https://github.com/torvalds/linux
Revision 8d650cdedaabb33e85e9b7c517c0c71fcecc1de9 authored by Eric Dumazet on 19 July 2019, 02:28:14 UTC, committed by David S. Miller on 19 July 2019, 03:33:48 UTC
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>
1 parent 269b7c5
Tip revision: 8d650cdedaabb33e85e9b7c517c0c71fcecc1de9 authored by Eric Dumazet on 19 July 2019, 02:28:14 UTC
tcp: fix tcp_set_congestion_control() use from bpf hook
tcp: fix tcp_set_congestion_control() use from bpf hook
Tip revision: 8d650cd
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| .cocciconfig | -rw-r--r-- | 59 bytes |
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| Makefile | -rw-r--r-- | 59.3 KB |
| README | -rw-r--r-- | 727 bytes |
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