From: Carlos <cneirabustos@xxxxxxxxx> Added self-tests for new helper bpf_get_current_pidns_info. Signed-off-by: Carlos Neira <cneirabustos@xxxxxxxxx> --- tools/include/uapi/linux/bpf.h | 31 ++++- tools/testing/selftests/bpf/Makefile | 2 +- tools/testing/selftests/bpf/bpf_helpers.h | 3 + .../testing/selftests/bpf/progs/test_pidns_kern.c | 51 ++++++++ tools/testing/selftests/bpf/test_pidns.c | 138 +++++++++++++++++++++ 5 files changed, 223 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/test_pidns_kern.c create mode 100644 tools/testing/selftests/bpf/test_pidns.c diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 4393bd4b2419..db241857ec15 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2741,6 +2741,28 @@ union bpf_attr { * **-EOPNOTSUPP** kernel configuration does not enable SYN cookies * * **-EPROTONOSUPPORT** IP packet version is not 4 or 6 + * + * int bpf_get_current_pidns_info(struct bpf_pidns_info *pidns, u32 size_of_pidns) + * Description + * Copies into *pidns* pid, namespace id and tgid as seen by the + * current namespace and also device from /proc/self/ns/pid. + * *size_of_pidns* must be the size of *pidns* + * + * This helper is used when pid filtering is needed inside a + * container as bpf_get_current_tgid() helper returns always the + * pid id as seen by the root namespace. + * Return + * 0 on success + * + * **-EINVAL** if *size_of_pidns* is not valid or unable to get ns, pid + * or tgid of the current task. + * + * **-ECHILD** if /proc/self/ns/pid does not exists. + * + * **-ENOTDIR** if /proc/self/ns does not exists. + * + * **-ENOMEM** if allocation fails. + * */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2853,7 +2875,8 @@ union bpf_attr { FN(sk_storage_get), \ FN(sk_storage_delete), \ FN(send_signal), \ - FN(tcp_gen_syncookie), + FN(tcp_gen_syncookie), \ + FN(get_current_pidns_info), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call @@ -3604,4 +3627,10 @@ struct bpf_sockopt { __s32 retval; }; +struct bpf_pidns_info { + __u32 dev; + __u32 nsid; + __u32 tgid; + __u32 pid; +}; #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 3bd0f4a0336a..1f97b571b581 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -29,7 +29,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test 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_sockopt_sk \ - test_sockopt_multi test_tcp_rtt + test_sockopt_multi test_tcp_rtt test_pidns BPF_OBJ_FILES = $(patsubst %.c,%.o, $(notdir $(wildcard progs/*.c))) TEST_GEN_FILES = $(BPF_OBJ_FILES) diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h index 8b503ea142f0..3fae3b9fcd2c 100644 --- a/tools/testing/selftests/bpf/bpf_helpers.h +++ b/tools/testing/selftests/bpf/bpf_helpers.h @@ -231,6 +231,9 @@ static int (*bpf_send_signal)(unsigned sig) = (void *)BPF_FUNC_send_signal; static long long (*bpf_tcp_gen_syncookie)(struct bpf_sock *sk, void *ip, int ip_len, void *tcp, int tcp_len) = (void *) BPF_FUNC_tcp_gen_syncookie; +static int (*bpf_get_current_pidns_info)(struct bpf_pidns_info *buf, + unsigned int buf_size) = + (void *) BPF_FUNC_get_current_pidns_info; /* llvm builtin functions that eBPF C program may use to * emit BPF_LD_ABS and BPF_LD_IND instructions diff --git a/tools/testing/selftests/bpf/progs/test_pidns_kern.c b/tools/testing/selftests/bpf/progs/test_pidns_kern.c new file mode 100644 index 000000000000..e1d2facfa762 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_pidns_kern.