Commit 8a027dc0 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Alexei Starovoitov

selftests/bpf: add sockopt test that exercises sk helpers

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@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 9ec8a4c9
......@@ -40,3 +40,4 @@ test_hashmap
test_btf_dump
xdping
test_sockopt
test_sockopt_sk
......@@ -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
......
// 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;
}
// 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;
}
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment