socktop test that introduces new SOL_CUSTOM sockopt level and
stores whatever users sets in sk storage. Whenever getsockopt
is called, the original value is retrieved.
v9:
* SO_SNDBUF example to override user-supplied buffer
v7:
* use retval=0 and optlen-1
v6:
* test 'ret=1' use-case as well (Alexei Starovoitov)
v4:
* don't call bpf_sk_fullsock helper
v3:
* drop (__u8 *)(long) casts for optval{,_end}
v2:
* new test
Cc: Andrii Nakryiko <andriin@xxxxxx>
Cc: Martin Lau <kafai@xxxxxx>
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
tools/testing/selftests/bpf/.gitignore | 1 +
tools/testing/selftests/bpf/Makefile | 3 +-
.../testing/selftests/bpf/progs/sockopt_sk.c | 111 +++++++++
tools/testing/selftests/bpf/test_sockopt_sk.c | 214 ++++++++++++++++++
4 files changed, 328 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/progs/sockopt_sk.c
create mode 100644 tools/testing/selftests/bpf/test_sockopt_sk.c
diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index 3fe92601223d..8ac076c311d4 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -40,3 +40,4 @@ test_hashmap
test_btf_dump
xdping
test_sockopt
+test_sockopt_sk
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 7f2210402e57..57ae4e168ace 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -26,7 +26,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
test_sock test_btf test_sockmap get_cgroup_id_user test_socket_cookie \
test_cgroup_storage test_select_reuseport test_section_names \
test_netcnt test_tcpnotify_user test_sock_fields test_sysctl test_hashmap \
- test_btf_dump test_cgroup_attach xdping test_sockopt
+ test_btf_dump test_cgroup_attach xdping test_sockopt test_sockopt_sk
BPF_OBJ_FILES = $(patsubst %.c,%.o, $(notdir $(wildcard progs/*.c)))
TEST_GEN_FILES = $(BPF_OBJ_FILES)
@@ -104,6 +104,7 @@ $(OUTPUT)/test_sock_fields: cgroup_helpers.c
$(OUTPUT)/test_sysctl: cgroup_helpers.c
$(OUTPUT)/test_cgroup_attach: cgroup_helpers.c
$(OUTPUT)/test_sockopt: cgroup_helpers.c
+$(OUTPUT)/test_sockopt_sk: cgroup_helpers.c
.PHONY: force
diff --git a/tools/testing/selftests/bpf/progs/sockopt_sk.c b/tools/testing/selftests/bpf/progs/sockopt_sk.c
new file mode 100644
index 000000000000..076122c898e9
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/sockopt_sk.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <netinet/in.h>
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+__u32 _version SEC("version") = 1;
+
+#define SOL_CUSTOM 0xdeadbeef
+
+struct sockopt_sk {
+ __u8 val;
+};
+
+struct bpf_map_def SEC("maps") socket_storage_map = {
+ .type = BPF_MAP_TYPE_SK_STORAGE,
+ .key_size = sizeof(int),
+ .value_size = sizeof(struct sockopt_sk),
+ .map_flags = BPF_F_NO_PREALLOC,
+};
+BPF_ANNOTATE_KV_PAIR(socket_storage_map, int, struct sockopt_sk);
+
+SEC("cgroup/getsockopt")
+int _getsockopt(struct bpf_sockopt *ctx)
+{
+ __u8 *optval_end = ctx->optval_end;
+ __u8 *optval = ctx->optval;
+ struct sockopt_sk *storage;
+
+ if (ctx->level == SOL_IP && ctx->optname == IP_TOS)
+ /* Not interested in SOL_IP:IP_TOS;
+ * let next BPF program in the cgroup chain or kernel
+ * handle it.
+ */
+ return 1;
+
+ if (ctx->level == SOL_SOCKET && ctx->optname == SO_SNDBUF) {
+ /* Not interested in SOL_SOCKET:SO_SNDBUF;
+ * let next BPF program in the cgroup chain or kernel
+ * handle it.
