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 /security/smack | |
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 'security/smack')
0 files changed, 0 insertions, 0 deletions