[Devel] [PATCH RHEL7 COMMIT] ms/ipv6: fix NULL dereference in ip6_route_dev_notify()
Konstantin Khorenko
khorenko at virtuozzo.com
Tue Jun 26 11:13:12 MSK 2018
The commit is pushed to "branch-rh7-3.10.0-862.3.2.vz7.61.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-862.3.2.vz7.61.5
------>
commit d5644659f4ad1e1d51cf3c99120aa5912ef102e7
Author: Eric Dumazet <edumazet at google.com>
Date: Tue Aug 15 04:09:51 2017 -0700
ms/ipv6: fix NULL dereference in ip6_route_dev_notify()
Based on a syzkaller report [1], I found that a per cpu allocation
failure in snmp6_alloc_dev() would then lead to NULL dereference in
ip6_route_dev_notify().
It seems this is a very old bug, thus no Fixes tag in this submission.
Let's add in6_dev_put_clear() helper, as we will probably use
it elsewhere (once available/present in net-next)
[1]
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 17294 Comm: syz-executor6 Not tainted 4.13.0-rc2+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019f456680 task.stack: ffff8801c6e58000
RIP: 0010:__read_once_size include/linux/compiler.h:250 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:26 [inline]
RIP: 0010:refcount_sub_and_test+0x7d/0x1b0 lib/refcount.c:178
RSP: 0018:ffff8801c6e5f1b0 EFLAGS: 00010202
RAX: 0000000000000037 RBX: dffffc0000000000 RCX: ffffc90005d25000
RDX: ffff8801c6e5f218 RSI: ffffffff82342bbf RDI: 0000000000000001
RBP: ffff8801c6e5f240 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10038dcbe37
R13: 0000000000000006 R14: 0000000000000001 R15: 00000000000001b8
FS: 00007f21e0429700(0000) GS:ffff8801dc100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001ddbc22000 CR3: 00000001d632b000 CR4: 00000000001426e0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
refcount_dec_and_test+0x1a/0x20 lib/refcount.c:211
in6_dev_put include/net/addrconf.h:335 [inline]
ip6_route_dev_notify+0x1c9/0x4a0 net/ipv6/route.c:3732
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+0x51/0x90 net/core/dev.c:1678
call_netdevice_notifiers net/core/dev.c:1694 [inline]
rollback_registered_many+0x91c/0xe80 net/core/dev.c:7107
rollback_registered+0x1be/0x3c0 net/core/dev.c:7149
register_netdevice+0xbcd/0xee0 net/core/dev.c:7587
register_netdev+0x1a/0x30 net/core/dev.c:7669
loopback_net_init+0x76/0x160 drivers/net/loopback.c:214
ops_init+0x10a/0x570 net/core/net_namespace.c:118
setup_net+0x313/0x710 net/core/net_namespace.c:294
copy_net_ns+0x27c/0x580 net/core/net_namespace.c:418
create_new_namespaces+0x425/0x880 kernel/nsproxy.c:107
unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:206
SYSC_unshare kernel/fork.c:2347 [inline]
SyS_unshare+0x653/0xfa0 kernel/fork.c:2297
entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4512c9
RSP: 002b:00007f21e0428c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000718150 RCX: 00000000004512c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000062020200
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b973d
R13: 00000000ffffffff R14: 000000002001d000 R15: 00000000000002dd
Code: 50 2b 34 82 c7 00 f1 f1 f1 f1 c7 40 04 04 f2 f2 f2 c7 40 08 f3 f3
f3 f3 e8 a1 43 39 ff 4c 89 f8 48 8b 95 70 ff ff ff 48 c1 e8 03 <0f> b6
0c 18 4c 89 f8 83 e0 07 83 c0 03 38 c8 7c 08 84 c9 0f 85
RIP: __read_once_size include/linux/compiler.h:250 [inline] RSP:
ffff8801c6e5f1b0
RIP: atomic_read arch/x86/include/asm/atomic.h:26 [inline] RSP:
ffff8801c6e5f1b0
RIP: refcount_sub_and_test+0x7d/0x1b0 lib/refcount.c:178 RSP:
ffff8801c6e5f1b0
---[ end trace e441d046c6410d31 ]---
Signed-off-by: Eric Dumazet <edumazet at google.com>
Reported-by: Dmitry Vyukov <dvyukov at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
https://jira.sw.ru/browse/PSBM-86093
(cherry picked from commit 12d94a804946af291e24b80fc53ec86264765781)
Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
---
include/net/addrconf.h | 10 ++++++++++
net/ipv6/route.c | 6 +++---
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index d8a3ad53854a..a962327d19ca 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -322,6 +322,16 @@ static inline void in6_dev_put(struct inet6_dev *idev)
in6_dev_finish_destroy(idev);
}
+static inline void in6_dev_put_clear(struct inet6_dev **pidev)
+{
+ struct inet6_dev *idev = *pidev;
+
+ if (idev) {
+ in6_dev_put(idev);
+ *pidev = NULL;
+ }
+}
+
static inline void __in6_dev_put(struct inet6_dev *idev)
{
atomic_dec(&idev->refcnt);
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index d7b59806c909..503be275ce87 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3419,10 +3419,10 @@ static int ip6_route_dev_notify(struct notifier_block *this,
/* NETDEV_UNREGISTER could be fired for multiple times by
* netdev_wait_allrefs(). Make sure we only call this once.
*/
- in6_dev_put(net->ipv6.ip6_null_entry->rt6i_idev);
+ in6_dev_put_clear(&net->ipv6.ip6_null_entry->rt6i_idev);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
- in6_dev_put(net->ipv6.ip6_prohibit_entry->rt6i_idev);
- in6_dev_put(net->ipv6.ip6_blk_hole_entry->rt6i_idev);
+ in6_dev_put_clear(&net->ipv6.ip6_prohibit_entry->rt6i_idev);
+ in6_dev_put_clear(&net->ipv6.ip6_blk_hole_entry->rt6i_idev);
#endif
}
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