[PATCH v3 bpf-next 0/5] bpf: Hooks for sys_sendmsg

[PATCH v3 bpf-next 0/5] bpf: Hooks for sys_sendmsg

[Andrey Ignatov]

v2 -> v3:
* place BPF logic under static key in udp_sendmsg, udpv6_sendmsg;
* rebase.

v1 -> v2:
* return ENOTSUPP if bpf_prog rewrote IPv6-only with IPv4-mapped IPv6;
* add test for IPv4-mapped IPv6 use-case;
* fix build for CONFIG_CGROUP_BPF=n;
* rebase.

This path set adds BPF hooks for sys_sendmsg similar to existing hooks for
sys_bind and sys_connect.

Hooks allow to override source IP (including the case when it's set via
cmsg(3)) and destination IP:port for unconnected UDP (slow path). TCP and
connected UDP (fast path) are not affected. This makes UDP support
complete: connected UDP is handled by sys_connect hooks, unconnected by
sys_sendmsg ones.

Similar to sys_connect hooks, sys_sendmsg ones can be used to make system
calls such as sendmsg(2) and sendto(2) return EPERM.

Please see patch 0001 for more details.


Andrey Ignatov (5):
  bpf: Hooks for sys_sendmsg
  bpf: Sync bpf.h to tools/
  libbpf: Support guessing sendmsg{4,6} progs
  selftests/bpf: Prepare test_sock_addr for extension
  selftests/bpf: Selftest for sys_sendmsg hooks

 include/linux/bpf-cgroup.h                   |   23 +-
 include/linux/filter.h                       |    1 +
 include/uapi/linux/bpf.h                     |    8 +
 kernel/bpf/cgroup.c                          |   11 +-
 kernel/bpf/syscall.c                         |    8 +
 net/core/filter.c                            |   39 +
 net/ipv4/udp.c                               |   20 +-
 net/ipv6/udp.c                               |   24 +
 tools/include/uapi/linux/bpf.h               |    8 +
 tools/lib/bpf/libbpf.c                       |    2 +
 tools/testing/selftests/bpf/Makefile         |    2 +-
 tools/testing/selftests/bpf/sendmsg4_prog.c  |   49 ++
 tools/testing/selftests/bpf/sendmsg6_prog.c  |   60 ++
 tools/testing/selftests/bpf/test_sock_addr.c | 1155 +++++++++++++++++++++-----
 14 files changed, 1214 insertions(+), 196 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/sendmsg4_prog.c
 create mode 100644 tools/testing/selftests/bpf/sendmsg6_prog.c

-- 
2.9.5

[PATCH v3 bpf-next 1/5] bpf: Hooks for sys_sendmsg

[Andrey Ignatov]

In addition to already existing BPF hooks for sys_bind and sys_connect,
the patch provides new hooks for sys_sendmsg.

It leverages existing BPF program type `BPF_PROG_TYPE_CGROUP_SOCK_ADDR`
that provides access to socket itlself (properties like family, type,
protocol) and user-passed `struct sockaddr *` so that BPF program can
override destination IP and port for system calls such as sendto(2) or
sendmsg(2) and/or assign source IP to the socket.

The hooks are implemented as two new attach types:
`BPF_CGROUP_UDP4_SENDMSG` and `BPF_CGROUP_UDP6_SENDMSG` for UDPv4 and
UDPv6 correspondingly.

UDPv4 and UDPv6 separate attach types for same reason as sys_bind and
sys_connect hooks, i.e. to prevent reading from / writing to e.g.
user_ip6 fields when user passes sockaddr_in since it'd be out-of-bound.

The difference with already existing hooks is sys_sendmsg are
implemented only for unconnected UDP.

For TCP it doesn't make sense to change user-provided `struct sockaddr *`
at sendto(2)/sendmsg(2) time since socket either was already connected
and has source/destination set or wasn't connected and call to
sendto(2)/sendmsg(2) would lead to ENOTCONN anyway.

Connected UDP is already handled by sys_connect hooks that can override
source/destination at connect time and use fast-path later, i.e. these
hooks don't affect UDP fast-path.

Rewriting source IP is implemented differently than that in sys_connect
hooks. When sys_sendmsg is used with unconnected UDP it doesn't work to
just bind socket to desired local IP address since source IP can be set
on per-packet basis by using ancillary data (cmsg(3)). So no matter if
socket is bound or not, source IP has to be rewritten on every call to
sys_sendmsg.

To do so two new fields are added to UAPI `struct bpf_sock_addr`;
* `msg_src_ip4` to set source IPv4 for UDPv4;
* `msg_src_ip6` to set source IPv6 for UDPv6.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 include/linux/bpf-cgroup.h | 23 +++++++++++++++++------
 include/linux/filter.h     |  1 +
 include/uapi/linux/bpf.h   |  8 ++++++++
 kernel/bpf/cgroup.c        | 11 ++++++++++-
 kernel/bpf/syscall.c       |  8 ++++++++
 net/core/filter.c          | 39 +++++++++++++++++++++++++++++++++++++++
 net/ipv4/udp.c             | 20 ++++++++++++++++++--
 net/ipv6/udp.c             | 24 ++++++++++++++++++++++++
 8 files changed, 125 insertions(+), 9 deletions(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 30d15e6..29f8085 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -66,7 +66,8 @@ int __cgroup_bpf_run_filter_sk(struct sock *sk,
 
 int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
 				      struct sockaddr *uaddr,
-				      enum bpf_attach_type type);
+				      enum bpf_attach_type type,
+				      void *t_ctx);
 
 int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
 				     struct bpf_sock_ops_kern *sock_ops,
@@ -120,16 +121,18 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
 ({									       \
 	int __ret = 0;							       \
 	if (cgroup_bpf_enabled)						       \
-		__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, type);    \
+		__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, type,     \
+							  NULL);	       \
 	__ret;								       \
 })
 
-#define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, type)			       \
+#define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, type, t_ctx)		       \
 ({									       \
 	int __ret = 0;							       \
 	if (cgroup_bpf_enabled)	{					       \
 		lock_sock(sk);						       \
-		__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, type);    \
+		__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, type,     \
+							  t_ctx);	       \
 		release_sock(sk);					       \
 	}								       \
 	__ret;								       \
@@ -151,10 +154,16 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
 	BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET6_CONNECT)
 
 #define BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr)		       \
-	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET4_CONNECT)
+	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET4_CONNECT, NULL)
 
 #define BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr)		       \
-	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET6_CONNECT)
+	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET6_CONNECT, NULL)
+
+#define BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk, uaddr, t_ctx)		       \
+	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_UDP4_SENDMSG, t_ctx)
+
+#define BPF_CGROUP_RUN_PROG_UDP6_SENDMSG_LOCK(sk, uaddr, t_ctx)		       \
+	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_UDP6_SENDMSG, t_ctx)
 
 #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops)				       \
 ({									       \
@@ -197,6 +206,8 @@ static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; }
 #define BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr) ({ 0; })
+#define BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk, uaddr, t_ctx) ({ 0; })
+#define BPF_CGROUP_RUN_PROG_UDP6_SENDMSG_LOCK(sk, uaddr, t_ctx) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type,major,minor,access) ({ 0; })
 
diff --git a/include/linux/filter.h b/include/linux/filter.h
index d358d18..d90abda 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1010,6 +1010,7 @@ struct bpf_sock_addr_kern {
 	 * only two (src and dst) are available at convert_ctx_access time
 	 */
 	u64 tmp_reg;
+	void *t_ctx;	/* Attach type specific context. */
 };
 
 struct bpf_sock_ops_kern {
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 9b8c6e3..cc68787 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -160,6 +160,8 @@ enum bpf_attach_type {
 	BPF_CGROUP_INET6_CONNECT,
 	BPF_CGROUP_INET4_POST_BIND,
 	BPF_CGROUP_INET6_POST_BIND,
+	BPF_CGROUP_UDP4_SENDMSG,
+	BPF_CGROUP_UDP6_SENDMSG,
 	__MAX_BPF_ATTACH_TYPE
 };
 
@@ -2363,6 +2365,12 @@ struct bpf_sock_addr {
 	__u32 family;		/* Allows 4-byte read, but no write */
 	__u32 type;		/* Allows 4-byte read, but no write */
 	__u32 protocol;		/* Allows 4-byte read, but no write */
+	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read an 4-byte write.
+				 * Stored in network byte order.
+				 */
+	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.
+				 * Stored in network byte order.
+				 */
 };
 
 /* User bpf_sock_ops struct to access socket values and specify request ops
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 43171a0..f7c00bd 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -500,6 +500,7 @@ EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
  * @sk: sock struct that will use sockaddr
  * @uaddr: sockaddr struct provided by user
  * @type: The type of program to be exectuted
+ * @t_ctx: Pointer to attach type specific context
  *
  * socket is expected to be of type INET or INET6.
  *
@@ -508,12 +509,15 @@ EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
  */
 int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
 				      struct sockaddr *uaddr,
-				      enum bpf_attach_type type)
+				      enum bpf_attach_type type,
+				      void *t_ctx)
 {
 	struct bpf_sock_addr_kern ctx = {
 		.sk = sk,
 		.uaddr = uaddr,
+		.t_ctx = t_ctx,
 	};
+	struct sockaddr_storage unspec;
 	struct cgroup *cgrp;
 	int ret;
 
@@ -523,6 +527,11 @@ int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
 	if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
 		return 0;
 
+	if (!ctx.uaddr) {
+		memset(&unspec, 0, sizeof(unspec));
+		ctx.uaddr = (struct sockaddr *)&unspec;
+	}
+
 	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
 	ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx, BPF_PROG_RUN);
 
