* [PATCH bpf-next v2 2/3] selftests/bpf: Integrate the socket_cookie test to test_progs
2020-12-03 21:33 [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs Florent Revest
@ 2020-12-03 21:33 ` Florent Revest
2020-12-03 21:33 ` [PATCH bpf-next v2 3/3] bpf: Add a selftest for the tracing bpf_get_socket_cookie Florent Revest
` (2 subsequent siblings)
3 siblings, 0 replies; 9+ messages in thread
From: Florent Revest @ 2020-12-03 21:33 UTC (permalink / raw)
To: bpf; +Cc: ast, daniel, andrii, kpsingh, revest, linux-kernel
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@google.com>
---
tools/testing/selftests/bpf/Makefile | 3 +-
.../selftests/bpf/prog_tests/socket_cookie.c | 82 +++++++
.../selftests/bpf/progs/socket_cookie_prog.c | 2 -
.../selftests/bpf/test_socket_cookie.c | 208 ------------------
4 files changed, 83 insertions(+), 212 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/Makefile b/tools/testing/selftests/bpf/Makefile
index 894192c319fb..8c7ff88f0eb3 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -33,7 +33,7 @@ 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 \
@@ -161,7 +161,6 @@ $(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..53d0c44e7907
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
@@ -0,0 +1,82 @@
+// 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)
+{
+ socklen_t addr_len = sizeof(struct sockaddr_in6);
+ struct bpf_link *set_link, *update_link;
+ int server_fd, client_fd, cgroup_fd;
+ struct socket_cookie_prog *skel;
+ __u32 cookie_expected_value;
+ struct sockaddr_in6 addr;
+ struct socket_cookie val;
+ int err = 0;
+
+ skel = socket_cookie_prog__open_and_load();
+ if (CHECK(!skel, "socket_cookie_prog__open_and_load",
+ "skeleton open_and_load failed\n"))
+ return;
+
+ cgroup_fd = test__join_cgroup("/socket_cookie");
+ if (CHECK(cgroup_fd < 0, "join_cgroup", "cgroup creation failed\n"))
+ goto destroy_skel;
+
+ set_link = bpf_program__attach_cgroup(skel->progs.set_cookie,
+ cgroup_fd);
+ if (CHECK(IS_ERR(set_link), "set-link-cg-attach", "err %ld\n",
+ PTR_ERR(set_link)))
+ goto close_cgroup_fd;
+
+ update_link = bpf_program__attach_cgroup(skel->progs.update_cookie,
+ cgroup_fd);
+ if (CHECK(IS_ERR(update_link), "update-link-cg-attach", "err %ld\n",
+ PTR_ERR(update_link)))
+ goto free_set_link;
+
+ server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
+ if (CHECK(server_fd < 0, "start_server", "errno %d\n", errno))
+ goto free_update_link;
+
+ 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 (CHECK(err, "map_lookup", "err %d errno %d\n", err, errno))
+ goto close_client_fd;
+
+ err = getsockname(client_fd, (struct sockaddr *)&addr, &addr_len);
+ if (CHECK(err, "getsockname", "Can't get client local addr\n"))
+ goto close_client_fd;
+
+ cookie_expected_value = (ntohs(addr.sin6_port) << 8) | 0xFF;
+ CHECK(val.cookie_value != cookie_expected_value, "",
+ "Unexpected value in map: %x != %x\n", val.cookie_value,
+ cookie_expected_value);
+
+close_client_fd:
+ close(client_fd);
+close_server_fd:
+ close(server_fd);
+free_update_link:
+ bpf_link__destroy(update_link);
+free_set_link:
+ bpf_link__destroy(set_link);
+close_cgroup_fd:
+ close(cgroup_fd);
+destroy_skel:
+ 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;
-}
--
2.29.2.576.ga3fc446d84-goog
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH bpf-next v2 3/3] bpf: Add a selftest for the tracing bpf_get_socket_cookie
2020-12-03 21:33 [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs Florent Revest
2020-12-03 21:33 ` [PATCH bpf-next v2 2/3] selftests/bpf: Integrate the socket_cookie test to test_progs Florent Revest
@ 2020-12-03 21:33 ` Florent Revest
2020-12-04 18:56 ` [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs Daniel Borkmann
2020-12-04 19:47 ` Martin KaFai Lau
3 siblings, 0 replies; 9+ messages in thread
From: Florent Revest @ 2020-12-03 21:33 UTC (permalink / raw)
To: bpf; +Cc: ast, daniel, andrii, kpsingh, revest, linux-kernel
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.
