6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Phil Sutter <phil@xxxxxx>
[ Upstream commit 7ae836a3d630e146b732fe8ef7d86b243748751f ]
A concurrently running sock_orphan() may NULL the sk_socket pointer in
between check and deref. Follow other users (like nft_meta.c for
instance) and acquire sk_callback_lock before dereferencing sk_socket.
Fixes: 0265ab44bacc ("[NETFILTER]: merge ipt_owner/ip6t_owner in xt_owner")
Reported-by: Jann Horn <jannh@xxxxxxxxxx>
Signed-off-by: Phil Sutter <phil@xxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/netfilter/xt_owner.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/net/netfilter/xt_owner.c b/net/netfilter/xt_owner.c
index e85ce69924aee..50332888c8d23 100644
--- a/net/netfilter/xt_owner.c
+++ b/net/netfilter/xt_owner.c
@@ -76,18 +76,23 @@ owner_mt(const struct sk_buff *skb, struct xt_action_param *par)
*/
return false;
- filp = sk->sk_socket->file;
- if (filp == NULL)
+ read_lock_bh(&sk->sk_callback_lock);
+ filp = sk->sk_socket ? sk->sk_socket->file : NULL;
+ if (filp == NULL) {
+ read_unlock_bh(&sk->sk_callback_lock);
return ((info->match ^ info->invert) &
(XT_OWNER_UID | XT_OWNER_GID)) == 0;
+ }
if (info->match & XT_OWNER_UID) {
kuid_t uid_min = make_kuid(net->user_ns, info->uid_min);
kuid_t uid_max = make_kuid(net->user_ns, info->uid_max);
if ((uid_gte(filp->f_cred->fsuid, uid_min) &&
uid_lte(filp->f_cred->fsuid, uid_max)) ^
- !(info->invert & XT_OWNER_UID))
+ !(info->invert & XT_OWNER_UID)) {
+ read_unlock_bh(&sk->sk_callback_lock);
return false;
+ }
}
if (info->match & XT_OWNER_GID) {
@@ -112,10 +117,13 @@ owner_mt(const struct sk_buff *skb, struct xt_action_param *par)
}
}
- if (match ^ !(info->invert & XT_OWNER_GID))
+ if (match ^ !(info->invert & XT_OWNER_GID)) {
+ read_unlock_bh(&sk->sk_callback_lock);
return false;
+ }
}
+ read_unlock_bh(&sk->sk_callback_lock);
return true;
}
--
2.42.0
