From: Tamir Duberstein Add the ringbuf_null_cb subtest. A manager holding a ring with a sample callback and one added without must return -EINVAL from ring_buffer__consume_n(), ring_buffer__consume() and ring_buffer__poll() and leave the consumer position of the valid ring alone, since the checks run before any ring is consumed. A manager created with a NULL callback must return -EINVAL from the same entry points and from ring__consume_n() and ring__consume() on its ring, instead of calling through the NULL pointer. [kkd: split out of "libbpf: Prevent NULL callback crash" (Eduard)] Signed-off-by: Tamir Duberstein Signed-off-by: Kumar Kartikeya Dwivedi --- .../selftests/bpf/prog_tests/ringbuf.c | 93 +++++++++++++++++++ 1 file changed, 93 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c index 4f0558f14847..9ce996bcea8c 100644 --- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c +++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c @@ -401,6 +401,97 @@ static int process_n_sample(void *ctx, void *data, size_t len) return 0; } +static int process_noop_sample(void *ctx, void *data, size_t len) +{ + return 0; +} + +static void ringbuf_null_cb_subtest(void) +{ + struct test_ringbuf_n_lskel *skel_n; + struct ring_buffer *ringbuf = NULL; + struct ring *ring; + unsigned long consumer_pos; + int no_cb_map_fd = -1; + int err; + + skel_n = test_ringbuf_n_lskel__open(); + if (!ASSERT_OK_PTR(skel_n, "test_ringbuf_n_lskel__open")) + return; + + skel_n->maps.ringbuf.max_entries = getpagesize(); + skel_n->bss->pid = getpid(); + skel_n->bss->value = SAMPLE_VALUE; + + err = test_ringbuf_n_lskel__load(skel_n); + if (!ASSERT_OK(err, "test_ringbuf_n_lskel__load")) + goto cleanup; + + err = test_ringbuf_n_lskel__attach(skel_n); + if (!ASSERT_OK(err, "test_ringbuf_n_lskel__attach")) + goto cleanup; + + syscall(__NR_getpgid); + + no_cb_map_fd = bpf_map_create(BPF_MAP_TYPE_RINGBUF, NULL, 0, 0, + getpagesize(), NULL); + if (!ASSERT_OK_FD(no_cb_map_fd, "bpf_map_create")) + goto cleanup; + + /* Manager APIs must validate all rings before consuming any of them. */ + ringbuf = ring_buffer__new(skel_n->maps.ringbuf.map_fd, + process_noop_sample, NULL, NULL); + if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new")) + goto cleanup_fd; + + ring = ring_buffer__ring(ringbuf, 0); + if (!ASSERT_OK_PTR(ring, "ring_buffer__ring")) + goto cleanup_ringbuf; + + err = ring_buffer__add(ringbuf, no_cb_map_fd, NULL, NULL); + if (!ASSERT_OK(err, "ring_buffer__add_no_cb")) + goto cleanup_ringbuf; + + consumer_pos = ring__consumer_pos(ring); + ASSERT_GT(ring__producer_pos(ring), consumer_pos, + "producer_pos_mixed_cb"); + + err = ring_buffer__consume_n(ringbuf, 0); + ASSERT_EQ(err, -EINVAL, "ringbuf_consume_zero_mixed_cb"); + err = ring_buffer__consume(ringbuf); + ASSERT_EQ(err, -EINVAL, "ringbuf_consume_mixed_cb"); + err = ring_buffer__poll(ringbuf, 0); + ASSERT_EQ(err, -EINVAL, "ringbuf_poll_mixed_cb"); + ASSERT_EQ(ring__consumer_pos(ring), consumer_pos, + "consumer_pos_mixed_cb"); + + ring_buffer__free(ringbuf); + ringbuf = + ring_buffer__new(skel_n->maps.ringbuf.map_fd, NULL, NULL, NULL); + if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new_no_cb")) + goto cleanup_fd; + + ring = ring_buffer__ring(ringbuf, 0); + if (!ASSERT_OK_PTR(ring, "ring_buffer__ring_no_cb")) + goto cleanup_ringbuf; + consumer_pos = ring__consumer_pos(ring); + + err = ring_buffer__consume_n(ringbuf, 0); + ASSERT_EQ(err, -EINVAL, "ringbuf_consume_zero_no_cb"); + err = ring__consume_n(ring, 0); + ASSERT_EQ(err, -EINVAL, "ring_consume_zero_no_cb"); + err = ring__consume(ring); + ASSERT_EQ(err, -EINVAL, "ring_consume_no_cb"); + ASSERT_EQ(ring__consumer_pos(ring), consumer_pos, "consumer_pos_no_cb"); + +cleanup_ringbuf: + ring_buffer__free(ringbuf); +cleanup_fd: + close(no_cb_map_fd); +cleanup: + test_ringbuf_n_lskel__destroy(skel_n); +} + static void ringbuf_n_subtest(void) { struct test_ringbuf_n_lskel *skel_n; @@ -579,6 +670,8 @@ void test_ringbuf(void) ringbuf_subtest(); if (test__start_subtest("ringbuf_n")) ringbuf_n_subtest(); + if (test__start_subtest("ringbuf_null_cb")) + ringbuf_null_cb_subtest(); if (test__start_subtest("ringbuf_map_key")) ringbuf_map_key_subtest(); if (test__start_subtest("ringbuf_write")) -- 2.53.0