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authorPaolo Abeni <pabeni@redhat.com>2021-05-25 14:23:10 -0700
committerDavid S. Miller <davem@davemloft.net>2021-05-25 15:56:20 -0700
commit20b5759f21cf53a0e03031bd3fe539e332b13568 (patch)
tree1e4608d2155e141f7edfd383e65e9e4462f087f8
parentbab09fe2f65200a67209a360988bc24f3de4b95d (diff)
mptcp: avoid OOB access in setsockopt()
We can't use tcp_set_congestion_control() on an mptcp socket, as such function can end-up accessing a tcp-specific field - prior_ssthresh - causing an OOB access. To allow propagating the correct ca algo on subflow, cache the ca name at initialization time. Additionally avoid overriding the user-selected CA (if any) at clone time. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/182 Fixes: aa1fbd94e5c7 ("mptcp: sockopt: add TCP_CONGESTION and TCP_INFO") Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/mptcp/protocol.c14
-rw-r--r--net/mptcp/protocol.h1
-rw-r--r--net/mptcp/sockopt.c4
3 files changed, 14 insertions, 5 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 2d21a4793d9d..2bc199549a88 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2424,13 +2424,12 @@ static int __mptcp_init_sock(struct sock *sk)
timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0);
- tcp_assign_congestion_control(sk);
-
return 0;
}
static int mptcp_init_sock(struct sock *sk)
{
+ struct inet_connection_sock *icsk = inet_csk(sk);
struct net *net = sock_net(sk);
int ret;
@@ -2448,6 +2447,16 @@ static int mptcp_init_sock(struct sock *sk)
if (ret)
return ret;
+ /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
+ * propagate the correct value
+ */
+ tcp_assign_congestion_control(sk);
+ strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name);
+
+ /* no need to keep a reference to the ops, the name will suffice */
+ tcp_cleanup_congestion_control(sk);
+ icsk->icsk_ca_ops = NULL;
+
sk_sockets_allocated_inc(sk);
sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1];
@@ -2622,7 +2631,6 @@ static void __mptcp_destroy_sock(struct sock *sk)
sk_stream_kill_queues(sk);
xfrm_sk_free_policy(sk);
- tcp_cleanup_congestion_control(sk);
sk_refcnt_debug_release(sk);
mptcp_dispose_initial_subflow(msk);
sock_put(sk);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index edc0128730df..165c8b40b384 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -258,6 +258,7 @@ struct mptcp_sock {
} rcvq_space;
u32 setsockopt_seq;
+ char ca_name[TCP_CA_NAME_MAX];
};
#define mptcp_lock_sock(___sk, cb) do { \
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 00d941b66c1e..a79798189599 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -547,7 +547,7 @@ static int mptcp_setsockopt_sol_tcp_congestion(struct mptcp_sock *msk, sockptr_t
}
if (ret == 0)
- tcp_set_congestion_control(sk, name, false, cap_net_admin);
+ strcpy(msk->ca_name, name);
release_sock(sk);
return ret;
@@ -705,7 +705,7 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
sock_valbool_flag(ssk, SOCK_DBG, sock_flag(sk, SOCK_DBG));
if (inet_csk(sk)->icsk_ca_ops != inet_csk(ssk)->icsk_ca_ops)
- tcp_set_congestion_control(ssk, inet_csk(sk)->icsk_ca_ops->name, false, true);
+ tcp_set_congestion_control(ssk, msk->ca_name, false, true);
}
static void __mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)