From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A3FEC169C4 for ; Thu, 31 Jan 2019 16:47:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8E6C2086C for ; Thu, 31 Jan 2019 16:47:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="mof2j6of" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732651AbfAaQrO (ORCPT ); Thu, 31 Jan 2019 11:47:14 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:41180 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732391AbfAaQrO (ORCPT ); Thu, 31 Jan 2019 11:47:14 -0500 Received: by mail-pl1-f193.google.com with SMTP id u6so1712784plm.8 for ; Thu, 31 Jan 2019 08:47:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=ZOOOBFsewTuyTgDTDifSOGtEkOJeW3GI6CJc92lniDA=; b=mof2j6ofqCZ+2eBpOqyjzqY0Je/OX9D9ymq50uJN6hcJpKIWYx73p20JSt6HY7lulm ziaPha3rM19Ph5UfL5jQDHaQPhMieg8xhz9RICAPAL+wHKiFqmzmLeEYxBKdvujYZVnf 0kRnTIi2dJkR+g4sVDZ1oRZ9jEMA1lz+oVGAZk5zTnwMqbIalNI7EqjDsTezR4Ol9HWy /vUAJiaguhktu0GkYaRjyB1vHYBCZHqAv2RDaIs+AsfH1MGKF2q+M1wsfLuSqoB2Sfxv eGTqpiRhkO+hw6pMQrsKM7sE9iqQD1FZC4pSz9Oyd/thFBqQEg8h3EnwNUteRnOASs9/ sh2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=ZOOOBFsewTuyTgDTDifSOGtEkOJeW3GI6CJc92lniDA=; b=fA68hDY9fJt09ZeoV0iHVSYTSB/vmQAYL3+XuO4ezKQicq29eqTviBHUadszNk1CbE qEh5KBxxZupF2X1IqgWusFLOjIHvMyjl+KGg8bALhms94bKk64pOQUuttkl9ISKqg5Ne c/XStMVCPeO+ejU7s8fD7g0bYUSLCPEczwVJv5R4yMJedyvIQNcmZ9WZxZk54Zq3Q1Xt 213eID/MD7wB4cqLv9dRBR/UzhSlFOFNoFnwZbN2sQAVgESuB+ovNHSc1O29SCQAT1/g K9jtpnILIKyK9SiJfaVpd0/oq5FX+dUdQCmYfcy9EfwZb4zv9DWW31JkS8HQV78Z4lKn U6Wg== X-Gm-Message-State: AJcUukfB5z4rCVeV0J6Q+bZhGTIOUNoBrk45EKfSdynx91yU/Uw41SWT gOYpurj4GIGXUDVv7izWedA2XJVLeOM= X-Google-Smtp-Source: ALg8bN6k32e39M9SB9UQxxlefg6V9RibSWk0h3EMm9XEkoIjpAFDkzJ8PQuobvB67QBeeU0LP3vptw== X-Received: by 2002:a17:902:a411:: with SMTP id p17mr35114441plq.292.1548953232803; Thu, 31 Jan 2019 08:47:12 -0800 (PST) Received: from localhost ([2620:15c:2c4:201:f5a:7eca:440a:3ead]) by smtp.gmail.com with ESMTPSA id h15sm8902366pgl.43.2019.01.31.08.47.11 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 31 Jan 2019 08:47:11 -0800 (PST) From: Eric Dumazet To: "David S . Miller" Cc: netdev , Eric Dumazet , Eric Dumazet , syzbot , Sowmini Varadhan , Santosh Shilimkar , rds-devel@oss.oracle.com, Cong Wang Subject: [PATCH net] rds: fix refcount bug in rds_sock_addref Date: Thu, 31 Jan 2019 08:47:10 -0800 Message-Id: <20190131164710.230590-1-edumazet@google.com> X-Mailer: git-send-email 2.20.1.495.gaa96b0ce6b-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot was able to catch a bug in rds [1] The issue here is that the socket might be found in a hash table but that its refcount has already be set to 0 by another cpu. We need to use refcount_inc_not_zero() to be safe here. [1] refcount_t: increment on 0; use-after-free. WARNING: CPU: 1 PID: 23129 at lib/refcount.c:153 refcount_inc_checked lib/refcount.c:153 [inline] WARNING: CPU: 1 PID: 23129 at