This is a note to let you know that I've just added the patch titled
tipc: move bc link creation back to tipc_node_create
to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tipc-move-bc-link-creation-back-to-tipc_node_create.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From cb8092d70a6f5f01ec1490fce4d35efed3ed996c Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@xxxxxxxxx>
Date: Fri, 24 Jun 2022 12:24:31 -0400
Subject: tipc: move bc link creation back to tipc_node_create
From: Xin Long <lucien.xin@xxxxxxxxx>
commit cb8092d70a6f5f01ec1490fce4d35efed3ed996c upstream.
Shuang Li reported a NULL pointer dereference crash:
[] BUG: kernel NULL pointer dereference, address: 0000000000000068
[] RIP: 0010:tipc_link_is_up+0x5/0x10 [tipc]
[] Call Trace:
[] <IRQ>
[] tipc_bcast_rcv+0xa2/0x190 [tipc]
[] tipc_node_bc_rcv+0x8b/0x200 [tipc]
[] tipc_rcv+0x3af/0x5b0 [tipc]
[] tipc_udp_recv+0xc7/0x1e0 [tipc]
It was caused by the 'l' passed into tipc_bcast_rcv() is NULL. When it
creates a node in tipc_node_check_dest(), after inserting the new node
into hashtable in tipc_node_create(), it creates the bc link. However,
there is a gap between this insert and bc link creation, a bc packet
may come in and get the node from the hashtable then try to dereference
its bc link, which is NULL.
This patch is to fix it by moving the bc link creation before inserting
into the hashtable.
Note that for a preliminary node becoming "real", the bc link creation
should also be called before it's rehashed, as we don't create it for
preliminary nodes.
Fixes: 4cbf8ac2fe5a ("tipc: enable creating a "preliminary" node")
Reported-by: Shuang Li <shuali@xxxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Jon Maloy <jmaloy@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/tipc/node.c | 41 ++++++++++++++++++++++-------------------
1 file changed, 22 insertions(+), 19 deletions(-)
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -472,8 +472,8 @@ struct tipc_node *tipc_node_create(struc
bool preliminary)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
+ struct tipc_link *l, *snd_l = tipc_bc_sndlink(net);
struct tipc_node *n, *temp_node;
- struct tipc_link *l;
unsigned long intv;
int bearer_id;
int i;
@@ -488,6 +488,16 @@ struct tipc_node *tipc_node_create(struc
goto exit;
/* A preliminary node becomes "real" now, refresh its data */
tipc_node_write_lock(n);
+ if (!tipc_link_bc_create(net, tipc_own_addr(net), addr, peer_id, U16_MAX,
+ tipc_link_min_win(snd_l), tipc_link_max_win(snd_l),
+ n->capabilities, &n->bc_entry.inputq1,
+ &n->bc_entry.namedq, snd_l, &n->bc_entry.link)) {
+ pr_warn("Broadcast rcv link refresh failed, no memory\n");
+ tipc_node_write_unlock_fast(n);
+ tipc_node_put(n);
+ n = NULL;
+ goto exit;
+ }
n->preliminary = false;
n->addr = addr;
hlist_del_rcu(&n->hash);
@@ -567,7 +577,16 @@ update:
n->signature = INVALID_NODE_SIG;
n->active_links[0] = INVALID_BEARER_ID;
n->active_links[1] = INVALID_BEARER_ID;
- n->bc_entry.link = NULL;
+ if (!preliminary &&
+ !tipc_link_bc_create(net, tipc_own_addr(net), addr, peer_id, U16_MAX,
+ tipc_link_min_win(snd_l), tipc_link_max_win(snd_l),
+ n->capabilities, &n->bc_entry.inputq1,
+ &n->bc_entry.namedq, snd_l, &n->bc_entry.link)) {
+ pr_warn("Broadcast rcv link creation failed, no memory\n");
+ kfree(n);
+ n = NULL;
+ goto exit;
+ }
tipc_node_get(n);
timer_setup(&n->timer, tipc_node_timeout, 0);
/* Start a slow timer anyway, crypto needs it */
@@ -1155,7 +1174,7 @@ void tipc_node_check_dest(struct net *ne
bool *respond, bool *dupl_addr)
{
struct tipc_node *n;
- struct tipc_link *l, *snd_l;
+ struct tipc_link *l;
struct tipc_link_entry *le;
bool addr_match = false;
bool sign_match = false;
@@ -1175,22 +1194,6 @@ void tipc_node_check_dest(struct net *ne
return;
tipc_node_write_lock(n);
- if (unlikely(!n->bc_entry.link)) {
- snd_l = tipc_bc_sndlink(net);
- if (!tipc_link_bc_create(net, tipc_own_addr(net),
- addr, peer_id, U16_MAX,
- tipc_link_min_win(snd_l),
- tipc_link_max_win(snd_l),
- n->capabilities,
- &n->bc_entry.inputq1,
- &n->bc_entry.namedq, snd_l,
- &n->bc_entry.link)) {
- pr_warn("Broadcast rcv link creation failed, no mem\n");
- tipc_node_write_unlock_fast(n);
- tipc_node_put(n);
- return;
- }
- }
le = &n->links[b->identity];
Patches currently in stable-queue which might be from lucien.xin@xxxxxxxxx are
queue-5.18/tipc-move-bc-link-creation-back-to-tipc_node_create.patch
