secmark: export secctx, drop secmark in procfs

The current secmark code exports a secmark= field which just indicates if
there is special labeling on a packet or not.  We drop this field as it
isn't particularly useful and instead export a new field secctx= which is
the actual human readable text label.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: James Morris <jmorris@namei.org>

net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c

@@ -11,6 +11,7 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/percpu.h>
+#include <linux/security.h>
 #include <net/net_namespace.h>
 
 #include <linux/netfilter.h>
@@ -87,6 +88,29 @@ static void ct_seq_stop(struct seq_file *s, void *v)
 	rcu_read_unlock();
 }
 
+#ifdef CONFIG_NF_CONNTRACK_SECMARK
+static int ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
+{
+	int ret;
+	u32 len;
+	char *secctx;
+
+	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
+	if (ret)
+		return ret;
+
+	ret = seq_printf(s, "secctx=%s ", secctx);
+
+	security_release_secctx(secctx, len);
+	return ret;
+}
+#else
+static inline int ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
+{
+	return 0;
+}
+#endif
+
 static int ct_seq_show(struct seq_file *s, void *v)
 {
 	struct nf_conntrack_tuple_hash *hash = v;
@@ -148,10 +172,8 @@ static int ct_seq_show(struct seq_file *s, void *v)
 		goto release;
 #endif
 
-#ifdef CONFIG_NF_CONNTRACK_SECMARK
-	if (seq_printf(s, "secmark=%u ", ct->secmark))
+	if (ct_show_secctx(s, ct))
 		goto release;
-#endif
 
 	if (seq_printf(s, "use=%u\n", atomic_read(&ct->ct_general.use)))
 		goto release;

net/netfilter/nf_conntrack_standalone.c

@@ -15,6 +15,7 @@
 #include <linux/seq_file.h>
 #include <linux/percpu.h>
 #include <linux/netdevice.h>
+#include <linux/security.h>
 #include <net/net_namespace.h>
 #ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
@@ -108,6 +109,29 @@ static void ct_seq_stop(struct seq_file *s, void *v)
 	rcu_read_unlock();
 }
 
+#ifdef CONFIG_NF_CONNTRACK_SECMARK
+static int ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
+{
+	int ret;
+	u32 len;
+	char *secctx;
+
+	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
+	if (ret)
+		return ret;
+
+	ret = seq_printf(s, "secctx=%s ", secctx);
+
+	security_release_secctx(secctx, len);
+	return ret;
+}
+#else
+static inline int ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
+{
+	return 0;
+}
+#endif
+
 /* return 0 on success, 1 in case of error */
 static int ct_seq_show(struct seq_file *s, void *v)
 {
@@ -168,10 +192,8 @@ static int ct_seq_show(struct seq_file *s, void *v)
 		goto release;
 #endif
 
-#ifdef CONFIG_NF_CONNTRACK_SECMARK
-	if (seq_printf(s, "secmark=%u ", ct->secmark))
+	if (ct_show_secctx(s, ct))
 		goto release;
-#endif
 
 #ifdef CONFIG_NF_CONNTRACK_ZONES
 	if (seq_printf(s, "zone=%u ", nf_ct_zone(ct)))