Skip to content

L
linux
Switch branch/tag
  1. 07 Jan, 2022 4 commits
    • Alexei Starovoitov's avatar
      Merge branch 'net: bpf: handle return value of post_bind{4,6} and add selftests for it' · eff14fcd
      Alexei Starovoitov authored 
      Menglong Dong says:

====================

From: Menglong Dong <imagedong@tencent.com>

The return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND() in
__inet_bind() is not handled properly. While the return value
is non-zero, it will set inet_saddr and inet_rcv_saddr to 0 and
exit:

        err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk);
        if (err) {
                inet->inet_saddr = inet->inet_rcv_saddr = 0;
                goto out_release_sock;
        }

Let's take UDP for example and see what will happen. For UDP
socket, it will be added to 'udp_prot.h.udp_table->hash' and
'udp_prot.h.udp_table->hash2' after the sk->sk_prot->get_port()
called success. If 'inet->inet_rcv_saddr' is specified here,
then 'sk' will be in the 'hslot2' of 'hash2' that it don't belong
to (because inet_saddr is changed to 0), and UDP packet received
will not be passed to this sock. If 'inet->inet_rcv_saddr' is not
specified here, the sock will work fine, as it can receive packet
properly, which is wired, as the 'bind()' is already failed.

To undo the get_port() operation, introduce the 'put_port' field
for 'struct proto'. For TCP proto, it is inet_put_port(); For UDP
proto, it is udp_lib_unhash(); For icmp proto, it is
ping_unhash().

Therefore, after sys_bind() fail caused by
BPF_CGROUP_RUN_PROG_INET4_POST_BIND(), it will be unbinded, which
means that it can try to be binded to another port.

The second patch use C99 initializers in test_sock.c

The third patch is the selftests for this modification.

Changes since v4:
- use C99 initializers in test_sock.c before adding the test case

Changes since v3:
- add the third patch which use C99 initializers in test_sock.c

Changes since v2:
- NULL check for sk->sk_prot->put_port

Changes since v1:
- introduce 'put_port' field for 'struct proto'
- add selftests for it
====================
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      eff14fcd
    • Menglong Dong's avatar
      bpf: selftests: Add bind retry for post_bind{4, 6} · f7342481
      Menglong Dong authored 
      With previous patch, kernel is able to 'put_port' after sys_bind()
fails. Add the test for that case: rebind another port after
sys_bind() fails. If the bind success, it means previous bind
operation is already undoed.
Signed-off-by: default avatarMenglong Dong <imagedong@tencent.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220106132022.3470772-4-imagedong@tencent.com
      f7342481
    • Menglong Dong's avatar
      bpf: selftests: Use C99 initializers in test_sock.c · 6fd92c7f
      Menglong Dong authored 
      Use C99 initializers for the initialization of 'tests' in test_sock.c.
Signed-off-by: default avatarMenglong Dong <imagedong@tencent.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220106132022.3470772-3-imagedong@tencent.com
      6fd92c7f
    • Menglong Dong's avatar
      net: bpf: Handle return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND() · 91a760b2
      Menglong Dong authored 
      The return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND() in
__inet_bind() is not handled properly. While the return value
is non-zero, it will set inet_saddr and inet_rcv_saddr to 0 and
exit:

	err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk);
	if (err) {
		inet->inet_saddr = inet->inet_rcv_saddr = 0;
		goto out_release_sock;
	}

Let's take UDP for example and see what will happen. For UDP
socket, it will be added to 'udp_prot.h.udp_table->hash' and
'udp_prot.h.udp_table->hash2' after the sk->sk_prot->get_port()
called success. If 'inet->inet_rcv_saddr' is specified here,
then 'sk' will be in the 'hslot2' of 'hash2' that it don't belong
to (because inet_saddr is changed to 0), and UDP packet received
will not be passed to this sock. If 'inet->inet_rcv_saddr' is not
specified here, the sock will work fine, as it can receive packet
properly, which is wired, as the 'bind()' is already failed.

To undo the get_port() operation, introduce the 'put_port' field
for 'struct proto'. For TCP proto, it is inet_put_port(); For UDP
proto, it is udp_lib_unhash(); For icmp proto, it is
ping_unhash().

Therefore, after sys_bind() fail caused by
BPF_CGROUP_RUN_PROG_INET4_POST_BIND(), it will be unbinded, which
means that it can try to be binded to another port.
Signed-off-by: default avatarMenglong Dong <imagedong@tencent.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220106132022.3470772-2-imagedong@tencent.com
      91a760b2
  3. 06 Jan, 2022 18 commits
  5. 05 Jan, 2022 18 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7