+ */
+ return 1;
+ }
+
+ if (ctx->level != SOL_CUSTOM)
+ return 0; /* EPERM, deny everything except custom level */
+
+ if (optval + 1 > optval_end)
+ return 0; /* EPERM, bounds check */
+
+ storage = bpf_sk_storage_get(&socket_storage_map, ctx->sk, 0,
+ BPF_SK_STORAGE_GET_F_CREATE);
+ if (!storage)
+ return 0; /* EPERM, couldn't get sk storage */
+
+ if (!ctx->retval)
+ return 0; /* EPERM, kernel should not have handled
+ * SOL_CUSTOM, something is wrong!
+ */
+ ctx->retval = 0; /* Reset system call return value to zero */
+
+ optval[0] = storage->val;
+ ctx->optlen = 1;
+
+ return 1;
+}
+
+SEC("cgroup/setsockopt")
+int _setsockopt(struct bpf_sockopt *ctx)
+{
+ __u8 *optval_end = ctx->optval_end;
+ __u8 *optval = ctx->optval;
+ struct sockopt_sk *storage;
+
+ if (ctx->level == SOL_IP && ctx->optname == IP_TOS)
+ /* Not interested in SOL_IP:IP_TOS;
+ * let next BPF program in the cgroup chain or kernel
+ * handle it.
+ */
+ return 1;
+
+ if (ctx->level == SOL_SOCKET && ctx->optname == SO_SNDBUF) {
+ /* Overwrite SO_SNDBUF value */
+
+ if (optval + sizeof(__u32) > optval_end)
+ return 0; /* EPERM, bounds check */
+
+ *(__u32 *)optval = 0x55AA;
+ ctx->optlen = 4;
+
+ return 1;
+ }
+
+ if (ctx->level != SOL_CUSTOM)
+ return 0; /* EPERM, deny everything except custom level */
+
+ if (optval + 1 > optval_end)
+ return 0; /* EPERM, bounds check */
+
+ storage = bpf_sk_storage_get(&socket_storage_map, ctx->sk, 0,
+ BPF_SK_STORAGE_GET_F_CREATE);
+ if (!storage)
+ return 0; /* EPERM, couldn't get sk storage */
+
+ storage->val = optval[0];
+ ctx->optlen = -1; /* BPF has consumed this option, don't call kernel
+ * setsockopt handler.
+ */
+
+ return 1;
+}
diff --git a/tools/testing/selftests/bpf/test_sockopt_sk.c b/tools/testing/selftests/bpf/test_sockopt_sk.c
new file mode 100644
index 000000000000..12e79ed075ce
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_sockopt_sk.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include <linux/filter.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "bpf_rlimit.h"
+#include "bpf_util.h"
+#include "cgroup_helpers.h"
+
+#define CG_PATH "/sockopt"
+
+#define SOL_CUSTOM 0xdeadbeef
+
+static int getsetsockopt(void)
+{
+ int fd, err;
+ char buf[4] = {};
+ socklen_t optlen;
+
+ fd = socket(AF_INET, SOCK_STREAM, 0);
+ if (fd < 0) {
+ log_err("Failed to create socket");
+ return -1;
+ }
+
+ /* IP_TOS - BPF bypass */
+
+ buf[0] = 0x08;
+ err = setsockopt(fd, SOL_IP, IP_TOS, buf, 1);
+ if (err) {
+ log_err("Failed to call setsockopt(IP_TOS)");
+ goto err;
+ }
+
+ buf[0] = 0x00;
+ optlen = 1;
+ err = getsockopt(fd, SOL_IP, IP_TOS, buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(IP_TOS)");
+ goto err;
+ }
+
+ if (buf[0] != 0x08) {
+ log_err("Unexpected getsockopt(IP_TOS) buf[0] 0x%02x != 0x08",
+ buf[0]);
+ goto err;
+ }
+
+ /* IP_TTL - EPERM */
+
+ buf[0] = 1;
+ err = setsockopt(fd, SOL_IP, IP_TTL, buf, 1);
+ if (!err || errno != EPERM) {
+ log_err("Unexpected success from setsockopt(IP_TTL)");