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 388d4fe..e254526 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1249,6 +1249,8 @@ bpf_prog_load_check_attach_type(enum bpf_prog_type prog_type,
 		case BPF_CGROUP_INET6_BIND:
 		case BPF_CGROUP_INET4_CONNECT:
 		case BPF_CGROUP_INET6_CONNECT:
+		case BPF_CGROUP_UDP4_SENDMSG:
+		case BPF_CGROUP_UDP6_SENDMSG:
 			return 0;
 		default:
 			return -EINVAL;
@@ -1565,6 +1567,8 @@ static int bpf_prog_attach(const union bpf_attr *attr)
 	case BPF_CGROUP_INET6_BIND:
 	case BPF_CGROUP_INET4_CONNECT:
 	case BPF_CGROUP_INET6_CONNECT:
+	case BPF_CGROUP_UDP4_SENDMSG:
+	case BPF_CGROUP_UDP6_SENDMSG:
 		ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
 		break;
 	case BPF_CGROUP_SOCK_OPS:
@@ -1635,6 +1639,8 @@ static int bpf_prog_detach(const union bpf_attr *attr)
 	case BPF_CGROUP_INET6_BIND:
 	case BPF_CGROUP_INET4_CONNECT:
 	case BPF_CGROUP_INET6_CONNECT:
+	case BPF_CGROUP_UDP4_SENDMSG:
+	case BPF_CGROUP_UDP6_SENDMSG:
 		ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
 		break;
 	case BPF_CGROUP_SOCK_OPS:
@@ -1692,6 +1698,8 @@ static int bpf_prog_query(const union bpf_attr *attr,
 	case BPF_CGROUP_INET6_POST_BIND:
 	case BPF_CGROUP_INET4_CONNECT:
 	case BPF_CGROUP_INET6_CONNECT:
+	case BPF_CGROUP_UDP4_SENDMSG:
+	case BPF_CGROUP_UDP6_SENDMSG:
 	case BPF_CGROUP_SOCK_OPS:
 	case BPF_CGROUP_DEVICE:
 		break;
diff --git a/net/core/filter.c b/net/core/filter.c
index acf1f4f..24e6ce8 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5299,6 +5299,7 @@ static bool sock_addr_is_valid_access(int off, int size,
 		switch (prog->expected_attach_type) {
 		case BPF_CGROUP_INET4_BIND:
 		case BPF_CGROUP_INET4_CONNECT:
+		case BPF_CGROUP_UDP4_SENDMSG:
 			break;
 		default:
 			return false;
@@ -5308,6 +5309,24 @@ static bool sock_addr_is_valid_access(int off, int size,
 		switch (prog->expected_attach_type) {
 		case BPF_CGROUP_INET6_BIND:
 		case BPF_CGROUP_INET6_CONNECT:
+		case BPF_CGROUP_UDP6_SENDMSG:
+			break;
+		default:
+			return false;
+		}
+		break;
+	case bpf_ctx_range(struct bpf_sock_addr, msg_src_ip4):
+		switch (prog->expected_attach_type) {
+		case BPF_CGROUP_UDP4_SENDMSG:
+			break;
+		default:
+			return false;
+		}
+		break;
+	case bpf_ctx_range_till(struct bpf_sock_addr, msg_src_ip6[0],
+				msg_src_ip6[3]):
+		switch (prog->expected_attach_type) {
+		case BPF_CGROUP_UDP6_SENDMSG:
 			break;
 		default:
 			return false;
@@ -5318,6 +5337,9 @@ static bool sock_addr_is_valid_access(int off, int size,
 	switch (off) {
 	case bpf_ctx_range(struct bpf_sock_addr, user_ip4):
 	case bpf_ctx_range_till(struct bpf_sock_addr, user_ip6[0], user_ip6[3]):
+	case bpf_ctx_range(struct bpf_sock_addr, msg_src_ip4):
+	case bpf_ctx_range_till(struct bpf_sock_addr, msg_src_ip6[0],
+				msg_src_ip6[3]):
 		/* Only narrow read access allowed for now. */
 		if (type == BPF_READ) {
 			bpf_ctx_record_field_size(info, size_default);
@@ -6072,6 +6094,23 @@ static u32 sock_addr_convert_ctx_access(enum bpf_access_type type,
 		*insn++ = BPF_ALU32_IMM(BPF_RSH, si->dst_reg,
 					SK_FL_PROTO_SHIFT);
 		break;
+
+	case offsetof(struct bpf_sock_addr, msg_src_ip4):
+		/* Treat t_ctx as struct in_addr for msg_src_ip4. */
+		SOCK_ADDR_LOAD_OR_STORE_NESTED_FIELD_SIZE_OFF(
+			struct bpf_sock_addr_kern, struct in_addr, t_ctx,
+			s_addr, BPF_SIZE(si->code), 0, tmp_reg);
+		break;
+
+	case bpf_ctx_range_till(struct bpf_sock_addr, msg_src_ip6[0],
+				msg_src_ip6[3]):
+		off = si->off;
+		off -= offsetof(struct bpf_sock_addr, msg_src_ip6[0]);
+		/* Treat t_ctx as struct in6_addr for msg_src_ip6. */
+		SOCK_ADDR_LOAD_OR_STORE_NESTED_FIELD_SIZE_OFF(
+			struct bpf_sock_addr_kern, struct in6_addr, t_ctx,
+			s6_addr32[0], BPF_SIZE(si->code), off, tmp_reg);
+		break;
 	}
 
 	return insn - insn_buf;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d71f1f3..3c27d00 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -901,6 +901,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 {
 	struct inet_sock *inet = inet_sk(sk);
 	struct udp_sock *up = udp_sk(sk);
+	DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 	struct flowi4 fl4_stack;
 	struct flowi4 *fl4;
 	int ulen = len;
@@ -955,8 +956,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	/*
 	 *	Get and verify the address.
 	 */
-	if (msg->msg_name) {
-		DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
+	if (usin) {
 		if (msg->msg_namelen < sizeof(*usin))
 			return -EINVAL;
 		if (usin->sin_family != AF_INET) {
@@ -1010,6 +1010,22 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		rcu_read_unlock();
 	}
 
+	if (cgroup_bpf_enabled && !connected) {
+		err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk,
+					    (struct sockaddr *)usin, &ipc.addr);
+		if (err)
+			goto out_free;
+		if (usin) {
+			if (usin->sin_port == 0) {
+				/* BPF program set invalid port. Reject it. */
+				err = -EINVAL;
+				goto out_free;
+			}
+			daddr = usin->sin_addr.s_addr;
+			dport = usin->sin_port;
+		}
+	}
+
 	saddr = ipc.addr;
 	ipc.addr = faddr = daddr;
 
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 426c9d2..9f729a7 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1316,6 +1316,29 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		fl6.saddr = np->saddr;
 	fl6.fl6_sport = inet->inet_sport;
 
+	if (cgroup_bpf_enabled && !connected) {
+		err = BPF_CGROUP_RUN_PROG_UDP6_SENDMSG_LOCK(sk,
+					   (struct sockaddr *)sin6, &fl6.saddr);
+		if (err)
+			goto out_no_dst;
+		if (sin6) {
+			if (ipv6_addr_v4mapped(&sin6->sin6_addr)) {
+				/* BPF program rewrote IPv6-only by IPv4-mapped
+				 * IPv6. It's currently unsupported.
+				 */
+				err = -ENOTSUPP;
+				goto out_no_dst;
+			}
+			if (sin6->sin6_port == 0) {
+				/* BPF program set invalid port. Reject it. */
+				err = -EINVAL;
+				goto out_no_dst;
+			}
+			fl6.fl6_dport = sin6->sin6_port;
+			fl6.daddr = sin6->sin6_addr;
+		}
+	}
+
 	final_p = fl6_update_dst(&fl6, opt, &final);
 	if (final_p)
 		connected = false;
@@ -1395,6 +1418,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 out:
 	dst_release(dst);
+out_no_dst:
 	fl6_sock_release(flowlabel);
 	txopt_put(opt_to_free);
 	if (!err)
-- 
2.9.5

[PATCH v3 bpf-next 2/5] bpf: Sync bpf.h to tools/

[Andrey Ignatov]

Sync new `BPF_CGROUP_UDP4_SENDMSG` and `BPF_CGROUP_UDP6_SENDMSG`
attach types to tools/.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 tools/include/uapi/linux/bpf.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 9b8c6e3..cc68787 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -160,6 +160,8 @@ enum bpf_attach_type {
 	BPF_CGROUP_INET6_CONNECT,
 	BPF_CGROUP_INET4_POST_BIND,
 	BPF_CGROUP_INET6_POST_BIND,
+	BPF_CGROUP_UDP4_SENDMSG,
+	BPF_CGROUP_UDP6_SENDMSG,
 	__MAX_BPF_ATTACH_TYPE
 };
 
@@ -2363,6 +2365,12 @@ struct bpf_sock_addr {
 	__u32 family;		/* Allows 4-byte read, but no write */
 	__u32 type;		/* Allows 4-byte read, but no write */
 	__u32 protocol;		/* Allows 4-byte read, but no write */
+	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read an 4-byte write.
+				 * Stored in network byte order.
+				 */
+	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.
+				 * Stored in network byte order.
+				 */
 };
 
 /* User bpf_sock_ops struct to access socket values and specify request ops
-- 
2.9.5

[PATCH v3 bpf-next 3/5] libbpf: Support guessing sendmsg{4,6} progs

[Andrey Ignatov]

libbpf can guess prog type and expected attach type based on section
name. Add hints for "cgroup/sendmsg4" and "cgroup/sendmsg6" section
names.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 tools/lib/bpf/libbpf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d20411e..b1a60ac 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2043,6 +2043,8 @@ static const struct {
 	BPF_SA_PROG_SEC("cgroup/bind6",	BPF_CGROUP_INET6_BIND),
 	BPF_SA_PROG_SEC("cgroup/connect4", BPF_CGROUP_INET4_CONNECT),
 	BPF_SA_PROG_SEC("cgroup/connect6", BPF_CGROUP_INET6_CONNECT),
+	BPF_SA_PROG_SEC("cgroup/sendmsg4", BPF_CGROUP_UDP4_SENDMSG),
+	BPF_SA_PROG_SEC("cgroup/sendmsg6", BPF_CGROUP_UDP6_SENDMSG),
 	BPF_S_PROG_SEC("cgroup/post_bind4", BPF_CGROUP_INET4_POST_BIND),
 	BPF_S_PROG_SEC("cgroup/post_bind6", BPF_CGROUP_INET6_POST_BIND),
 };
-- 
2.9.5

[PATCH v3 bpf-next 4/5] selftests/bpf: Prepare test_sock_addr for extension

[Andrey Ignatov]

test_sock_addr was not easy to extend since it was focused on sys_bind
and sys_connect quite a bit.