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2018 Carlos Neira cneirabustos@xxxxxxxxx + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ + +#include <linux/bpf.h> +#include <errno.h> +#include "bpf_helpers.h" + +struct bpf_map_def SEC("maps") nsidmap = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 1, +}; + +struct bpf_map_def SEC("maps") pidmap = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 1, +}; + +SEC("tracepoint/syscalls/sys_enter_nanosleep") +int trace(void *ctx) +{ + struct bpf_pidns_info nsinfo; + __u32 key = 0, *expected_pid, *val; + char fmt[] = "ERROR nspid:%d\n"; + + if (bpf_get_current_pidns_info(&nsinfo, sizeof(nsinfo))) + return -EINVAL; + + expected_pid = bpf_map_lookup_elem(&pidmap, &key); + + + if (!expected_pid || *expected_pid != nsinfo.pid) + return 0; + + val = bpf_map_lookup_elem(&nsidmap, &key); + if (val) + *val = nsinfo.nsid; + + return 0; +} + +char _license[] SEC("license") = "GPL"; +__u32 _version SEC("version") = 1; diff --git a/tools/testing/selftests/bpf/test_pidns.c b/tools/testing/selftests/bpf/test_pidns.c new file mode 100644 index 000000000000..a7254055f294 --- /dev/null +++ b/tools/testing/selftests/bpf/test_pidns.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2018 Carlos Neira cneirabustos@xxxxxxxxx + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <fcntl.h> +#include <syscall.h> +#include <unistd.h> +#include <linux/perf_event.h> +#include <sys/ioctl.h> +#include <sys/time.h> +#include <sys/types.h> +#include <sys/stat.h> + +#include <linux/bpf.h> +#include <bpf/bpf.h> +#include <bpf/libbpf.h> + +#include "cgroup_helpers.h" +#include "bpf_rlimit.h" + +#define CHECK(condition, tag, format...) ({ \ + int __ret = !!(condition); \ + if (__ret) { \ + printf("%s:FAIL:%s ", __func__, tag); \ + printf(format); \ + } else { \ + printf("%s:PASS:%s\n", __func__, tag); \ + } \ + __ret; \ +}) + +static int bpf_find_map(const char *test, struct bpf_object *obj, + const char *name) +{ + struct bpf_map *map; + + map = bpf_object__find_map_by_name(obj, name); + if (!map) + return -1; + return bpf_map__fd(map); +} + + +int main(int argc, char **argv) +{ + const char *probe_name = "syscalls/sys_enter_nanosleep"; + const char *file = "test_pidns_kern.o"; + int err, bytes, efd, prog_fd, pmu_fd; + int pidmap_fd, nsidmap_fd; + struct perf_event_attr attr = {}; + struct bpf_object *obj; + __u32 knsid = 0; + __u32 key = 0, pid; + int exit_code = 1; + struct stat st; + char buf[256]; + + err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd); + if (CHECK(err, "bpf_prog_load", "err %d errno %d\n", err, errno)) + goto cleanup_cgroup_env; + + nsidmap_fd = bpf_find_map(__func__, obj, "nsidmap"); + if (CHECK(nsidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", + nsidmap_fd, errno)) + goto close_prog; + + pidmap_fd = bpf_find_map(__func__, obj, "pidmap"); + if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", + pidmap_fd, errno)) + goto close_prog; + + pid = getpid(); + bpf_map_update_elem(pidmap_fd, &key, &pid, 0); + + snprintf(buf, sizeof(buf), + "/sys/kernel/debug/tracing/events/%s/id", probe_name); + efd = open(buf, O_RDONLY, 0); + if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) + goto close_prog; + bytes = read(efd, buf, sizeof(buf)); + close(efd); + if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read", + "bytes %d errno %d\n", bytes, errno)) + goto close_prog; + + attr.config = strtol(buf, NULL, 0); + attr.type = PERF_TYPE_TRACEPOINT; + attr.sample_type = PERF_SAMPLE_RAW; + attr.sample_period = 1; + attr.wakeup_events = 1; + + pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0); + if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd, + errno)) + goto close_prog; + + err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); + if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err, + errno)) + goto close_pmu; + + err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); + if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err, + errno)) + goto close_pmu; + + /* trigger some syscalls */ + sleep(1); + + err = bpf_map_lookup_elem(nsidmap_fd, &key, &knsid); + if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno)) + goto close_pmu; + + if (stat("/proc/self/ns/pid", &st)) + goto close_pmu; + + if (CHECK(knsid != (__u32) st.st_ino, "compare_namespace_id", + "kern knsid %u user unsid %u\n", knsid, (__u32) st.st_ino)) + goto close_pmu; + + exit_code = 0; + printf("%s:PASS\n", argv[0]); + +close_pmu: + close(pmu_fd); +close_prog: + bpf_object__close(obj); +cleanup_cgroup_env: + return exit_code; +} -- 2.11.0