Adding a tracing program to the existing objects requires a different
attachment strategy and different headers.
Signed-off-by: Florent Revest <revest@google.com>
---
.../selftests/bpf/prog_tests/socket_cookie.c | 24 +++++++----
.../selftests/bpf/progs/socket_cookie_prog.c | 41 ++++++++++++++++---
2 files changed, 52 insertions(+), 13 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
index 53d0c44e7907..e5c5e2ea1deb 100644
--- a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
@@ -15,8 +15,8 @@ struct socket_cookie {
void test_socket_cookie(void)
{
+ struct bpf_link *set_link, *update_sockops_link, *update_tracing_link;
socklen_t addr_len = sizeof(struct sockaddr_in6);
- struct bpf_link *set_link, *update_link;
int server_fd, client_fd, cgroup_fd;
struct socket_cookie_prog *skel;
__u32 cookie_expected_value;
@@ -39,15 +39,21 @@ void test_socket_cookie(void)
PTR_ERR(set_link)))
goto close_cgroup_fd;
- update_link = bpf_program__attach_cgroup(skel->progs.update_cookie,
- cgroup_fd);
- if (CHECK(IS_ERR(update_link), "update-link-cg-attach", "err %ld\n",
- PTR_ERR(update_link)))
+ update_sockops_link = bpf_program__attach_cgroup(
+ skel->progs.update_cookie_sockops, cgroup_fd);
+ if (CHECK(IS_ERR(update_sockops_link), "update-sockops-link-cg-attach",
+ "err %ld\n", PTR_ERR(update_sockops_link)))
goto free_set_link;
+ update_tracing_link = bpf_program__attach(
+ skel->progs.update_cookie_tracing);
+ if (CHECK(IS_ERR(update_tracing_link), "update-tracing-link-attach",
+ "err %ld\n", PTR_ERR(update_tracing_link)))
+ goto free_update_sockops_link;
+
server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
if (CHECK(server_fd < 0, "start_server", "errno %d\n", errno))
- goto free_update_link;
+ goto free_update_tracing_link;
client_fd = connect_to_fd(server_fd, 0);
if (CHECK(client_fd < 0, "connect_to_fd", "errno %d\n", errno))
@@ -71,8 +77,10 @@ void test_socket_cookie(void)
close(client_fd);
close_server_fd:
close(server_fd);
-free_update_link:
- bpf_link__destroy(update_link);
+free_update_tracing_link:
+ bpf_link__destroy(update_tracing_link);
+free_update_sockops_link:
+ bpf_link__destroy(update_sockops_link);
free_set_link:
bpf_link__destroy(set_link);
close_cgroup_fd:
diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
index 81e84be6f86d..1f770b732cb1 100644
--- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
+++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
@@ -1,11 +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>
+#include <bpf/bpf_tracing.h>
+
+#define AF_INET6 10
struct socket_cookie {
__u64 cookie_key;
@@ -19,6 +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)
{
@@ -32,14 +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;
struct socket_cookie *p;
@@ -60,9 +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";
--
2.29.2.576.ga3fc446d84-goog
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs
2020-12-03 21:33 [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs Florent Revest
2020-12-03 21:33 ` [PATCH bpf-next v2 2/3] selftests/bpf: Integrate the socket_cookie test to test_progs Florent Revest
2020-12-03 21:33 ` [PATCH bpf-next v2 3/3] bpf: Add a selftest for the tracing bpf_get_socket_cookie Florent Revest
@ 2020-12-04 18:56 ` Daniel Borkmann
2020-12-04 19:03 ` Daniel Borkmann
2020-12-04 19:47 ` Martin KaFai Lau
3 siblings, 1 reply; 9+ messages in thread
From: Daniel Borkmann @ 2020-12-04 18:56 UTC (permalink / raw)
To: Florent Revest, bpf; +Cc: ast, andrii, kpsingh, revest, linux-kernel
On 12/3/20 10:33 PM, Florent Revest wrote:
> This creates a new helper proto because the existing
> bpf_get_socket_cookie_sock_proto has a ARG_PTR_TO_CTX argument and only
> works for BPF programs where the context is a sock.
