[PATCH 4.14 044/115] tcp, ulp: add alias for all ulp modules

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>

[ Upstream commit 037b0b86ecf5646f8eae777d8b52ff8b401692ec ]

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 <sys/types.h>
  #include <sys/socket.h>
  #include <linux/tcp.h>
  #include <linux/in.h>

  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 <daniel@xxxxxxxxxxxxx>
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 include/net/tcp.h  |    4 ++++
 net/ipv4/tcp_ulp.c |    2 +-
 net/tls/tls_main.c |    1 +
 3 files changed, 6 insertions(+), 1 deletion(-)

--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2063,6 +2063,10 @@ int tcp_set_ulp(struct sock *sk, const c
 void tcp_get_available_ulp(char *buf, size_t len);
 void tcp_cleanup_ulp(struct sock *sk);
 
+#define MODULE_ALIAS_TCP_ULP(name)				\
+	__MODULE_INFO(alias, alias_userspace, name);		\
+	__MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name)
+
 /* Call BPF_SOCK_OPS program that returns an int. If the return value
  * is < 0, then the BPF op failed (for example if the loaded BPF
  * program does not support the chosen operation or there is no BPF
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -39,7 +39,7 @@ static const struct tcp_ulp_ops *__tcp_u
 #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);
 	}
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -44,6 +44,7 @@
 MODULE_AUTHOR("Mellanox Technologies");
 MODULE_DESCRIPTION("Transport Layer Security Support");
 MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS_TCP_ULP("tls");
 
 static struct proto tls_base_prot;
 static struct proto tls_sw_prot;