Reorganized it so that it'll be easier to cover new test-cases for
`BPF_PROG_TYPE_CGROUP_SOCK_ADDR`:

- decouple test-cases so that only one BPF prog is tested at a time;

- check programmatically that local IP:port for sys_bind, source IP and
  destination IP:port for sys_connect are rewritten property by tested
  BPF programs.

The output of new version:
  # test_sock_addr.sh 2>/dev/null
  Wait for testing IPv4/IPv6 to become available ... OK
  Test case: bind4: load prog with wrong expected attach type .. [PASS]
  Test case: bind4: attach prog with wrong attach type .. [PASS]
  Test case: bind4: rewrite IP & TCP port in .. [PASS]
  Test case: bind4: rewrite IP & UDP port in .. [PASS]
  Test case: bind6: load prog with wrong expected attach type .. [PASS]
  Test case: bind6: attach prog with wrong attach type .. [PASS]
  Test case: bind6: rewrite IP & TCP port in .. [PASS]
  Test case: bind6: rewrite IP & UDP port in .. [PASS]
  Test case: connect4: load prog with wrong expected attach type .. [PASS]
  Test case: connect4: attach prog with wrong attach type .. [PASS]
  Test case: connect4: rewrite IP & TCP port .. [PASS]
  Test case: connect4: rewrite IP & UDP port .. [PASS]
  Test case: connect6: load prog with wrong expected attach type .. [PASS]
  Test case: connect6: attach prog with wrong attach type .. [PASS]
  Test case: connect6: rewrite IP & TCP port .. [PASS]
  Test case: connect6: rewrite IP & UDP port .. [PASS]
  Summary: 16 PASSED, 0 FAILED

(stderr contains errors from libbpf when testing load/attach with
invalid arguments)

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 tools/testing/selftests/bpf/test_sock_addr.c | 655 +++++++++++++++++++--------
 1 file changed, 460 insertions(+), 195 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_sock_addr.c b/tools/testing/selftests/bpf/test_sock_addr.c
index 2950f80..ed3e397 100644
--- a/tools/testing/selftests/bpf/test_sock_addr.c
+++ b/tools/testing/selftests/bpf/test_sock_addr.c
@@ -17,34 +17,292 @@
 #include "cgroup_helpers.h"
 #include "bpf_rlimit.h"
 
+#ifndef ARRAY_SIZE
+# define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
 #define CG_PATH	"/foo"
 #define CONNECT4_PROG_PATH	"./connect4_prog.o"
 #define CONNECT6_PROG_PATH	"./connect6_prog.o"
 
 #define SERV4_IP		"192.168.1.254"
 #define SERV4_REWRITE_IP	"127.0.0.1"
+#define SRC4_REWRITE_IP		"127.0.0.4"
 #define SERV4_PORT		4040
 #define SERV4_REWRITE_PORT	4444
 
 #define SERV6_IP		"face:b00c:1234:5678::abcd"
 #define SERV6_REWRITE_IP	"::1"
+#define SRC6_REWRITE_IP		"::6"
 #define SERV6_PORT		6060
 #define SERV6_REWRITE_PORT	6666
 
 #define INET_NTOP_BUF	40
 
-typedef int (*load_fn)(enum bpf_attach_type, const char *comment);
+struct sock_addr_test;
+
+typedef int (*load_fn)(const struct sock_addr_test *test);
 typedef int (*info_fn)(int, struct sockaddr *, socklen_t *);
 
-struct program {
-	enum bpf_attach_type type;
-	load_fn	loadfn;
-	int fd;
-	const char *name;
-	enum bpf_attach_type invalid_type;
+char bpf_log_buf[BPF_LOG_BUF_SIZE];
+
+struct sock_addr_test {
+	const char *descr;
+	/* BPF prog properties */
+	load_fn loadfn;
+	enum bpf_attach_type expected_attach_type;
+	enum bpf_attach_type attach_type;
+	/* Socket properties */
+	int domain;
+	int type;
+	/* IP:port pairs for BPF prog to override */
+	const char *requested_ip;
+	unsigned short requested_port;
+	const char *expected_ip;
+	unsigned short expected_port;
+	const char *expected_src_ip;
+	/* Expected test result */
+	enum {
+		LOAD_REJECT,
+		ATTACH_REJECT,
+		SUCCESS,
+	} expected_result;
 };
 
-char bpf_log_buf[BPF_LOG_BUF_SIZE];
+static int bind4_prog_load(const struct sock_addr_test *test);
+static int bind6_prog_load(const struct sock_addr_test *test);
+static int connect4_prog_load(const struct sock_addr_test *test);
+static int connect6_prog_load(const struct sock_addr_test *test);
+
+static struct sock_addr_test tests[] = {
+	/* bind */
+	{
+		"bind4: load prog with wrong expected attach type",
+		bind4_prog_load,
+		BPF_CGROUP_INET6_BIND,
+		BPF_CGROUP_INET4_BIND,
+		AF_INET,
+		SOCK_STREAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		LOAD_REJECT,
+	},
+	{
+		"bind4: attach prog with wrong attach type",
+		bind4_prog_load,
+		BPF_CGROUP_INET4_BIND,
+		BPF_CGROUP_INET6_BIND,
+		AF_INET,
+		SOCK_STREAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		ATTACH_REJECT,
+	},
+	{
+		"bind4: rewrite IP & TCP port in",
+		bind4_prog_load,
+		BPF_CGROUP_INET4_BIND,
+		BPF_CGROUP_INET4_BIND,
+		AF_INET,
+		SOCK_STREAM,
+		SERV4_IP,
+		SERV4_PORT,
+		SERV4_REWRITE_IP,
+		SERV4_REWRITE_PORT,
+		NULL,
+		SUCCESS,
+	},
+	{
+		"bind4: rewrite IP & UDP port in",
+		bind4_prog_load,
+		BPF_CGROUP_INET4_BIND,
+		BPF_CGROUP_INET4_BIND,
+		AF_INET,
+		SOCK_DGRAM,
+		SERV4_IP,
+		SERV4_PORT,
+		SERV4_REWRITE_IP,
+		SERV4_REWRITE_PORT,
+		NULL,
+		SUCCESS,
+	},
+	{
+		"bind6: load prog with wrong expected attach type",
+		bind6_prog_load,
+		BPF_CGROUP_INET4_BIND,
+		BPF_CGROUP_INET6_BIND,
+		AF_INET6,
+		SOCK_STREAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		LOAD_REJECT,
+	},
+	{
+		"bind6: attach prog with wrong attach type",
+		bind6_prog_load,
+		BPF_CGROUP_INET6_BIND,
+		BPF_CGROUP_INET4_BIND,
+		AF_INET,
+		SOCK_STREAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		ATTACH_REJECT,
+	},
+	{
+		"bind6: rewrite IP & TCP port in",
+		bind6_prog_load,
+		BPF_CGROUP_INET6_BIND,
+		BPF_CGROUP_INET6_BIND,
+		AF_INET6,
+		SOCK_STREAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		NULL,
+		SUCCESS,
+	},
+	{
+		"bind6: rewrite IP & UDP port in",
+		bind6_prog_load,
+		BPF_CGROUP_INET6_BIND,
+		BPF_CGROUP_INET6_BIND,
+		AF_INET6,
+		SOCK_DGRAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		NULL,
+		SUCCESS,
+	},
+
+	/* connect */
+	{
+		"connect4: load prog with wrong expected attach type",
+		connect4_prog_load,
+		BPF_CGROUP_INET6_CONNECT,
+		BPF_CGROUP_INET4_CONNECT,
+		AF_INET,
+		SOCK_STREAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		LOAD_REJECT,
+	},
+	{
+		"connect4: attach prog with wrong attach type",
+		connect4_prog_load,
+		BPF_CGROUP_INET4_CONNECT,
+		BPF_CGROUP_INET6_CONNECT,
+		AF_INET,
+		SOCK_STREAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		ATTACH_REJECT,
+	},
+	{
+		"connect4: rewrite IP & TCP port",
+		connect4_prog_load,
+		BPF_CGROUP_INET4_CONNECT,
+		BPF_CGROUP_INET4_CONNECT,
+		AF_INET,
+		SOCK_STREAM,
+		SERV4_IP,
+		SERV4_PORT,
+		SERV4_REWRITE_IP,
+		SERV4_REWRITE_PORT,
+		SRC4_REWRITE_IP,
+		SUCCESS,
+	},
+	{
+		"connect4: rewrite IP & UDP port",
+		connect4_prog_load,
+		BPF_CGROUP_INET4_CONNECT,
+		BPF_CGROUP_INET4_CONNECT,
+		AF_INET,
+		SOCK_DGRAM,
+		SERV4_IP,
+		SERV4_PORT,
+		SERV4_REWRITE_IP,
+		SERV4_REWRITE_PORT,
+		SRC4_REWRITE_IP,
+		SUCCESS,
+	},
+	{
+		"connect6: load prog with wrong expected attach type",
+		connect6_prog_load,
+		BPF_CGROUP_INET4_CONNECT,
+		BPF_CGROUP_INET6_CONNECT,
+		AF_INET6,
+		SOCK_STREAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		LOAD_REJECT,
+	},
+	{
+		"connect6: attach prog with wrong attach type",
+		connect6_prog_load,
+		BPF_CGROUP_INET6_CONNECT,
+		BPF_CGROUP_INET4_CONNECT,
+		AF_INET,
+		SOCK_STREAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		ATTACH_REJECT,
+	},
+	{
+		"connect6: rewrite IP & TCP port",
+		connect6_prog_load,
+		BPF_CGROUP_INET6_CONNECT,
+		BPF_CGROUP_INET6_CONNECT,
+		AF_INET6,
+		SOCK_STREAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		SRC6_REWRITE_IP,
+		SUCCESS,
+	},
+	{
+		"connect6: rewrite IP & UDP port",
+		connect6_prog_load,
+		BPF_CGROUP_INET6_CONNECT,
+		BPF_CGROUP_INET6_CONNECT,
+		AF_INET6,
+		SOCK_DGRAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		SRC6_REWRITE_IP,
+		SUCCESS,
+	},
+};
 
 static int mk_sockaddr(int domain, const char *ip, unsigned short port,
 		       struct sockaddr *addr, socklen_t addr_len)
@@ -84,25 +342,23 @@ static int mk_sockaddr(int domain, const char *ip, unsigned short port,
 	return 0;
 }
 
