Patch "ipv6: addrconf: increment ifp refcount before ipv6_del_addr()" has been added to the 4.13-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    ipv6: addrconf: increment ifp refcount before ipv6_del_addr()

to the 4.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ipv6-addrconf-increment-ifp-refcount-before-ipv6_del_addr.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Nov 15 17:25:34 CET 2017
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 30 Oct 2017 22:47:09 -0700
Subject: ipv6: addrconf: increment ifp refcount before ipv6_del_addr()

From: Eric Dumazet <edumazet@google.com>


[ 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 <edumazet@google.com>
Cc: David Ahern <dsahern@gmail.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv6/addrconf.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3367,6 +3367,7 @@ 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);
 


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.13/tcp-refresh-tp-timestamp-before-tcp_mtu_probe.patch
queue-4.13/net-call-cgroup_sk_alloc-earlier-in-sk_clone_lock.patch
queue-4.13/tcp-dccp-fix-ireq-opt-races.patch
queue-4.13/tcp-fix-tcp_mtu_probe-vs-highest_sack.patch
queue-4.13/ipv6-addrconf-increment-ifp-refcount-before-ipv6_del_addr.patch
queue-4.13/ipv6-flowlabel-do-not-leave-opt-tot_len-with-garbage.patch
queue-4.13/packet-avoid-panic-in-packet_getsockopt.patch
queue-4.13/sctp-add-the-missing-sock_owned_by_user-check-in-sctp_icmp_redirect.patch
queue-4.13/net_sched-avoid-matching-qdisc-with-zero-handle.patch
queue-4.13/tun-tap-sanitize-tunsetsndbuf-input.patch
queue-4.13/tcp-dccp-fix-lockdep-splat-in-inet_csk_route_req.patch
queue-4.13/tcp-dccp-fix-other-lockdep-splats-accessing-ireq_opt.patch