From 1410620cf20e7e23cce17983e9a81af659b28583 Mon Sep 17 00:00:00 2001 From: Udip Pant Date: Tue, 25 Aug 2020 16:20:03 -0700 Subject: [PATCH] selftests/bpf: Test for map update access from within EXT programs This adds further tests to ensure access permissions and restrictions are applied properly for some map types such as sock-map. It also adds another negative tests to assert static functions cannot be replaced. In the 'unreliable' mode it still fails with error 'tracing progs cannot use bpf_spin_lock yet' with the change in the verifier Signed-off-by: Udip Pant Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200825232003.2877030-5-udippant@fb.com --- .../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 33 +++++++++++++-- .../bpf/progs/freplace_attach_probe.c | 40 +++++++++++++++++++ .../bpf/progs/freplace_cls_redirect.c | 34 ++++++++++++++++ 3 files changed, 104 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/freplace_attach_probe.c create mode 100644 tools/testing/selftests/bpf/progs/freplace_cls_redirect.c diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c index d295ca9bbf96..a550dab9ba7a 100644 --- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c +++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c @@ -142,7 +142,20 @@ static void test_func_replace_verify(void) prog_name, false); } -static void test_func_replace_return_code(void) +static void test_func_sockmap_update(void) +{ + const char *prog_name[] = { + "freplace/cls_redirect", + }; + test_fexit_bpf2bpf_common("./freplace_cls_redirect.o", + "./test_cls_redirect.o", + ARRAY_SIZE(prog_name), + prog_name, false); +} + +static void test_obj_load_failure_common(const char *obj_file, + const char *target_obj_file) + { /* * standalone test that asserts failure to load freplace prog @@ -151,8 +164,6 @@ static void test_func_replace_return_code(void) struct bpf_object *obj = NULL, *pkt_obj; int err, pkt_fd; __u32 duration = 0; - const char *target_obj_file = "./connect4_prog.o"; - const char *obj_file = "./freplace_connect_v4_prog.o"; err = bpf_prog_load(target_obj_file, BPF_PROG_TYPE_UNSPEC, &pkt_obj, &pkt_fd); @@ -181,11 +192,27 @@ close_prog: bpf_object__close(pkt_obj); } +static void test_func_replace_return_code(void) +{ + /* test invalid return code in the replaced program */ + test_obj_load_failure_common("./freplace_connect_v4_prog.o", + "./connect4_prog.o"); +} + +static void test_func_map_prog_compatibility(void) +{ + /* test with spin lock map value in the replaced program */ + test_obj_load_failure_common("./freplace_attach_probe.o", + "./test_attach_probe.o"); +} + void test_fexit_bpf2bpf(void) { test_target_no_callees(); test_target_yes_callees(); test_func_replace(); test_func_replace_verify(); + test_func_sockmap_update(); test_func_replace_return_code(); + test_func_map_prog_compatibility(); } diff --git a/tools/testing/selftests/bpf/progs/freplace_attach_probe.c b/tools/testing/selftests/bpf/progs/freplace_attach_probe.c new file mode 100644 index 000000000000..bb2a77c5b62b --- /dev/null +++ b/tools/testing/selftests/bpf/progs/freplace_attach_probe.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook + +#include +#include +#include +#include + +#define VAR_NUM 2 + +struct hmap_elem { + struct bpf_spin_lock lock; + int var[VAR_NUM]; +}; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, struct hmap_elem); +} hash_map SEC(".maps"); + +SEC("freplace/handle_kprobe") +int new_handle_kprobe(struct pt_regs *ctx) +{ + struct hmap_elem zero = {}, *val; + int key = 0; + + val = bpf_map_lookup_elem(&hash_map, &key); + if (!val) + return 1; + /* spin_lock in hash map */ + bpf_spin_lock(&val->lock); + val->var[0] = 99; + bpf_spin_unlock(&val->lock); + + return 0; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/freplace_cls_redirect.c b/tools/testing/selftests/bpf/progs/freplace_cls_redirect.c new file mode 100644 index 000000000000..68a5a9db928a --- /dev/null +++ b/tools/testing/selftests/bpf/progs/freplace_cls_redirect.c @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook + +#include +#include +#include +#include +#include + +struct bpf_map_def SEC("maps") sock_map = { + .type = BPF_MAP_TYPE_SOCKMAP, + .key_size = sizeof(int), + .value_size = sizeof(int), + .max_entries = 2, +}; + +SEC("freplace/cls_redirect") +int freplace_cls_redirect_test(struct __sk_buff *skb) +{ + int ret = 0; + const int zero = 0; + struct bpf_sock *sk; + + sk = bpf_map_lookup_elem(&sock_map, &zero); + if (!sk) + return TC_ACT_SHOT; + + ret = bpf_map_update_elem(&sock_map, &zero, sk, 0); + bpf_sk_release(sk); + + return ret == 0 ? TC_ACT_OK : TC_ACT_SHOT; +} + +char _license[] SEC("license") = "GPL";