From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760649AbdKPSLX (ORCPT ); Thu, 16 Nov 2017 13:11:23 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35136 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965882AbdKPRp3 (ORCPT ); Thu, 16 Nov 2017 12:45:29 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , David Ahern , "David S. Miller" Subject: [PATCH 4.9 03/39] ipv6: addrconf: increment ifp refcount before ipv6_del_addr() Date: Thu, 16 Nov 2017 18:42:22 +0100 Message-Id: <20171116174213.451163698@linuxfoundation.org> X-Mailer: git-send-email 2.15.0 In-Reply-To: <20171116174213.321860523@linuxfoundation.org> References: <20171116174213.321860523@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit e669b86945478b3d90d2d87e3793a6eed06d332f ] In the (unlikely) event fixup_permanent_addr() returns a failure, addrconf_permanent_addr() calls ipv6_del_addr() without the mandatory call to in6_ifa_hold(), leading to a refcount error, spotted by syzkaller : WARNING: CPU: 1 PID: 3142 at lib/refcount.c:227 refcount_dec+0x4c/0x50 lib/refcount.c:227 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 3142 Comm: ip Not tainted 4.14.0-rc4-next-20171009+ #33 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 panic+0x1e4/0x41c kernel/panic.c:181 __warn+0x1c4/0x1e0 kernel/panic.c:544 report_bug+0x211/0x2d0 lib/bug.c:183 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178 do_trap_no_signal arch/x86/kernel/traps.c:212 [inline] do_trap+0x260/0x390 arch/x86/kernel/traps.c:261 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905 RIP: 0010:refcount_dec+0x4c/0x50 lib/refcount.c:227 RSP: 0018:ffff8801ca49e680 EFLAGS: 00010286 RAX: 000000000000002c RBX: ffff8801d07cfcdc RCX: 0000000000000000 RDX: 000000000000002c RSI: 1ffff10039493c90 RDI: ffffed0039493cc4 RBP: ffff8801ca49e688 R08: ffff8801ca49dd70 R09: 0000000000000000 R10: ffff8801ca49df58 R11: 0000000000000000 R12: 1ffff10039493cd9 R13: ffff8801ca49e6e8 R14: ffff8801ca49e7e8 R15: ffff8801d07cfcdc __in6_ifa_put include/net/addrconf.h:369 [inline] ipv6_del_addr+0x42b/0xb60 net/ipv6/addrconf.c:1208 addrconf_permanent_addr net/ipv6/addrconf.c:3327 [inline] addrconf_notify+0x1c66/0x2190 net/ipv6/addrconf.c:3393 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x32/0x60 net/core/dev.c:1697 call_netdevice_notifiers net/core/dev.c:1715 [inline] __dev_notify_flags+0x15d/0x430 net/core/dev.c:6843 dev_change_flags+0xf5/0x140 net/core/dev.c:6879 do_setlink+0xa1b/0x38e0 net/core/rtnetlink.c:2113 rtnl_newlink+0xf0d/0x1a40 net/core/rtnetlink.c:2661 rtnetlink_rcv_msg+0x733/0x1090 net/core/rtnetlink.c:4301 netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2408 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4313 netlink_unicast_kernel net/netlink/af_netlink.c:1273 [inline] netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1299 netlink_sendmsg+0xa4a/0xe70 net/netlink/af_netlink.c:1862 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg+0xca/0x110 net/socket.c:643 ___sys_sendmsg+0x75b/0x8a0 net/socket.c:2049 __sys_sendmsg+0xe5/0x210 net/socket.c:2083 SYSC_sendmsg net/socket.c:2094 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2090 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x7fa9174d3320 RSP: 002b:00007ffe302ae9e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ffe302b2ae0 RCX: 00007fa9174d3320 RDX: 0000000000000000 RSI: 00007ffe302aea20 RDI: 0000000000000016 RBP: 0000000000000082 R08: 0000000000000000 R09: 000000000000000f R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe302b32a0 R13: 0000000000000000 R14: 00007ffe302b2ab8 R15: 00007ffe302b32b8 Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional") Signed-off-by: Eric Dumazet Cc: David Ahern Acked-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/addrconf.c | 1 + 1 file changed, 1 insertion(+) --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -3299,6 +3299,7 @@ static void addrconf_permanent_addr(stru if ((ifp->flags & IFA_F_PERMANENT) && fixup_permanent_addr(idev, ifp) < 0) { write_unlock_bh(&idev->lock); + in6_ifa_hold(ifp); ipv6_del_addr(ifp); write_lock_bh(&idev->lock);