sock_diag: allow to dump bpf filters
This patch allows to dump BPF filters attached to a socket with
SO_ATTACH_FILTER.
Note that we check CAP_SYS_ADMIN before allowing to dump this info.
For now, only AF_PACKET sockets use this feature.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index a29e90c..d5bef0b0 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -49,6 +49,39 @@
}
EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
+int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk,
+ struct sk_buff *skb, int attrtype)
+{
+ struct nlattr *attr;
+ struct sk_filter *filter;
+ unsigned int len;
+ int err = 0;
+
+ if (!ns_capable(user_ns, CAP_NET_ADMIN)) {
+ nla_reserve(skb, attrtype, 0);
+ return 0;
+ }
+
+ rcu_read_lock();
+
+ filter = rcu_dereference(sk->sk_filter);
+ len = filter ? filter->len * sizeof(struct sock_filter) : 0;
+
+ attr = nla_reserve(skb, attrtype, len);
+ if (attr == NULL) {
+ err = -EMSGSIZE;
+ goto out;
+ }
+
+ if (filter)
+ memcpy(nla_data(attr), filter->insns, len);
+
+out:
+ rcu_read_unlock();
+ return err;
+}
+EXPORT_SYMBOL(sock_diag_put_filterinfo);
+
void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
{
mutex_lock(&sock_diag_table_mutex);
diff --git a/net/packet/diag.c b/net/packet/diag.c
index 822fe9b..a9584a2 100644
--- a/net/packet/diag.c
+++ b/net/packet/diag.c
@@ -170,6 +170,10 @@
sock_diag_put_meminfo(sk, skb, PACKET_DIAG_MEMINFO))
goto out_nlmsg_trim;
+ if ((req->pdiag_show & PACKET_SHOW_FILTER) &&
+ sock_diag_put_filterinfo(user_ns, sk, skb, PACKET_DIAG_FILTER))
+ goto out_nlmsg_trim;
+
return nlmsg_end(skb, nlh);
out_nlmsg_trim: