| Message ID | 20220701072519.96097-1-kuniyu@amazon.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v1,net-next] af_unix: Put a named socket in the global hash table. | expand |
> Note when dumping sockets by sock_diag, procfs, and bpf_iter, they are > filtered only by netns. In other words, sockets with different netns > and the same mount ns are skipped while iterating sockets. Thus, we > need a fix only for finding a peer socket. > > This patch adds a global hash table for named sockets, links them with > sk_bind_node, and uses it in unix_find_socket_byinode(). By doing so, > we can keep all sockets in per-netns hash tables and dump them easily. > > Thank Sachin Sant and Leonard Crestez for reports, logs and a reproducer. > > Fixes: cf2f225e2653 ("af_unix: Put a socket into a per-netns hash table.") > Reported-by: Sachin Sant <sachinp@linux.ibm.com> > Reported-by: Leonard Crestez <cdleonard@gmail.com> > Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> > --- > net/unix/af_unix.c | 47 ++++++++++++++++++++++++++++++++++++---------- > 1 file changed, 37 insertions(+), 10 deletions(-) > Thanks for the fix. The patch fixes the reported problem. Tested-by: Sachin Sant <sachinp@linux.ibm.com> - Sachin
On Fri, Jul 1, 2022 at 9:25 AM Kuniyuki Iwashima <kuniyu@amazon.com> wrote: > > Commit cf2f225e2653 ("af_unix: Put a socket into a per-netns hash > table.") accidentally broke user API for named sockets. A named > socket was able to connect() to a peer in the same mount namespace > even if they were in different network namespaces. > > The commit put all sockets into each per-netns hash table. As a > result, connect() to a socket in a different netns failed to find > the peer and returned -ECONNREFUSED even when they had the same > mount namespace. > > We can reproduce this issue by > > Console A: > > # python3 > >>> from socket import * > >>> s = socket(AF_UNIX, SOCK_STREAM, 0) > >>> s.bind('test') > >>> s.listen(32) > > Console B: > > # ip netns add test > # ip netns exec test sh > # python3 > >>> from socket import * > >>> s = socket(AF_UNIX, SOCK_STREAM, 0) > >>> s.connect('test') > I think this deserves a new test perhaps...
From: Eric Dumazet <edumazet@google.com> Date: Fri, 1 Jul 2022 18:36:21 +0200 > On Fri, Jul 1, 2022 at 9:25 AM Kuniyuki Iwashima <kuniyu@amazon.com> wrote: > > > > Commit cf2f225e2653 ("af_unix: Put a socket into a per-netns hash > > table.") accidentally broke user API for named sockets. A named > > socket was able to connect() to a peer in the same mount namespace > > even if they were in different network namespaces. > > > > The commit put all sockets into each per-netns hash table. As a > > result, connect() to a socket in a different netns failed to find > > the peer and returned -ECONNREFUSED even when they had the same > > mount namespace. > > > > We can reproduce this issue by > > > > Console A: > > > > # python3 > > >>> from socket import * > > >>> s = socket(AF_UNIX, SOCK_STREAM, 0) > > >>> s.bind('test') > > >>> s.listen(32) > > > > Console B: > > > > # ip netns add test > > # ip netns exec test sh > > # python3 > > >>> from socket import * > > >>> s = socket(AF_UNIX, SOCK_STREAM, 0) > > >>> s.connect('test') > > > > I think this deserves a new test perhaps... Exactly. I will add a selftest in v2. Thank you.
