New subject: [PATCH OLK-5.10] phonet/pep: fix racy skb_queue_empty() use

5 Jun 2024

From: Rémi Denis-Courmont courmisch@gmail.com
mainline inclusion
from mainline-v6.8-rc6
commit 7d2a894d7f487dcb894df023e9d3014cf5b93fe5
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9Q8LU
CVE: CVE-2024-27402
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
The receive queues are protected by their respective spin-lock, not
the socket lock. This could lead to skb_peek() unexpectedly
returning NULL or a pointer to an already dequeued socket buffer.
Fixes: 9641458d3ec4 ("Phonet: Pipe End Point for Phonet Pipes protocol")
Signed-off-by: Rémi Denis-Courmont courmisch@gmail.com
Link: https://lore.kernel.org/r/20240218081214.4806-2-remi@remlab.net
Signed-off-by: Paolo Abeni pabeni@redhat.com
Conflicts:
    net/phonet/pep.c
[ Context conflict ]
Signed-off-by: Yipeng Zou zouyipeng@huawei.com
---
 net/phonet/pep.c | 41 ++++++++++++++++++++++++++++++++---------
 1 file changed, 32 insertions(+), 9 deletions(-)

diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index 65d463ad8770..3ea23e7caab6 100644
--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -916,6 +916,37 @@ static int pep_sock_enable(struct sock *sk, struct sockaddr *addr, int len)
    return 0;
 }
+static unsigned int pep_first_packet_length(struct sock *sk)
+{
+	struct pep_sock *pn = pep_sk(sk);
+	struct sk_buff_head *q;
+	struct sk_buff *skb;
+	unsigned int len = 0;
+	bool found = false;
+
+	if (sock_flag(sk, SOCK_URGINLINE)) {
+		q = &pn->ctrlreq_queue;
+		spin_lock_bh(&q->lock);
+		skb = skb_peek(q);
+		if (skb) {
+			len = skb->len;
+			found = true;
+		}
+		spin_unlock_bh(&q->lock);
+	}
+
+	if (likely(!found)) {
+		q = &sk->sk_receive_queue;
+		spin_lock_bh(&q->lock);
+		skb = skb_peek(q);
+		if (skb)
+			len = skb->len;
+		spin_unlock_bh(&q->lock);
+	}
+
+	return len;
+}
+
 static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg)
 {
    struct pep_sock *pn = pep_sk(sk);
@@ -929,15 +960,7 @@ static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg)
    		break;
    	}
-		lock_sock(sk);
-		if (sock_flag(sk, SOCK_URGINLINE) &&
-		    !skb_queue_empty(&pn->ctrlreq_queue))
-			answ = skb_peek(&pn->ctrlreq_queue)->len;
-		else if (!skb_queue_empty(&sk->sk_receive_queue))
-			answ = skb_peek(&sk->sk_receive_queue)->len;
-		else
-			answ = 0;
-		release_sock(sk);
+		answ = pep_first_packet_length(sk);
    	ret = put_user(answ, (int __user *)arg);
    	break;
-- 
2.34.1


    

[PATCH openEuler-22.03-LTS-SP1] phonet/pep: fix racy skb_queue_empty() use