I think i forgot to mention one important thing the function: security_sk_getsecid is not in the kernel yet, i posted a patch to add it on the linux-security-module mailing list: http://marc.info/?t=143254934900006&r=1&w=2 It actually does not do anything it's a definition only, the actual code belong to the currently active LSM in the kernel. On 05/27/2015 01:04 PM, Roman Kubiak wrote: > I removed the part where i was adding NULL, i also changed as per suggestions and slightly > streamlined the code. > > > This patch adds an additional attribute when sending > packet information via netlink in netfilter_queue module. > It will send additional security context data, so that > userspace applications can verify this context against > their own security databases. > > Signed-off-by: Roman Kubiak <r.kubiak@xxxxxxxxxxx> > --- > v2: > - nfqnl_get_sk_secctx returns seclen now, this changes > - updated size calculation > - changed NFQA_SECCTX comment > - removed duplicate testing of NFQA_CFG_F flags > > v3: > - NULL is not added to the security context anymore > - return 0 when socket is invalid in nfqnl_get_sk_secctx > - small intent change > - removed ret variable in nfqnl_get_sk_secctx > --- > include/uapi/linux/netfilter/nfnetlink_queue.h | 4 +++- > net/netfilter/nfnetlink_queue_core.c | 31 ++++++++++++++++++++++++++ > 2 files changed, 34 insertions(+), 1 deletion(-) > > diff --git a/include/uapi/linux/netfilter/nfnetlink_queue.h b/include/uapi/linux/netfilter/nfnetlink_queue.h > index 8dd819e..b67a853 100644 > --- a/include/uapi/linux/netfilter/nfnetlink_queue.h > +++ b/include/uapi/linux/netfilter/nfnetlink_queue.h > @@ -49,6 +49,7 @@ enum nfqnl_attr_type { > NFQA_EXP, /* nf_conntrack_netlink.h */ > NFQA_UID, /* __u32 sk uid */ > NFQA_GID, /* __u32 sk gid */ > + NFQA_SECCTX, /* security context string */ > > __NFQA_MAX > }; > @@ -102,7 +103,8 @@ enum nfqnl_attr_config { > #define NFQA_CFG_F_CONNTRACK (1 << 1) > #define NFQA_CFG_F_GSO (1 << 2) > #define NFQA_CFG_F_UID_GID (1 << 3) > -#define NFQA_CFG_F_MAX (1 << 4) > +#define NFQA_CFG_F_SECCTX (1 << 4) > +#define NFQA_CFG_F_MAX (1 << 5) > > /* 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 0b98c74..ae4f520 100644 > --- a/net/netfilter/nfnetlink_queue_core.c > +++ b/net/netfilter/nfnetlink_queue_core.c > @@ -278,6 +278,24 @@ nla_put_failure: > return -1; > } > > +static u32 nfqnl_get_sk_secctx(struct sock *sk, char **secdata) > +{ > + u32 secid = 0; > + u32 seclen = 0; > + > + if (!sk || !sk_fullsock(sk)) > + return 0; > + > + read_lock_bh(&sk->sk_callback_lock); > + security_sk_getsecid(sk, &secid); > + > + if (secid && security_secid_to_secctx(secid, secdata, &seclen)) > + seclen = 0; > + > + read_unlock_bh(&sk->sk_callback_lock); > + return seclen; > +} > + > static struct sk_buff * > nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, > struct nf_queue_entry *entry, > @@ -297,6 +315,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, > struct nf_conn *ct = NULL; > enum ip_conntrack_info uninitialized_var(ctinfo); > bool csum_verify; > + char *secdata = NULL; > + u32 seclen = 0; > > size = nlmsg_total_size(sizeof(struct nfgenmsg)) > + nla_total_size(sizeof(struct nfqnl_msg_packet_hdr)) > @@ -352,6 +372,12 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, > + nla_total_size(sizeof(u_int32_t))); /* gid */ > } > > + if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) { > + seclen = nfqnl_get_sk_secctx(entskb->sk, &secdata); > + if (seclen) > + size += nla_total_size(seclen); > + } > + > skb = nfnetlink_alloc_skb(net, size, queue->peer_portid, > GFP_ATOMIC); > if (!skb) { > @@ -479,6 +505,11 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, > nfqnl_put_sk_uidgid(skb, entskb->sk) < 0) > goto nla_put_failure; > > + if (seclen) { > + if (nla_put(skb, NFQA_SECCTX, seclen, secdata)) > + goto nla_put_failure; > + } > + > if (ct && nfqnl_ct_put(skb, ct, ctinfo) < 0) > goto nla_put_failure; > > -- -------------- Roman Kubiak -------------- -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