On Fri, Jul 01, 2022 at 12:25:19AM -0700, Kuniyuki Iwashima wrote: > Commit cf2f225e2653 ("af_unix: Put a socket into a per-netns hash > table.") accidentally broke user API for named sockets. A named > socket was able to connect() to a peer in the same mount namespace > even if they were in different network namespaces. > > The commit put all sockets into each per-netns hash table. As a > result, connect() to a socket in a different netns failed to find > the peer and returned -ECONNREFUSED even when they had the same > mount namespace. > > We can reproduce this issue by > > Console A: > > # python3 > >>> from socket import * > >>> s = socket(AF_UNIX, SOCK_STREAM, 0) > >>> s.bind('test') > >>> s.listen(32) > > Console B: > > # ip netns add test > # ip netns exec test sh > # python3 > >>> from socket import * > >>> s = socket(AF_UNIX, SOCK_STREAM, 0) > >>> s.connect('test') > > Note when dumping sockets by sock_diag, procfs, and bpf_iter, they are > filtered only by netns. In other words, sockets with different netns > and the same mount ns are skipped while iterating sockets. Thus, we > need a fix only for finding a peer socket. > > This patch adds a global hash table for named sockets, links them with > sk_bind_node, and uses it in unix_find_socket_byinode(). By doing so, > we can keep all sockets in per-netns hash tables and dump them easily. > > Thank Sachin Sant and Leonard Crestez for reports, logs and a reproducer. > > Fixes: cf2f225e2653 ("af_unix: Put a socket into a per-netns hash table.") > Reported-by: Sachin Sant <sachinp@linux.ibm.com> > Reported-by: Leonard Crestez <cdleonard@gmail.com> > Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> I noticed that all my test systems failed to start systemd-hostnamed during boot, which I bisected to cf2f225e2653. This patch resolves the problem for me as well. Tested-by: Nathan Chancellor <nathan@kernel.org> > --- > net/unix/af_unix.c | 47 ++++++++++++++++++++++++++++++++++++---------- > 1 file changed, 37 insertions(+), 10 deletions(-) > > diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c > index 49f6626330c3..526b872cc710 100644 > --- a/net/unix/af_unix.c > +++ b/net/unix/af_unix.c > @@ -119,6 +119,8 @@ > #include "scm.h" > > static atomic_long_t unix_nr_socks; > +static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2]; > +static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2]; > > /* SMP locking strategy: > * hash table is protected with spinlock. > @@ -328,6 +330,24 @@ static void unix_insert_unbound_socket(struct net *net, struct sock *sk) > spin_unlock(&net->unx.table.locks[sk->sk_hash]); > } > > +static void unix_insert_bsd_socket(struct sock *sk) > +{ > + spin_lock(&bsd_socket_locks[sk->sk_hash]); > + sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]); > + spin_unlock(&bsd_socket_locks[sk->sk_hash]); > +} > + > +static void unix_remove_bsd_socket(struct sock *sk) > +{ > + if (!hlist_unhashed(&sk->sk_bind_node)) { > + spin_lock(&bsd_socket_locks[sk->sk_hash]); > + __sk_del_bind_node(sk); > + spin_unlock(&bsd_socket_locks[sk->sk_hash]); > + > + sk_node_init(&sk->sk_bind_node); > + } > +} > + > static struct sock *__unix_find_socket_byname(struct net *net, > struct sockaddr_un *sunname, > int len, unsigned int hash) > @@ -358,22 +378,22 @@ static inline struct sock *unix_find_socket_byname(struct net *net, > return s; > } > > -static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i) > +static struct sock *unix_find_socket_byinode(struct inode *i) > { > unsigned int hash = unix_bsd_hash(i); > struct sock *s; > > - spin_lock(&net->unx.table.locks[hash]); > - sk_for_each(s, &net->unx.table.buckets[hash]) { > + spin_lock(&bsd_socket_locks[hash]); > + sk_for_each_bound(s, &bsd_socket_buckets[hash]) { > struct dentry *dentry = unix_sk(s)->path.dentry; > > if (dentry && d_backing_inode(dentry) == i) { > sock_hold(s); > - spin_unlock(&net->unx.table.locks[hash]); > + spin_unlock(&bsd_socket_locks[hash]); > return s; > } > } > - spin_unlock(&net->unx.table.locks[hash]); > + spin_unlock(&bsd_socket_locks[hash]); > return NULL; > } > > @@ -577,6 +597,7 @@ static void unix_release_sock(struct sock *sk, int embrion) > int state; > > unix_remove_socket(sock_net(sk), sk); > + unix_remove_bsd_socket(sk); > > /* Clear state */ > unix_state_lock(sk); > @@ -988,8 +1009,8 @@ static int unix_release(struct socket *sock) > return 0; > } > > -static struct sock *unix_find_bsd(struct net *net, struct sockaddr_un *sunaddr, > - int addr_len, int type) > +static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len, > + int type) > { > struct inode *inode; > struct path path; > @@ -1010,7 +1031,7 @@ static struct sock *unix_find_bsd(struct net *net, struct sockaddr_un *sunaddr, > if (!S_ISSOCK(inode->i_mode)) > goto path_put; > > - sk = unix_find_socket_byinode(net, inode); > + sk = unix_find_socket_byinode(inode); > if (!sk) > goto path_put; > > @@ -1058,7 +1079,7 @@ static struct sock *unix_find_other(struct net *net, > struct sock *sk; > > if (sunaddr->sun_path[0]) > - sk = unix_find_bsd(net, sunaddr, addr_len, type); > + sk = unix_find_bsd(sunaddr, addr_len, type); > else > sk = unix_find_abstract(net, sunaddr, addr_len, type); > > @@ -1179,6 +1200,7 @@ static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr, > u->path.dentry = dget(dentry); > __unix_set_addr_hash(net, sk, addr, new_hash); > unix_table_double_unlock(net, old_hash, new_hash); > + unix_insert_bsd_socket(sk); > mutex_unlock(&u->bindlock); > done_path_create(&parent, dentry); > return 0; > @@ -3682,10 +3704,15 @@ static void __init bpf_iter_register(void) > > static int __init af_unix_init(void) > { > - int rc = -1; > + int i, rc = -1; > > BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb)); > > + for (i = 0; i < UNIX_HASH_SIZE / 2; i++) { > + spin_lock_init(&bsd_socket_locks[i]); > + INIT_HLIST_HEAD(&bsd_socket_buckets[i]); > + } > + > rc = proto_register(&unix_dgram_proto, 1); > if (rc != 0) { > pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__); > -- > 2.30.2 > >
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 49f6626330c3..526b872cc710 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -119,6 +119,8 @@ #include "scm.h" static atomic_long_t unix_nr_socks; +static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2]; +static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2]; /* SMP locking strategy: * hash table is protected with spinlock. @@ -328,6 +330,24 @@ static void unix_insert_unbound_socket(struct net *net, struct sock *sk) spin_unlock(&net->unx.table.locks[sk->sk_hash]); } +static void unix_insert_bsd_socket(struct sock *sk) +{ + spin_lock(&bsd_socket_locks[sk->sk_hash]); + sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]); + spin_unlock(&bsd_socket_locks[sk->sk_hash]); +} + +static void unix_remove_bsd_socket(struct sock *sk) +{ + if (!hlist_unhashed(&sk->sk_bind_node)) { + spin_lock(&bsd_socket_locks[sk->sk_hash]); + __sk_del_bind_node(sk); + spin_unlock(&bsd_socket_locks[sk->sk_hash]); + + sk_node_init(&sk->sk_bind_node); + } +} + static struct sock *__unix_find_socket_byname(struct net *net, struct sockaddr_un *sunname, int len, unsigned int hash) @@ -358,22 +378,22 @@ static inline struct sock *unix_find_socket_byname(struct net *net, return s; } -static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i) +static struct sock *unix_find_socket_byinode(struct inode *i) { unsigned int hash = unix_bsd_hash(i); struct sock *s; - spin_lock(&net->unx.table.locks[hash]); - sk_for_each(s, &net->unx.table.buckets[hash]) { + spin_lock(&bsd_socket_locks[hash]); + sk_for_each_bound(s, &bsd_socket_buckets[hash]) { struct