apparmor: add base infastructure for socket mediation

version 2 - Force an abi break. Network mediation will only be
            available in v8 abi complaint policy.

Provide a basic mediation of sockets. This is not a full net mediation
but just whether a spcific family of socket can be used by an
application, along with setting up some basic infrastructure for
network mediation to follow.

the user space rule hav the basic form of
  NETWORK RULE = [ QUALIFIERS ] 'network' [ DOMAIN ]
                 [ TYPE | PROTOCOL ]

  DOMAIN = ( 'inet' | 'ax25' | 'ipx' | 'appletalk' | 'netrom' |
             'bridge' | 'atmpvc' | 'x25' | 'inet6' | 'rose' |
	     'netbeui' | 'security' | 'key' | 'packet' | 'ash' |
	     'econet' | 'atmsvc' | 'sna' | 'irda' | 'pppox' |
	     'wanpipe' | 'bluetooth' | 'netlink' | 'unix' | 'rds' |
	     'llc' | 'can' | 'tipc' | 'iucv' | 'rxrpc' | 'isdn' |
	     'phonet' | 'ieee802154' | 'caif' | 'alg' | 'nfc' |
	     'vsock' | 'mpls' | 'ib' | 'kcm' ) ','

  TYPE = ( 'stream' | 'dgram' | 'seqpacket' |  'rdm' | 'raw' |
           'packet' )

  PROTOCOL = ( 'tcp' | 'udp' | 'icmp' )

eg.
  network,
  network inet,

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>

1 files changed, 187 insertions, 0 deletions

diff --git a/security/apparmor/net.c b/security/apparmor/net.c
new file mode 100644
index 000000000000..bb24cfa0a164
--- /dev/null
+++ b/security/apparmor/net.c
@@ -0,0 +1,187 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor network mediation
+ *
+ * Copyright (C) 1998-2008 Novell/SUSE
+ * Copyright 2009-2017 Canonical Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ */
+
+#include "include/apparmor.h"
+#include "include/audit.h"
+#include "include/cred.h"
+#include "include/label.h"
+#include "include/net.h"
+#include "include/policy.h"
+
+#include "net_names.h"
+
+
+struct aa_sfs_entry aa_sfs_entry_network[] = {
+	AA_SFS_FILE_STRING("af_mask",	AA_SFS_AF_MASK),
+	{ }
+};
+
+static const char * const net_mask_names[] = {
+	"unknown",
+	"send",
+	"receive",
+	"unknown",
+
+	"create",
+	"shutdown",
+	"connect",
+	"unknown",
+
+	"setattr",
+	"getattr",
+	"setcred",
+	"getcred",
+
+	"chmod",
+	"chown",
+	"chgrp",
+	"lock",
+
+	"mmap",
+	"mprot",
+	"unknown",
+	"unknown",
+
+	"accept",
+	"bind",
+	"listen",
+	"unknown",
+
+	"setopt",
+	"getopt",
+	"unknown",
+	"unknown",
+
+	"unknown",
+	"unknown",
+	"unknown",
+	"unknown",
+};
+
+
+/* audit callback for net specific fields */
+void audit_net_cb(struct audit_buffer *ab, void *va)
+{
+	struct common_audit_data *sa = va;
+
+	audit_log_format(ab, " family=");
+	if (address_family_names[sa->u.net->family])
+		audit_log_string(ab, address_family_names[sa->u.net->family]);
+	else
+		audit_log_format(ab, "\"unknown(%d)\"", sa->u.net->family);
+	audit_log_format(ab, " sock_type=");
+	if (sock_type_names[aad(sa)->net.type])
+		audit_log_string(ab, sock_type_names[aad(sa)->net.type]);
+	else
+		audit_log_format(ab, "\"unknown(%d)\"", aad(sa)->net.type);
+	audit_log_format(ab, " protocol=%d", aad(sa)->net.protocol);
+
+	if (aad(sa)->request & NET_PERMS_MASK) {
+		audit_log_format(ab, " requested_mask=");
+		aa_audit_perm_mask(ab, aad(sa)->request, NULL, 0,
+				   net_mask_names, NET_PERMS_MASK);
+
+		if (aad(sa)->denied & NET_PERMS_MASK) {
+			audit_log_format(ab, " denied_mask=");
+			aa_audit_perm_mask(ab, aad(sa)->denied, NULL, 0,
+					   net_mask_names, NET_PERMS_MASK);
+		}
+	}
+	if (aad(sa)->peer) {
+		audit_log_format(ab, " peer=");
+		aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
+				FLAGS_NONE, GFP_ATOMIC);
+	}
+}
+
+/* Generic af perm */
+int aa_profile_af_perm(struct aa_profile *profile, struct common_audit_data *sa,
+		       u32 request, u16 family, int type)
+{
+	struct aa_perms perms = { };
+	unsigned int state;
+	__be16 buffer[2];
+
+	AA_BUG(family >= AF_MAX);
+	AA_BUG(type < 0 || type >= SOCK_MAX);
+
+	if (profile_unconfined(profile))
+		return 0;
+	state = PROFILE_MEDIATES(profile, AA_CLASS_NET);
+	if (!state)
+		return 0;
+
+	buffer[0] = cpu_to_be16(family);
+	buffer[1] = cpu_to_be16((u16) type);
+	state = aa_dfa_match_len(profile->policy.dfa, state, (char *) &buffer,
+				 4);
+	aa_compute_perms(profile->policy.dfa, state, &perms);
+	aa_apply_modes_to_perms(profile, &perms);
+
+	return aa_check_perms(profile, &perms, request, sa, audit_net_cb);
+}
+
+int aa_af_perm(struct aa_label *label, const char *op, u32 request, u16 family,
+	       int type, int protocol)
+{
+	struct aa_profile *profile;
+	DEFINE_AUDIT_NET(sa, op, NULL, family, type, protocol);
+
+	return fn_for_each_confined(label, profile,
+			aa_profile_af_perm(profile, &sa, request, family,
+					   type));
+}
+
+static int aa_label_sk_perm(struct aa_label *label, const char *op, u32 request,
+			    struct sock *sk)
+{
+	struct aa_profile *profile;
+	DEFINE_AUDIT_SK(sa, op, sk);
+
+	AA_BUG(!label);
+	AA_BUG(!sk);
+
+	if (unconfined(label))
+		return 0;
+
+	return fn_for_each_confined(label, profile,
+			aa_profile_af_sk_perm(profile, &sa, request, sk));
+}
+
+int aa_sk_perm(const char *op, u32 request, struct sock *sk)
+{
+	struct aa_label *label;
+	int error;
+
+	AA_BUG(!sk);
+	AA_BUG(in_interrupt());
+
+	/* TODO: switch to begin_current_label ???? */
+	label = begin_current_label_crit_section();
+	error = aa_label_sk_perm(label, op, request, sk);
+	end_current_label_crit_section(label);
+
+	return error;
+}
+
+
+int aa_sock_file_perm(struct aa_label *label, const char *op, u32 request,
+		      struct socket *sock)
+{
+	AA_BUG(!label);
+	AA_BUG(!sock);
+	AA_BUG(!sock->sk);
+
+	return aa_label_sk_perm(label, op, request, sock->sk);
+}