TYPE_ALERT:
> +			ret = -ENOTCONN;
> +			break;
> +		default:
> +			ret = -EAGAIN;
> +		}
> +	}
> +	return ret;
> +}
> +
> +static int
> +xs_sock_recv_cmsg(struct socket *sock, struct msghdr *msg, int flags)
> +{
> +	union {
> +		struct cmsghdr	cmsg;
> +		u8		buf[CMSG_SPACE(sizeof(u8))];
> +	} u;
> +	int ret;
> +
> +	msg->msg_control = &u;
> +	msg->msg_controllen = sizeof(u);
> +	ret = sock_recvmsg(sock, msg, flags);
> +	if (msg->msg_controllen != sizeof(u))

Do you also need to check for ret < 0 here? Can msg_controllen be
trusted if sock_recvmsg returns an error?

> +		ret = xs_sock_process_cmsg(sock, msg, &u.cmsg, ret);
> +	return ret;
> +}
> +
>  static ssize_t
>  xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek)
>  {
>  	ssize_t ret;
>  	if (seek != 0)
>  		iov_iter_advance(&msg->msg_iter, seek);
> -	ret = sock_recvmsg(sock, msg, flags);
> +	ret = xs_sock_recv_cmsg(sock, msg, flags);
>  	return ret > 0 ? ret + seek : ret;
>  }
>  
> @@ -382,7 +427,7 @@ xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
>  		size_t count)
>  {
>  	iov_iter_discard(&msg->msg_iter, READ, count);
> -	return sock_recvmsg(sock, msg, flags);
> +	return xs_sock_recv_cmsg(sock, msg, flags);
>  }
>  
>  #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
> 
>
Chuck Lever July 19, 2022, 9:43 p.m. UTC | #2
> On Jul 18, 2022, at 3:53 PM, Jeff Layton <jlayton@kernel.org> wrote:
> 
> On Mon, 2022-06-06 at 10:51 -0400, Chuck Lever wrote:
>> kTLS sockets use cmsg to report decryption errors and the need
>> for session re-keying. An "application data" message contains a ULP
>> payload, and that is passed along to the RPC client. An "alert"
>> message triggers connection reset. Everything else is discarded.
>> 
>> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
>> ---
>> include/net/tls.h             |    2 ++
>> include/trace/events/sunrpc.h |   40 +++++++++++++++++++++++++++++++++
>> net/sunrpc/xprtsock.c         |   49 +++++++++++++++++++++++++++++++++++++++--
>> 3 files changed, 89 insertions(+), 2 deletions(-)
>> 
>> diff --git a/include/net/tls.h b/include/net/tls.h
>> index 6b1bf46daa34..54bccb2e4014 100644
>> --- a/include/net/tls.h
>> +++ b/include/net/tls.h
>> @@ -71,6 +71,8 @@ static inline struct tlsh_sock *tlsh_sk(struct sock *sk)
>> 
>> #define TLS_CRYPTO_INFO_READY(info)	((info)->cipher_type)
>> 
>> +#define TLS_RECORD_TYPE_ALERT		0x15
>> +#define TLS_RECORD_TYPE_HANDSHAKE	0x16
>> #define TLS_RECORD_TYPE_DATA		0x17
>> 
>> #define TLS_AAD_SPACE_SIZE		13
>> diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
>> index 986e135e314f..d7d07f3b850e 100644
>> --- a/include/trace/events/sunrpc.h
>> +++ b/include/trace/events/sunrpc.h
>> @@ -1319,6 +1319,46 @@ TRACE_EVENT(xs_data_ready,
>> 	TP_printk("peer=[%s]:%s", __get_str(addr), __get_str(port))
>> );
>> 
>> +/*
>> + * From https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml
>> + *
>> + * Captured March 2022. Other values are unassigned or reserved.
>> + */
>> +#define rpc_show_tls_content_type(type) \
>> +	__print_symbolic(type, \
>> +		{ 20,		"change cipher spec" }, \
>> +		{ 21,		"alert" }, \
>> +		{ 22,		"handshake" }, \
>> +		{ 23,		"application data" }, \
>> +		{ 24,		"heartbeat" }, \
>> +		{ 25,		"tls12_cid" }, \
>> +		{ 26,		"ACK" })
>> +
>> +TRACE_EVENT(xs_tls_contenttype,
>> +	TP_PROTO(
>> +		const struct rpc_xprt *xprt,
>> +		unsigned char ctype
>> +	),
>> +
>> +	TP_ARGS(xprt, ctype),
>> +
>> +	TP_STRUCT__entry(
>> +		__string(addr, xprt->address_strings[RPC_DISPLAY_ADDR])
>> +		__string(port, xprt->address_strings[RPC_DISPLAY_PORT])
>> +		__field(unsigned long, ctype)
>> +	),
>> +
>> +	TP_fast_assign(
>> +		__assign_str(addr, xprt->address_strings[RPC_DISPLAY_ADDR]);
>> +		__assign_str(port, xprt->address_strings[RPC_DISPLAY_PORT]);
>> +		__entry->ctype = ctype;
>> +	),
>> +
>> +	TP_printk("peer=[%s]:%s: %s", __get_str(addr), __get_str(port),
>> +		rpc_show_tls_content_type(__entry->ctype)
>> +	)
>> +);
>> +
>> TRACE_EVENT(xs_stream_read_data,
>> 	TP_PROTO(struct rpc_xprt *xprt, ssize_t err, size_t total),
>> 
>> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
>> index 0a521aee0b2f..c73af8f1c3d4 100644
>> --- a/net/sunrpc/xprtsock.c
>> +++ b/net/sunrpc/xprtsock.c
>> @@ -47,6 +47,8 @@
>> #include <net/checksum.h>
>> #include <net/udp.h>
>> #include <net/tcp.h>
>> +#include <net/tls.h>
>> +
>> #include <linux/bvec.h>
>> #include <linux/highmem.h>
>> #include <linux/uio.h>
>> @@ -350,13 +352,56 @@ xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp)
>> 	return want;
>> }
>> 
>> +static int
>> +xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg,
>> +		     struct cmsghdr *cmsg, int ret)
>> +{
>> +	if (cmsg->cmsg_level == SOL_TLS &&
>> +	    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
>> +		u8 content_type = *((u8 *)CMSG_DATA(cmsg));
>> +
>> +		trace_xs_tls_contenttype(xprt_from_sock(sock->sk), content_type);
>> +		switch (content_type) {
>> +		case TLS_RECORD_TYPE_DATA:
>> +			/* TLS sets EOR at the end of each application data
>> +			 * record, even though there might be more frames
>> +			 * waiting to be decrypted. */
>> +			msg->msg_flags &= ~MSG_EOR;
>> +			break;
>> +		case TLS_RECORD_TYPE_ALERT:
>> +			ret = -ENOTCONN;
>> +			break;
>> +		default:
>> +			ret = -EAGAIN;
>> +		}
>> +	}
>> +	return ret;
>> +}
>> +
>> +static int
>> +xs_sock_recv_cmsg(struct socket *sock, struct msghdr *msg, int flags)
>> +{
>> +	union {
>> +		struct cmsghdr	cmsg;
>> +		u8		buf[CMSG_SPACE(sizeof(u8))];
>> +	} u;
>> +	int ret;
>> +
>> +	msg->msg_control = &u;
>> +	msg->msg_controllen = sizeof(u);
>> +	ret = sock_recvmsg(sock, msg, flags);
>> +	if (msg->msg_controllen != sizeof(u))
> 
> Do you also need to check for ret < 0 here? Can msg_controllen be
> trusted if sock_recvmsg returns an error?

