From patchwork Sat Jul 2 01:44:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12903868 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 854AEC433EF for ; Sat, 2 Jul 2022 01:45:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230028AbiGBBpa (ORCPT ); Fri, 1 Jul 2022 21:45:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229458AbiGBBp3 (ORCPT ); Fri, 1 Jul 2022 21:45:29 -0400 Received: from smtp-fw-80007.amazon.com (smtp-fw-80007.amazon.com [99.78.197.218]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D173377C5 for ; Fri, 1 Jul 2022 18:45:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1656726328; x=1688262328; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=iSPvtEwqb2farvuP5+K/W2fsoQMcJ6najV1kUHoolTI=; b=TBjcZ/q+QUlPR9Pj6nzKoxc4rmcRRx+XSe8BO7c5XSD9W3iXQwDK4vrm jX456pUsIF2vBOeW2Y0eaOFEcgzcRk0uvl6aD+d1cZXVEzYpF3xaswtMQ IqZ85dI8+DgvUfpT/vshs96G+0qFNxGtPFXd87ZV2kPwMDM9M25Vw3hQp o=; X-IronPort-AV: E=Sophos;i="5.92,238,1650931200"; d="scan'208";a="104212784" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-iad-1e-fc41acad.us-east-1.amazon.com) ([10.25.36.214]) by smtp-border-fw-80007.pdx80.corp.amazon.com with ESMTP; 02 Jul 2022 01:45:11 +0000 Received: from EX13MTAUWB001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-iad-1e-fc41acad.us-east-1.amazon.com (Postfix) with ESMTPS id 91A24C090C; Sat, 2 Jul 2022 01:45:09 +0000 (UTC) Received: from EX13D04ANC001.ant.amazon.com (10.43.157.89) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Sat, 2 Jul 2022 01:45:08 +0000 Received: from 88665a182662.ant.amazon.com (10.43.160.135) by EX13D04ANC001.ant.amazon.com (10.43.157.89) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Sat, 2 Jul 2022 01:45:05 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni CC: Sachin Sant , Leonard Crestez , Nathan Chancellor , "Kuniyuki Iwashima" , Kuniyuki Iwashima , Subject: [PATCH v2 net-next 1/2] af_unix: Put a named socket in the global hash table. Date: Fri, 1 Jul 2022 18:44:46 -0700 Message-ID: <20220702014447.93746-2-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220702014447.93746-1-kuniyu@amazon.com> References: <20220702014447.93746-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.160.135] X-ClientProxiedBy: EX13D13UWA003.ant.amazon.com (10.43.160.181) To EX13D04ANC001.ant.amazon.com (10.43.157.89) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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 whose file was visible even if they were in different network namespaces. The commit puts all sockets into a per-netns hash table. As a result, connect() to a socket in a different netns fails to find the peer and returns -ECONNREFUSED even when the task can view the peer socket file. 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, even if they are visible and connectable, all sockets in different netns 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 sockets in per-netns hash tables and dump them easily. Thanks to 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 Reported-by: Leonard Crestez Tested-by: Sachin Sant Tested-by: Nathan Chancellor Signed-off-by: Kuniyuki Iwashima --- 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__);