-static int load_insns(enum bpf_attach_type attach_type,
-		      const struct bpf_insn *insns, size_t insns_cnt,
-		      const char *comment)
+static int load_insns(const struct sock_addr_test *test,
+		      const struct bpf_insn *insns, size_t insns_cnt)
 {
 	struct bpf_load_program_attr load_attr;
 	int ret;
 
 	memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
 	load_attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
-	load_attr.expected_attach_type = attach_type;
+	load_attr.expected_attach_type = test->expected_attach_type;
 	load_attr.insns = insns;
 	load_attr.insns_cnt = insns_cnt;
 	load_attr.license = "GPL";
 
 	ret = bpf_load_program_xattr(&load_attr, bpf_log_buf, BPF_LOG_BUF_SIZE);
-	if (ret < 0 && comment) {
-		log_err(">>> Loading %s program error.\n"
-			">>> Output from verifier:\n%s\n-------\n",
-			comment, bpf_log_buf);
+	if (ret < 0 && test->expected_result != LOAD_REJECT) {
+		log_err(">>> Loading program error.\n"
+			">>> Verifier output:\n%s\n-------\n", bpf_log_buf);
 	}
 
 	return ret;
@@ -119,8 +375,7 @@ static int load_insns(enum bpf_attach_type attach_type,
  * to count jumps properly.
  */
 
-static int bind4_prog_load(enum bpf_attach_type attach_type,
-			   const char *comment)
+static int bind4_prog_load(const struct sock_addr_test *test)
 {
 	union {
 		uint8_t u4_addr8[4];
@@ -186,12 +441,10 @@ static int bind4_prog_load(enum bpf_attach_type attach_type,
 		BPF_EXIT_INSN(),
 	};
 
-	return load_insns(attach_type, insns,
-			  sizeof(insns) / sizeof(struct bpf_insn), comment);
+	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
 }
 
-static int bind6_prog_load(enum bpf_attach_type attach_type,
-			   const char *comment)
+static int bind6_prog_load(const struct sock_addr_test *test)
 {
 	struct sockaddr_in6 addr6_rw;
 	struct in6_addr ip6;
@@ -254,13 +507,10 @@ static int bind6_prog_load(enum bpf_attach_type attach_type,
 		BPF_EXIT_INSN(),
 	};
 
-	return load_insns(attach_type, insns,
-			  sizeof(insns) / sizeof(struct bpf_insn), comment);
+	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
 }
 
-static int connect_prog_load_path(const char *path,
-				  enum bpf_attach_type attach_type,
-				  const char *comment)
+static int load_path(const struct sock_addr_test *test, const char *path)
 {
 	struct bpf_prog_load_attr attr;
 	struct bpf_object *obj;
@@ -269,75 +519,83 @@ static int connect_prog_load_path(const char *path,
 	memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
 	attr.file = path;
 	attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
-	attr.expected_attach_type = attach_type;
+	attr.expected_attach_type = test->expected_attach_type;
 
 	if (bpf_prog_load_xattr(&attr, &obj, &prog_fd)) {
-		if (comment)
-			log_err(">>> Loading %s program at %s error.\n",
-				comment, path);
+		if (test->expected_result != LOAD_REJECT)
+			log_err(">>> Loading program (%s) error.\n", path);
 		return -1;
 	}
 
 	return prog_fd;
 }
 
-static int connect4_prog_load(enum bpf_attach_type attach_type,
-			      const char *comment)
+static int connect4_prog_load(const struct sock_addr_test *test)
 {
-	return connect_prog_load_path(CONNECT4_PROG_PATH, attach_type, comment);
+	return load_path(test, CONNECT4_PROG_PATH);
 }
 
-static int connect6_prog_load(enum bpf_attach_type attach_type,
-			      const char *comment)
+static int connect6_prog_load(const struct sock_addr_test *test)
 {
-	return connect_prog_load_path(CONNECT6_PROG_PATH, attach_type, comment);
+	return load_path(test, CONNECT6_PROG_PATH);
 }
 
-static void print_ip_port(int sockfd, info_fn fn, const char *fmt)
+static int cmp_addr(const struct sockaddr_storage *addr1,
+		    const struct sockaddr_storage *addr2, int cmp_port)
 {
-	char addr_buf[INET_NTOP_BUF];
-	struct sockaddr_storage addr;
-	struct sockaddr_in6 *addr6;
-	struct sockaddr_in *addr4;
-	socklen_t addr_len;
-	unsigned short port;
-	void *nip;
-
-	addr_len = sizeof(struct sockaddr_storage);
-	memset(&addr, 0, addr_len);
-
-	if (fn(sockfd, (struct sockaddr *)&addr, (socklen_t *)&addr_len) == 0) {
-		if (addr.ss_family == AF_INET) {
-			addr4 = (struct sockaddr_in *)&addr;
-			nip = (void *)&addr4->sin_addr;
-			port = ntohs(addr4->sin_port);
-		} else if (addr.ss_family == AF_INET6) {
-			addr6 = (struct sockaddr_in6 *)&addr;
-			nip = (void *)&addr6->sin6_addr;
-			port = ntohs(addr6->sin6_port);
-		} else {
-			return;
-		}
-		const char *addr_str =
-			inet_ntop(addr.ss_family, nip, addr_buf, INET_NTOP_BUF);
-		printf(fmt, addr_str ? addr_str : "??", port);
+	const struct sockaddr_in *four1, *four2;
+	const struct sockaddr_in6 *six1, *six2;
+
+	if (addr1->ss_family != addr2->ss_family)
+		return -1;
+
+	if (addr1->ss_family == AF_INET) {
+		four1 = (const struct sockaddr_in *)addr1;
+		four2 = (const struct sockaddr_in *)addr2;
+		return !((four1->sin_port == four2->sin_port || !cmp_port) &&
+			 four1->sin_addr.s_addr == four2->sin_addr.s_addr);
+	} else if (addr1->ss_family == AF_INET6) {
+		six1 = (const struct sockaddr_in6 *)addr1;
+		six2 = (const struct sockaddr_in6 *)addr2;
+		return !((six1->sin6_port == six2->sin6_port || !cmp_port) &&
+			 !memcmp(&six1->sin6_addr, &six2->sin6_addr,
+				 sizeof(struct in6_addr)));
 	}
+
+	return -1;
+}
+
+static int cmp_sock_addr(info_fn fn, int sock1,
+			 const struct sockaddr_storage *addr2, int cmp_port)
+{
+	struct sockaddr_storage addr1;
+	socklen_t len1 = sizeof(addr1);
+
+	memset(&addr1, 0, len1);
+	if (fn(sock1, (struct sockaddr *)&addr1, (socklen_t *)&len1) != 0)
+		return -1;
+
+	return cmp_addr(&addr1, addr2, cmp_port);
+}
+
+static int cmp_local_ip(int sock1, const struct sockaddr_storage *addr2)
+{
+	return cmp_sock_addr(getsockname, sock1, addr2, /*cmp_port*/ 0);
 }
 
-static void print_local_ip_port(int sockfd, const char *fmt)
+static int cmp_local_addr(int sock1, const struct sockaddr_storage *addr2)
 {
-	print_ip_port(sockfd, getsockname, fmt);
+	return cmp_sock_addr(getsockname, sock1, addr2, /*cmp_port*/ 1);
 }
 
-static void print_remote_ip_port(int sockfd, const char *fmt)
+static int cmp_peer_addr(int sock1, const struct sockaddr_storage *addr2)
 {
-	print_ip_port(sockfd, getpeername, fmt);
+	return cmp_sock_addr(getpeername, sock1, addr2, /*cmp_port*/ 1);
 }
 
 static int start_server(int type, const struct sockaddr_storage *addr,
 			socklen_t addr_len)
 {
-
 	int fd;
 
 	fd = socket(addr->ss_family, type, 0);
@@ -358,8 +616,6 @@ static int start_server(int type, const struct sockaddr_storage *addr,
 		}
 	}
 
-	print_local_ip_port(fd, "\t   Actual: bind(%s, %d)\n");
-
 	goto out;
 close_out:
 	close(fd);
@@ -372,19 +628,19 @@ static int connect_to_server(int type, const struct sockaddr_storage *addr,
 			     socklen_t addr_len)
 {
 	int domain;
-	int fd;
+	int fd = -1;
 
 	domain = addr->ss_family;
 
 	if (domain != AF_INET && domain != AF_INET6) {
 		log_err("Unsupported address family");
-		return -1;
+		goto err;
 	}
 
 	fd = socket(domain, type, 0);
 	if (fd == -1) {
-		log_err("Failed to creating client socket");
-		return -1;
+		log_err("Failed to create client socket");
+		goto err;
 	}
 
 	if (connect(fd, (const struct sockaddr *)addr, addr_len) == -1) {
@@ -392,162 +648,188 @@ static int connect_to_server(int type, const struct sockaddr_storage *addr,
 		goto err;
 	}
 
-	print_remote_ip_port(fd, "\t   Actual: connect(%s, %d)");
-	print_local_ip_port(fd, " from (%s, %d)\n");
-
-	return 0;
+	goto out;
 err:
 	close(fd);
-	return -1;
+	fd = -1;
+out:
+	return fd;
 }
 
-static void print_test_case_num(int domain, int type)
+static int init_addrs(const struct sock_addr_test *test,
+		      struct sockaddr_storage *requested_addr,
+		      struct sockaddr_storage *expected_addr,
+		      struct sockaddr_storage *expected_src_addr)
 {
-	static int test_num;
-
-	printf("Test case #%d (%s/%s):\n", ++test_num,
-	       (domain == AF_INET ? "IPv4" :
-		domain == AF_INET6 ? "IPv6" :
-		"unknown_domain"),
-	       (type == SOCK_STREAM ? "TCP" :
-		type == SOCK_DGRAM ? "UDP" :
-		"unknown_type"));
+	socklen_t addr_len = sizeof(struct sockaddr_storage);
+
+	if (mk_sockaddr(test->domain, test->expected_ip, test->expected_port,
+			(struct sockaddr *)expected_addr, addr_len) == -1)
+		goto err;
+
+	if (mk_sockaddr(test->domain, test->requested_ip, test->requested_port,
+			(struct sockaddr *)requested_addr, addr_len) == -1)
+		goto err;
+
+	if (test->expected_src_ip &&
+	    mk_sockaddr(test->domain, test->expected_src_ip, 0,
+			(struct sockaddr *)expected_src_addr, addr_len) == -1)
+		goto err;
+
+	return 0;
+err:
+	return -1;
 }
 
-static int run_test_case(int domain, int type, const char *ip,
-			 unsigned short port)
+static int run_bind_test_case(const struct sock_addr_test *test)
 {
-	struct sockaddr_storage addr;
-	socklen_t addr_len = sizeof(addr);
+	socklen_t addr_len = sizeof(struct sockaddr_storage);
+	struct sockaddr_storage requested_addr;
+	struct sockaddr_storage expected_addr;
+	int clientfd = -1;
 	int servfd = -1;
 	int err = 0;
 
-	print_test_case_num(domain, type);
-
-	if (mk_sockaddr(domain, ip, port, (struct sockaddr *)&addr,
-			addr_len) == -1)
-		return -1;
+	if (init_addrs(test, &requested_addr, &expected_addr, NULL))
+		goto err;
 
-	printf("\tRequested: bind(%s, %d) ..\n", ip, port);
-	servfd = start_server(type, &addr, addr_len);
+	servfd = start_server(test->type, &requested_addr, addr_len);
 	if (servfd == -1)
 		goto err;
 
-	printf("\tRequested: connect(%s, %d) from (*, *) ..\n", ip, port);
-	if (connect_to_server(type, &addr, addr_len))
+	if (cmp_local_addr(servfd, &expected_addr))
+		goto err;
+
+	/* Try to connect to server just in case */
+	clientfd = connect_to_server(test->type, &expected_addr, addr_len);
+	if (clientfd == -1)
 		goto err;
 
 	goto out;
 err:
 	err = -1;
 out:
+	close(clientfd);
 	close(servfd);
 	return err;
 }
 
-static void close_progs_fds(struct program *progs, size_t prog_cnt)
+static int run_connect_test_case(const struct sock_addr_test *test)
 {
-	size_t i;
+	socklen_t addr_len = sizeof(struct sockaddr_storage);
+	struct sockaddr_storage expected_src_addr;
+	struct sockaddr_storage requested_addr;
+	struct sockaddr_storage expected_addr;
+	int clientfd = -1;
+	int servfd = -1;
+	int err = 0;
 
-	for (i = 0; i < prog_cnt; ++i) {
-		close(progs[i].fd);
-		progs[i].fd = -1;
-	}
-}
+	if (init_addrs(test, &requested_addr, &expected_addr,
+		       &expected_src_addr))
+		goto err;
 
-static int load_and_attach_progs(int cgfd, struct program *progs,
-				 size_t prog_cnt)
-{
-	size_t i;
-
-	for (i = 0; i < prog_cnt; ++i) {
-		printf("Load %s with invalid type (can pollute stderr) ",
-		       progs[i].name);
-		fflush(stdout);
-		progs[i].fd = progs[i].loadfn(progs[i].invalid_type, NULL);
-		if (progs[i].fd != -1) {
-			log_err("Load with invalid type accepted for %s",
-				progs[i].name);
-			goto err;
-		}
-		printf("... REJECTED\n");
+	/* Prepare server to connect to */
+	servfd = start_server(test->type, &expected_addr, addr_len);
+	if (servfd == -1)
+		goto err;
 
-		printf("Load %s with valid type", progs[i].name);
-		progs[i].fd = progs[i].loadfn(progs[i].type, progs[i].name);
-		if (progs[i].fd == -1) {
-			log_err("Failed to load program %s", progs[i].name);
-			goto err;
-		}
-		printf(" ... OK\n");
-
-		printf("Attach %s with invalid type", progs[i].name);
-		if (bpf_prog_attach(progs[i].fd, cgfd, progs[i].invalid_type,
-				    BPF_F_ALLOW_OVERRIDE) != -1) {
-			log_err("Attach with invalid type accepted for %s",
-				progs[i].name);
-			goto err;
-		}
-		printf(" ... REJECTED\n");
+	clientfd = connect_to_server(test->type, &requested_addr, addr_len);
+	if (clientfd == -1)
+		goto err;
 
-		printf("Attach %s with valid type", progs[i].name);
-		if (bpf_prog_attach(progs[i].fd, cgfd, progs[i].type,
-				    BPF_F_ALLOW_OVERRIDE) == -1) {
-			log_err("Failed to attach program %s", progs[i].name);
-			goto err;
-		}
-		printf(" ... OK\n");
-	}
+	/* Make sure src and dst addrs were overridden properly */
+	if (cmp_peer_addr(clientfd, &expected_addr))
+		goto err;
 
-	return 0;
+	if (cmp_local_ip(clientfd, &expected_src_addr))
+		goto err;
+
+	goto out;
 err:
-	close_progs_fds(progs, prog_cnt);
-	return -1;
+	err = -1;
+out:
+	close(clientfd);
+	close(servfd);
+	return err;
 }
 
-static int run_domain_test(int domain, int cgfd, struct program *progs,
-			   size_t prog_cnt, const char *ip, unsigned short port)
+static int run_test_case(int cgfd, const struct sock_addr_test *test)
 {
+	int progfd = -1;
 	int err = 0;
 
-	if (load_and_attach_progs(cgfd, progs, prog_cnt) == -1)
+	printf("Test case: %s .. ", test->descr);
+
+	progfd = test->loadfn(test);
+	if (test->expected_result == LOAD_REJECT && progfd < 0)
+		goto out;
+	else if (test->expected_result == LOAD_REJECT || progfd < 0)
+		goto err;
+
+	err = bpf_prog_attach(progfd, cgfd, test->attach_type,
+			      BPF_F_ALLOW_OVERRIDE);
+	if (test->expected_result == ATTACH_REJECT && err) {
+		err = 0; /* error was expected, reset it */
+		goto out;
+	} else if (test->expected_result == ATTACH_REJECT || err) {
 		goto err;
+	}
 
-	if (run_test_case(domain, SOCK_STREAM, ip, port) == -1)
+	switch (test->attach_type) {
+	case BPF_CGROUP_INET4_BIND:
+	case BPF_CGROUP_INET6_BIND:
+		err = run_bind_test_case(test);
+		break;
+	case BPF_CGROUP_INET4_CONNECT:
+	case BPF_CGROUP_INET6_CONNECT:
+		err = run_connect_test_case(test);
+		break;
+	default:
 		goto err;
+	}
 
-	if (run_test_case(domain, SOCK_DGRAM, ip, port) == -1)
+	if (err || test->expected_result != SUCCESS)
 		goto err;
 
 	goto out;
 err:
 	err = -1;
 out:
-	close_progs_fds(progs, prog_cnt);
+	/* Detaching w/o checking return code: best effort attempt. */
+	if (progfd != -1)
+		bpf_prog_detach(cgfd, test->attach_type);
+	close(progfd);
+	printf("[%s]\n", err ? "FAIL" : "PASS");
 	return err;
 }
 
-static int run_test(void)
+static int run_tests(int cgfd)
+{
+	int passes = 0;
+	int fails = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(tests); ++i) {
+		if (run_test_case(cgfd, &tests[i]))
+			++fails;
+		else
+			++passes;
+	}
+	printf("Summary: %d PASSED, %d FAILED\n", passes, fails);
+	return fails ? -1 : 0;
+}
+
+int main(int argc, char **argv)
 {
-	size_t inet6_prog_cnt;
-	size_t inet_prog_cnt;
 	int cgfd = -1;
 	int err = 0;
 
-	struct program inet6_progs[] = {
-		{BPF_CGROUP_INET6_BIND, bind6_prog_load, -1, "bind6",
-		 BPF_CGROUP_INET4_BIND},
-		{BPF_CGROUP_INET6_CONNECT, connect6_prog_load, -1, "connect6",
-		 BPF_CGROUP_INET4_CONNECT},
-	};
-	inet6_prog_cnt = sizeof(inet6_progs) / sizeof(struct program);
-
-	struct program inet_progs[] = {
-		{BPF_CGROUP_INET4_BIND, bind4_prog_load, -1, "bind4",
-		 BPF_CGROUP_INET6_BIND},
-		{BPF_CGROUP_INET4_CONNECT, connect4_prog_load, -1, "connect4",
-		 BPF_CGROUP_INET6_CONNECT},
-	};
-	inet_prog_cnt = sizeof(inet_progs) / sizeof(struct program);
+	if (argc < 2) {
+		fprintf(stderr,
+			"%s has to be run via %s.sh. Skip direct run.\n",
+			argv[0], argv[0]);
+		exit(err);
+	}
 
 	if (setup_cgroup_environment())
 		goto err;
@@ -559,12 +841,7 @@ static int run_test(void)
 	if (join_cgroup(CG_PATH))
 		goto err;
 
-	if (run_domain_test(AF_INET, cgfd, inet_progs, inet_prog_cnt, SERV4_IP,
-			    SERV4_PORT) == -1)
-		goto err;
-
-	if (run_domain_test(AF_INET6, cgfd, inet6_progs, inet6_prog_cnt,
-			    SERV6_IP, SERV6_PORT) == -1)
+	if (run_tests(cgfd))
 		goto err;
 
 	goto out;
@@ -573,17 +850,5 @@ static int run_test(void)
 out:
 	close(cgfd);
 	cleanup_cgroup_environment();
-	printf(err ? "### FAIL\n" : "### SUCCESS\n");
 	return err;
 }
-
-int main(int argc, char **argv)
-{
-	if (argc < 2) {
-		fprintf(stderr,
-			"%s has to be run via %s.sh. Skip direct run.\n",
-			argv[0], argv[0]);
-		exit(0);
-	}
-	return run_test();
-}
-- 
2.9.5

[PATCH v3 bpf-next 5/5] selftests/bpf: Selftest for sys_sendmsg hooks

[Andrey Ignatov]

Add selftest for BPF_CGROUP_UDP4_SENDMSG and BPF_CGROUP_UDP6_SENDMSG
attach types.