This is not the most clear of APIs, and code I audited to help me
understand how it should work was inconsistent. Some just outright
does not work.

sock_recvmsg() has to explicitly modify the msg_controllen field
to indicate there is a control message. I think we are good here.

Also, no-one barked at this when it was posted on netdev.


>> +		ret = xs_sock_process_cmsg(sock, msg, &u.cmsg, ret);
>> +	return ret;
>> +}
>> +
>> static ssize_t
>> xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek)
>> {
>> 	ssize_t ret;
>> 	if (seek != 0)
>> 		iov_iter_advance(&msg->msg_iter, seek);
>> -	ret = sock_recvmsg(sock, msg, flags);
>> +	ret = xs_sock_recv_cmsg(sock, msg, flags);
>> 	return ret > 0 ? ret + seek : ret;
>> }
>> 
>> @@ -382,7 +427,7 @@ xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
>> 		size_t count)
>> {
>> 	iov_iter_discard(&msg->msg_iter, READ, count);
>> -	return sock_recvmsg(sock, msg, flags);
>> +	return xs_sock_recv_cmsg(sock, msg, flags);
>> }
>> 
>> #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
>> 
>> 
> 
> -- 
> Jeff Layton <jlayton@kernel.org>

--
Chuck Lever
diff mbox series

Patch

diff --git a/include/net/tls.h b/include/net/tls.h
index 6b1bf46daa34..54bccb2e4014 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -71,6 +71,8 @@  static inline struct tlsh_sock *tlsh_sk(struct sock *sk)
 
 #define TLS_CRYPTO_INFO_READY(info)	((info)->cipher_type)
 
