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llc: Check netns in llc_dgram_match().

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We will remove this restriction in llc_rcv() soon, which means that the
protocol handler must be aware of netns.

	if (!net_eq(dev_net(dev), &init_net))
		goto drop;

llc_rcv() fetches llc_type_handlers[llc_pdu_type(skb) - 1] and calls it
if not NULL.

If the PDU type is LLC_DEST_SAP, llc_sap_handler() is called to pass skb
to corresponding sockets.  Then, we must look up a proper socket in the
same netns with skb->dev.

If the destination is a multicast address, llc_sap_handler() calls
llc_sap_mcast().  It calculates a hash based on DSAP and skb->dev->ifindex,
iterates on a socket list, and calls llc_mcast_match() to check if the
socket is the correct destination.  Then, llc_mcast_match() checks if
skb->dev matches with llc_sk(sk)->dev.  So, we need not check netns here.

OTOH, if the destination is a unicast address, llc_sap_handler() calls
llc_lookup_dgram() to look up a socket, but it does not check the netns.

Therefore, we need to add netns check in llc_lookup_dgram().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Kuniyuki Iwashima 2023-07-18 10:41:49 -07:00 committed by Paolo Abeni
parent 9f9d4c1a2e
commit 9b64e93e83
1 changed files with 11 additions and 7 deletions
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18
net/llc/llc_sap.c
View file

@ -294,25 +294,29 @@ static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb,
static inline bool llc_dgram_match(const struct llc_sap *sap,
const struct llc_addr *laddr,
const struct sock *sk)
const struct sock *sk,
const struct net *net)
{
struct llc_sock *llc = llc_sk(sk);
return sk->sk_type == SOCK_DGRAM &&
llc->laddr.lsap == laddr->lsap &&
ether_addr_equal(llc->laddr.mac, laddr->mac);
net_eq(sock_net(sk), net) &&
llc->laddr.lsap == laddr->lsap &&
ether_addr_equal(llc->laddr.mac, laddr->mac);
}
/**
* llc_lookup_dgram - Finds dgram socket for the local sap/mac
* @sap: SAP
* @laddr: address of local LLC (MAC + SAP)
* @net: netns to look up a socket in
*
* Search socket list of the SAP and finds connection using the local
* mac, and local sap. Returns pointer for socket found, %NULL otherwise.
*/
static struct sock *llc_lookup_dgram(struct llc_sap *sap,
const struct llc_addr *laddr)
const struct llc_addr *laddr,
const struct net *net)
{
struct sock *rc;
struct hlist_nulls_node *node;
@ -322,12 +326,12 @@ static struct sock *llc_lookup_dgram(struct llc_sap *sap,
rcu_read_lock_bh();
again:
sk_nulls_for_each_rcu(rc, node, laddr_hb) {
if (llc_dgram_match(sap, laddr, rc)) {
if (llc_dgram_match(sap, laddr, rc, net)) {
/* Extra checks required by SLAB_TYPESAFE_BY_RCU */
if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
goto again;
if (unlikely(llc_sk(rc)->sap != sap ||
!llc_dgram_match(sap, laddr, rc))) {
!llc_dgram_match(sap, laddr, rc, net))) {
sock_put(rc);
continue;
}
@ -429,7 +433,7 @@ void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
llc_sap_mcast(sap, &laddr, skb);
kfree_skb(skb);
} else {
struct sock *sk = llc_lookup_dgram(sap, &laddr);
struct sock *sk = llc_lookup_dgram(sap, &laddr, dev_net(skb->dev));
if (sk) {
llc_sap_rcv(sap, skb, sk);
sock_put(sk);