Try to sendmsg(2) to specific IP:port and test that:
* source IP is overridden as expected.
* remote IP:port pair is overridden as expected;

Both UDPv4 and UDPv6 are tested.

Output:
  # test_sock_addr.sh 2>/dev/null
  Wait for testing IPv4/IPv6 to become available ... OK
  ... pre-existing test-cases skipped ...
  Test case: sendmsg4: load prog with wrong expected attach type .. [PASS]
  Test case: sendmsg4: attach prog with wrong attach type .. [PASS]
  Test case: sendmsg4: rewrite IP & port (asm) .. [PASS]
  Test case: sendmsg4: rewrite IP & port (C) .. [PASS]
  Test case: sendmsg4: deny call .. [PASS]
  Test case: sendmsg6: load prog with wrong expected attach type .. [PASS]
  Test case: sendmsg6: attach prog with wrong attach type .. [PASS]
  Test case: sendmsg6: rewrite IP & port (asm) .. [PASS]
  Test case: sendmsg6: rewrite IP & port (C) .. [PASS]
  Test case: sendmsg6: IPv4-mapped IPv6 .. [PASS]
  Test case: sendmsg6: deny call .. [PASS]
  Summary: 27 PASSED, 0 FAILED

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 tools/testing/selftests/bpf/Makefile         |   2 +-
 tools/testing/selftests/bpf/sendmsg4_prog.c  |  49 +++
 tools/testing/selftests/bpf/sendmsg6_prog.c  |  60 ++++
 tools/testing/selftests/bpf/test_sock_addr.c | 518 +++++++++++++++++++++++++++
 4 files changed, 628 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/sendmsg4_prog.c
 create mode 100644 tools/testing/selftests/bpf/sendmsg6_prog.c

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 8504444..a1b66da 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -34,7 +34,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
 	sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
 	test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \
 	test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
-	test_lwt_seg6local.o
+	test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o
 
 # Order correspond to 'make run_tests' order
 TEST_PROGS := test_kmod.sh \
diff --git a/tools/testing/selftests/bpf/sendmsg4_prog.c b/tools/testing/selftests/bpf/sendmsg4_prog.c
new file mode 100644
index 0000000..a91536b
--- /dev/null
+++ b/tools/testing/selftests/bpf/sendmsg4_prog.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Facebook
+
+#include <linux/stddef.h>
+#include <linux/bpf.h>
+#include <sys/socket.h>
+
+#include "bpf_helpers.h"
+#include "bpf_endian.h"
+
+#define SRC1_IP4		0xAC100001U /* 172.16.0.1 */
+#define SRC2_IP4		0x00000000U
+#define SRC_REWRITE_IP4		0x7f000004U
+#define DST_IP4			0xC0A801FEU /* 192.168.1.254 */
+#define DST_REWRITE_IP4		0x7f000001U
+#define DST_PORT		4040
+#define DST_REWRITE_PORT4	4444
+
+int _version SEC("version") = 1;
+
+SEC("cgroup/sendmsg4")
+int sendmsg_v4_prog(struct bpf_sock_addr *ctx)
+{
+	if (ctx->type != SOCK_DGRAM)
+		return 0;
+
+	/* Rewrite source. */
+	if (ctx->msg_src_ip4 == bpf_htonl(SRC1_IP4) ||
+	    ctx->msg_src_ip4 == bpf_htonl(SRC2_IP4)) {
+		ctx->msg_src_ip4 = bpf_htonl(SRC_REWRITE_IP4);
+	} else {
+		/* Unexpected source. Reject sendmsg. */
+		return 0;
+	}
+
+	/* Rewrite destination. */
+	if ((ctx->user_ip4 >> 24) == (bpf_htonl(DST_IP4) >> 24) &&
+	     ctx->user_port == bpf_htons(DST_PORT)) {
+		ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
+		ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
+	} else {
+		/* Unexpected source. Reject sendmsg. */
+		return 0;
+	}
+
+	return 1;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/sendmsg6_prog.c b/tools/testing/selftests/bpf/sendmsg6_prog.c
new file mode 100644
index 0000000..5aeaa28
--- /dev/null
+++ b/tools/testing/selftests/bpf/sendmsg6_prog.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Facebook
+
+#include <linux/stddef.h>
+#include <linux/bpf.h>
+#include <sys/socket.h>
+
+#include "bpf_helpers.h"
+#include "bpf_endian.h"
+
+#define SRC_REWRITE_IP6_0	0
+#define SRC_REWRITE_IP6_1	0
+#define SRC_REWRITE_IP6_2	0
+#define SRC_REWRITE_IP6_3	6
+
+#define DST_REWRITE_IP6_0	0
+#define DST_REWRITE_IP6_1	0
+#define DST_REWRITE_IP6_2	0
+#define DST_REWRITE_IP6_3	1
+
+#define DST_REWRITE_PORT6	6666
+
+int _version SEC("version") = 1;
+
+SEC("cgroup/sendmsg6")
+int sendmsg_v6_prog(struct bpf_sock_addr *ctx)
+{
+	if (ctx->type != SOCK_DGRAM)
+		return 0;
+
+	/* Rewrite source. */
+	if (ctx->msg_src_ip6[3] == bpf_htonl(1) ||
+	    ctx->msg_src_ip6[3] == bpf_htonl(0)) {
+		ctx->msg_src_ip6[0] = bpf_htonl(SRC_REWRITE_IP6_0);
+		ctx->msg_src_ip6[1] = bpf_htonl(SRC_REWRITE_IP6_1);
+		ctx->msg_src_ip6[2] = bpf_htonl(SRC_REWRITE_IP6_2);
+		ctx->msg_src_ip6[3] = bpf_htonl(SRC_REWRITE_IP6_3);
+	} else {
+		/* Unexpected source. Reject sendmsg. */
+		return 0;
+	}
+
+	/* Rewrite destination. */
+	if ((ctx->user_ip6[0] & 0xFFFF) == bpf_htons(0xFACE) &&
+	     ctx->user_ip6[0] >> 16 == bpf_htons(0xB00C)) {
+		ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_0);
+		ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_1);
+		ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2);
+		ctx->user_ip6[3] = bpf_htonl(DST_REWRITE_IP6_3);
+
+		ctx->user_port = bpf_htons(DST_REWRITE_PORT6);
+	} else {
+		/* Unexpected destination. Reject sendmsg. */
+		return 0;
+	}
+
+	return 1;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/test_sock_addr.c b/tools/testing/selftests/bpf/test_sock_addr.c
index ed3e397..a5e76b9 100644
--- a/tools/testing/selftests/bpf/test_sock_addr.c
+++ b/tools/testing/selftests/bpf/test_sock_addr.c
@@ -1,12 +1,16 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2018 Facebook
 
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 
 #include <arpa/inet.h>
+#include <netinet/in.h>
 #include <sys/types.h>
+#include <sys/select.h>
 #include <sys/socket.h>
 
 #include <linux/filter.h>
@@ -17,6 +21,10 @@
 #include "cgroup_helpers.h"
 #include "bpf_rlimit.h"
 
+#ifndef ENOTSUPP
+# define ENOTSUPP 524
+#endif
+
 #ifndef ARRAY_SIZE
 # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 #endif
@@ -24,15 +32,20 @@
 #define CG_PATH	"/foo"
 #define CONNECT4_PROG_PATH	"./connect4_prog.o"
 #define CONNECT6_PROG_PATH	"./connect6_prog.o"
+#define SENDMSG4_PROG_PATH	"./sendmsg4_prog.o"
+#define SENDMSG6_PROG_PATH	"./sendmsg6_prog.o"
 
 #define SERV4_IP		"192.168.1.254"
 #define SERV4_REWRITE_IP	"127.0.0.1"
+#define SRC4_IP			"172.16.0.1"
 #define SRC4_REWRITE_IP		"127.0.0.4"
 #define SERV4_PORT		4040
 #define SERV4_REWRITE_PORT	4444
 
 #define SERV6_IP		"face:b00c:1234:5678::abcd"
 #define SERV6_REWRITE_IP	"::1"
+#define SERV6_V4MAPPED_IP	"::ffff:192.168.0.4"
+#define SRC6_IP			"::1"
 #define SRC6_REWRITE_IP		"::6"
 #define SERV6_PORT		6060
 #define SERV6_REWRITE_PORT	6666
@@ -65,6 +78,8 @@ struct sock_addr_test {
 	enum {
 		LOAD_REJECT,
 		ATTACH_REJECT,
+		SYSCALL_EPERM,
+		SYSCALL_ENOTSUPP,
 		SUCCESS,
 	} expected_result;
 };
@@ -73,6 +88,12 @@ static int bind4_prog_load(const struct sock_addr_test *test);
 static int bind6_prog_load(const struct sock_addr_test *test);
 static int connect4_prog_load(const struct sock_addr_test *test);
 static int connect6_prog_load(const struct sock_addr_test *test);
+static int sendmsg_deny_prog_load(const struct sock_addr_test *test);
+static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test);
+static int sendmsg4_rw_c_prog_load(const struct sock_addr_test *test);
+static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test);
+static int sendmsg6_rw_c_prog_load(const struct sock_addr_test *test);
+static int sendmsg6_rw_v4mapped_prog_load(const struct sock_addr_test *test);
 
