apparmor: add base infastructure for socket mediation

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, 387 insertions, 0 deletions

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 4ad0b3a45142..cc5ab23a2d84 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -33,6 +33,7 @@
 #include "include/context.h"
 #include "include/file.h"
 #include "include/ipc.h"
+#include "include/net.h"
 #include "include/path.h"
 #include "include/label.h"
 #include "include/policy.h"
@@ -736,6 +737,368 @@ static int apparmor_task_kill(struct task_struct *target, struct siginfo *info,
 	return error;
 }
 
+/**
+ * apparmor_sk_alloc_security - allocate and attach the sk_security field
+ */
+static int apparmor_sk_alloc_security(struct sock *sk, int family, gfp_t flags)
+{
+	struct aa_sk_ctx *ctx;
+
+	ctx = kzalloc(sizeof(*ctx), flags);
+	if (!ctx)
+		return -ENOMEM;
+
+	SK_CTX(sk) = ctx;
+
+	return 0;
+}
+
+/**
+ * apparmor_sk_free_security - free the sk_security field
+ */
+static void apparmor_sk_free_security(struct sock *sk)
+{
+	struct aa_sk_ctx *ctx = SK_CTX(sk);
+
+	SK_CTX(sk) = NULL;
+	aa_put_label(ctx->label);
+	aa_put_label(ctx->peer);
+	path_put(&ctx->path);
+	kfree(ctx);
+}
+
+/**
+ * apparmor_clone_security - clone the sk_security field
+ */
+static void apparmor_sk_clone_security(const struct sock *sk,
+				       struct sock *newsk)
+{
+	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *new = SK_CTX(newsk);
+
+	new->label = aa_get_label(ctx->label);
+	new->peer = aa_get_label(ctx->peer);
+	new->path = ctx->path;
+	path_get(&new->path);
+}
+
+static int aa_sock_create_perm(struct aa_label *label, int family, int type,
+			       int protocol)
+{
+	AA_BUG(!label);
+	AA_BUG(in_interrupt());
+
+	return aa_af_perm(label, OP_CREATE, AA_MAY_CREATE, family, type,
+			  protocol);
+}
+
+
+/**
+ * apparmor_socket_create - check perms before creating a new socket
+ */
+static int apparmor_socket_create(int family, int type, int protocol, int kern)
+{
+	struct aa_label *label;
+	int error = 0;
+
+	label = begin_current_label_crit_section();
+	if (!(kern || unconfined(label)))
+		error = aa_sock_create_perm(label, family, type, protocol);
+	end_current_label_crit_section(label);
+
+	return error;
+}
+
+/**
+ * apparmor_socket_post_create - setup the per-socket security struct
+ *
+ * Note:
+ * -   kernel sockets currently labeled unconfined but we may want to
+ *     move to a special kernel label
+ * -   socket may not have sk here if created with sock_create_lite or
+ *     sock_alloc. These should be accept cases which will be handled in
+ *     sock_graft.
+ */
+static int apparmor_socket_post_create(struct socket *sock, int family,
+				       int type, int protocol, int kern)
+{
+	struct aa_label *label;
+
+	if (kern) {
+		struct aa_ns *ns = aa_get_current_ns();
+
+		label = aa_get_label(ns_unconfined(ns));
+		aa_put_ns(ns);
+	} else
+		label = aa_get_current_label();
+
+	if (sock->sk) {
+		struct aa_sk_ctx *ctx = SK_CTX(sock->sk);
+
+		aa_put_label(ctx->label);
+		ctx->label = aa_get_label(label);
+	}
+	aa_put_label(label);
+
+	return 0;
+}
+
+/**
+ * apparmor_socket_bind - check perms before bind addr to socket
+ */
+static int apparmor_socket_bind(struct socket *sock,
+				struct sockaddr *address, int addrlen)
+{
+	AA_BUG(!sock);
+	AA_BUG(!sock->sk);
+	AA_BUG(!address);
+	AA_BUG(in_interrupt());
+
+	return aa_sk_perm(OP_BIND, AA_MAY_BIND, sock->sk);
+}
+
+/**
+ * apparmor_socket_connect - check perms before connecting @sock to @address
+ */
+static int apparmor_socket_connect(struct socket *sock,
+				   struct sockaddr *address, int addrlen)
+{
+	AA_BUG(!sock);
+	AA_BUG(!sock->sk);
+	AA_BUG(!address);
+	AA_BUG(in_interrupt());
+
+	return aa_sk_perm(OP_CONNECT, AA_MAY_CONNECT, sock->sk);
+}
+
+/**
+ * apparmor_socket_list - check perms before allowing listen
+ */
+static int apparmor_socket_listen(struct socket *sock, int backlog)
+{
+	AA_BUG(!sock);
+	AA_BUG(!sock->sk);
+	AA_BUG(in_interrupt());
+
+	return aa_sk_perm(OP_LISTEN, AA_MAY_LISTEN, sock->sk);
+}
+
+/**
+ * apparmor_socket_accept - check perms before accepting a new connection.
