diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nfnetlink_queue.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 7f5248b5f1ee..27300d3663da 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -545,14 +545,23 @@ nfqnl_put_packet_info(struct sk_buff *nlskb, struct sk_buff *packet, static int nfqnl_put_sk_uidgid(struct sk_buff *skb, struct sock *sk) { + const struct socket *sock; + const struct file *file; const struct cred *cred; if (!sk_fullsock(sk)) return 0; - read_lock_bh(&sk->sk_callback_lock); - if (sk->sk_socket && sk->sk_socket->file) { - cred = sk->sk_socket->file->f_cred; + /* The sk pointer remains valid as long as the skb is. + * The sk_socket and file pointer may become NULL + * if the socket is closed. + * Both structures (including file->cred) are RCU freed + * which means they can be accessed within a RCU read section. + */ + sock = READ_ONCE(sk->sk_socket); + file = sock ? READ_ONCE(sock->file) : NULL; + if (file) { + cred = file->f_cred; if (nla_put_be32(skb, NFQA_UID, htonl(from_kuid_munged(&init_user_ns, cred->fsuid)))) goto nla_put_failure; @@ -560,11 +569,9 @@ static int nfqnl_put_sk_uidgid(struct sk_buff *skb, struct sock *sk) htonl(from_kgid_munged(&init_user_ns, cred->fsgid)))) goto nla_put_failure; } - read_unlock_bh(&sk->sk_callback_lock); return 0; nla_put_failure: - read_unlock_bh(&sk->sk_callback_lock); return -1; } |