 static struct sock_addr_test tests[] = {
 	/* bind */
@@ -302,6 +323,162 @@ static struct sock_addr_test tests[] = {
 		SRC6_REWRITE_IP,
 		SUCCESS,
 	},
+
+	/* sendmsg */
+	{
+		"sendmsg4: load prog with wrong expected attach type",
+		sendmsg4_rw_asm_prog_load,
+		BPF_CGROUP_UDP6_SENDMSG,
+		BPF_CGROUP_UDP4_SENDMSG,
+		AF_INET,
+		SOCK_DGRAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		LOAD_REJECT,
+	},
+	{
+		"sendmsg4: attach prog with wrong attach type",
+		sendmsg4_rw_asm_prog_load,
+		BPF_CGROUP_UDP4_SENDMSG,
+		BPF_CGROUP_UDP6_SENDMSG,
+		AF_INET,
+		SOCK_DGRAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		ATTACH_REJECT,
+	},
+	{
+		"sendmsg4: rewrite IP & port (asm)",
+		sendmsg4_rw_asm_prog_load,
+		BPF_CGROUP_UDP4_SENDMSG,
+		BPF_CGROUP_UDP4_SENDMSG,
+		AF_INET,
+		SOCK_DGRAM,
+		SERV4_IP,
+		SERV4_PORT,
+		SERV4_REWRITE_IP,
+		SERV4_REWRITE_PORT,
+		SRC4_REWRITE_IP,
+		SUCCESS,
+	},
+	{
+		"sendmsg4: rewrite IP & port (C)",
+		sendmsg4_rw_c_prog_load,
+		BPF_CGROUP_UDP4_SENDMSG,
+		BPF_CGROUP_UDP4_SENDMSG,
+		AF_INET,
+		SOCK_DGRAM,
+		SERV4_IP,
+		SERV4_PORT,
+		SERV4_REWRITE_IP,
+		SERV4_REWRITE_PORT,
+		SRC4_REWRITE_IP,
+		SUCCESS,
+	},
+	{
+		"sendmsg4: deny call",
+		sendmsg_deny_prog_load,
+		BPF_CGROUP_UDP4_SENDMSG,
+		BPF_CGROUP_UDP4_SENDMSG,
+		AF_INET,
+		SOCK_DGRAM,
+		SERV4_IP,
+		SERV4_PORT,
+		SERV4_REWRITE_IP,
+		SERV4_REWRITE_PORT,
+		SRC4_REWRITE_IP,
+		SYSCALL_EPERM,
+	},
+	{
+		"sendmsg6: load prog with wrong expected attach type",
+		sendmsg6_rw_asm_prog_load,
+		BPF_CGROUP_UDP4_SENDMSG,
+		BPF_CGROUP_UDP6_SENDMSG,
+		AF_INET6,
+		SOCK_DGRAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		LOAD_REJECT,
+	},
+	{
+		"sendmsg6: attach prog with wrong attach type",
+		sendmsg6_rw_asm_prog_load,
+		BPF_CGROUP_UDP6_SENDMSG,
+		BPF_CGROUP_UDP4_SENDMSG,
+		AF_INET6,
+		SOCK_DGRAM,
+		NULL,
+		0,
+		NULL,
+		0,
+		NULL,
+		ATTACH_REJECT,
+	},
+	{
+		"sendmsg6: rewrite IP & port (asm)",
+		sendmsg6_rw_asm_prog_load,
+		BPF_CGROUP_UDP6_SENDMSG,
+		BPF_CGROUP_UDP6_SENDMSG,
+		AF_INET6,
+		SOCK_DGRAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		SRC6_REWRITE_IP,
+		SUCCESS,
+	},
+	{
+		"sendmsg6: rewrite IP & port (C)",
+		sendmsg6_rw_c_prog_load,
+		BPF_CGROUP_UDP6_SENDMSG,
+		BPF_CGROUP_UDP6_SENDMSG,
+		AF_INET6,
+		SOCK_DGRAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		SRC6_REWRITE_IP,
+		SUCCESS,
+	},
+	{
+		"sendmsg6: IPv4-mapped IPv6",
+		sendmsg6_rw_v4mapped_prog_load,
+		BPF_CGROUP_UDP6_SENDMSG,
+		BPF_CGROUP_UDP6_SENDMSG,
+		AF_INET6,
+		SOCK_DGRAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		SRC6_REWRITE_IP,
+		SYSCALL_ENOTSUPP,
+	},
+	{
+		"sendmsg6: deny call",
+		sendmsg_deny_prog_load,
+		BPF_CGROUP_UDP6_SENDMSG,
+		BPF_CGROUP_UDP6_SENDMSG,
+		AF_INET6,
+		SOCK_DGRAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		SRC6_REWRITE_IP,
+		SYSCALL_EPERM,
+	},
 };
 
 static int mk_sockaddr(int domain, const char *ip, unsigned short port,
@@ -540,6 +717,141 @@ static int connect6_prog_load(const struct sock_addr_test *test)
 	return load_path(test, CONNECT6_PROG_PATH);
 }
 
+static int sendmsg_deny_prog_load(const struct sock_addr_test *test)
+{
+	struct bpf_insn insns[] = {
+		/* return 0 */
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
+}
+
+static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test)
+{
+	struct sockaddr_in dst4_rw_addr;
+	struct in_addr src4_rw_ip;
+
+	if (inet_pton(AF_INET, SRC4_REWRITE_IP, (void *)&src4_rw_ip) != 1) {
+		log_err("Invalid IPv4: %s", SRC4_REWRITE_IP);
+		return -1;
+	}
+
+	if (mk_sockaddr(AF_INET, SERV4_REWRITE_IP, SERV4_REWRITE_PORT,
+			(struct sockaddr *)&dst4_rw_addr,
+			sizeof(dst4_rw_addr)) == -1)
+		return -1;
+
+	struct bpf_insn insns[] = {
+		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+
+		/* if (sk.family == AF_INET && */
+		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
+			    offsetof(struct bpf_sock_addr, family)),
+		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET, 8),
+
+		/*     sk.type == SOCK_DGRAM)  { */
+		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
+			    offsetof(struct bpf_sock_addr, type)),
+		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, SOCK_DGRAM, 6),
+
+		/*      msg_src_ip4 = src4_rw_ip */
+		BPF_MOV32_IMM(BPF_REG_7, src4_rw_ip.s_addr),
+		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
+			    offsetof(struct bpf_sock_addr, msg_src_ip4)),
+
+		/*      user_ip4 = dst4_rw_addr.sin_addr */
+		BPF_MOV32_IMM(BPF_REG_7, dst4_rw_addr.sin_addr.s_addr),
+		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
+			    offsetof(struct bpf_sock_addr, user_ip4)),
+
+		/*      user_port = dst4_rw_addr.sin_port */
+		BPF_MOV32_IMM(BPF_REG_7, dst4_rw_addr.sin_port),
+		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
+			    offsetof(struct bpf_sock_addr, user_port)),
+		/* } */
+
+		/* return 1 */
+		BPF_MOV64_IMM(BPF_REG_0, 1),
+		BPF_EXIT_INSN(),
+	};
+
+	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
+}
+
+static int sendmsg4_rw_c_prog_load(const struct sock_addr_test *test)
+{
+	return load_path(test, SENDMSG4_PROG_PATH);
+}
+
+static int sendmsg6_rw_dst_asm_prog_load(const struct sock_addr_test *test,
+					 const char *rw_dst_ip)
+{
+	struct sockaddr_in6 dst6_rw_addr;
+	struct in6_addr src6_rw_ip;
+
+	if (inet_pton(AF_INET6, SRC6_REWRITE_IP, (void *)&src6_rw_ip) != 1) {
+		log_err("Invalid IPv6: %s", SRC6_REWRITE_IP);
+		return -1;
+	}
+
+	if (mk_sockaddr(AF_INET6, rw_dst_ip, SERV6_REWRITE_PORT,
+			(struct sockaddr *)&dst6_rw_addr,
+			sizeof(dst6_rw_addr)) == -1)
+		return -1;
+
+	struct bpf_insn insns[] = {
+		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+
+		/* if (sk.family == AF_INET6) { */
+		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
+			    offsetof(struct bpf_sock_addr, family)),
+		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET6, 18),
+
+#define STORE_IPV6_WORD_N(DST, SRC, N)					       \
+		BPF_MOV32_IMM(BPF_REG_7, SRC[N]),			       \
+		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,		       \
+			    offsetof(struct bpf_sock_addr, DST[N]))
+
+#define STORE_IPV6(DST, SRC)						       \
+		STORE_IPV6_WORD_N(DST, SRC, 0),				       \
+		STORE_IPV6_WORD_N(DST, SRC, 1),				       \
+		STORE_IPV6_WORD_N(DST, SRC, 2),				       \
+		STORE_IPV6_WORD_N(DST, SRC, 3)
+
+		STORE_IPV6(msg_src_ip6, src6_rw_ip.s6_addr32),
+		STORE_IPV6(user_ip6, dst6_rw_addr.sin6_addr.s6_addr32),
+
+		/*      user_port = dst6_rw_addr.sin6_port */
+		BPF_MOV32_IMM(BPF_REG_7, dst6_rw_addr.sin6_port),
+		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,
+			    offsetof(struct bpf_sock_addr, user_port)),
+
+		/* } */
+
+		/* return 1 */
+		BPF_MOV64_IMM(BPF_REG_0, 1),
+		BPF_EXIT_INSN(),
+	};
+
+	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));
+}
+
+static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test)
+{
+	return sendmsg6_rw_dst_asm_prog_load(test, SERV6_REWRITE_IP);
+}
+
+static int sendmsg6_rw_v4mapped_prog_load(const struct sock_addr_test *test)
+{
+	return sendmsg6_rw_dst_asm_prog_load(test, SERV6_V4MAPPED_IP);
+}
+
+static int sendmsg6_rw_c_prog_load(const struct sock_addr_test *test)
+{
+	return load_path(test, SENDMSG6_PROG_PATH);
+}
+
 static int cmp_addr(const struct sockaddr_storage *addr1,
 		    const struct sockaddr_storage *addr2, int cmp_port)
 {
@@ -656,6 +968,135 @@ static int connect_to_server(int type, const struct sockaddr_storage *addr,
 	return fd;
 }
 
