summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorXin Long <lucien.xin@gmail.com>2018-03-10 18:57:50 +0800
committerDavid S. Miller <davem@davemloft.net>2018-03-12 11:03:42 -0400
commitbf2ae2e4bf9360e07c0cdfa166bcdc0afd92f4ce (patch)
tree2f0c209f6a4056f3b51ecfdceee2a549875e9ece
parent9e5fb7207024e53700bdac23f53d1e44d530a7f6 (diff)
sock_diag: request _diag module only when the family or proto has been registered
Now when using 'ss' in iproute, kernel would try to load all _diag modules, which also causes corresponding family and proto modules to be loaded as well due to module dependencies. Like after running 'ss', sctp, dccp, af_packet (if it works as a module) would be loaded. For example: $ lsmod|grep sctp $ ss $ lsmod|grep sctp sctp_diag 16384 0 sctp 323584 5 sctp_diag inet_diag 24576 4 raw_diag,tcp_diag,sctp_diag,udp_diag libcrc32c 16384 3 nf_conntrack,nf_nat,sctp As these family and proto modules are loaded unintentionally, it could cause some problems, like: - Some debug tools use 'ss' to collect the socket info, which loads all those diag and family and protocol modules. It's noisy for identifying issues. - Users usually expect to drop sctp init packet silently when they have no sense of sctp protocol instead of sending abort back. - It wastes resources (especially with multiple netns), and SCTP module can't be unloaded once it's loaded. ... In short, it's really inappropriate to have these family and proto modules loaded unexpectedly when just doing debugging with inet_diag. This patch is to introduce sock_load_diag_module() where it loads the _diag module only when it's corresponding family or proto has been already registered. Note that we can't just load _diag module without the family or proto loaded, as some symbols used in _diag module are from the family or proto module. v1->v2: - move inet proto check to inet_diag to avoid a compiling err. v2->v3: - define sock_load_diag_module in sock.c and export one symbol only. - improve the changelog. Reported-by: Sabrina Dubroca <sd@queasysnail.net> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Phil Sutter <phil@nwl.cc> Acked-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/net.h1
-rw-r--r--include/net/sock.h1
-rw-r--r--net/core/sock.c21
-rw-r--r--net/core/sock_diag.c12
-rw-r--r--net/ipv4/inet_diag.c3
-rw-r--r--net/socket.c5
6 files changed, 33 insertions, 10 deletions
diff --git a/include/linux/net.h b/include/linux/net.h
index 91216b16feb7..2a0391eea05c 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -222,6 +222,7 @@ enum {
int sock_wake_async(struct socket_wq *sk_wq, int how, int band);
int sock_register(const struct net_proto_family *fam);
void sock_unregister(int family);
+bool sock_is_registered(int family);
int __sock_create(struct net *net, int family, int type, int proto,
struct socket **res, int kern);
int sock_create(int family, int type, int proto, struct socket **res);
diff --git a/include/net/sock.h b/include/net/sock.h
index 169c92afcafa..ae23f3b389ca 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1137,6 +1137,7 @@ struct proto {
int proto_register(struct proto *prot, int alloc_slab);
void proto_unregister(struct proto *prot);
+int sock_load_diag_module(int family, int protocol);
#ifdef SOCK_REFCNT_DEBUG
static inline void sk_refcnt_debug_inc(struct sock *sk)
diff --git a/net/core/sock.c b/net/core/sock.c
index c501499a04fe..85b0b64e7f9d 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3261,6 +3261,27 @@ void proto_unregister(struct proto *prot)
}
EXPORT_SYMBOL(proto_unregister);
+int sock_load_diag_module(int family, int protocol)
+{
+ if (!protocol) {
+ if (!sock_is_registered(family))
+ return -ENOENT;
+
+ return request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
+ NETLINK_SOCK_DIAG, family);
+ }
+
+#ifdef CONFIG_INET
+ if (family == AF_INET &&
+ !rcu_access_pointer(inet_protos[protocol]))
+ return -ENOENT;
+#endif
+
+ return request_module("net-pf-%d-proto-%d-type-%d-%d", PF_NETLINK,
+ NETLINK_SOCK_DIAG, family, protocol);
+}
+EXPORT_SYMBOL(sock_load_diag_module);
+
#ifdef CONFIG_PROC_FS
static void *proto_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(proto_list_mutex)
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 146b50e30659..c37b5be7c5e4 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -220,8 +220,7 @@ static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
return -EINVAL;
if (sock_diag_handlers[req->sdiag_family] == NULL)
- request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
- NETLINK_SOCK_DIAG, req->sdiag_family);
+ sock_load_diag_module(req->sdiag_family, 0);
mutex_lock(&sock_diag_table_mutex);
hndl = sock_diag_handlers[req->sdiag_family];
@@ -247,8 +246,7 @@ static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
case TCPDIAG_GETSOCK:
case DCCPDIAG_GETSOCK:
if (inet_rcv_compat == NULL)
- request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
- NETLINK_SOCK_DIAG, AF_INET);
+ sock_load_diag_module(AF_INET, 0);
mutex_lock(&sock_diag_table_mutex);
if (inet_rcv_compat != NULL)
@@ -281,14 +279,12 @@ static int sock_diag_bind(struct net *net, int group)
case SKNLGRP_INET_TCP_DESTROY:
case SKNLGRP_INET_UDP_DESTROY:
if (!sock_diag_handlers[AF_INET])
- request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
- NETLINK_SOCK_DIAG, AF_INET);
+ sock_load_diag_module(AF_INET, 0);
break;
case SKNLGRP_INET6_TCP_DESTROY:
case SKNLGRP_INET6_UDP_DESTROY:
if (!sock_diag_handlers[AF_INET6])
- request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
- NETLINK_SOCK_DIAG, AF_INET6);
+ sock_load_diag_module(AF_INET6, 0);
break;
}
return 0;
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index a383f299ce24..4e5bc4b2f14e 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -53,8 +53,7 @@ static DEFINE_MUTEX(inet_diag_table_mutex);
static const struct inet_diag_handler *inet_diag_lock_handler(int proto)
{
if (!inet_diag_table[proto])
- request_module("net-pf-%d-proto-%d-type-%d-%d", PF_NETLINK,
- NETLINK_SOCK_DIAG, AF_INET, proto);
+ sock_load_diag_module(AF_INET, proto);
mutex_lock(&inet_diag_table_mutex);
if (!inet_diag_table[proto])
diff --git a/net/socket.c b/net/socket.c
index a93c99b518ca..08847c3b8c39 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2587,6 +2587,11 @@ void sock_unregister(int family)
}
EXPORT_SYMBOL(sock_unregister);
+bool sock_is_registered(int family)
+{
+ return family < NPROTO && rcu_access_pointer(net_families[family]);
+}
+
static int __init sock_init(void)
{
int err;