From 76100a8a64bc2ae898bc49d51dd28c1f4f5ed37b Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Wed, 18 Mar 2015 09:32:57 +0800 Subject: tipc: fix netns refcnt leak When the TIPC module is loaded, we launch a topology server in kernel space, which in its turn is creating TIPC sockets for communication with topology server users. Because both the socket's creator and provider reside in the same module, it is necessary that the TIPC module's reference count remains zero after the server is started and the socket created; otherwise it becomes impossible to perform "rmmod" even on an idle module. Currently, we achieve this by defining a separate "tipc_proto_kern" protocol struct, that is used only for kernel space socket allocations. This structure has the "owner" field set to NULL, which restricts the module reference count from being be bumped when sk_alloc() for local sockets is called. Furthermore, we have defined three kernel-specific functions, tipc_sock_create_local(), tipc_sock_release_local() and tipc_sock_accept_local(), to avoid the module counter being modified when module local sockets are created or deleted. This has worked well until we introduced name space support. However, after name space support was introduced, we have observed that a reference count leak occurs, because the netns counter is not decremented in tipc_sock_delete_local(). This commit remedies this problem. But instead of just modifying tipc_sock_delete_local(), we eliminate the whole parallel socket handling infrastructure, and start using the regular sk_create_kern(), kernel_accept() and sk_release_kernel() calls. Since those functions manipulate the module counter, we must now compensate for that by explicitly decrementing the counter after module local sockets are created, and increment it just before calling sk_release_kernel(). Fixes: a62fbccecd62 ("tipc: make subscriber server support net namespace") Signed-off-by: Ying Xue Reviewed-by: Jon Maloy Reviewed-by: Erik Hugne Reported-by: Cong Wang Tested-by: Erik Hugne Signed-off-by: David S. Miller --- net/tipc/server.c | 44 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 38 insertions(+), 6 deletions(-) (limited to 'net/tipc/server.c') diff --git a/net/tipc/server.c b/net/tipc/server.c index eadd4ed45905..a57c8407cbf3 100644 --- a/net/tipc/server.c +++ b/net/tipc/server.c @@ -37,11 +37,13 @@ #include "core.h" #include "socket.h" #include +#include /* Number of messages to send before rescheduling */ #define MAX_SEND_MSG_COUNT 25 #define MAX_RECV_MSG_COUNT 25 #define CF_CONNECTED 1 +#define CF_SERVER 2 #define sock2con(x) ((struct tipc_conn *)(x)->sk_user_data) @@ -88,9 +90,16 @@ static void tipc_clean_outqueues(struct tipc_conn *con); static void tipc_conn_kref_release(struct kref *kref) { struct tipc_conn *con = container_of(kref, struct tipc_conn, kref); + struct socket *sock = con->sock; + struct sock *sk; - if (con->sock) { - tipc_sock_release_local(con->sock); + if (sock) { + sk = sock->sk; + if (test_bit(CF_SERVER, &con->flags)) { + __module_get(sock->ops->owner); + __module_get(sk->sk_prot_creator->owner); + } + sk_release_kernel(sk); con->sock = NULL; } @@ -281,7 +290,7 @@ static int tipc_accept_from_sock(struct tipc_conn *con) struct tipc_conn *newcon; int ret; - ret = tipc_sock_accept_local(sock, &newsock, O_NONBLOCK); + ret = kernel_accept(sock, &newsock, O_NONBLOCK); if (ret < 0) return ret; @@ -309,9 +318,12 @@ static struct socket *tipc_create_listen_sock(struct tipc_conn *con) struct socket *sock = NULL; int ret; - ret = tipc_sock_create_local(s->net, s->type, &sock); + ret = sock_create_kern(AF_TIPC, SOCK_SEQPACKET, 0, &sock); if (ret < 0) return NULL; + + sk_change_net(sock->sk, s->net); + ret = kernel_setsockopt(sock, SOL_TIPC, TIPC_IMPORTANCE, (char *)&s->imp, sizeof(s->imp)); if (ret < 0) @@ -337,11 +349,31 @@ static struct socket *tipc_create_listen_sock(struct tipc_conn *con) pr_err("Unknown socket type %d\n", s->type); goto create_err; } + + /* As server's listening socket owner and creator is the same module, + * we have to decrease TIPC module reference count to guarantee that + * it remains zero after the server socket is created, otherwise, + * executing "rmmod" command is unable to make TIPC module deleted + * after TIPC module is inserted successfully. + * + * However, the reference count is ever increased twice in + * sock_create_kern(): one is to increase the reference count of owner + * of TIPC socket's proto_ops struct; another is to