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Eric Dumazet 7d9b1b578d ip6mr: fix use-after-free in ip6mr_sk_done()
Apparently addrconf_exit_net() is called before igmp6_net_exit()
and ndisc_net_exit() at netns dismantle time:

 net_namespace: call ip6table_mangle_net_exit()
 net_namespace: call ip6_tables_net_exit()
 net_namespace: call ipv6_sysctl_net_exit()
 net_namespace: call ioam6_net_exit()
 net_namespace: call seg6_net_exit()
 net_namespace: call ping_v6_proc_exit_net()
 net_namespace: call tcpv6_net_exit()
 ip6mr_sk_done sk=ffffa354c78a74c0
 net_namespace: call ipv6_frags_exit_net()
 net_namespace: call addrconf_exit_net()
 net_namespace: call ip6addrlbl_net_exit()
 net_namespace: call ip6_flowlabel_net_exit()
 net_namespace: call ip6_route_net_exit_late()
 net_namespace: call fib6_rules_net_exit()
 net_namespace: call xfrm6_net_exit()
 net_namespace: call fib6_net_exit()
 net_namespace: call ip6_route_net_exit()
 net_namespace: call ipv6_inetpeer_exit()
 net_namespace: call if6_proc_net_exit()
 net_namespace: call ipv6_proc_exit_net()
 net_namespace: call udplite6_proc_exit_net()
 net_namespace: call raw6_exit_net()
 net_namespace: call igmp6_net_exit()
 ip6mr_sk_done sk=ffffa35472b2a180
 ip6mr_sk_done sk=ffffa354c78a7980
 net_namespace: call ndisc_net_exit()
 ip6mr_sk_done sk=ffffa35472b2ab00
 net_namespace: call ip6mr_net_exit()
 net_namespace: call inet6_net_exit()

This was fine because ip6mr_sk_done() would not reach the point decreasing
net->ipv6.devconf_all->mc_forwarding until my patch in ip6mr_sk_done().

To fix this without changing struct pernet_operations ordering,
we can clear net->ipv6.devconf_dflt and net->ipv6.devconf_all
when they are freed from addrconf_exit_net()

BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in ip6mr_sk_done+0x11b/0x410 net/ipv6/ip6mr.c:1578
Read of size 4 at addr ffff88801ff08688 by task kworker/u4:4/963

CPU: 0 PID: 963 Comm: kworker/u4:4 Not tainted 5.17.0-rc2-syzkaller-00650-g5a8fb33e5305 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 ip6mr_sk_done+0x11b/0x410 net/ipv6/ip6mr.c:1578
 rawv6_close+0x58/0x80 net/ipv6/raw.c:1201
 inet_release+0x12e/0x280 net/ipv4/af_inet.c:428
 inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:478
 __sock_release net/socket.c:650 [inline]
 sock_release+0x87/0x1b0 net/socket.c:678
 inet_ctl_sock_destroy include/net/inet_common.h:65 [inline]
 igmp6_net_exit+0x6b/0x170 net/ipv6/mcast.c:3173
 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:168
 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:600
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Fixes: f2f2325ec7 ("ip6mr: ip6mr_sk_done() can exit early in common cases")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 12:07:45 +00:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-03 17:36:16 -08:00
block block: add bio_start_io_acct_time() to control start_time 2022-01-28 12:28:15 -07:00
certs certs: Fix build error when CONFIG_MODULE_SIG_KEY is empty 2022-01-23 00:08:44 +09:00
crypto lib/crypto: add prompts back to crypto libraries 2022-01-18 13:03:55 +01:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-03 17:36:16 -08:00
drivers mlxsw: Support FLOW_ACTION_MANGLE for SIP and DIP IPv6 addresses 2022-02-07 11:59:57 +00:00
fs Notable bug fixes: 2022-02-02 10:14:31 -08:00
include net: udp: use kfree_skb_reason() in __udp_queue_rcv_skb() 2022-02-07 11:18:49 +00:00
init net: initialize init_net earlier 2022-02-06 11:04:29 +00:00
ipc proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-03 17:36:16 -08:00
lib ref_tracker: remove filter_irq_stacks() call 2022-02-06 11:05:28 +00:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm Revert "mm/gup: small refactoring: simplify try_grab_page()" 2022-02-03 06:51:42 -08:00
net ip6mr: fix use-after-free in ip6mr_sk_done() 2022-02-07 12:07:45 +00:00
samples Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2022-01-24 15:42:29 -08:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-03 17:36:16 -08:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-03 17:36:16 -08:00
sound proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
tools selftests: forwarding: Add a test for pedit munge SIP and DIP 2022-02-07 11:59:57 +00:00
usr kbuild: remove include/linux/cyclades.h from header file check 2022-01-27 08:51:08 +01:00
virt Two larger x86 series: 2022-01-28 19:00:26 +02:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update Christian Brauner's email address 2022-02-01 11:21:31 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Removing Ohad from remoteproc/rpmsg maintenance 2021-12-08 10:09:40 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-03 17:36:16 -08:00
Makefile Linux 5.17-rc2 2022-01-30 15:37:07 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.