[PATCH bpf-next v7 1/5] bpf: Be less specific about socket cookies guarantees

[PATCH bpf-next v7 1/5] bpf: Be less specific about socket cookies guarantees

[Florent Revest]

Since "92acdc58ab11 bpf, net: Rework cookie generator as per-cpu one"
socket cookies are not guaranteed to be non-decreasing. The
bpf_get_socket_cookie helper descriptions are currently specifying that
cookies are non-decreasing but we don't want users to rely on that.

Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: KP Singh <kpsingh@kernel.org>
---
 include/uapi/linux/bpf.h       | 8 ++++----
 tools/include/uapi/linux/bpf.h | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c001766adcbc..0b735c2729b2 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1656,22 +1656,22 @@ union bpf_attr {
  * 		networking traffic statistics as it provides a global socket
  * 		identifier that can be assumed unique.
  * 	Return
- * 		A 8-byte long non-decreasing number on success, or 0 if the
- * 		socket field is missing inside *skb*.
+ * 		A 8-byte long unique number on success, or 0 if the socket
+ * 		field is missing inside *skb*.
  *
  * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
  * 	Description
  * 		Equivalent to bpf_get_socket_cookie() helper that accepts
  * 		*skb*, but gets socket from **struct bpf_sock_addr** context.
  * 	Return
- * 		A 8-byte long non-decreasing number.
+ * 		A 8-byte long unique number.
  *
  * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
  * 	Description
  * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
  * 		*skb*, but gets socket from **struct bpf_sock_ops** context.
  * 	Return
- * 		A 8-byte long non-decreasing number.
+ * 		A 8-byte long unique number.
  *
  * u32 bpf_get_socket_uid(struct sk_buff *skb)
  * 	Return
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c001766adcbc..0b735c2729b2 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1656,22 +1656,22 @@ union bpf_attr {
  * 		networking traffic statistics as it provides a global socket
  * 		identifier that can be assumed unique.
  * 	Return
- * 		A 8-byte long non-decreasing number on success, or 0 if the
- * 		socket field is missing inside *skb*.
+ * 		A 8-byte long unique number on success, or 0 if the socket
+ * 		field is missing inside *skb*.
  *
  * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
  * 	Description
  * 		Equivalent to bpf_get_socket_cookie() helper that accepts
  * 		*skb*, but gets socket from **struct bpf_sock_addr** context.
  * 	Return
- * 		A 8-byte long non-decreasing number.
+ * 		A 8-byte long unique number.
  *
  * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
  * 	Description
  * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
  * 		*skb*, but gets socket from **struct bpf_sock_ops** context.
  * 	Return
- * 		A 8-byte long non-decreasing number.
+ * 		A 8-byte long unique number.
  *
  * u32 bpf_get_socket_uid(struct sk_buff *skb)
  * 	Return
-- 
2.30.0.478.g8a0d178c01-goog

[PATCH bpf-next v7 2/5] bpf: Expose bpf_get_socket_cookie to tracing programs

[Florent Revest]

This needs a new helper that:
- can work in a sleepable context (using sock_gen_cookie)
- takes a struct sock pointer and checks that it's not NULL

Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: KP Singh <kpsingh@kernel.org>
---
 include/linux/bpf.h            |  1 +
 include/uapi/linux/bpf.h       |  8 ++++++++
 kernel/trace/bpf_trace.c       |  2 ++
 net/core/filter.c              | 12 ++++++++++++
 tools/include/uapi/linux/bpf.h |  8 ++++++++
 5 files changed, 31 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 321966fc35db..d212ae7d9731 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1888,6 +1888,7 @@ extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
 extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
 extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
 extern const struct bpf_func_proto bpf_sock_from_file_proto;
+extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto;
 
 const struct bpf_func_proto *bpf_tracing_func_proto(
 	enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0b735c2729b2..a8d9ad543300 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1673,6 +1673,14 @@ union bpf_attr {
  * 	Return
  * 		A 8-byte long unique number.
  *
+ * u64 bpf_get_socket_cookie(struct sock *sk)
+ * 	Description
+ * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
+ * 		*sk*, but gets socket from a BTF **struct sock**. This helper
+ * 		also works for sleepable programs.
+ * 	Return
+ * 		A 8-byte long unique number or 0 if *sk* is NULL.
+ *
  * u32 bpf_get_socket_uid(struct sk_buff *skb)
  * 	Return
  * 		The owner UID of the socket associated to *skb*. If the socket
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 6c0018abe68a..845b2168e006 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1760,6 +1760,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_sk_storage_delete_tracing_proto;
 	case BPF_FUNC_sock_from_file:
 		return &bpf_sock_from_file_proto;
+	case BPF_FUNC_get_socket_cookie:
+		return &bpf_get_socket_ptr_cookie_proto;
 #endif
 	case BPF_FUNC_seq_printf:
 		return prog->expected_attach_type == BPF_TRACE_ITER ?
diff --git a/net/core/filter.c b/net/core/filter.c
index e15d4741719a..57aaed478362 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4631,6 +4631,18 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_proto = {
 	.arg1_type	= ARG_PTR_TO_CTX,
 };
 