increment the + * reference count of owner of TIPC proto struct. Therefore, we must + * decrement the module reference count twice to ensure that it keeps + * zero after server's listening socket is created. Of course, we + * must bump the module reference count twice as well before the socket + * is closed. + */ + module_put(sock->ops->owner); + module_put(sock->sk->sk_prot_creator->owner); + set_bit(CF_SERVER, &con->flags); + return sock; create_err: - sock_release(sock); - con->sock = NULL; + kernel_sock_shutdown(sock, SHUT_RDWR); + sk_release_kernel(sock->sk); return NULL; } -- cgit v1.2.3 From 2b9bb7f338502d9d01543daa9fdf4a7f104bd572 Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Wed, 18 Mar 2015 09:32:59 +0800 Subject: tipc: withdraw tipc topology server name when namespace is deleted The TIPC topology server is a per namespace service associated with the tipc name {1, 1}. When a namespace is deleted, that name must be withdrawn before we call sk_release_kernel because the kernel socket release is done in init_net and trying to withdraw a TIPC name published in another namespace will fail with an error as: [ 170.093264] Unable to remove local publication [ 170.093264] (type=1, lower=1, ref=2184244004, key=2184244005) We fix this by breaking the association between the topology server name and socket before calling sk_release_kernel. Signed-off-by: Ying Xue Reviewed-by: Erik Hugne Signed-off-by: David S. Miller --- net/tipc/server.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/tipc/server.c') diff --git a/net/tipc/server.c b/net/tipc/server.c index a57c8407cbf3..ab6183cdb121 100644 --- a/net/tipc/server.c +++ b/net/tipc/server.c @@ -90,6 +90,7 @@ static void tipc_clean_outqueues(struct tipc_conn *con); static void tipc_conn_kref_release(struct kref *kref) { struct tipc_conn *con = container_of(kref, struct tipc_conn, kref); + struct sockaddr_tipc *saddr = con->server->saddr; struct socket *sock = con->sock; struct sock *sk; @@ -99,6 +100,8 @@ static void tipc_conn_kref_release(struct kref *kref) __module_get(sock->ops->owner); __module_get(sk->sk_prot_creator->owner); } + saddr->scope = -TIPC_NODE_SCOPE; + kernel_bind(sock, (struct sockaddr *)saddr, sizeof(*saddr)); sk_release_kernel(sk); con->sock = NULL; } -- cgit v1.2.3 From def81f69bfbd70a3278a7592a4ab8717300cbac1 Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Thu, 23 Apr 2015 09:37:38 -0400 Subject: tipc: fix topology server broken issue When a new topology server is launched in a new namespace, its listening socket is inserted into the "init ns" namespace's socket hash table rather than the one owned by the new namespace. Although the socket's namespace is forcedly changed to the new namespace later, the socket is still stored in the socket hash table of "init ns" namespace. When a client created in the new namespace connects its own topology server, the connection is failed as its server's socket could not be found from its own namespace's socket table. If __sock_create() instead of original sock_create_kern() is used to create the server's socket through specifying an expected namesapce, the socket will be inserted into the specified namespace's socket table, thereby avoiding to the topology server broken issue. Fixes: 76100a8a64bc ("tipc: fix netns refcnt leak") Reported-by: Erik Hugne Signed-off-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/server.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'net/tipc/server.c') diff --git a/net/tipc/server.c b/net/tipc/server.c index ab6183cdb121..77ff03ed1e18 100644 --- a/net/tipc/server.c +++ b/net/tipc/server.c @@ -102,7 +102,7 @@ static void tipc_conn_kref_release(struct kref *kref) } saddr->scope = -TIPC_NODE_SCOPE; kernel_bind(sock, (struct sockaddr *)saddr, sizeof(*saddr)); - sk_release_kernel(sk); + sock_release(sock); con->sock = NULL; } @@ -321,12 +321,9 @@ static struct socket *tipc_create_listen_sock(struct tipc_conn *con) struct socket *sock = NULL; int ret; - ret = sock_create_kern(AF_TIPC, SOCK_SEQPACKET, 0, &sock); + ret = __sock_create(s->net, AF_TIPC, SOCK_SEQPACKET, 0, &sock, 1); if (ret < 0) return NULL; - - sk_change_net(sock->sk, s->net); - ret = kernel_setsockopt(sock, SOL_TIPC, TIPC_IMPORTANCE, (char *)&s->imp, sizeof(s->imp)); if (ret < 0) @@ -376,7 +373,7 @@ static struct socket *tipc_create_listen_sock(struct tipc_conn *con) create_err: kernel_sock_shutdown(sock, SHUT_RDWR); - sk_release_kernel(sock->sk); + sock_release(sock); return NULL; } -- cgit v1.2.3