>
> This helper could also be useful to other BPF program types such as LSM.
>
> Signed-off-by: Florent Revest <revest@google.com>
> ---
> include/uapi/linux/bpf.h | 7 +++++++
> kernel/trace/bpf_trace.c | 4 ++++
> net/core/filter.c | 7 +++++++
> tools/include/uapi/linux/bpf.h | 7 +++++++
> 4 files changed, 25 insertions(+)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index c3458ec1f30a..3e0e33c43998 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -1662,6 +1662,13 @@ union bpf_attr {
> * Return
> * A 8-byte long non-decreasing number.
> *
> + * u64 bpf_get_socket_cookie(void *sk)
> + * Description
> + * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
> + * *sk*, but gets socket from a BTF **struct sock**.
> + * Return
> + * A 8-byte long non-decreasing number.
I would not mention this here since it's not fully correct and we should avoid users
taking non-decreasing granted in their progs. The only assumption you can make is
that it can be considered a unique number. See also [0] with reverse counter..
[0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92acdc58ab11af66fcaef485433fde61b5e32fac
> + *
> * 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 d255bc9b2bfa..14ad96579813 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1725,6 +1725,8 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> }
> }
>
> +extern const struct bpf_func_proto bpf_get_socket_cookie_sock_tracing_proto;
> +
> const struct bpf_func_proto *
> tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> {
> @@ -1748,6 +1750,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> return &bpf_sk_storage_get_tracing_proto;
> case BPF_FUNC_sk_storage_delete:
> return &bpf_sk_storage_delete_tracing_proto;
> + case BPF_FUNC_get_socket_cookie:
> + return &bpf_get_socket_cookie_sock_tracing_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 2ca5eecebacf..177c4e5e529d 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -4631,6 +4631,13 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_proto = {
> .arg1_type = ARG_PTR_TO_CTX,
> };
>
> +const struct bpf_func_proto bpf_get_socket_cookie_sock_tracing_proto = {
> + .func = bpf_get_socket_cookie_sock,
> + .gpl_only = false,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
> +};
> +
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs
2020-12-04 18:56 ` [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs Daniel Borkmann
@ 2020-12-04 19:03 ` Daniel Borkmann
2020-12-08 19:30 ` Florent Revest
0 siblings, 1 reply; 9+ messages in thread
From: Daniel Borkmann @ 2020-12-04 19:03 UTC (permalink / raw)
To: Florent Revest, bpf; +Cc: ast, andrii, kpsingh, revest, linux-kernel
On 12/4/20 7:56 PM, Daniel Borkmann wrote:
> On 12/3/20 10:33 PM, Florent Revest wrote:
>> This creates a new helper proto because the existing
>> bpf_get_socket_cookie_sock_proto has a ARG_PTR_TO_CTX argument and only
>> works for BPF programs where the context is a sock.
>>
>> This helper could also be useful to other BPF program types such as LSM.
>>
>> Signed-off-by: Florent Revest <revest@google.com>
>> ---
>> include/uapi/linux/bpf.h | 7 +++++++
>> kernel/trace/bpf_trace.c | 4 ++++
>> net/core/filter.c | 7 +++++++
>> tools/include/uapi/linux/bpf.h | 7 +++++++
>> 4 files changed, 25 insertions(+)
>>
>> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
>> index c3458ec1f30a..3e0e33c43998 100644
>> --- a/include/uapi/linux/bpf.h
>> +++ b/include/uapi/linux/bpf.h
>> @@ -1662,6 +1662,13 @@ union bpf_attr {
>> * Return
>> * A 8-byte long non-decreasing number.