+ *
+ * Note: while @newsock is created and has some information, the accept
+ *       has not been done.
+ */
+static int apparmor_socket_accept(struct socket *sock, struct socket *newsock)
+{
+	AA_BUG(!sock);
+	AA_BUG(!sock->sk);
+	AA_BUG(!newsock);
+	AA_BUG(in_interrupt());
+
+	return aa_sk_perm(OP_ACCEPT, AA_MAY_ACCEPT, sock->sk);
+}
+
+static int aa_sock_msg_perm(const char *op, u32 request, struct socket *sock,
+			    struct msghdr *msg, int size)
+{
+	AA_BUG(!sock);
+	AA_BUG(!sock->sk);
+	AA_BUG(!msg);
+	AA_BUG(in_interrupt());
+
+	return aa_sk_perm(op, request, sock->sk);
+}
+
+/**
+ * apparmor_socket_sendmsg - check perms before sending msg to another socket
+ */
+static int apparmor_socket_sendmsg(struct socket *sock,
+				   struct msghdr *msg, int size)
+{
+	return aa_sock_msg_perm(OP_SENDMSG, AA_MAY_SEND, sock, msg, size);
+}
+
+/**
+ * apparmor_socket_recvmsg - check perms before receiving a message
+ */
+static int apparmor_socket_recvmsg(struct socket *sock,
+				   struct msghdr *msg, int size, int flags)
+{
+	return aa_sock_msg_perm(OP_RECVMSG, AA_MAY_RECEIVE, sock, msg, size);
+}
+
+/* revaliation, get/set attr, shutdown */
+static int aa_sock_perm(const char *op, u32 request, struct socket *sock)
+{
+	AA_BUG(!sock);
+	AA_BUG(!sock->sk);
+	AA_BUG(in_interrupt());
+
+	return aa_sk_perm(op, request, sock->sk);
+}
+
+/**
+ * apparmor_socket_getsockname - check perms before getting the local address
+ */
+static int apparmor_socket_getsockname(struct socket *sock)
+{
+	return aa_sock_perm(OP_GETSOCKNAME, AA_MAY_GETATTR, sock);
+}
+
+/**
+ * apparmor_socket_getpeername - check perms before getting remote address
+ */
+static int apparmor_socket_getpeername(struct socket *sock)
+{
+	return aa_sock_perm(OP_GETPEERNAME, AA_MAY_GETATTR, sock);
+}
+
+/* revaliation, get/set attr, opt */
+static int aa_sock_opt_perm(const char *op, u32 request, struct socket *sock,
+			    int level, int optname)
+{
+	AA_BUG(!sock);
+	AA_BUG(!sock->sk);
+	AA_BUG(in_interrupt());
+
+	return aa_sk_perm(op, request, sock->sk);
+}
+
+/**
+ * apparmor_getsockopt - check perms before getting socket options
+ */
+static int apparmor_socket_getsockopt(struct socket *sock, int level,
+				      int optname)
+{
+	return aa_sock_opt_perm(OP_GETSOCKOPT, AA_MAY_GETOPT, sock,
+				level, optname);
+}
+
+/**
+ * apparmor_setsockopt - check perms before setting socket options
+ */
+static int apparmor_socket_setsockopt(struct socket *sock, int level,
+				      int optname)
+{
+	return aa_sock_opt_perm(OP_SETSOCKOPT, AA_MAY_SETOPT, sock,
+				level, optname);
+}
+
+/**
+ * apparmor_socket_shutdown - check perms before shutting down @sock conn
+ */
+static int apparmor_socket_shutdown(struct socket *sock, int how)
+{
+	return aa_sock_perm(OP_SHUTDOWN, AA_MAY_SHUTDOWN, sock);
+}
+
+/**
+ * apparmor_socket_sock_recv_skb - check perms before associating skb to sk
+ *
+ * Note: can not sleep may be called with locks held
+ *
+ * dont want protocol specific in __skb_recv_datagram()
+ * to deny an incoming connection  socket_sock_rcv_skb()
+ */
+static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+	return 0;
+}
+
+
+static struct aa_label *sk_peer_label(struct sock *sk)
+{
+	struct aa_sk_ctx *ctx = SK_CTX(sk);
+
+	if (ctx->peer)
+		return ctx->peer;
+
+	return ERR_PTR(-ENOPROTOOPT);
+}
+
+/**
+ * apparmor_socket_getpeersec_stream - get security context of peer
+ *
+ * Note: for tcp only valid if using ipsec or cipso on lan
+ */
+static int apparmor_socket_getpeersec_stream(struct socket *sock,
+					     char __user *optval,