+ goto err;
+ }
+
+ /* SOL_CUSTOM - handled by BPF */
+
+ buf[0] = 0x01;
+ err = setsockopt(fd, SOL_CUSTOM, 0, buf, 1);
+ if (err) {
+ log_err("Failed to call setsockopt");
+ goto err;
+ }
+
+ buf[0] = 0x00;
+ optlen = 4;
+ err = getsockopt(fd, SOL_CUSTOM, 0, buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt");
+ goto err;
+ }
+
+ if (optlen != 1) {
+ log_err("Unexpected optlen %d != 1", optlen);
+ goto err;
+ }
+ if (buf[0] != 0x01) {
+ log_err("Unexpected buf[0] 0x%02x != 0x01", buf[0]);
+ goto err;
+ }
+
+ /* SO_SNDBUF is overwritten */
+
+ buf[0] = 0x01;
+ buf[1] = 0x01;
+ buf[2] = 0x01;
+ buf[3] = 0x01;
+ err = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, buf, 4);
+ if (err) {
+ log_err("Failed to call setsockopt(SO_SNDBUF)");
+ goto err;
+ }
+
+ buf[0] = 0x00;
+ buf[1] = 0x00;
+ buf[2] = 0x00;
+ buf[3] = 0x00;
+ optlen = 4;
+ err = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(SO_SNDBUF)");
+ goto err;
+ }
+
+ if (*(__u32 *)buf != 0x55AA*2) {
+ log_err("Unexpected getsockopt(SO_SNDBUF) 0x%x != 0x55AA*2",
+ *(__u32 *)buf);
+ goto err;
+ }
+
+ close(fd);
+ return 0;
+err:
+ close(fd);
+ return -1;
+}
+
+static int prog_attach(struct bpf_object *obj, int cgroup_fd, const char *title)
+{
+ enum bpf_attach_type attach_type;
+ enum bpf_prog_type prog_type;
+ struct bpf_program *prog;
+ int err;
+
+ err = libbpf_prog_type_by_name(title, &prog_type, &attach_type);
+ if (err) {
+ log_err("Failed to deduct types for %s BPF program", title);
+ return -1;
+ }
+
+ prog = bpf_object__find_program_by_title(obj, title);
+ if (!prog) {
+ log_err("Failed to find %s BPF program", title);
+ return -1;
+ }
+
+ err = bpf_prog_attach(bpf_program__fd(prog), cgroup_fd,
+ attach_type, 0);
+ if (err) {
+ log_err("Failed to attach %s BPF program", title);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int run_test(int cgroup_fd)
+{
+ struct bpf_prog_load_attr attr = {
+ .file = "./sockopt_sk.o",
+ };
+ struct bpf_object *obj;
+ int ignored;
+ int err;
+
+ err = bpf_prog_load_xattr(&attr, &obj, &ignored);
+ if (err) {
+ log_err("Failed to load BPF object");
+ return -1;
+ }
+
+ err = prog_attach(obj, cgroup_fd, "cgroup/getsockopt");
+ if (err)
+ goto close_bpf_object;
+
+ err = prog_attach(obj, cgroup_fd, "cgroup/setsockopt");
+ if (err)
+ goto close_bpf_object;
+
+ err = getsetsockopt();
+
+close_bpf_object:
+ bpf_object__close(obj);
+ return err;
+}
+
+int main(int args, char **argv)
+{
+ int cgroup_fd;
+ int err = EXIT_SUCCESS;
+
+ if (setup_cgroup_environment())
+ goto cleanup_obj;
+
+ cgroup_fd = create_and_get_cgroup(CG_PATH);
+ if (cgroup_fd < 0)
+ goto cleanup_cgroup_env;
+
+ if (join_cgroup(CG_PATH))
+ goto cleanup_cgroup;
+
+ if (run_test(cgroup_fd))
+ err = EXIT_FAILURE;
+
+ printf("test_sockopt_sk: %s\n",
+ err == EXIT_SUCCESS ? "PASSED" : "FAILED");
+
+cleanup_cgroup:
+ close(cgroup_fd);
+cleanup_cgroup_env:
+ cleanup_cgroup_environment();
+cleanup_obj:
+ return err;
+}
--
2.22.0.410.gd8fdbe21b5-goog