+BPF_CALL_1(bpf_get_socket_ptr_cookie, struct sock *, sk)
+{
+	return sk ? sock_gen_cookie(sk) : 0;
+}
+
+const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto = {
+	.func		= bpf_get_socket_ptr_cookie,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID_SOCK_COMMON,
+};
+
 BPF_CALL_1(bpf_get_socket_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx)
 {
 	return __sock_gen_cookie(ctx->sk);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 0b735c2729b2..a8d9ad543300 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1673,6 +1673,14 @@ union bpf_attr {
  * 	Return
  * 		A 8-byte long unique number.
  *
+ * u64 bpf_get_socket_cookie(struct sock *sk)
+ * 	Description
+ * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
+ * 		*sk*, but gets socket from a BTF **struct sock**. This helper
+ * 		also works for sleepable programs.
+ * 	Return
+ * 		A 8-byte long unique number or 0 if *sk* is NULL.
+ *
  * u32 bpf_get_socket_uid(struct sk_buff *skb)
  * 	Return
  * 		The owner UID of the socket associated to *skb*. If the socket
-- 
2.30.0.478.g8a0d178c01-goog

[PATCH bpf-next v7 3/5] selftests/bpf: Integrate the socket_cookie test to test_progs

[Florent Revest]

Currently, the selftest for the BPF socket_cookie helpers is built and
run independently from test_progs. It's easy to forget and hard to
maintain.

This patch moves the socket cookies test into prog_tests/ and vastly
simplifies its logic by:
- rewriting the loading code with BPF skeletons
- rewriting the server/client code with network helpers
- rewriting the cgroup code with test__join_cgroup
- rewriting the error handling code with CHECKs

Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/testing/selftests/bpf/.gitignore        |   1 -
 tools/testing/selftests/bpf/Makefile          |   3 +-
 .../selftests/bpf/prog_tests/socket_cookie.c  |  71 ++++++
 .../selftests/bpf/progs/socket_cookie_prog.c  |   2 -
 .../selftests/bpf/test_socket_cookie.c        | 208 ------------------
 5 files changed, 72 insertions(+), 213 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/socket_cookie.c
 delete mode 100644 tools/testing/selftests/bpf/test_socket_cookie.c

diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index 9abca0616ec0..c0c48fdb9ac1 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -17,7 +17,6 @@ test_sockmap
 test_lirc_mode2_user
 get_cgroup_id_user
 test_skb_cgroup_id_user
-test_socket_cookie
 test_cgroup_storage
 test_flow_dissector
 flow_dissector_load
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index f0674d406f40..044bfdcf5b74 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -31,7 +31,7 @@ LDLIBS += -lcap -lelf -lz -lrt -lpthread
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
 	test_verifier_log test_dev_cgroup \
-	test_sock test_sockmap get_cgroup_id_user test_socket_cookie \
+	test_sock test_sockmap get_cgroup_id_user \
 	test_cgroup_storage \
 	test_netcnt test_tcpnotify_user test_sysctl \
 	test_progs-no_alu32
@@ -185,7 +185,6 @@ $(OUTPUT)/test_dev_cgroup: cgroup_helpers.c
 $(OUTPUT)/test_skb_cgroup_id_user: cgroup_helpers.c
 $(OUTPUT)/test_sock: cgroup_helpers.c
 $(OUTPUT)/test_sock_addr: cgroup_helpers.c
-$(OUTPUT)/test_socket_cookie: cgroup_helpers.c
 $(OUTPUT)/test_sockmap: cgroup_helpers.c
 $(OUTPUT)/test_tcpnotify_user: cgroup_helpers.c trace_helpers.c
 $(OUTPUT)/get_cgroup_id_user: cgroup_helpers.c
diff --git a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
new file mode 100644
index 000000000000..e12a31d3752c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Google LLC.
+// Copyright (c) 2018 Facebook
+
+#include <test_progs.h>
+#include "socket_cookie_prog.skel.h"
+#include "network_helpers.h"
+
+static int duration;
+
+struct socket_cookie {
+	__u64 cookie_key;
+	__u32 cookie_value;
+};
+
+void test_socket_cookie(void)
+{
+	int server_fd = 0, client_fd = 0, cgroup_fd = 0, err = 0;
+	socklen_t addr_len = sizeof(struct sockaddr_in6);
+	struct socket_cookie_prog *skel;
+	__u32 cookie_expected_value;
+	struct sockaddr_in6 addr;
+	struct socket_cookie val;
+
+	skel = socket_cookie_prog__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		return;
+
+	cgroup_fd = test__join_cgroup("/socket_cookie");
+	if (CHECK(cgroup_fd < 0, "join_cgroup", "cgroup creation failed\n"))
+		goto out;
+
+	skel->links.set_cookie = bpf_program__attach_cgroup(
+		skel->progs.set_cookie, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.set_cookie, "prog_attach"))
+		goto close_cgroup_fd;
+
+	skel->links.update_cookie = bpf_program__attach_cgroup(
+		skel->progs.update_cookie, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.update_cookie, "prog_attach"))
+		goto close_cgroup_fd;
+
+	server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
+	if (CHECK(server_fd < 0, "start_server", "errno %d\n", errno))
+		goto close_cgroup_fd;
+
+	client_fd = connect_to_fd(server_fd, 0);
+	if (CHECK(client_fd < 0, "connect_to_fd", "errno %d\n", errno))
+		goto close_server_fd;
+
+	err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.socket_cookies),
+				  &client_fd, &val);
+	if (!ASSERT_OK(err, "map_lookup(socket_cookies)"))
+		goto close_client_fd;
+
+	err = getsockname(client_fd, (struct sockaddr *)&addr, &addr_len);
+	if (!ASSERT_OK(err, "getsockname"))
+		goto close_client_fd;
+
+	cookie_expected_value = (ntohs(addr.sin6_port) << 8) | 0xFF;
+	ASSERT_EQ(val.cookie_value, cookie_expected_value, "cookie_value");
+
+close_client_fd:
+	close(client_fd);
+close_server_fd:
+	close(server_fd);
+close_cgroup_fd:
+	close(cgroup_fd);
+out:
+	socket_cookie_prog__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
index 0cb5656a22b0..81e84be6f86d 100644
--- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
+++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
@@ -65,6 +65,4 @@ int update_cookie(struct bpf_sock_ops *ctx)
 	return 1;
 }
 