>> *
>> + * u64 bpf_get_socket_cookie(void *sk)
>> + * Description
>> + * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
>> + * *sk*, but gets socket from a BTF **struct sock**.
>> + * Return
>> + * A 8-byte long non-decreasing number.
>
> I would not mention this here since it's not fully correct and we should avoid users
> taking non-decreasing granted in their progs. The only assumption you can make is
> that it can be considered a unique number. See also [0] with reverse counter..
>
> [0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92acdc58ab11af66fcaef485433fde61b5e32fac
One more thought, in case you plan to use this from sleepable context, you would
need to use sock_gen_cookie() variant in the BPF helper instead.
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs
2020-12-04 19:03 ` Daniel Borkmann
@ 2020-12-08 19:30 ` Florent Revest
2020-12-09 8:29 ` Daniel Borkmann
0 siblings, 1 reply; 9+ messages in thread
From: Florent Revest @ 2020-12-08 19:30 UTC (permalink / raw)
To: Daniel Borkmann, bpf; +Cc: ast, andrii, kpsingh, revest, linux-kernel
On Fri, 2020-12-04 at 20:03 +0100, Daniel Borkmann wrote:
> On 12/4/20 7:56 PM, Daniel Borkmann wrote:
> > On 12/3/20 10:33 PM, Florent Revest wrote:
> > > This creates a new helper proto because the existing
> > > bpf_get_socket_cookie_sock_proto has a ARG_PTR_TO_CTX argument
> > > and only
> > > works for BPF programs where the context is a sock.
> > >
> > > This helper could also be useful to other BPF program types such
> > > as LSM.
> > >
> > > Signed-off-by: Florent Revest <revest@google.com>
> > > ---
> > > include/uapi/linux/bpf.h | 7 +++++++
> > > kernel/trace/bpf_trace.c | 4 ++++
> > > net/core/filter.c | 7 +++++++
> > > tools/include/uapi/linux/bpf.h | 7 +++++++
> > > 4 files changed, 25 insertions(+)
> > >
> > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > > index c3458ec1f30a..3e0e33c43998 100644
> > > --- a/include/uapi/linux/bpf.h
> > > +++ b/include/uapi/linux/bpf.h
> > > @@ -1662,6 +1662,13 @@ union bpf_attr {
> > > * Return
> > > * A 8-byte long non-decreasing number.
> > > *
> > > + * u64 bpf_get_socket_cookie(void *sk)
> > > + * Description
> > > + * Equivalent to **bpf_get_socket_cookie**\ () helper
> > > that accepts
> > > + * *sk*, but gets socket from a BTF **struct sock**.
> > > + * Return
> > > + * A 8-byte long non-decreasing number.
> >
> > I would not mention this here since it's not fully correct and we
> > should avoid users taking non-decreasing granted in their progs.
> > The only assumption you can make is that it can be considered a
> > unique number. See also [0] with reverse counter..
> >
> > [0]
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92acdc58ab11af66fcaef485433fde61b5e32fac
Ah this is a good point, thank you! I will send a v3 with an extra
patch that s/non-decreasing/unique/ in the other descriptions. I had
not given it any extra thought, I just stupidly copied/pasted existing
descriptions. :)
> One more thought, in case you plan to use this from sleepable
> context, you would need to use sock_gen_cookie() variant in the BPF
> helper instead.
Out of curiosity, why don't we just always call sock_gen_cookie? Is it
to avoid the performance impact of increasing the preempt counter and
introducing a memory barriers ?