+					     int __user *optlen,
+					     unsigned int len)
+{
+	char *name;
+	int slen, error = 0;
+	struct aa_label *label;
+	struct aa_label *peer;
+
+	label = begin_current_label_crit_section();
+	peer = sk_peer_label(sock->sk);
+	if (IS_ERR(peer)) {
+		error = PTR_ERR(peer);
+		goto done;
+	}
+	slen = aa_label_asxprint(&name, labels_ns(label), peer,
+				 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
+				 FLAG_HIDDEN_UNCONFINED, GFP_KERNEL);
+	/* don't include terminating \0 in slen, it breaks some apps */
+	if (slen < 0) {
+		error = -ENOMEM;
+	} else {
+		if (slen > len) {
+			error = -ERANGE;
+		} else if (copy_to_user(optval, name, slen)) {
+			error = -EFAULT;
+			goto out;
+		}
+		if (put_user(slen, optlen))
+			error = -EFAULT;
+out:
+		kfree(name);
+
+	}
+
+done:
+	end_current_label_crit_section(label);
+
+	return error;
+}
+
+/**
+ * apparmor_socket_getpeersec_dgram - get security label of packet
+ * @sock: the peer socket
+ * @skb: packet data
+ * @secid: pointer to where to put the secid of the packet
+ *
+ * Sets the netlabel socket state on sk from parent
+ */
+static int apparmor_socket_getpeersec_dgram(struct socket *sock,
+					    struct sk_buff *skb, u32 *secid)
+
+{
+	/* TODO: requires secid support */
+	return -ENOPROTOOPT;
+}
+
+/**
+ * apparmor_sock_graft - Initialize newly created socket
+ * @sk: child sock
+ * @parent: parent socket
+ *
+ * Note: could set off of SOCK_CTX(parent) but need to track inode and we can
+ *       just set sk security information off of current creating process label
+ *       Labeling of sk for accept case - probably should be sock based
+ *       instead of task, because of the case where an implicitly labeled
+ *       socket is shared by different tasks.
+ */
+static void apparmor_sock_graft(struct sock *sk, struct socket *parent)
+{
+	struct aa_sk_ctx *ctx = SK_CTX(sk);
+
+	if (!ctx->label)
+		ctx->label = aa_get_current_label();
+}
+
 static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
@@ -770,6 +1133,30 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
 	LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),
 
+	LSM_HOOK_INIT(sk_alloc_security, apparmor_sk_alloc_security),
+	LSM_HOOK_INIT(sk_free_security, apparmor_sk_free_security),
+	LSM_HOOK_INIT(sk_clone_security, apparmor_sk_clone_security),
+
+	LSM_HOOK_INIT(socket_create, apparmor_socket_create),
+	LSM_HOOK_INIT(socket_post_create, apparmor_socket_post_create),
+	LSM_HOOK_INIT(socket_bind, apparmor_socket_bind),
+	LSM_HOOK_INIT(socket_connect, apparmor_socket_connect),
+	LSM_HOOK_INIT(socket_listen, apparmor_socket_listen),
+	LSM_HOOK_INIT(socket_accept, apparmor_socket_accept),
+	LSM_HOOK_INIT(socket_sendmsg, apparmor_socket_sendmsg),
+	LSM_HOOK_INIT(socket_recvmsg, apparmor_socket_recvmsg),
+	LSM_HOOK_INIT(socket_getsockname, apparmor_socket_getsockname),
+	LSM_HOOK_INIT(socket_getpeername, apparmor_socket_getpeername),
+	LSM_HOOK_INIT(socket_getsockopt, apparmor_socket_getsockopt),
+	LSM_HOOK_INIT(socket_setsockopt, apparmor_socket_setsockopt),
+	LSM_HOOK_INIT(socket_shutdown, apparmor_socket_shutdown),
+	LSM_HOOK_INIT(socket_sock_rcv_skb, apparmor_socket_sock_rcv_skb),
+	LSM_HOOK_INIT(socket_getpeersec_stream,
+		      apparmor_socket_getpeersec_stream),
+	LSM_HOOK_INIT(socket_getpeersec_dgram,
+		      apparmor_socket_getpeersec_dgram),
+	LSM_HOOK_INIT(sock_graft, apparmor_sock_graft),
+
 	LSM_HOOK_INIT(cred_alloc_blank, apparmor_cred_alloc_blank),
 	LSM_HOOK_INIT(cred_free, apparmor_cred_free),
 	LSM_HOOK_INIT(cred_prepare, apparmor_cred_prepare),