-int _version SEC("version") = 1;
-
 char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/test_socket_cookie.c b/tools/testing/selftests/bpf/test_socket_cookie.c
deleted file mode 100644
index ca7ca87e91aa..000000000000
--- a/tools/testing/selftests/bpf/test_socket_cookie.c
+++ /dev/null
@@ -1,208 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (c) 2018 Facebook
-
-#include <string.h>
-#include <unistd.h>
-
-#include <arpa/inet.h>
-#include <netinet/in.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-
-#include <bpf/bpf.h>
-#include <bpf/libbpf.h>
-
-#include "bpf_rlimit.h"
-#include "cgroup_helpers.h"
-
-#define CG_PATH			"/foo"
-#define SOCKET_COOKIE_PROG	"./socket_cookie_prog.o"
-
-struct socket_cookie {
-	__u64 cookie_key;
-	__u32 cookie_value;
-};
-
-static int start_server(void)
-{
-	struct sockaddr_in6 addr;
-	int fd;
-
-	fd = socket(AF_INET6, SOCK_STREAM, 0);
-	if (fd == -1) {
-		log_err("Failed to create server socket");
-		goto out;
-	}
-
-	memset(&addr, 0, sizeof(addr));
-	addr.sin6_family = AF_INET6;
-	addr.sin6_addr = in6addr_loopback;
-	addr.sin6_port = 0;
-
-	if (bind(fd, (const struct sockaddr *)&addr, sizeof(addr)) == -1) {
-		log_err("Failed to bind server socket");
-		goto close_out;
-	}
-
-	if (listen(fd, 128) == -1) {
-		log_err("Failed to listen on server socket");
-		goto close_out;
-	}
-
-	goto out;
-
-close_out:
-	close(fd);
-	fd = -1;
-out:
-	return fd;
-}
-
-static int connect_to_server(int server_fd)
-{
-	struct sockaddr_storage addr;
-	socklen_t len = sizeof(addr);
-	int fd;
-
-	fd = socket(AF_INET6, SOCK_STREAM, 0);
-	if (fd == -1) {
-		log_err("Failed to create client socket");
-		goto out;
-	}
-
-	if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
-		log_err("Failed to get server addr");
-		goto close_out;
-	}
-
-	if (connect(fd, (const struct sockaddr *)&addr, len) == -1) {
-		log_err("Fail to connect to server");
-		goto close_out;
-	}
-
-	goto out;
-
-close_out:
-	close(fd);
-	fd = -1;
-out:
-	return fd;
-}
-
-static int validate_map(struct bpf_map *map, int client_fd)
-{
-	__u32 cookie_expected_value;
-	struct sockaddr_in6 addr;
-	socklen_t len = sizeof(addr);
-	struct socket_cookie val;
-	int err = 0;
-	int map_fd;
-
-	if (!map) {
-		log_err("Map not found in BPF object");
-		goto err;
-	}
-
-	map_fd = bpf_map__fd(map);
-
-	err = bpf_map_lookup_elem(map_fd, &client_fd, &val);
-
-	err = getsockname(client_fd, (struct sockaddr *)&addr, &len);
-	if (err) {
-		log_err("Can't get client local addr");
-		goto out;
-	}
-
-	cookie_expected_value = (ntohs(addr.sin6_port) << 8) | 0xFF;
-	if (val.cookie_value != cookie_expected_value) {
-		log_err("Unexpected value in map: %x != %x", val.cookie_value,
-			cookie_expected_value);
-		goto err;
-	}
-
-	goto out;
-err:
-	err = -1;
-out:
-	return err;
-}
-
-static int run_test(int cgfd)
-{
-	enum bpf_attach_type attach_type;
-	struct bpf_prog_load_attr attr;
-	struct bpf_program *prog;
-	struct bpf_object *pobj;
-	const char *prog_name;
-	int server_fd = -1;
-	int client_fd = -1;
-	int prog_fd = -1;
-	int err = 0;
-
-	memset(&attr, 0, sizeof(attr));
-	attr.file = SOCKET_COOKIE_PROG;
-	attr.prog_type = BPF_PROG_TYPE_UNSPEC;
-	attr.prog_flags = BPF_F_TEST_RND_HI32;
-
-	err = bpf_prog_load_xattr(&attr, &pobj, &prog_fd);
-	if (err) {
-		log_err("Failed to load %s", attr.file);
-		goto out;
-	}
-
-	bpf_object__for_each_program(prog, pobj) {
-		prog_name = bpf_program__section_name(prog);
-
-		if (libbpf_attach_type_by_name(prog_name, &attach_type))
-			goto err;
-
-		err = bpf_prog_attach(bpf_program__fd(prog), cgfd, attach_type,
-				      BPF_F_ALLOW_OVERRIDE);
-		if (err) {
-			log_err("Failed to attach prog %s", prog_name);
-			goto out;
-		}
-	}
-
-	server_fd = start_server();
-	if (server_fd == -1)
-		goto err;
-
-	client_fd = connect_to_server(server_fd);
-	if (client_fd == -1)
-		goto err;
-
-	if (validate_map(bpf_map__next(NULL, pobj), client_fd))
-		goto err;
-
-	goto out;
-err:
-	err = -1;
-out:
-	close(client_fd);
-	close(server_fd);
-	bpf_object__close(pobj);
-	printf("%s\n", err ? "FAILED" : "PASSED");
-	return err;
-}
-
-int main(int argc, char **argv)
-{
-	int cgfd = -1;
-	int err = 0;
-
-	cgfd = cgroup_setup_and_join(CG_PATH);
-	if (cgfd < 0)
-		goto err;
-
-	if (run_test(cgfd))
-		goto err;
-
-	goto out;
-err:
-	err = -1;
-out:
-	close(cgfd);
-	cleanup_cgroup_environment();
-	return err;
-}
-- 
2.30.0.478.g8a0d178c01-goog

[PATCH bpf-next v7 4/5] selftests/bpf: Use vmlinux.h in socket_cookie_prog.c

[Florent Revest]

When migrating from the bpf.h's to the vmlinux.h's definition of struct
bps_sock, an interesting LLVM behavior happened. LLVM started producing
two fetches of ctx->sk in the sockops program this means that the
verifier could not keep track of the NULL-check on ctx->sk. Therefore,
we need to extract ctx->sk in a variable before checking and
dereferencing it.

Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Florent Revest <revest@chromium.org>
---
 .../testing/selftests/bpf/progs/socket_cookie_prog.c  | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
index 81e84be6f86d..fbd5eaf39720 100644
--- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
+++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
@@ -1,12 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2018 Facebook
 
-#include <linux/bpf.h>
-#include <sys/socket.h>
+#include "vmlinux.h"
 
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
 
+#define AF_INET6 10
+
 struct socket_cookie {
 	__u64 cookie_key;
 	__u32 cookie_value;
@@ -41,7 +42,7 @@ int set_cookie(struct bpf_sock_addr *ctx)
 SEC("sockops")
 int update_cookie(struct bpf_sock_ops *ctx)
 {
-	struct bpf_sock *sk;
+	struct bpf_sock *sk = ctx->sk;
 	struct socket_cookie *p;
 
 	if (ctx->family != AF_INET6)
@@ -50,10 +51,10 @@ int update_cookie(struct bpf_sock_ops *ctx)
 	if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
 		return 1;
 
-	if (!ctx->sk)
+	if (!sk)
 		return 1;
 
-	p = bpf_sk_storage_get(&socket_cookies, ctx->sk, 0, 0);
+	p = bpf_sk_storage_get(&socket_cookies, sk, 0, 0);
 	if (!p)
 		return 1;
 
-- 
2.30.0.478.g8a0d178c01-goog

[PATCH bpf-next v7 5/5] selftests/bpf: Add a selftest for the tracing bpf_get_socket_cookie

[Florent Revest]

This builds up on the existing socket cookie test which checks whether
the bpf_get_socket_cookie helpers provide the same value in
cgroup/connect6 and sockops programs for a socket created by the
userspace part of the test.

Instead of having an update_cookie sockops program tag a socket local
storage with 0xFF, this uses both an update_cookie_sockops program and
an update_cookie_tracing program which succesively tag the socket with
0x0F and then 0xF0.

Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: KP Singh <kpsingh@kernel.org>
---
 .../selftests/bpf/prog_tests/socket_cookie.c  | 11 ++++--
 .../selftests/bpf/progs/socket_cookie_prog.c  | 36 +++++++++++++++++--
 2 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
index e12a31d3752c..232db28dde18 100644
--- a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
@@ -35,9 +35,14 @@ void test_socket_cookie(void)
 	if (!ASSERT_OK_PTR(skel->links.set_cookie, "prog_attach"))
 		goto close_cgroup_fd;
 
-	skel->links.update_cookie = bpf_program__attach_cgroup(
-		skel->progs.update_cookie, cgroup_fd);
-	if (!ASSERT_OK_PTR(skel->links.update_cookie, "prog_attach"))
+	skel->links.update_cookie_sockops = bpf_program__attach_cgroup(
+		skel->progs.update_cookie_sockops, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.update_cookie_sockops, "prog_attach"))
+		goto close_cgroup_fd;
+
+	skel->links.update_cookie_tracing = bpf_program__attach(
+		skel->progs.update_cookie_tracing);
+	if (!ASSERT_OK_PTR(skel->links.update_cookie_tracing, "prog_attach"))
 		goto close_cgroup_fd;
 
 	server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
index fbd5eaf39720..35630a5aaf5f 100644
--- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
+++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
@@ -5,6 +5,7 @@
 
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
+#include <bpf/bpf_tracing.h>
 
 #define AF_INET6 10
 
@@ -20,6 +21,14 @@ struct {
 	__type(value, struct socket_cookie);
 } socket_cookies SEC(".maps");
 
+/*
+ * These three programs get executed in a row on connect() syscalls. The
+ * userspace side of the test creates a client socket, issues a connect() on it
+ * and then checks that the local storage associated with this socket has:
+ * cookie_value == local_port << 8 | 0xFF
+ * The different parts of this cookie_value are appended by those hooks if they
+ * all agree on the output of bpf_get_socket_cookie().
+ */
 SEC("cgroup/connect6")
 int set_cookie(struct bpf_sock_addr *ctx)
 {
@@ -33,14 +42,14 @@ int set_cookie(struct bpf_sock_addr *ctx)
 	if (!p)
 		return 1;
 