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs
2020-12-08 19:30 ` Florent Revest
@ 2020-12-09 8:29 ` Daniel Borkmann
0 siblings, 0 replies; 9+ messages in thread
From: Daniel Borkmann @ 2020-12-09 8:29 UTC (permalink / raw)
To: Florent Revest, bpf; +Cc: ast, andrii, kpsingh, revest, linux-kernel
On 12/8/20 8:30 PM, Florent Revest wrote:
> On Fri, 2020-12-04 at 20:03 +0100, Daniel Borkmann wrote:
>> On 12/4/20 7:56 PM, Daniel Borkmann wrote:
>>> On 12/3/20 10:33 PM, Florent Revest wrote:
>>>> This creates a new helper proto because the existing
>>>> bpf_get_socket_cookie_sock_proto has a ARG_PTR_TO_CTX argument
>>>> and only
>>>> works for BPF programs where the context is a sock.
>>>>
>>>> This helper could also be useful to other BPF program types such
>>>> as LSM.
>>>>
>>>> Signed-off-by: Florent Revest <revest@google.com>
>>>> ---
>>>> include/uapi/linux/bpf.h | 7 +++++++
>>>> kernel/trace/bpf_trace.c | 4 ++++
>>>> net/core/filter.c | 7 +++++++
>>>> tools/include/uapi/linux/bpf.h | 7 +++++++
>>>> 4 files changed, 25 insertions(+)
>>>>
>>>> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
>>>> index c3458ec1f30a..3e0e33c43998 100644
>>>> --- a/include/uapi/linux/bpf.h
>>>> +++ b/include/uapi/linux/bpf.h
>>>> @@ -1662,6 +1662,13 @@ union bpf_attr {
>>>> * Return
>>>> * A 8-byte long non-decreasing number.
>>>> *
>>>> + * u64 bpf_get_socket_cookie(void *sk)
>>>> + * Description
>>>> + * Equivalent to **bpf_get_socket_cookie**\ () helper
>>>> that accepts
>>>> + * *sk*, but gets socket from a BTF **struct sock**.
>>>> + * Return
>>>> + * A 8-byte long non-decreasing number.
>>>
>>> I would not mention this here since it's not fully correct and we
>>> should avoid users taking non-decreasing granted in their progs.
>>> The only assumption you can make is that it can be considered a
>>> unique number. See also [0] with reverse counter..
>>>
>>> [0]
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92acdc58ab11af66fcaef485433fde61b5e32fac
>
> Ah this is a good point, thank you! I will send a v3 with an extra
> patch that s/non-decreasing/unique/ in the other descriptions. I had
> not given it any extra thought, I just stupidly copied/pasted existing
> descriptions. :)
>
>> One more thought, in case you plan to use this from sleepable
>> context, you would need to use sock_gen_cookie() variant in the BPF
>> helper instead.
>
> Out of curiosity, why don't we just always call sock_gen_cookie? Is it
> to avoid the performance impact of increasing the preempt counter and
> introducing a memory barriers ?
Yes, all the other contexts where the existing helpers are used already have
preemption disabled, so the extra preempt_{disable,enable}() is unnecessary
overhead given we want the cookie generation be efficient.
Thanks,
Daniel
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs
2020-12-03 21:33 [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs Florent Revest
` (2 preceding siblings ...)
2020-12-04 18:56 ` [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs Daniel Borkmann
@ 2020-12-04 19:47 ` Martin KaFai Lau
2020-12-08 19:40 ` Florent Revest
3 siblings, 1 reply; 9+ messages in thread
From: Martin KaFai Lau @ 2020-12-04 19:47 UTC (permalink / raw)
To: Florent Revest; +Cc: bpf, ast, daniel, andrii, kpsingh, revest, linux-kernel
On Thu, Dec 03, 2020 at 10:33:28PM +0100, Florent Revest wrote:
> This creates a new helper proto because the existing
> bpf_get_socket_cookie_sock_proto has a ARG_PTR_TO_CTX argument and only
> works for BPF programs where the context is a sock.
>
> This helper could also be useful to other BPF program types such as LSM.
