From 8a027dc0d8f5d421eba953a7116aea991459b202 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Thu, 27 Jun 2019 13:38:52 -0700 Subject: [PATCH] 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 Cc: Martin Lau Signed-off-by: Stanislav Fomichev Signed-off-by: Alexei Starovoitov --- 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 +#include +#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 +#include +#include +#include +#include +#include + +#include +#include +#include + +#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; +} -- 2.30.2