-	p->cookie_value = 0xFF;
+	p->cookie_value = 0xF;
 	p->cookie_key = bpf_get_socket_cookie(ctx);
 
 	return 1;
 }
 
 SEC("sockops")
-int update_cookie(struct bpf_sock_ops *ctx)
+int update_cookie_sockops(struct bpf_sock_ops *ctx)
 {
 	struct bpf_sock *sk = ctx->sk;
 	struct socket_cookie *p;
@@ -61,9 +70,30 @@ int update_cookie(struct bpf_sock_ops *ctx)
 	if (p->cookie_key != bpf_get_socket_cookie(ctx))
 		return 1;
 
-	p->cookie_value = (ctx->local_port << 8) | p->cookie_value;
+	p->cookie_value |= (ctx->local_port << 8);
 
 	return 1;
 }
 
+SEC("fexit/inet_stream_connect")
+int BPF_PROG(update_cookie_tracing, struct socket *sock,
+	     struct sockaddr *uaddr, int addr_len, int flags)
+{
+	struct socket_cookie *p;
+
+	if (uaddr->sa_family != AF_INET6)
+		return 0;
+
+	p = bpf_sk_storage_get(&socket_cookies, sock->sk, 0, 0);
+	if (!p)
+		return 0;
+
+	if (p->cookie_key != bpf_get_socket_cookie(sock->sk))
+		return 0;
+
+	p->cookie_value |= 0xF0;
+
+	return 0;
+}
+
 char _license[] SEC("license") = "GPL";
-- 
2.30.0.478.g8a0d178c01-goog

Re: [PATCH bpf-next v7 2/5] bpf: Expose bpf_get_socket_cookie to tracing programs

[Andrii Nakryiko]

On Wed, Feb 10, 2021 at 3:14 AM Florent Revest <revest@chromium.org> wrote:
>
> This needs a new helper that:
> - can work in a sleepable context (using sock_gen_cookie)
> - takes a struct sock pointer and checks that it's not NULL
>
> Signed-off-by: Florent Revest <revest@chromium.org>
> Acked-by: KP Singh <kpsingh@kernel.org>
> ---

It's customary to send cover letter with patch sets of 2 or more
related patches. It's a good place to explain the motivation of a
patch set. And a good place to ack all patches in one go ;)

Acked-by: Andrii Nakryiko <andrii@kernel.org>


>  include/linux/bpf.h            |  1 +
>  include/uapi/linux/bpf.h       |  8 ++++++++
>  kernel/trace/bpf_trace.c       |  2 ++
>  net/core/filter.c              | 12 ++++++++++++
>  tools/include/uapi/linux/bpf.h |  8 ++++++++
>  5 files changed, 31 insertions(+)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 321966fc35db..d212ae7d9731 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1888,6 +1888,7 @@ extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
>  extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
>  extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
>  extern const struct bpf_func_proto bpf_sock_from_file_proto;
> +extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto;
>
>  const struct bpf_func_proto *bpf_tracing_func_proto(
>         enum bpf_func_id func_id, const struct bpf_prog *prog);
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 0b735c2729b2..a8d9ad543300 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -1673,6 +1673,14 @@ union bpf_attr {
>   *     Return
>   *             A 8-byte long unique number.
>   *
> + * u64 bpf_get_socket_cookie(struct sock *sk)
> + *     Description
> + *             Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
> + *             *sk*, but gets socket from a BTF **struct sock**. This helper
> + *             also works for sleepable programs.
> + *     Return
> + *             A 8-byte long unique number or 0 if *sk* is NULL.
> + *
>   * u32 bpf_get_socket_uid(struct sk_buff *skb)
>   *     Return
>   *             The owner UID of the socket associated to *skb*. If the socket
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 6c0018abe68a..845b2168e006 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1760,6 +1760,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
>                 return &bpf_sk_storage_delete_tracing_proto;
>         case BPF_FUNC_sock_from_file:
>                 return &bpf_sock_from_file_proto;
> +       case BPF_FUNC_get_socket_cookie:
> +               return &bpf_get_socket_ptr_cookie_proto;
>  #endif
>         case BPF_FUNC_seq_printf:
>                 return prog->expected_attach_type == BPF_TRACE_ITER ?
> diff --git a/net/core/filter.c b/net/core/filter.c
> index e15d4741719a..57aaed478362 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -4631,6 +4631,18 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_proto = {
>         .arg1_type      = ARG_PTR_TO_CTX,
>  };
>
> +BPF_CALL_1(bpf_get_socket_ptr_cookie, struct sock *, sk)
> +{
> +       return sk ? sock_gen_cookie(sk) : 0;
> +}
> +
> +const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto = {
> +       .func           = bpf_get_socket_ptr_cookie,
> +       .gpl_only       = false,
> +       .ret_type       = RET_INTEGER,
> +       .arg1_type      = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
> +};
> +
>  BPF_CALL_1(bpf_get_socket_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx)
>  {
>         return __sock_gen_cookie(ctx->sk);
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 0b735c2729b2..a8d9ad543300 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -1673,6 +1673,14 @@ union bpf_attr {
>   *     Return
>   *             A 8-byte long unique number.
>   *
> + * u64 bpf_get_socket_cookie(struct sock *sk)
> + *     Description
> + *             Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
> + *             *sk*, but gets socket from a BTF **struct sock**. This helper
> + *             also works for sleepable programs.
> + *     Return
> + *             A 8-byte long unique number or 0 if *sk* is NULL.
> + *
>   * u32 bpf_get_socket_uid(struct sk_buff *skb)
>   *     Return
>   *             The owner UID of the socket associated to *skb*. If the socket
> --
> 2.30.0.478.g8a0d178c01-goog
>

Re: [PATCH bpf-next v7 2/5] bpf: Expose bpf_get_socket_cookie to tracing programs

[Florent Revest]

On Wed, Feb 10, 2021 at 8:52 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Wed, Feb 10, 2021 at 3:14 AM Florent Revest <revest@chromium.org> wrote:
> >
> > This needs a new helper that:
> > - can work in a sleepable context (using sock_gen_cookie)
> > - takes a struct sock pointer and checks that it's not NULL
> >
> > Signed-off-by: Florent Revest <revest@chromium.org>
> > Acked-by: KP Singh <kpsingh@kernel.org>
> > ---
>
> It's customary to send cover letter with patch sets of 2 or more
> related patches. It's a good place to explain the motivation of a
> patch set. And a good place to ack all patches in one go ;)

You're right :) I first (naively!) thought it would be a short series
but it grew bigger than I originally thought. I will make sure I do in
the future. ;)

> Acked-by: Andrii Nakryiko <andrii@kernel.org>
>
>
> >  include/linux/bpf.h            |  1 +
> >  include/uapi/linux/bpf.h       |  8 ++++++++
> >  kernel/trace/bpf_trace.c       |  2 ++
> >  net/core/filter.c              | 12 ++++++++++++
> >  tools/include/uapi/linux/bpf.h |  8 ++++++++
> >  5 files changed, 31 insertions(+)
> >
> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index 321966fc35db..d212ae7d9731 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -1888,6 +1888,7 @@ extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
> >  extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
> >  extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
> >  extern const struct bpf_func_proto bpf_sock_from_file_proto;
> > +extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto;
> >
> >  const struct bpf_func_proto *bpf_tracing_func_proto(
> >         enum bpf_func_id func_id, const struct bpf_prog *prog);
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index 0b735c2729b2..a8d9ad543300 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -1673,6 +1673,14 @@ union bpf_attr {
> >   *     Return
> >   *             A 8-byte long unique number.
> >   *
> > + * u64 bpf_get_socket_cookie(struct sock *sk)
> > + *     Description
> > + *             Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
> > + *             *sk*, but gets socket from a BTF **struct sock**. This helper
> > + *             also works for sleepable programs.
> > + *     Return
> > + *             A 8-byte long unique number or 0 if *sk* is NULL.
> > + *
> >   * u32 bpf_get_socket_uid(struct sk_buff *skb)
> >   *     Return
> >   *             The owner UID of the socket associated to *skb*. If the socket
> > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> > index 6c0018abe68a..845b2168e006 100644
> > --- a/kernel/trace/bpf_trace.c
> > +++ b/kernel/trace/bpf_trace.c
> > @@ -1760,6 +1760,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> >                 return &bpf_sk_storage_delete_tracing_proto;
> >         case BPF_FUNC_sock_from_file:
> >                 return &bpf_sock_from_file_proto;
> > +       case BPF_FUNC_get_socket_cookie:
> > +               return &bpf_get_socket_ptr_cookie_proto;
> >  #endif
> >         case BPF_FUNC_seq_printf:
> >                 return prog->expected_attach_type == BPF_TRACE_ITER ?
> > diff --git a/net/core/filter.c b/net/core/filter.c
> > index e15d4741719a..57aaed478362 100644
> > --- a/net/core/filter.c
> > +++ b/net/core/filter.c
> > @@ -4631,6 +4631,18 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_proto = {
> >         .arg1_type      = ARG_PTR_TO_CTX,
> >  };
> >
> > +BPF_CALL_1(bpf_get_socket_ptr_cookie, struct sock *, sk)
> > +{
> > +       return sk ? sock_gen_cookie(sk) : 0;
> > +}
> > +
> > +const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto = {
> > +       .func           = bpf_get_socket_ptr_cookie,
> > +       .gpl_only       = false,
> > +       .ret_type       = RET_INTEGER,
> > +       .arg1_type      = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
> > +};
> > +
> >  BPF_CALL_1(bpf_get_socket_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx)
> >  {
> >         return __sock_gen_cookie(ctx->sk);
> > diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> > index 0b735c2729b2..a8d9ad543300 100644
> > --- a/tools/include/uapi/linux/bpf.h
> > +++ b/tools/include/uapi/linux/bpf.h
> > @@ -1673,6 +1673,14 @@ union bpf_attr {
> >   *     Return
> >   *             A 8-byte long unique number.
> >   *
> > + * u64 bpf_get_socket_cookie(struct sock *sk)
> > + *     Description
> > + *             Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
> > + *             *sk*, but gets socket from a BTF **struct sock**. This helper
> > + *             also works for sleepable programs.
> > + *     Return
> > + *             A 8-byte long unique number or 0 if *sk* is NULL.
> > + *
> >   * u32 bpf_get_socket_uid(struct sk_buff *skb)
> >   *     Return
> >   *             The owner UID of the socket associated to *skb*. If the socket
> > --
> > 2.30.0.478.g8a0d178c01-goog
> >

