diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-07-19 05:28:14 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-07-19 06:33:48 +0300 |
| commit | 8d650cdedaabb33e85e9b7c517c0c71fcecc1de9 (patch) | |
| tree | ab0428e5e973eb2b4e8b1f4859a508e2c0d07859 /include/net | |
| parent | 269b7c5ff78264e3728b95828d219e0e0eeaec94 (diff) | |
| download | linux-8d650cdedaabb33e85e9b7c517c0c71fcecc1de9.tar.xz | |
tcp: fix tcp_set_congestion_control() use from bpf hook
Neal reported incorrect use of ns_capable() from bpf hook.
bpf_setsockopt(...TCP_CONGESTION...)
-> tcp_set_congestion_control()
-> ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)
-> ns_capable_common()
-> current_cred()
-> rcu_dereference_protected(current->cred, 1)
Accessing 'current' in bpf context makes no sense, since packets
are processed from softirq context.
As Neal stated : The capability check in tcp_set_congestion_control()
was written assuming a system call context, and then was reused from
a BPF call site.
The fix is to add a new parameter to tcp_set_congestion_control(),
so that the ns_capable() call is only performed under the right
context.
Fixes: 91b5b21c7c16 ("bpf: Add support for changing congestion control")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Lawrence Brakmo <brakmo@fb.com>
Reported-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/tcp.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index cca3c59b98bf..f42d300f0cfa 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1064,7 +1064,8 @@ void tcp_get_default_congestion_control(struct net *net, char *name); void tcp_get_available_congestion_control(char *buf, size_t len); void tcp_get_allowed_congestion_control(char *buf, size_t len); int tcp_set_allowed_congestion_control(char *allowed); -int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, bool reinit); +int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, + bool reinit, bool cap_net_admin); u32 tcp_slow_start(struct tcp_sock *tp, u32 acked); void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked); |