netfilter: nfnetlink_queue: enable UID/GID socket info retrieval

Thanks to commits 41063e9 (ipv4: Early TCP socket demux) and 421b388
(udp: ipv4: Add udp early demux) it is now possible to parse UID and
GID socket info also for incoming TCP and UDP connections. Having
this info available, it is convenient to let NFQUEUE parse it in
order to improve and refine the traffic analysis in userspace.

Signed-off-by: Valentina Giusti <valentina.giusti@bmw-carit.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/uapi/linux/netfilter/nfnetlink_queue.h b/include/uapi/linux/netfilter/nfnetlink_queue.h
index 0132bad79de7f6860120d13c6df2d508ad2d5d14..8dd819e2b5feddf4afa4ba0389b9e324973a9b9c 100644 (file)
--- a/include/uapi/linux/netfilter/nfnetlink_queue.h
+++ b/include/uapi/linux/netfilter/nfnetlink_queue.h
@@ -47,6 +47,8 @@ enum nfqnl_attr_type {
        NFQA_CAP_LEN,                   /* __u32 length of captured packet */
        NFQA_SKB_INFO,                  /* __u32 skb meta information */
        NFQA_EXP,                       /* nf_conntrack_netlink.h */
+       NFQA_UID,                       /* __u32 sk uid */
+       NFQA_GID,                       /* __u32 sk gid */
 
        __NFQA_MAX
 };
@@ -99,7 +101,8 @@ enum nfqnl_attr_config {
 #define NFQA_CFG_F_FAIL_OPEN                   (1 << 0)
 #define NFQA_CFG_F_CONNTRACK                   (1 << 1)
 #define NFQA_CFG_F_GSO                         (1 << 2)
-#define NFQA_CFG_F_MAX                         (1 << 3)
+#define NFQA_CFG_F_UID_GID                     (1 << 3)
+#define NFQA_CFG_F_MAX                         (1 << 4)
 
 /* flags for NFQA_SKB_INFO */
 /* packet appears to have wrong checksums, but they are ok */

diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c
index 21258cf7009118c3820c7b9575b4a4bd1b331f1f..d3cf12b83174df36496fd4554519dc5663d3413f 100644 (file)
--- a/net/netfilter/nfnetlink_queue_core.c
+++ b/net/netfilter/nfnetlink_queue_core.c
@@ -297,6 +297,31 @@ nfqnl_put_packet_info(struct sk_buff *nlskb, struct sk_buff *packet,
        return flags ? nla_put_be32(nlskb, NFQA_SKB_INFO, htonl(flags)) : 0;
 }
 
+static int nfqnl_put_sk_uidgid(struct sk_buff *skb, struct sock *sk)
+{
+       const struct cred *cred;
+
+       if (sk->sk_state == TCP_TIME_WAIT)
+               return 0;
+
+       read_lock_bh(&sk->sk_callback_lock);
+       if (sk->sk_socket && sk->sk_socket->file) {
+               cred = sk->sk_socket->file->f_cred;
+               if (nla_put_be32(skb, NFQA_UID,
+                   htonl(from_kuid_munged(&init_user_ns, cred->fsuid))))
+                       goto nla_put_failure;
+               if (nla_put_be32(skb, NFQA_GID,
+                   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;
+}
+
 static struct sk_buff *
 nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
                           struct nf_queue_entry *entry,
@@ -372,6 +397,11 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
        if (queue->flags & NFQA_CFG_F_CONNTRACK)
                ct = nfqnl_ct_get(entskb, &size, &ctinfo);
 
+       if (queue->flags & NFQA_CFG_F_UID_GID) {
+               size +=  (nla_total_size(sizeof(u_int32_t))     /* uid */
+                       + nla_total_size(sizeof(u_int32_t)));   /* gid */
+       }
+
        skb = nfnetlink_alloc_skb(net, size, queue->peer_portid,
                                  GFP_ATOMIC);
        if (!skb)
@@ -484,6 +514,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
                        goto nla_put_failure;
        }
 
+       if ((queue->flags & NFQA_CFG_F_UID_GID) && entskb->sk &&
+           nfqnl_put_sk_uidgid(skb, entskb->sk) < 0)
+               goto nla_put_failure;
+
        if (ct && nfqnl_ct_put(skb, ct, ctinfo) < 0)
                goto nla_put_failure;