+int init_pktinfo(int domain, struct cmsghdr *cmsg)
+{
+	struct in6_pktinfo *pktinfo6;
+	struct in_pktinfo *pktinfo4;
+
+	if (domain == AF_INET) {
+		cmsg->cmsg_level = SOL_IP;
+		cmsg->cmsg_type = IP_PKTINFO;
+		cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
+		pktinfo4 = (struct in_pktinfo *)CMSG_DATA(cmsg);
+		memset(pktinfo4, 0, sizeof(struct in_pktinfo));
+		if (inet_pton(domain, SRC4_IP,
+			      (void *)&pktinfo4->ipi_spec_dst) != 1)
+			return -1;
+	} else if (domain == AF_INET6) {
+		cmsg->cmsg_level = SOL_IPV6;
+		cmsg->cmsg_type = IPV6_PKTINFO;
+		cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
+		pktinfo6 = (struct in6_pktinfo *)CMSG_DATA(cmsg);
+		memset(pktinfo6, 0, sizeof(struct in6_pktinfo));
+		if (inet_pton(domain, SRC6_IP,
+			      (void *)&pktinfo6->ipi6_addr) != 1)
+			return -1;
+	} else {
+		return -1;
+	}
+
+	return 0;
+}
+
+static int sendmsg_to_server(const struct sockaddr_storage *addr,
+			     socklen_t addr_len, int set_cmsg, int *syscall_err)
+{
+	union {
+		char buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
+		struct cmsghdr align;
+	} control6;
+	union {
+		char buf[CMSG_SPACE(sizeof(struct in_pktinfo))];
+		struct cmsghdr align;
+	} control4;
+	struct msghdr hdr;
+	struct iovec iov;
+	char data = 'a';
+	int domain;
+	int fd = -1;
+
+	domain = addr->ss_family;
+
+	if (domain != AF_INET && domain != AF_INET6) {
+		log_err("Unsupported address family");
+		goto err;
+	}
+
+	fd = socket(domain, SOCK_DGRAM, 0);
+	if (fd == -1) {
+		log_err("Failed to create client socket");
+		goto err;
+	}
+
+	memset(&iov, 0, sizeof(iov));
+	iov.iov_base = &data;
+	iov.iov_len = sizeof(data);
+
+	memset(&hdr, 0, sizeof(hdr));
+	hdr.msg_name = (void *)addr;
+	hdr.msg_namelen = addr_len;
+	hdr.msg_iov = &iov;
+	hdr.msg_iovlen = 1;
+
+	if (set_cmsg) {
+		if (domain == AF_INET) {
+			hdr.msg_control = &control4;
+			hdr.msg_controllen = sizeof(control4.buf);
+		} else if (domain == AF_INET6) {
+			hdr.msg_control = &control6;
+			hdr.msg_controllen = sizeof(control6.buf);
+		}
+		if (init_pktinfo(domain, CMSG_FIRSTHDR(&hdr))) {
+			log_err("Fail to init pktinfo");
+			goto err;
+		}
+	}
+
+	if (sendmsg(fd, &hdr, 0) != sizeof(data)) {
+		log_err("Fail to send message to server");
+		*syscall_err = errno;
+		goto err;
+	}
+
+	goto out;
+err:
+	close(fd);
+	fd = -1;
+out:
+	return fd;
+}
+
+static int recvmsg_from_client(int sockfd, struct sockaddr_storage *src_addr)
+{
+	struct timeval tv;
+	struct msghdr hdr;
+	struct iovec iov;
+	char data[64];
+	fd_set rfds;
+
+	FD_ZERO(&rfds);
+	FD_SET(sockfd, &rfds);
+
+	tv.tv_sec = 2;
+	tv.tv_usec = 0;
+
+	if (select(sockfd + 1, &rfds, NULL, NULL, &tv) <= 0 ||
+	    !FD_ISSET(sockfd, &rfds))
+		return -1;
+
+	memset(&iov, 0, sizeof(iov));
+	iov.iov_base = data;
+	iov.iov_len = sizeof(data);
+
+	memset(&hdr, 0, sizeof(hdr));
+	hdr.msg_name = src_addr;
+	hdr.msg_namelen = sizeof(struct sockaddr_storage);
+	hdr.msg_iov = &iov;
+	hdr.msg_iovlen = 1;
+
+	return recvmsg(sockfd, &hdr, 0);
+}
+
 static int init_addrs(const struct sock_addr_test *test,
 		      struct sockaddr_storage *requested_addr,
 		      struct sockaddr_storage *expected_addr,
@@ -753,6 +1194,69 @@ static int run_connect_test_case(const struct sock_addr_test *test)
 	return err;
 }
 
+static int run_sendmsg_test_case(const struct sock_addr_test *test)
+{
+	socklen_t addr_len = sizeof(struct sockaddr_storage);
+	struct sockaddr_storage expected_src_addr;
+	struct sockaddr_storage requested_addr;
+	struct sockaddr_storage expected_addr;
+	struct sockaddr_storage real_src_addr;
+	int clientfd = -1;
+	int servfd = -1;
+	int set_cmsg;
+	int err = 0;
+
+	if (test->type != SOCK_DGRAM)
+		goto err;
+
+	if (init_addrs(test, &requested_addr, &expected_addr,
+		       &expected_src_addr))
+		goto err;
+
+	/* Prepare server to sendmsg to */
+	servfd = start_server(test->type, &expected_addr, addr_len);
+	if (servfd == -1)
+		goto err;
+
+	for (set_cmsg = 0; set_cmsg <= 1; ++set_cmsg) {
+		if (clientfd >= 0)
+			close(clientfd);
+
+		clientfd = sendmsg_to_server(&requested_addr, addr_len,
+					     set_cmsg, &err);
+		if (err)
+			goto out;
+		else if (clientfd == -1)
+			goto err;
+
+		/* Try to receive message on server instead of using
+		 * getpeername(2) on client socket, to check that client's
+		 * destination address was rewritten properly, since
+		 * getpeername(2) doesn't work with unconnected datagram
+		 * sockets.
+		 *
+		 * Get source address from recvmsg(2) as well to make sure
+		 * source was rewritten properly: getsockname(2) can't be used
+		 * since socket is unconnected and source defined for one
+		 * specific packet may differ from the one used by default and
+		 * returned by getsockname(2).
+		 */
+		if (recvmsg_from_client(servfd, &real_src_addr) == -1)
+			goto err;
+
+		if (cmp_addr(&real_src_addr, &expected_src_addr, /*cmp_port*/0))
+			goto err;
+	}
+
+	goto out;
+err:
+	err = -1;
+out:
+	close(clientfd);
+	close(servfd);
+	return err;
+}
+
 static int run_test_case(int cgfd, const struct sock_addr_test *test)
 {
 	int progfd = -1;
@@ -784,10 +1288,24 @@ static int run_test_case(int cgfd, const struct sock_addr_test *test)
 	case BPF_CGROUP_INET6_CONNECT:
 		err = run_connect_test_case(test);
 		break;
+	case BPF_CGROUP_UDP4_SENDMSG:
+	case BPF_CGROUP_UDP6_SENDMSG:
+		err = run_sendmsg_test_case(test);
+		break;
 	default:
 		goto err;
 	}
 
+	if (test->expected_result == SYSCALL_EPERM && err == EPERM) {
+		err = 0; /* error was expected, reset it */
+		goto out;
+	}
+
+	if (test->expected_result == SYSCALL_ENOTSUPP && err == ENOTSUPP) {
+		err = 0; /* error was expected, reset it */
+		goto out;
+	}
+
 	if (err || test->expected_result != SUCCESS)
 		goto err;
 
-- 
2.9.5

Re: [PATCH v3 bpf-next 0/5] bpf: Hooks for sys_sendmsg

[Daniel Borkmann]

On 05/25/2018 07:09 AM, Andrey Ignatov wrote:
> v2 -> v3:
> * place BPF logic under static key in udp_sendmsg, udpv6_sendmsg;
> * rebase.
> 
> v1 -> v2:
> * return ENOTSUPP if bpf_prog rewrote IPv6-only with IPv4-mapped IPv6;
> * add test for IPv4-mapped IPv6 use-case;
> * fix build for CONFIG_CGROUP_BPF=n;
> * rebase.
> 
> This path set adds BPF hooks for sys_sendmsg similar to existing hooks for
> sys_bind and sys_connect.
> 
> Hooks allow to override source IP (including the case when it's set via
> cmsg(3)) and destination IP:port for unconnected UDP (slow path). TCP and
> connected UDP (fast path) are not affected. This makes UDP support
> complete: connected UDP is handled by sys_connect hooks, unconnected by
> sys_sendmsg ones.
> 
> Similar to sys_connect hooks, sys_sendmsg ones can be used to make system
> calls such as sendmsg(2) and sendto(2) return EPERM.
> 
> Please see patch 0001 for more details.
> 
> 
> Andrey Ignatov (5):
>   bpf: Hooks for sys_sendmsg
>   bpf: Sync bpf.h to tools/
>   libbpf: Support guessing sendmsg{4,6} progs
>   selftests/bpf: Prepare test_sock_addr for extension
>   selftests/bpf: Selftest for sys_sendmsg hooks
> 
>  include/linux/bpf-cgroup.h                   |   23 +-
>  include/linux/filter.h                       |    1 +
>  include/uapi/linux/bpf.h                     |    8 +
>  kernel/bpf/cgroup.c                          |   11 +-
>  kernel/bpf/syscall.c                         |    8 +
>  net/core/filter.c                            |   39 +
>  net/ipv4/udp.c                               |   20 +-
>  net/ipv6/udp.c                               |   24 +
>  tools/include/uapi/linux/bpf.h               |    8 +
>  tools/lib/bpf/libbpf.c                       |    2 +
>  tools/testing/selftests/bpf/Makefile         |    2 +-
>  tools/testing/selftests/bpf/sendmsg4_prog.c  |   49 ++
>  tools/testing/selftests/bpf/sendmsg6_prog.c  |   60 ++
>  tools/testing/selftests/bpf/test_sock_addr.c | 1155 +++++++++++++++++++++-----
>  14 files changed, 1214 insertions(+), 196 deletions(-)
>  create mode 100644 tools/testing/selftests/bpf/sendmsg4_prog.c
>  create mode 100644 tools/testing/selftests/bpf/sendmsg6_prog.c
> 

Applied to bpf-next, thanks Andrey!

Re: [PATCH v3 bpf-next 0/5] bpf: Hooks for sys_sendmsg

[Daniel Borkmann]

On 05/28/2018 12:56 AM, Daniel Borkmann wrote:
> On 05/25/2018 07:09 AM, Andrey Ignatov wrote:
>> v2 -> v3:
>> * place BPF logic under static key in udp_sendmsg, udpv6_sendmsg;
>> * rebase.
[...]
> 
> Applied to bpf-next, thanks Andrey!

Woops, and I meant of course v4 [0] of the series not v3. ;-)

  [0] https://patchwork.ozlabs.org/project/netdev/list/?series=46691&state=*