diff options
| author | Tung Nguyen <tung.q.nguyen@dektech.com.au> | 2022-03-04 03:25:18 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-03-04 13:19:13 +0000 |
| commit | be4977b847f5d5cedb64d50eaaf2218c3a55a3a3 (patch) | |
| tree | a0c051c749ce207fa5a19601edb8004bda0e892f /net/tipc | |
| parent | 0bf476fc3624e3a72af4ba7340d430a91c18cd67 (diff) | |
tipc: fix kernel panic when enabling bearer
When enabling a bearer on a node, a kernel panic is observed:
[ 4.498085] RIP: 0010:tipc_mon_prep+0x4e/0x130 [tipc]
...
[ 4.520030] Call Trace:
[ 4.520689] <IRQ>
[ 4.521236] tipc_link_build_proto_msg+0x375/0x750 [tipc]
[ 4.522654] tipc_link_build_state_msg+0x48/0xc0 [tipc]
[ 4.524034] __tipc_node_link_up+0xd7/0x290 [tipc]
[ 4.525292] tipc_rcv+0x5da/0x730 [tipc]
[ 4.526346] ? __netif_receive_skb_core+0xb7/0xfc0
[ 4.527601] tipc_l2_rcv_msg+0x5e/0x90 [tipc]
[ 4.528737] __netif_receive_skb_list_core+0x20b/0x260
[ 4.530068] netif_receive_skb_list_internal+0x1bf/0x2e0
[ 4.531450] ? dev_gro_receive+0x4c2/0x680
[ 4.532512] napi_complete_done+0x6f/0x180
[ 4.533570] virtnet_poll+0x29c/0x42e [virtio_net]
...
The node in question is receiving activate messages in another
thread after changing bearer status to allow message sending/
receiving in current thread:
thread 1 | thread 2
-------- | --------
|
tipc_enable_bearer() |
test_and_set_bit_lock() |
tipc_bearer_xmit_skb() |
| tipc_l2_rcv_msg()
| tipc_rcv()
| __tipc_node_link_up()
| tipc_link_build_state_msg()
| tipc_link_build_proto_msg()
| tipc_mon_prep()
| {
| ...
| // null-pointer dereference
| u16 gen = mon->dom_gen;
| ...
| }
// Not being executed yet |
tipc_mon_create() |
{ |
... |
// allocate |
mon = kzalloc(); |
... |
} |
Monitoring pointer in thread 2 is dereferenced before monitoring data
is allocated in thread 1. This causes kernel panic.
This commit fixes it by allocating the monitoring data before enabling
the bearer to receive messages.
Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework")
Reported-by: Shuang Li <shuali@redhat.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc')
| -rw-r--r-- | net/tipc/bearer.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index 473a790f5894..a2f9c9640716 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -352,16 +352,18 @@ static int tipc_enable_bearer(struct net *net, const char *name, goto rejected; } - test_and_set_bit_lock(0, &b->up); - rcu_assign_pointer(tn->bearer_list[bearer_id], b); - if (skb) - tipc_bearer_xmit_skb(net, bearer_id, skb, &b->bcast_addr); - + /* Create monitoring data before accepting activate messages */ if (tipc_mon_create(net, bearer_id)) { bearer_disable(net, b); + kfree_skb(skb); return -ENOMEM; } + test_and_set_bit_lock(0, &b->up); + rcu_assign_pointer(tn->bearer_list[bearer_id], b); + if (skb) + tipc_bearer_xmit_skb(net, bearer_id, skb, &b->bcast_addr); + pr_info("Enabled bearer <%s>, priority %u\n", name, prio); return res; |