dentry *dentry = unix_sk(s)->path.dentry; if (dentry && d_backing_inode(dentry) == i) { sock_hold(s); - spin_unlock(&net->unx.table.locks[hash]); + spin_unlock(&bsd_socket_locks[hash]); return s; } } - spin_unlock(&net->unx.table.locks[hash]); + spin_unlock(&bsd_socket_locks[hash]); return NULL; } @@ -577,6 +597,7 @@ static void unix_release_sock(struct sock *sk, int embrion) int state; unix_remove_socket(sock_net(sk), sk); + unix_remove_bsd_socket(sk); /* Clear state */ unix_state_lock(sk); @@ -988,8 +1009,8 @@ static int unix_release(struct socket *sock) return 0; } -static struct sock *unix_find_bsd(struct net *net, struct sockaddr_un *sunaddr, - int addr_len, int type) +static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len, + int type) { struct inode *inode; struct path path; @@ -1010,7 +1031,7 @@ static struct sock *unix_find_bsd(struct net *net, struct sockaddr_un *sunaddr, if (!S_ISSOCK(inode->i_mode)) goto path_put; - sk = unix_find_socket_byinode(net, inode); + sk = unix_find_socket_byinode(inode); if (!sk) goto path_put; @@ -1058,7 +1079,7 @@ static struct sock *unix_find_other(struct net *net, struct sock *sk; if (sunaddr->sun_path[0]) - sk = unix_find_bsd(net, sunaddr, addr_len, type); + sk = unix_find_bsd(sunaddr, addr_len, type); else sk = unix_find_abstract(net, sunaddr, addr_len, type); @@ -1179,6 +1200,7 @@ static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr, u->path.dentry = dget(dentry); __unix_set_addr_hash(net, sk, addr, new_hash); unix_table_double_unlock(net, old_hash, new_hash); + unix_insert_bsd_socket(sk); mutex_unlock(&u->bindlock); done_path_create(&parent, dentry); return 0; @@ -3682,10 +3704,15 @@ static void __init bpf_iter_register(void) static int __init af_unix_init(void) { - int rc = -1; + int i, rc = -1; BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb)); + for (i = 0; i < UNIX_HASH_SIZE / 2; i++) { + spin_lock_init(&bsd_socket_locks[i]); + INIT_HLIST_HEAD(&bsd_socket_buckets[i]); + } + rc = proto_register(&unix_dgram_proto, 1); if (rc != 0) { pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
Commit cf2f225e2653 ("af_unix: Put a socket into a per-netns hash table.") accidentally broke user API for named sockets. A named socket was able to connect() to a peer in the same mount namespace even if they were in different network namespaces. The commit put all sockets into each per-netns hash table. As a result, connect() to a socket in a different netns failed to find the peer and returned -ECONNREFUSED even when they had the same mount namespace. We can reproduce this issue by Console A: # python3 >>> from socket import * >>> s = socket(AF_UNIX, SOCK_STREAM, 0) >>> s.bind('test') >>> s.listen(32) Console B: # ip netns add test # ip netns exec test sh # python3 >>> from socket import * >>> s = socket(AF_UNIX, SOCK_STREAM, 0) >>> s.connect('test') Note when dumping sockets by sock_diag, procfs, and bpf_iter, they are filtered only by netns. In other words, sockets with different netns and the same mount ns are skipped while iterating sockets. Thus, we need a fix only for finding a peer socket. This patch adds a global hash table for named sockets, links them with sk_bind_node, and uses it in unix_find_socket_byinode(). By doing so, we can keep all sockets in per-netns hash tables and dump them easily. Thank Sachin Sant and Leonard Crestez for reports, logs and a reproducer. Fixes: cf2f225e2653 ("af_unix: Put a socket into a per-netns hash table.") Reported-by: Sachin Sant <sachinp@linux.ibm.com> Reported-by: Leonard Crestez <cdleonard@gmail.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> --- net/unix/af_unix.c | 47 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 37 insertions(+), 10 deletions(-)