From 037b0b86ecf5646f8eae777d8b52ff8b401692ec Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 16 Aug 2018 21:49:06 +0200 Subject: tcp, ulp: add alias for all ulp modules Lets not turn the TCP ULP lookup into an arbitrary module loader as we only intend to load ULP modules through this mechanism, not other unrelated kernel modules: [root@bar]# cat foo.c #include #include #include #include int main(void) { int sock = socket(PF_INET, SOCK_STREAM, 0); setsockopt(sock, IPPROTO_TCP, TCP_ULP, "sctp", sizeof("sctp")); return 0; } [root@bar]# gcc foo.c -O2 -Wall [root@bar]# lsmod | grep sctp [root@bar]# ./a.out [root@bar]# lsmod | grep sctp sctp 1077248 4 libcrc32c 16384 3 nf_conntrack,nf_nat,sctp [root@bar]# Fix it by adding module alias to TCP ULP modules, so probing module via request_module() will be limited to tcp-ulp-[name]. The existing modules like kTLS will load fine given tcp-ulp-tls alias, but others will fail to load: [root@bar]# lsmod | grep sctp [root@bar]# ./a.out [root@bar]# lsmod | grep sctp [root@bar]# Sockmap is not affected from this since it's either built-in or not. Fixes: 734942cc4ea6 ("tcp: ULP infrastructure") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Song Liu Signed-off-by: Alexei Starovoitov --- net/ipv4/tcp_ulp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/ipv4/tcp_ulp.c') diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c index 622caa4039e0..7dd44b6156c7 100644 --- a/net/ipv4/tcp_ulp.c +++ b/net/ipv4/tcp_ulp.c @@ -51,7 +51,7 @@ static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name) #ifdef CONFIG_MODULES if (!ulp && capable(CAP_NET_ADMIN)) { rcu_read_unlock(); - request_module("%s", name); + request_module("tcp-ulp-%s", name); rcu_read_lock(); ulp = tcp_ulp_find(name); } -- cgit v1.2.3 From 90545cdc3f2b2ea700e24335610cd181e73756da Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 16 Aug 2018 21:49:07 +0200 Subject: tcp, ulp: fix leftover icsk_ulp_ops preventing sock from reattach I found that in BPF sockmap programs once we either delete a socket from the map or we updated a map slot and the old socket was purged from the map that these socket can never get reattached into a map even though their related psock has been dropped entirely at that point. Reason is that tcp_cleanup_ulp() leaves the old icsk->icsk_ulp_ops intact, so that on the next tcp_set_ulp_id() the kernel returns an -EEXIST thinking there is still some active ULP attached. BPF sockmap is the only one that has this issue as the other user, kTLS, only calls tcp_cleanup_ulp() from tcp_v4_destroy_sock() whereas sockmap semantics allow dropping the socket from the map with all related psock state being cleaned up. Fixes: 1aa12bdf1bfb ("bpf: sockmap, add sock close() hook to remove socks") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Song Liu Signed-off-by: Alexei Starovoitov --- net/ipv4/tcp_ulp.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/ipv4/tcp_ulp.c') diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c index 7dd44b6156c7..a5995bb2eaca 100644 --- a/net/ipv4/tcp_ulp.c +++ b/net/ipv4/tcp_ulp.c @@ -129,6 +129,8 @@ void tcp_cleanup_ulp(struct sock *sk) if (icsk->icsk_ulp_ops->release) icsk->icsk_ulp_ops->release(sk); module_put(icsk->icsk_ulp_ops->owner); + + icsk->icsk_ulp_ops = NULL; } /* Change upper layer protocol for socket */ -- cgit v1.2.3