diff options
author | Andrii Nakryiko <andriin@fb.com> | 2020-04-10 13:26:13 -0700 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-04-14 21:28:57 +0200 |
commit | 642c1654702731ab42a3be771bebbd6ef938f0dc (patch) | |
tree | 766a7490a2cdb507523f1369f73ec902fb699e85 /tools/testing/selftests | |
parent | 1f6cb19be2e231fe092f40decb71f066eba090d7 (diff) |
selftests/bpf: Validate frozen map contents stays frozen
Test that frozen and mmap()'ed BPF map can't be mprotect()'ed as writable or
executable memory. Also validate that "downgrading" from writable to read-only
doesn't screw up internal writable count accounting for the purposes of map
freezing.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200410202613.3679837-2-andriin@fb.com
Diffstat (limited to 'tools/testing/selftests')
-rw-r--r-- | tools/testing/selftests/bpf/prog_tests/mmap.c | 62 |
1 files changed, 60 insertions, 2 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/mmap.c b/tools/testing/selftests/bpf/prog_tests/mmap.c index 16a814eb4d64..56d80adcf4bd 100644 --- a/tools/testing/selftests/bpf/prog_tests/mmap.c +++ b/tools/testing/selftests/bpf/prog_tests/mmap.c @@ -19,15 +19,16 @@ void test_mmap(void) const size_t map_sz = roundup_page(sizeof(struct map_data)); const int zero = 0, one = 1, two = 2, far = 1500; const long page_size = sysconf(_SC_PAGE_SIZE); - int err, duration = 0, i, data_map_fd; + int err, duration = 0, i, data_map_fd, data_map_id, tmp_fd; struct bpf_map *data_map, *bss_map; void *bss_mmaped = NULL, *map_mmaped = NULL, *tmp1, *tmp2; struct test_mmap__bss *bss_data; + struct bpf_map_info map_info; + __u32 map_info_sz = sizeof(map_info); struct map_data *map_data; struct test_mmap *skel; __u64 val = 0; - skel = test_mmap__open_and_load(); if (CHECK(!skel, "skel_open_and_load", "skeleton open/load failed\n")) return; @@ -36,6 +37,14 @@ void test_mmap(void) data_map = skel->maps.data_map; data_map_fd = bpf_map__fd(data_map); + /* get map's ID */ + memset(&map_info, 0, map_info_sz); + err = bpf_obj_get_info_by_fd(data_map_fd, &map_info, &map_info_sz); + if (CHECK(err, "map_get_info", "failed %d\n", errno)) + goto cleanup; + data_map_id = map_info.id; + + /* mmap BSS map */ bss_mmaped = mmap(NULL, bss_sz, PROT_READ | PROT_WRITE, MAP_SHARED, bpf_map__fd(bss_map), 0); if (CHECK(bss_mmaped == MAP_FAILED, "bss_mmap", @@ -98,6 +107,10 @@ void test_mmap(void) "data_map freeze succeeded: err=%d, errno=%d\n", err, errno)) goto cleanup; + err = mprotect(map_mmaped, map_sz, PROT_READ); + if (CHECK(err, "mprotect_ro", "mprotect to r/o failed %d\n", errno)) + goto cleanup; + /* unmap R/W mapping */ err = munmap(map_mmaped, map_sz); map_mmaped = NULL; @@ -111,6 +124,12 @@ void test_mmap(void) map_mmaped = NULL; goto cleanup; } + err = mprotect(map_mmaped, map_sz, PROT_WRITE); + if (CHECK(!err, "mprotect_wr", "mprotect() succeeded unexpectedly!\n")) + goto cleanup; + err = mprotect(map_mmaped, map_sz, PROT_EXEC); + if (CHECK(!err, "mprotect_ex", "mprotect() succeeded unexpectedly!\n")) + goto cleanup; map_data = map_mmaped; /* map/unmap in a loop to test ref counting */ @@ -197,6 +216,45 @@ void test_mmap(void) CHECK_FAIL(map_data->val[far] != 3 * 321); munmap(tmp2, 4 * page_size); + + tmp1 = mmap(NULL, map_sz, PROT_READ, MAP_SHARED, data_map_fd, 0); + if (CHECK(tmp1 == MAP_FAILED, "last_mmap", "failed %d\n", errno)) + goto cleanup; + + test_mmap__destroy(skel); + skel = NULL; + CHECK_FAIL(munmap(bss_mmaped, bss_sz)); + bss_mmaped = NULL; + CHECK_FAIL(munmap(map_mmaped, map_sz)); + map_mmaped = NULL; + + /* map should be still held by active mmap */ + tmp_fd = bpf_map_get_fd_by_id(data_map_id); + if (CHECK(tmp_fd < 0, "get_map_by_id", "failed %d\n", errno)) { + munmap(tmp1, map_sz); + goto cleanup; + } + close(tmp_fd); + + /* this should release data map finally */ + munmap(tmp1, map_sz); + + /* we need to wait for RCU grace period */ + for (i = 0; i < 10000; i++) { + __u32 id = data_map_id - 1; + if (bpf_map_get_next_id(id, &id) || id > data_map_id) + break; + usleep(1); + } + + /* should fail to get map FD by non-existing ID */ + tmp_fd = bpf_map_get_fd_by_id(data_map_id); + if (CHECK(tmp_fd >= 0, "get_map_by_id_after", + "unexpectedly succeeded %d\n", tmp_fd)) { + close(tmp_fd); + goto cleanup; + } + cleanup: if (bss_mmaped) CHECK_FAIL(munmap(bss_mmaped, bss_sz)); |