src: add security context information

This commit adds security context information structures
and functions.

This will allow userspace to find the security context of each
packet (if it exists) and make decisions based on that.
It should work for SELinux and SMACK.

Signed-off-by: Roman Kubiak <r.kubiak@samsung.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 24 insertions, 0 deletions

diff --git a/src/libnetfilter_queue.c b/src/libnetfilter_queue.c
index c9ed865..84184ee 100644
--- a/src/libnetfilter_queue.c
+++ b/src/libnetfilter_queue.c
@@ -1218,6 +1218,29 @@ int nfq_get_gid(struct nfq_data *nfad, uint32_t *gid)
 }
 EXPORT_SYMBOL(nfq_get_gid);
 
+
+/**
+ * nfq_get_secctx - get the security context for this packet
+ * \param nfad Netlink packet data handle passed to callback function
+ * \param secdata data to write the security context to
+ *
+ * \return -1 on error, otherwise > 0
+ */
+int nfq_get_secctx(struct nfq_data *nfad, unsigned char **secdata)
+{
+	if (!nfnl_attr_present(nfad->data, NFQA_SECCTX))
+		return -1;
+
+	*secdata = (unsigned char *)nfnl_get_pointer_to_data(nfad->data,
+							NFQA_SECCTX, char);
+
+	if (*secdata)
+		return NFA_PAYLOAD(nfad->data[NFQA_SECCTX-1]);
+
+	return 0;
+}
+EXPORT_SYMBOL(nfq_get_secctx);
+
 /**
  * nfq_get_payload - get payload 
  * \param nfad Netlink packet data handle passed to callback function
diff --git a/src/nlmsg.c b/src/nlmsg.c
index aebdd5e..cabd8be 100644
--- a/src/nlmsg.c
+++ b/src/nlmsg.c
@@ -137,6 +137,7 @@ static int nfq_pkt_parse_attr_cb(const struct nlattr *attr, void *data)
 	case NFQA_IFINDEX_PHYSOUTDEV:
 	case NFQA_CAP_LEN:
 	case NFQA_SKB_INFO:
+	case NFQA_SECCTX:
 	case NFQA_UID:
 	case NFQA_GID:
 		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)