For write-only stacks and queues bpf_map_update_elem should be allowed, but bpf_map_lookup_elem and bpf_map_lookup_and_delete_elem should fail with EPERM.
Signed-off-by: Anton Protopopov a.s.protopopov@gmail.com --- tools/testing/selftests/bpf/test_maps.c | 40 ++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c index 08d63948514a..6a12a0e01e07 100644 --- a/tools/testing/selftests/bpf/test_maps.c +++ b/tools/testing/selftests/bpf/test_maps.c @@ -1405,7 +1405,7 @@ static void test_map_rdonly(void) close(fd); }
-static void test_map_wronly(void) +static void test_map_wronly_hash(void) { int fd, key = 0, value = 0;
@@ -1429,6 +1429,44 @@ static void test_map_wronly(void) close(fd); }
+static void test_map_wronly_stack_or_queue(enum bpf_map_type map_type) +{ + int fd, value = 0; + + assert(map_type == BPF_MAP_TYPE_QUEUE || + map_type == BPF_MAP_TYPE_STACK); + fd = bpf_create_map(map_type, 0, sizeof(value), MAP_SIZE, + map_flags | BPF_F_WRONLY); + /* Stack/Queue maps do not support BPF_F_NO_PREALLOC */ + if (map_flags & BPF_F_NO_PREALLOC) { + assert(fd < 0 && errno == EINVAL); + return; + } + if (fd < 0) { + printf("Failed to create map '%s'!\n", strerror(errno)); + exit(1); + } + + value = 1234; + assert(bpf_map_update_elem(fd, NULL, &value, BPF_ANY) == 0); + + /* Peek element should fail */ + assert(bpf_map_lookup_elem(fd, NULL, &value) == -1 && errno == EPERM); + + /* Pop element should fail */ + assert(bpf_map_lookup_and_delete_elem(fd, NULL, &value) == -1 && + errno == EPERM); + + close(fd); +} + +static void test_map_wronly(void) +{ + test_map_wronly_hash(); + test_map_wronly_stack_or_queue(BPF_MAP_TYPE_STACK); + test_map_wronly_stack_or_queue(BPF_MAP_TYPE_QUEUE); +} + static void prepare_reuseport_grp(int type, int map_fd, size_t map_elem_size, __s64 *fds64, __u64 *sk_cookies, unsigned int n)