selftests/bpf: Verify optval=NULL case

Make sure we get optlen exported instead of getting EFAULT.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230418225343.553806-3-sdf@google.com

diff --git a/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c b/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
index 60d952719d275bc732cecd3de355e14d0e3dbf60..4512dd808c335ee5750466a6804eb67dadfbc10f 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
@@ -3,6 +3,7 @@
 #include "cgroup_helpers.h"
 
 #include <linux/tcp.h>
+#include <linux/netlink.h>
 #include "sockopt_sk.skel.h"
 
 #ifndef SOL_TCP
@@ -183,6 +184,33 @@ static int getsetsockopt(void)
                goto err;
        }
 
+       /* optval=NULL case is handled correctly */
+
+       close(fd);
+       fd = socket(AF_NETLINK, SOCK_RAW, 0);
+       if (fd < 0) {
+               log_err("Failed to create AF_NETLINK socket");
+               return -1;
+       }
+
+       buf.u32 = 1;
+       optlen = sizeof(__u32);
+       err = setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &buf, optlen);
+       if (err) {
+               log_err("Unexpected getsockopt(NETLINK_ADD_MEMBERSHIP) err=%d errno=%d",
+                       err, errno);
+               goto err;
+       }
+
+       optlen = 0;
+       err = getsockopt(fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, NULL, &optlen);
+       if (err) {
+               log_err("Unexpected getsockopt(NETLINK_LIST_MEMBERSHIPS) err=%d errno=%d",
+                       err, errno);
+               goto err;
+       }
+       ASSERT_EQ(optlen, 4, "Unexpected NETLINK_LIST_MEMBERSHIPS value");
+
        free(big_buf);
        close(fd);
        return 0;

diff --git a/tools/testing/selftests/bpf/progs/sockopt_sk.c b/tools/testing/selftests/bpf/progs/sockopt_sk.c
index c8d810010a94674cfd0a827d09e4c7ac9a41b619..fe1df4cd206eb14ad2db24ae5f3a5c0f8a7b3dd4 100644 (file)
--- a/tools/testing/selftests/bpf/progs/sockopt_sk.c
+++ b/tools/testing/selftests/bpf/progs/sockopt_sk.c
@@ -32,6 +32,12 @@ int _getsockopt(struct bpf_sockopt *ctx)
        __u8 *optval_end = ctx->optval_end;
        __u8 *optval = ctx->optval;
        struct sockopt_sk *storage;
+       struct bpf_sock *sk;
+
+       /* Bypass AF_NETLINK. */
+       sk = ctx->sk;
+       if (sk && sk->family == AF_NETLINK)
+               return 1;
 
        /* Make sure bpf_get_netns_cookie is callable.
         */
@@ -131,6 +137,12 @@ int _setsockopt(struct bpf_sockopt *ctx)
        __u8 *optval_end = ctx->optval_end;
        __u8 *optval = ctx->optval;
        struct sockopt_sk *storage;
+       struct bpf_sock *sk;
+
+       /* Bypass AF_NETLINK. */
+       sk = ctx->sk;
+       if (sk && sk->family == AF_NETLINK)
+               return 1;
 
        /* Make sure bpf_get_netns_cookie is callable.
         */