smc: Use __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match().

[ Upstream commit 235f81045c ]

smc_clc_prfx_match() is called from smc_listen_work() and
not under RCU nor RTNL.

Using sk_dst_get(sk)->dev could trigger UAF.

Let's use __sk_dst_get() and dst_dev_rcu().

Note that the returned value of smc_clc_prfx_match() is not
used in the caller.

Fixes: a046d57da1 ("smc: CLC handshake (incl. preparation steps)")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250916214758.650211-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kuniyuki Iwashima
2025-09-16 21:47:21 +00:00
committed by Greg Kroah-Hartman
parent 0736993bfe
commit d26e80f7fb

View File

@@ -657,26 +657,26 @@ static int smc_clc_prfx_match6_rcu(struct net_device *dev,
int smc_clc_prfx_match(struct socket *clcsock,
struct smc_clc_msg_proposal_prefix *prop)
{
struct dst_entry *dst = sk_dst_get(clcsock->sk);
struct net_device *dev;
struct dst_entry *dst;
int rc;
if (!dst) {
rc = -ENOTCONN;
rcu_read_lock();
dst = __sk_dst_get(clcsock->sk);
dev = dst ? dst_dev_rcu(dst) : NULL;
if (!dev) {
rc = -ENODEV;
goto out;
}
if (!dst->dev) {
rc = -ENODEV;
goto out_rel;
}
rcu_read_lock();
if (!prop->ipv6_prefixes_cnt)
rc = smc_clc_prfx_match4_rcu(dst->dev, prop);
rc = smc_clc_prfx_match4_rcu(dev, prop);
else
rc = smc_clc_prfx_match6_rcu(dst->dev, prop);
rcu_read_unlock();
out_rel:
dst_release(dst);
rc = smc_clc_prfx_match6_rcu(dev, prop);
out:
rcu_read_unlock();
return rc;
}