+#define TLS_RECORD_TYPE_ALERT		0x15
+#define TLS_RECORD_TYPE_HANDSHAKE	0x16
 #define TLS_RECORD_TYPE_DATA		0x17
 
 #define TLS_AAD_SPACE_SIZE		13
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 986e135e314f..d7d07f3b850e 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -1319,6 +1319,46 @@  TRACE_EVENT(xs_data_ready,
 	TP_printk("peer=[%s]:%s", __get_str(addr), __get_str(port))
 );
 
+/*
+ * From https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml
+ *
+ * Captured March 2022. Other values are unassigned or reserved.
+ */
+#define rpc_show_tls_content_type(type) \
+	__print_symbolic(type, \
+		{ 20,		"change cipher spec" }, \
+		{ 21,		"alert" }, \
+		{ 22,		"handshake" }, \
+		{ 23,		"application data" }, \
+		{ 24,		"heartbeat" }, \
+		{ 25,		"tls12_cid" }, \
+		{ 26,		"ACK" })
+
+TRACE_EVENT(xs_tls_contenttype,
+	TP_PROTO(
+		const struct rpc_xprt *xprt,
+		unsigned char ctype
+	),
+
+	TP_ARGS(xprt, ctype),
+
+	TP_STRUCT__entry(
+		__string(addr, xprt->address_strings[RPC_DISPLAY_ADDR])
+		__string(port, xprt->address_strings[RPC_DISPLAY_PORT])
+		__field(unsigned long, ctype)
+	),
+
+	TP_fast_assign(
+		__assign_str(addr, xprt->address_strings[RPC_DISPLAY_ADDR]);
+		__assign_str(port, xprt->address_strings[RPC_DISPLAY_PORT]);
+		__entry->ctype = ctype;
+	),
+
+	TP_printk("peer=[%s]:%s: %s", __get_str(addr), __get_str(port),
+		rpc_show_tls_content_type(__entry->ctype)
+	)
+);
+
 TRACE_EVENT(xs_stream_read_data,
 	TP_PROTO(struct rpc_xprt *xprt, ssize_t err, size_t total),
 
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 0a521aee0b2f..c73af8f1c3d4 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -47,6 +47,8 @@ 
 #include <net/checksum.h>
 #include <net/udp.h>
 #include <net/tcp.h>
+#include <net/tls.h>
+
 #include <linux/bvec.h>
 #include <linux/highmem.h>
 #include <linux/uio.h>
@@ -350,13 +352,56 @@  xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp)
 	return want;
 }
 
+static int
+xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg,
+		     struct cmsghdr *cmsg, int ret)
+{
+	if (cmsg->cmsg_level == SOL_TLS &&
+	    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
+		u8 content_type = *((u8 *)CMSG_DATA(cmsg));
+
+		trace_xs_tls_contenttype(xprt_from_sock(sock->sk), content_type);
+		switch (content_type) {
+		case TLS_RECORD_TYPE_DATA:
+			/* TLS sets EOR at the end of each application data
+			 * record, even though there might be more frames
+			 * waiting to be decrypted. */
+			msg->msg_flags &= ~MSG_EOR;
+			break;
+		case TLS_RECORD_TYPE_ALERT:
+			ret = -ENOTCONN;
+			break;
+		default:
+			ret = -EAGAIN;
+		}
+	}
+	return ret;
+}
+
+static int
+xs_sock_recv_cmsg(struct socket *sock, struct msghdr *msg, int flags)
+{
+	union {
+		struct cmsghdr	cmsg;
+		u8		buf[CMSG_SPACE(sizeof(u8))];
+	} u;
+	int ret;
+
+	msg->msg_control = &u;
+	msg->msg_controllen = sizeof(u);
+	ret = sock_recvmsg(sock, msg, flags);
+	if (msg->msg_controllen != sizeof(u))
+		ret = xs_sock_process_cmsg(sock, msg, &u.cmsg, ret);
+	return ret;
+}
+
 static ssize_t
 xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek)
 {
 	ssize_t ret;
 	if (seek != 0)
 		iov_iter_advance(&msg->msg_iter, seek);
-	ret = sock_recvmsg(sock, msg, flags);
+	ret = xs_sock_recv_cmsg(sock, msg, flags);
 	return ret > 0 ? ret + seek : ret;
 }
 
@@ -382,7 +427,7 @@  xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
 		size_t count)
 {
 	iov_iter_discard(&msg->msg_iter, READ, count);
-	return sock_recvmsg(sock, msg, flags);
+	return xs_sock_recv_cmsg(sock, msg, flags);
 }
 
 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE