| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20200908145911.4090480-1-edumazet@google.com>
Date: Tue, 8 Sep 2020 07:59:11 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>,
Eric Dumazet <edumazet@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>,
syzbot <syzkaller@...glegroups.com>,
"Jason A . Donenfeld" <Jason@...c4.com>, wireguard@...ts.zx2c4.com
Subject: [PATCH net] wireguard: fix race in wg_index_hashtable_replace()
syzbot got a NULL dereference in wg_index_hashtable_replace() [1]
Issue here is that right after checking hlist_unhashed(&old->index_hash)
another cpu might have removed @old already from the hash.
Since we are dealing with a very unlikely case, we can simply
acquire the table lock earlier.
[1]
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 7395 Comm: kworker/0:3 Not tainted 5.9.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-kex-wg1 wg_packet_handshake_receive_worker
RIP: 0010:hlist_replace_rcu include/linux/rculist.h:505 [inline]
RIP: 0010:wg_index_hashtable_replace+0x176/0x330 drivers/net/wireguard/peerlookup.c:174
Code: 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 44 01 00 00 48 b9 00 00 00 00 00 fc ff df 48 8b 45 10 48 89 c6 48 c1 ee 03 <80> 3c 0e 00 0f 85 06 01 00 00 48 85 d2 4c 89 28 74 47 e8 a3 4f b5
RSP: 0018:ffffc90006a97bf8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888050ffc4f8 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88808e04e010
RBP: ffff88808e04e000 R08: 0000000000000001 R09: ffff8880543d0000
R10: ffffed100a87a000 R11: 000000000000016e R12: ffff8880543d0000
R13: ffff88808e04e008 R14: ffff888050ffc508 R15: ffff888050ffc500
FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f5505db0 CR3: 0000000097cf7000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
wg_noise_handshake_begin_session+0x752/0xc9a drivers/net/wireguard/noise.c:820
wg_receive_handshake_packet drivers/net/wireguard/receive.c:183 [inline]
wg_packet_handshake_receive_worker+0x33b/0x730 drivers/net/wireguard/receive.c:220
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Modules linked in:
---[ end trace 0d737db78b72da84 ]---
RIP: 0010:hlist_replace_rcu include/linux/rculist.h:505 [inline]
RIP: 0010:wg_index_hashtable_replace+0x176/0x330 drivers/net/wireguard/peerlookup.c:174
Code: 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 44 01 00 00 48 b9 00 00 00 00 00 fc ff df 48 8b 45 10 48 89 c6 48 c1 ee 03 <80> 3c 0e 00 0f 85 06 01 00 00 48 85 d2 4c 89 28 74 47 e8 a3 4f b5
RSP: 0018:ffffc90006a97bf8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888050ffc4f8 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88808e04e010
RBP: ffff88808e04e000 R08: 0000000000000001 R09: ffff8880543d0000
R10: ffffed100a87a000 R11: 000000000000016e R12: ffff8880543d0000
R13: ffff88808e04e008 R14: ffff888050ffc508 R15: ffff888050ffc500
FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f5505db0 CR3: 0000000097cf7000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Reported-by: syzbot <syzkaller@...glegroups.com>
Cc: Jason A. Donenfeld <Jason@...c4.com>
Cc: wireguard@...ts.zx2c4.com
---
drivers/net/wireguard/peerlookup.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)
diff --git a/drivers/net/wireguard/peerlookup.c b/drivers/net/wireguard/peerlookup.c
index e4deb331476b3d67c1d24eb269b26f587798cbc2..d82eba263292474a7cdfb133b2ba1862a2e9352c 100644
--- a/drivers/net/wireguard/peerlookup.c
+++ b/drivers/net/wireguard/peerlookup.c
@@ -167,21 +167,25 @@ bool wg_index_hashtable_replace(struct index_hashtable *table,
struct index_hashtable_entry *old,
struct index_hashtable_entry *new)
{
- if (unlikely(hlist_unhashed(&old->index_hash)))
- return false;
+
+ bool replaced = false;
+
spin_lock_bh(&table->lock);
- new->index = old->index;
- hlist_replace_rcu(&old->index_hash, &new->index_hash);
+ if (likely(!hlist_unhashed(&old->index_hash))) {
+ replaced = true;
+ new->index = old->index;
+ hlist_replace_rcu(&old->index_hash, &new->index_hash);
- /* Calling init here NULLs out index_hash, and in fact after this
- * function returns, it's theoretically possible for this to get
- * reinserted elsewhere. That means the RCU lookup below might either
- * terminate early or jump between buckets, in which case the packet
- * simply gets dropped, which isn't terrible.
- */
- INIT_HLIST_NODE(&old->index_hash);
+ /* Calling init here NULLs out index_hash, and in fact after this
+ * function returns, it's theoretically possible for this to get
+ * reinserted elsewhere. That means the RCU lookup below might either
+ * terminate early or jump between buckets, in which case the packet
+ * simply gets dropped, which isn't terrible.
+ */
+ INIT_HLIST_NODE(&old->index_hash);
+ }
spin_unlock_bh(&table->lock);
- return true;
+ return replaced;
}
void wg_index_hashtable_remove(struct index_hashtable *table,
--
2.28.0.526.ge36021eeef-goog
Powered by blists - more mailing lists