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| author |  Eric Dumazet <edumazet@google.com>
| 2022-02-06 07:56:00 -0800 |
|---|---|---|
| committer |  David S. Miller <davem@davemloft.net>
| 2022-02-07 12:07:45 +0000 |
| commit | 7d9b1b578d67a14ae7a7a526ee115b233fa264c4 (patch) | |
| tree | cba3559f935bdf8705da94ed8d83c3d280b5d760 /net/ipv6/addrconf.c | |
| parent | caif: cleanup double word in comment (diff) | |
| download | linux-7d9b1b578d67a14ae7a7a526ee115b233fa264c4.tar.gz linux-7d9b1b578d67a14ae7a7a526ee115b233fa264c4.tar.bz2 linux-7d9b1b578d67a14ae7a7a526ee115b233fa264c4.zip | |
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: f2f2325ec799 ("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>
Diffstat (limited to 'net/ipv6/addrconf.c')
| -rw-r--r-- | net/ipv6/addrconf.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index ff1b2484b8ed..ef23e7dc538a 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -7184,7 +7184,9 @@ static void __net_exit addrconf_exit_net(struct net *net) NETCONFA_IFINDEX_ALL); #endif kfree(net->ipv6.devconf_dflt); + net->ipv6.devconf_dflt = NULL; kfree(net->ipv6.devconf_all); + net->ipv6.devconf_all = NULL; } static struct pernet_operations addrconf_ops = { |