diff mbox series

[net,1/6] wireguard: receive: annotate data-race around receiving_counter.counter

Message ID 20240314224911.6653-2-Jason@zx2c4.com (mailing list archive)
State Accepted
Commit bba045dc4d996d03dce6fe45726e78a1a1f6d4c3
Delegated to: Netdev Maintainers
Headers show
Series wireguard fixes for 6.9-rc1 | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 939 this patch: 939
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 3 maintainers not CCed: pabeni@redhat.com edumazet@google.com wireguard@lists.zx2c4.com
netdev/build_clang success Errors and warnings before: 956 this patch: 956
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 956 this patch: 956
netdev/checkpatch warning WARNING: line length of 91 exceeds 80 columns WARNING: line length of 92 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-03-15--03-00 (tests: 907)

Commit Message

Jason A. Donenfeld March 14, 2024, 10:49 p.m. UTC 
From: Nikita Zhandarovich <n.zhandarovich@fintech.ru>

Syzkaller with KCSAN identified a data-race issue when accessing
keypair->receiving_counter.counter. Use READ_ONCE() and WRITE_ONCE()
annotations to mark the data race as intentional.

    BUG: KCSAN: data-race in wg_packet_decrypt_worker / wg_packet_rx_poll

    write to 0xffff888107765888 of 8 bytes by interrupt on cpu 0:
     counter_validate drivers/net/wireguard/receive.c:321 [inline]
     wg_packet_rx_poll+0x3ac/0xf00 drivers/net/wireguard/receive.c:461
     __napi_poll+0x60/0x3b0 net/core/dev.c:6536
     napi_poll net/core/dev.c:6605 [inline]
     net_rx_action+0x32b/0x750 net/core/dev.c:6738
     __do_softirq+0xc4/0x279 kernel/softirq.c:553
     do_softirq+0x5e/0x90 kernel/softirq.c:454
     __local_bh_enable_ip+0x64/0x70 kernel/softirq.c:381
     __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
     _raw_spin_unlock_bh+0x36/0x40 kernel/locking/spinlock.c:210
     spin_unlock_bh include/linux/spinlock.h:396 [inline]
     ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline]
     wg_packet_decrypt_worker+0x6c5/0x700 drivers/net/wireguard/receive.c:499
     process_one_work kernel/workqueue.c:2633 [inline]
     ...

    read to 0xffff888107765888 of 8 bytes by task 3196 on cpu 1:
     decrypt_packet drivers/net/wireguard/receive.c:252 [inline]
     wg_packet_decrypt_worker+0x220/0x700 drivers/net/wireguard/receive.c:501
     process_one_work kernel/workqueue.c:2633 [inline]
     process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2706
     worker_thread+0x525/0x730 kernel/workqueue.c:2787
     ...

Fixes: a9e90d9931f3 ("wireguard: noise: separate receive counter from send counter")
Reported-by: syzbot+d1de830e4ecdaac83d89@syzkaller.appspotmail.com
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/net/wireguard/receive.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/wireguard/receive.c b/drivers/net/wireguard/receive.c
index df275b4fccb6..eb8851113654 100644
--- a/drivers/net/wireguard/receive.c
+++ b/drivers/net/wireguard/receive.c
@@ -251,7 +251,7 @@  static bool decrypt_packet(struct sk_buff *skb, struct noise_keypair *keypair)
 
 	if (unlikely(!READ_ONCE(keypair->receiving.is_valid) ||
 		  wg_birthdate_has_expired(keypair->receiving.birthdate, REJECT_AFTER_TIME) ||
-		  keypair->receiving_counter.counter >= REJECT_AFTER_MESSAGES)) {
+		  READ_ONCE(keypair->receiving_counter.counter) >= REJECT_AFTER_MESSAGES)) {
 		WRITE_ONCE(keypair->receiving.is_valid, false);
 		return false;
 	}
@@ -318,7 +318,7 @@  static bool counter_validate(struct noise_replay_counter *counter, u64 their_cou
 		for (i = 1; i <= top; ++i)
 			counter->backtrack[(i + index_current) &
 				((COUNTER_BITS_TOTAL / BITS_PER_LONG) - 1)] = 0;
-		counter->counter = their_counter;
+		WRITE_ONCE(counter->counter, their_counter);
 	}
 
 	index &= (COUNTER_BITS_TOTAL / BITS_PER_LONG) - 1;
@@ -463,7 +463,7 @@  int wg_packet_rx_poll(struct napi_struct *napi, int budget)
 			net_dbg_ratelimited("%s: Packet has invalid nonce %llu (max %llu)\n",
 					    peer->device->dev->name,
 					    PACKET_CB(skb)->nonce,
-					    keypair->receiving_counter.counter);
+					    READ_ONCE(keypair->receiving_counter.counter));
 			goto next;
 		}