>
> Signed-off-by: Florent Revest <revest@google.com>
> ---
> include/uapi/linux/bpf.h | 7 +++++++
> kernel/trace/bpf_trace.c | 4 ++++
> net/core/filter.c | 7 +++++++
> tools/include/uapi/linux/bpf.h | 7 +++++++
> 4 files changed, 25 insertions(+)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index c3458ec1f30a..3e0e33c43998 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -1662,6 +1662,13 @@ union bpf_attr {
> * Return
> * A 8-byte long non-decreasing number.
> *
> + * u64 bpf_get_socket_cookie(void *sk)
> + * Description
> + * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
> + * *sk*, but gets socket from a BTF **struct sock**.
> + * Return
> + * A 8-byte long non-decreasing number.
> + *
> * 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 d255bc9b2bfa..14ad96579813 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1725,6 +1725,8 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> }
> }
>
> +extern const struct bpf_func_proto bpf_get_socket_cookie_sock_tracing_proto;
> +
> const struct bpf_func_proto *
> tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> {
> @@ -1748,6 +1750,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> return &bpf_sk_storage_get_tracing_proto;
> case BPF_FUNC_sk_storage_delete:
> return &bpf_sk_storage_delete_tracing_proto;
> + case BPF_FUNC_get_socket_cookie:
> + return &bpf_get_socket_cookie_sock_tracing_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 2ca5eecebacf..177c4e5e529d 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -4631,6 +4631,13 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_proto = {
> .arg1_type = ARG_PTR_TO_CTX,
> };
>
> +const struct bpf_func_proto bpf_get_socket_cookie_sock_tracing_proto = {
> + .func = bpf_get_socket_cookie_sock,
> + .gpl_only = false,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
In tracing where it gets a sk pointer, the sk could be NULL.
A NULL check is required in the helper. Please refer to
bpf_skc_to_tcp_sock[_proto] as an example.
This proto is in general also useful for non tracing context where
it can get a hold of a sk pointer. (e.g. another similar usage that will
have a hold on a sk pointer for BPF_PROG_TYPE_SK_REUSEPORT [0]).
In case if you don't need sleepable at this point as Daniel
mentioned in another thread. Does it make sense to rename this
proto to something like bpf_get_socket_pointer_cookie_proto?
[0]: https://lore.kernel.org/bpf/20201201144418.35045-10-kuniyu@amazon.co.jp/
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs
2020-12-04 19:47 ` Martin KaFai Lau
@ 2020-12-08 19:40 ` Florent Revest
0 siblings, 0 replies; 9+ messages in thread
From: Florent Revest @ 2020-12-08 19:40 UTC (permalink / raw)
To: Martin KaFai Lau; +Cc: bpf, ast, daniel, andrii, kpsingh, revest, linux-kernel
On Fri, 2020-12-04 at 11:47 -0800, Martin KaFai Lau wrote:
> On Thu, Dec 03, 2020 at 10:33:28PM +0100, Florent Revest wrote:
> > +const struct bpf_func_proto
> > bpf_get_socket_cookie_sock_tracing_proto = {
> > + .func = bpf_get_socket_cookie_sock,
> > + .gpl_only = false,
> > + .ret_type = RET_INTEGER,
> > + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
>
> In tracing where it gets a sk pointer, the sk could be NULL.
> A NULL check is required in the helper. Please refer to
> bpf_skc_to_tcp_sock[_proto] as an example.
Ah, good catch! :)
> This proto is in general also useful for non tracing context where
> it can get a hold of a sk pointer. (e.g. another similar usage that
> will have a hold on a sk pointer for BPF_PROG_TYPE_SK_REUSEPORT [0]).
Agreed.
> In case if you don't need sleepable at this point as Daniel
> mentioned in another thread. Does it make sense to rename this
> proto to something like bpf_get_socket_pointer_cookie_proto?
My understanding is that I could have two helpers definitions and
protos, one calling sock_gen_cookie and the other one calling
__sock_gen_cookie. Then I could just use:
return prog->aux->sleepable
? bpf_get_socket_pointer_cookie_sleepable_proto
: bpf_get_socket_pointer_cookie_proto;
Would that work ?
^ permalink raw reply [flat|nested] 9+ messages in thread