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Paolo Abeni 516c855cf5 netfilter: on sockopt() acquire sock lock only in the required scope commit `3f34cfae12` upstream. Syzbot reported several deadlocks in the netfilter area caused by rtnl lock and socket lock being acquired with a different order on different code paths, leading to backtraces like the following one: ====================================================== WARNING: possible circular locking dependency detected 4.15.0-rc9+ #212 Not tainted ------------------------------------------------------ syzkaller041579/3682 is trying to acquire lock: (sk_lock-AF_INET6){+.+.}, at: [<000000008775e4dd>] lock_sock include/net/sock.h:1463 [inline] (sk_lock-AF_INET6){+.+.}, at: [<000000008775e4dd>] do_ipv6_setsockopt.isra.8+0x3c5/0x39d0 net/ipv6/ipv6_sockglue.c:167 but task is already holding lock: (rtnl_mutex){+.+.}, at: [<000000004342eaa9>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (rtnl_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 register_netdevice_notifier+0xad/0x860 net/core/dev.c:1607 tee_tg_check+0x1a0/0x280 net/netfilter/xt_TEE.c:106 xt_check_target+0x22c/0x7d0 net/netfilter/x_tables.c:845 check_target net/ipv6/netfilter/ip6_tables.c:538 [inline] find_check_entry.isra.7+0x935/0xcf0 net/ipv6/netfilter/ip6_tables.c:580 translate_table+0xf52/0x1690 net/ipv6/netfilter/ip6_tables.c:749 do_replace net/ipv6/netfilter/ip6_tables.c:1165 [inline] do_ip6t_set_ctl+0x370/0x5f0 net/ipv6/netfilter/ip6_tables.c:1691 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt+0x115/0x150 net/ipv6/ipv6_sockglue.c:928 udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1422 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2978 SYSC_setsockopt net/socket.c:1849 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1828 entry_SYSCALL_64_fastpath+0x29/0xa0 -> #0 (sk_lock-AF_INET6){+.+.}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914 lock_sock_nested+0xc2/0x110 net/core/sock.c:2780 lock_sock include/net/sock.h:1463 [inline] do_ipv6_setsockopt.isra.8+0x3c5/0x39d0 net/ipv6/ipv6_sockglue.c:167 ipv6_setsockopt+0xd7/0x150 net/ipv6/ipv6_sockglue.c:922 udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1422 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2978 SYSC_setsockopt net/socket.c:1849 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1828 entry_SYSCALL_64_fastpath+0x29/0xa0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(sk_lock-AF_INET6); lock(rtnl_mutex); lock(sk_lock-AF_INET6); * DEADLOCK * 1 lock held by syzkaller041579/3682: #0: (rtnl_mutex){+.+.}, at: [<000000004342eaa9>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 The problem, as Florian noted, is that nf_setsockopt() is always called with the socket held, even if the lock itself is required only for very tight scopes and only for some operation. This patch addresses the issues moving the lock_sock() call only where really needed, namely in ipv*_getorigdst(), so that nf_setsockopt() does not need anymore to acquire both locks. Fixes: `22265a5c3c` ("netfilter: xt_TEE: resolve oif using netdevice notifiers") Reported-by: syzbot+a4c2dc980ac1af699b36@syzkaller.appspotmail.com Suggested-by: Florian Westphal <fw@strlen.de> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		History 2018-02-25 11:07:50 +01:00
arch	KVM: x86: fix escape of guest dr6 to the host	2018-02-25 11:07:49 +01:00
block	blk_rq_map_user_iov: fix error override	2018-02-25 11:07:49 +01:00
certs	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
crypto	kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK	2018-02-22 15:42:23 +01:00
Documentation	ext4: correct documentation for grpid mount option	2018-02-22 15:42:26 +01:00
drivers	staging: android: ion: Switch from WARN to pr_warn	2018-02-25 11:07:49 +01:00
firmware	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
fs	dnotify: Handle errors from fsnotify_add_mark_locked() in fcntl_dirnotify()	2018-02-25 11:07:47 +01:00
include	ptr_ring: try vmalloc() when kmalloc() fails	2018-02-25 11:07:48 +01:00
init	kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK	2018-02-22 15:42:23 +01:00
ipc	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
kernel	kcov: detect double association with a single task	2018-02-25 11:07:50 +01:00
lib	kmemcheck: rip it out	2018-02-22 15:42:24 +01:00
mm	mm,vmscan: Make unregister_shrinker() no-op if register_shrinker() failed.	2018-02-25 11:07:46 +01:00
net	netfilter: on sockopt() acquire sock lock only in the required scope	2018-02-25 11:07:50 +01:00
samples	samples/bpf: adjust rlimit RLIMIT_MEMLOCK for xdp1	2017-12-20 10:10:31 +01:00
scripts	kmemcheck: rip it out	2018-02-22 15:42:24 +01:00
security	selinux: skip bounded transition processing if the policy isn't loaded	2018-02-25 11:07:49 +01:00
sound	ALSA: bcd2000: Add a sanity check for invalid EPs	2018-02-25 11:07:48 +01:00
tools	bpf: mark dst unknown on inconsistent {s, u}bounds adjustments	2018-02-25 11:07:45 +01:00
usr	initramfs: fix initramfs rebuilds w/ compression after disabling	2017-11-03 07:39:19 -07:00
virt	KVM: arm/arm64: Handle CPU_PM_ENTER_FAILED	2018-02-16 20:23:03 +01:00
.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: rpm-pkg: keep spec file until make mrproper	2018-02-13 10:19:46 +01:00
.mailmap	.mailmap: Add Maciej W. Rozycki's Imagination e-mail address	2017-11-10 12:16:15 -08:00
COPYING	[PATCH] update FSF address in COPYING	2005-09-10 10:06:29 -07:00
CREDITS	MAINTAINERS: update TPM driver infrastructure changes	2017-11-09 17:58:40 -08:00
Kbuild	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
Kconfig	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
MAINTAINERS	kmemcheck: rip it out	2018-02-22 15:42:24 +01:00
Makefile	Linux 4.14.21	2018-02-22 15:42:33 +01:00
README	README: add a new README file, pointing to the Documentation/	2016-10-24 08:12:35 -02:00

README

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.