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authorEric Dumazet <edumazet@google.com>2019-07-18 19:28:14 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-31 07:28:46 +0200
commitadcac7370d7d9c6c8f58c590fff117d95c65fb61 (patch)
tree29f1e5f21b991129e9b050331ff2a312f10fa810 /include
parent8cf295c38ddeb44806fd71a8363cce9914a52bc4 (diff)
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tcp: fix tcp_set_congestion_control() use from bpf hook
[ Upstream commit 8d650cdedaabb33e85e9b7c517c0c71fcecc1de9 ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/net/tcp.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 1179ef4f0768..0b477a1e1177 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1043,7 +1043,8 @@ void tcp_get_default_congestion_control(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);