lib/refcount.c:153 refcount_inc_checked+0x61/0x70 lib/refcount.c:151 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 23129 Comm: syz-executor3 Not tainted 5.0.0-rc4+ #53 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 panic+0x2cb/0x65c kernel/panic.c:214 __warn.cold+0x20/0x48 kernel/panic.c:571 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:refcount_inc_checked lib/refcount.c:153 [inline] RIP: 0010:refcount_inc_checked+0x61/0x70 lib/refcount.c:151 Code: 1d 51 63 c8 06 31 ff 89 de e8 eb 1b f2 fd 84 db 75 dd e8 a2 1a f2 fd 48 c7 c7 60 9f 81 88 c6 05 31 63 c8 06 01 e8 af 65 bb fd <0f> 0b eb c1 90 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 54 49 RSP: 0018:ffff8880a0cbf1e8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90006113000 RDX: 000000000001047d RSI: ffffffff81685776 RDI: 0000000000000005 RBP: ffff8880a0cbf1f8 R08: ffff888097c9e100 R09: ffffed1015ce5021 R10: ffffed1015ce5020 R11: ffff8880ae728107 R12: ffff8880723c20c0 R13: ffff8880723c24b0 R14: dffffc0000000000 R15: ffffed1014197e64 sock_hold include/net/sock.h:647 [inline] rds_sock_addref+0x19/0x20 net/rds/af_rds.c:675 rds_find_bound+0x97c/0x1080 net/rds/bind.c:82 rds_recv_incoming+0x3be/0x1430 net/rds/recv.c:362 rds_loop_xmit+0xf3/0x2a0 net/rds/loop.c:96 rds_send_xmit+0x1355/0x2a10 net/rds/send.c:355 rds_sendmsg+0x323c/0x44e0 net/rds/send.c:1368 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 __sys_sendto+0x387/0x5f0 net/socket.c:1788 __do_sys_sendto net/socket.c:1800 [inline] __se_sys_sendto net/socket.c:1796 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458089 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc266df8c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000458089 RDX: 0000000000000000 RSI: 00000000204b3fff RDI: 0000000000000005 RBP: 000000000073bf00 R08: 00000000202b4000 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc266df96d4 R13: 00000000004c56e4 R14: 00000000004d94a8 R15: 00000000ffffffff Fixes: cc4dfb7f70a3 ("rds: fix two RCU related problems") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Sowmini Varadhan Cc: Santosh Shilimkar Cc: rds-devel@oss.oracle.com Cc: Cong Wang --- net/rds/bind.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/rds/bind.c b/net/rds/bind.c index 762d2c6788a385631a312a39625d67a1154ef596..17c9d9f0c8483b4b0a887e69e7caac246c369423 100644 --- a/net/rds/bind.c +++ b/net/rds/bind.c @@ -78,10 +78,10 @@ struct rds_sock *rds_find_bound(const struct in6_addr *addr, __be16 port, __rds_create_bind_key(key, addr, port, scope_id); rcu_read_lock(); rs = rhashtable_lookup(&bind_hash_table, key, ht_parms); - if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD)) - rds_sock_addref(rs); - else + if (rs && (sock_flag(rds_rs_to_sk(rs), SOCK_DEAD) || + !refcount_inc_not_zero(&rds_rs_to_sk(rs)->sk_refcnt))) rs = NULL; + rcu_read_unlock(); rdsdebug("returning rs %p for %pI6c:%u\n", rs, addr, -- 2.20.1.495.gaa96b0ce6b-goog