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Eric Dumazet e669b86945 ipv6: addrconf: increment ifp refcount before ipv6_del_addr()
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: f1705ec197 ("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>
2017-11-01 21:18:13 +09:00
arch pci-v4.14-fixes-6 2017-10-28 10:53:24 -07:00
block bio_copy_user_iov(): don't ignore ->iov_offset 2017-10-10 23:55:14 -04:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto Merge commit 'tags/keys-fixes-20171018' into fixes-v4.14-rc5 2017-10-19 12:28:38 +11:00
Documentation Kbuild fixes for v4.14 (2nd) 2017-10-28 11:01:57 -07:00
drivers tun/tap: sanitize TUNSETSNDBUF input 2017-11-01 20:52:36 +09:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs Various SMB3 fixes for 4.14 and stable 2017-10-28 08:39:35 -07:00
include bpf: remove SK_REDIRECT from UAPI 2017-11-01 11:43:50 +09:00
init kbuild: Fix optimization level choice default 2017-10-07 20:08:05 +09:00
ipc fix a typo in put_compat_shm_info() 2017-09-25 20:41:46 -04:00
kernel bpf: remove SK_REDIRECT from UAPI 2017-11-01 11:43:50 +09:00
lib assoc_array: Fix a buggy node-splitting case 2017-10-28 10:31:07 -07:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
net ipv6: addrconf: increment ifp refcount before ipv6_del_addr() 2017-11-01 21:18:13 +09:00
samples Fix tracing sample code warning. 2017-10-27 20:35:31 -07:00
scripts Kbuild fixes for v4.14 (2nd) 2017-10-28 11:01:57 -07:00
security Revert "apparmor: add base infastructure for socket mediation" 2017-10-26 19:35:35 +02:00
sound ALSA: hda - fix headset mic problem for Dell machines with alc236 2017-10-24 14:32:24 +02:00
tools bpf: remove SK_REDIRECT from UAPI 2017-11-01 11:43:50 +09:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap Update James Hogan's email address 2017-10-04 17:11:53 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS MAINTAINERS: Remove Yotam from mlxfw 2017-11-01 12:19:03 +09:00
Makefile Linux 4.14-rc7 2017-10-29 13:58:38 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.