From: Hoang Huu Le hoang.h.le@dektech.com.au
[ Upstream commit 7b50ee3dad2581dc022b4e32e55964d4fcdccf20 ]
In the function node_lost_contact(), we call __skb_queue_purge() without grabbing the list->lock. This can cause to a race-condition why processing the list 'namedq' in calling path tipc_named_rcv()->tipc_named_dequeue().
[] BUG: kernel NULL pointer dereference, address: 0000000000000000 [] #PF: supervisor read access in kernel mode [] #PF: error_code(0x0000) - not-present page [] PGD 7ca63067 P4D 7ca63067 PUD 6c553067 PMD 0 [] Oops: 0000 [#1] SMP NOPTI [] CPU: 1 PID: 15 Comm: ksoftirqd/1 Tainted: G O 5.9.0-rc6+ #2 [] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS [...] [] RIP: 0010:tipc_named_rcv+0x103/0x320 [tipc] [] Code: 41 89 44 24 10 49 8b 16 49 8b 46 08 49 c7 06 00 00 00 [...] [] RSP: 0018:ffffc900000a7c58 EFLAGS: 00000282 [] RAX: 00000000000012ec RBX: 0000000000000000 RCX: ffff88807bde1270 [] RDX: 0000000000002c7c RSI: 0000000000002c7c RDI: ffff88807b38f1a8 [] RBP: ffff88807b006288 R08: ffff88806a367800 R09: ffff88806a367900 [] R10: ffff88806a367a00 R11: ffff88806a367b00 R12: ffff88807b006258 [] R13: ffff88807b00628a R14: ffff888069334d00 R15: ffff88806a434600 [] FS: 0000000000000000(0000) GS:ffff888079480000(0000) knlGS:0[...] [] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [] CR2: 0000000000000000 CR3: 0000000077320000 CR4: 00000000000006e0 [] Call Trace: [] ? tipc_bcast_rcv+0x9a/0x1a0 [tipc] [] tipc_rcv+0x40d/0x670 [tipc] [] ? _raw_spin_unlock+0xa/0x20 [] tipc_l2_rcv_msg+0x55/0x80 [tipc] [] __netif_receive_skb_one_core+0x8c/0xa0 [] process_backlog+0x98/0x140 [] net_rx_action+0x13a/0x420 [] __do_softirq+0xdb/0x316 [] ? smpboot_thread_fn+0x2f/0x1e0 [] ? smpboot_thread_fn+0x74/0x1e0 [] ? smpboot_thread_fn+0x14e/0x1e0 [] run_ksoftirqd+0x1a/0x40 [] smpboot_thread_fn+0x149/0x1e0 [] ? sort_range+0x20/0x20 [] kthread+0x131/0x150 [] ? kthread_unuse_mm+0xa0/0xa0 [] ret_from_fork+0x22/0x30 [] Modules linked in: veth tipc(O) ip6_udp_tunnel udp_tunnel [...] [] CR2: 0000000000000000 [] ---[ end trace 65c276a8e2e2f310 ]---
To fix this, we need to grab the lock of the 'namedq' list on both path calling.
Fixes: cad2929dc432 ("tipc: update a binding service via broadcast") Acked-by: Jon Maloy jmaloy@redhat.com Signed-off-by: Hoang Huu Le hoang.h.le@dektech.com.au Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/tipc/name_distr.c | 10 +++++++++- net/tipc/node.c | 2 +- 2 files changed, 10 insertions(+), 2 deletions(-)
--- a/net/tipc/name_distr.c +++ b/net/tipc/name_distr.c @@ -327,8 +327,13 @@ static struct sk_buff *tipc_named_dequeu struct tipc_msg *hdr; u16 seqno;
+ spin_lock_bh(&namedq->lock); skb_queue_walk_safe(namedq, skb, tmp) { - skb_linearize(skb); + if (unlikely(skb_linearize(skb))) { + __skb_unlink(skb, namedq); + kfree_skb(skb); + continue; + } hdr = buf_msg(skb); seqno = msg_named_seqno(hdr); if (msg_is_last_bulk(hdr)) { @@ -338,12 +343,14 @@ static struct sk_buff *tipc_named_dequeu
if (msg_is_bulk(hdr) || msg_is_legacy(hdr)) { __skb_unlink(skb, namedq); + spin_unlock_bh(&namedq->lock); return skb; }
if (*open && (*rcv_nxt == seqno)) { (*rcv_nxt)++; __skb_unlink(skb, namedq); + spin_unlock_bh(&namedq->lock); return skb; }
@@ -353,6 +360,7 @@ static struct sk_buff *tipc_named_dequeu continue; } } + spin_unlock_bh(&namedq->lock); return NULL; }
--- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -1485,7 +1485,7 @@ static void node_lost_contact(struct tip
/* Clean up broadcast state */ tipc_bcast_remove_peer(n->net, n->bc_entry.link); - __skb_queue_purge(&n->bc_entry.namedq); + skb_queue_purge(&n->bc_entry.namedq);
/* Abort any ongoing link failover */ for (i = 0; i < MAX_BEARERS; i++) {