Re: [PATCH bpf-next v7 1/5] bpf: Be less specific about socket cookies guarantees

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (refs/heads/master):

On Wed, 10 Feb 2021 12:14:02 +0100 you wrote:
> Since "92acdc58ab11 bpf, net: Rework cookie generator as per-cpu one"
> socket cookies are not guaranteed to be non-decreasing. The
> bpf_get_socket_cookie helper descriptions are currently specifying that
> cookies are non-decreasing but we don't want users to rely on that.
> 
> Reported-by: Daniel Borkmann <daniel@iogearbox.net>
> Signed-off-by: Florent Revest <revest@chromium.org>
> Acked-by: KP Singh <kpsingh@kernel.org>
> 
> [...]

Here is the summary with links:
  - [bpf-next,v7,1/5] bpf: Be less specific about socket cookies guarantees
    https://git.kernel.org/bpf/bpf-next/c/07881ccbf40c
  - [bpf-next,v7,2/5] bpf: Expose bpf_get_socket_cookie to tracing programs
    https://git.kernel.org/bpf/bpf-next/c/c5dbb89fc2ac
  - [bpf-next,v7,3/5] selftests/bpf: Integrate the socket_cookie test to test_progs
    https://git.kernel.org/bpf/bpf-next/c/61f8c9c8f3c8
  - [bpf-next,v7,4/5] selftests/bpf: Use vmlinux.h in socket_cookie_prog.c
    https://git.kernel.org/bpf/bpf-next/c/6cd4dcc3fb81
  - [bpf-next,v7,5/5] selftests/bpf: Add a selftest for the tracing bpf_get_socket_cookie
    https://git.kernel.org/bpf/bpf-next/c/6fdd671baaf5

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH bpf-next v7 2/5] bpf: Expose bpf_get_socket_cookie to tracing programs

[Alexei Starovoitov]

On Wed, Feb 10, 2021 at 3:14 AM Florent Revest <revest@chromium.org> wrote:
>
> +BPF_CALL_1(bpf_get_socket_ptr_cookie, struct sock *, sk)
> +{
> +       return sk ? sock_gen_cookie(sk) : 0;
> +}
> +
> +const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto = {
> +       .func           = bpf_get_socket_ptr_cookie,
> +       .gpl_only       = false,
> +       .ret_type       = RET_INTEGER,
> +       .arg1_type      = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
> +};

As Daniel pointed out there is an sk_destruct issue here, but I don't
think it's fair
to penalize this set and future similar patches. They don't make things worse.
The issue has been there for some time due to sk_storage in tracing and
other helpers. We need to come up with a holistic approach to solve it.
I suspect allow/deny lists will certainly make it better, but won't
really address it,
and will be fragile over long term.
I think tracing would need to be integrated with bpf_lsm and start relying
on security_*_free callbacks to cover this last 1%.
I think that would be a great topic for the next bpf office hours on Feb 25.