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Date: Tue, 04 Aug 2009 17:22:04 -0400
From: Paul Moore <paul.moore@...com>
To: netdev@...r.kernel.org, linux-security-module@...r.kernel.org,
selinux@...ho.nsa.gov
Subject: [RFC PATCH v1 2/2] selinux: Support for the new TUN LSM hooks
Add support for the new TUN LSM hooks: security_tun_dev_create(),
security_tun_dev_post_create() and security_tun_dev_attach(). This includes
the addition of a new object class, tun_socket, which represents the socks
associated with TUN devices. The _tun_dev_create() and _tun_dev_post_create()
hooks are fairly similar to the standard socket functions but _tun_dev_attach()
is a bit special. The _tun_dev_attach() is unique because it involves a
domain attaching to an existing TUN device and its associated tun_socket
object, an operation which does not exist with standard sockets and most
closely resembles a relabel operation.
This patch also includes a new policy capability, tun_perms, to ensure that
the new access controls do not affect older SELinux policies.
--
NOTE: This relies on some changes to the policy to add the new object class
and its associated permissions, I will ensure that the policy is sorted
and merged before pushing this patch upstream. Also, you will notice
that the new tun_socket object class simply inherits the base socket
object class, thoughts?
---
security/selinux/hooks.c | 76 +++++++++++++++++++++++++++-
security/selinux/include/av_inherit.h | 1
security/selinux/include/av_permissions.h | 22 ++++++++
security/selinux/include/class_to_string.h | 1
security/selinux/include/flask.h | 1
security/selinux/include/security.h | 2 +
security/selinux/selinuxfs.c | 3 +
security/selinux/ss/services.c | 3 +
8 files changed, 106 insertions(+), 3 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 15c2a08..6ba99c2 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -13,8 +13,8 @@
* Eric Paris <eparis@...hat.com>
* Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
* <dgoeddel@...stedcs.com>
- * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
- * Paul Moore <paul.moore@...com>
+ * Copyright (C) 2006, 2007, 2009 Hewlett-Packard Development Company, L.P.
+ * Paul Moore <paul.moore@...com>
* Copyright (C) 2007 Hitachi Software Engineering Co., Ltd.
* Yuichi Nakamura <ynakam@...achisoft.jp>
*
@@ -4296,6 +4296,75 @@ static void selinux_req_classify_flow(const struct request_sock *req,
fl->secid = req->secid;
}
+static int selinux_tun_dev_create(void)
+{
+ u32 sid;
+ int err;
+
+ err = cap_tun_dev_create();
+ if (err)
+ return err;
+
+ if (!selinux_policycap_tunperm)
+ return 0;
+
+ /* we aren't taking into account the "sockcreate" SID since the socket
+ * that is being created here is not a socket in the traditional sense,
+ * instead it is a private sock, accessible only to the kernel, and
+ * representing a wide range of network traffic spanning multiple
+ * connections unlike traditional sockets - check the TUN driver to
+ * get a better understand of why this socket is special */
+
+ sid = current_sid();
+ return avc_has_perm(sid, sid, SECCLASS_TUN_SOCKET, TUN_SOCKET__CREATE,
+ NULL);
+}
+
+static void selinux_tun_dev_post_create(struct sock *tun_sk)
+{
+ struct sk_security_struct *sksec = tun_sk->sk_security;
+
+ /* see the comments in _tun_dev_create() about why we don't use the
+ * sockcreate SID here */
+
+ /* we don't currently perform any NetLabel based labeling here and it
+ * isn't clear that we would want to do so anyway: while we could apply
+ * labeling without the support of the TUN user the resulting labeled
+ * traffic from the other end of the connection would almost certainly
+ * cause confusion to the TUN user that had no idea network labeling
+ * protocols were being used */
+
+ sksec->sid = current_sid();
+ sksec->sclass = SECCLASS_TUN_SOCKET;
+}
+
+static int selinux_tun_dev_attach(struct sock *tun_sk)
+{
+ struct sk_security_struct *tun_sksec = tun_sk->sk_security;
+ u32 sid;
+ int err;
+
+ err = cap_tun_dev_attach();
+ if (err)
+ return err;
+
+ if (!selinux_policycap_tunperm)
+ return 0;
+
+ sid = current_sid();
+ err = avc_has_perm(sid, tun_sksec->sid, SECCLASS_TUN_SOCKET,
+ TUN_SOCKET__RELABELFROM, NULL);
+ if (err)
+ return err;
+ err = avc_has_perm(sid, sid, SECCLASS_RAWIP_SOCKET,
+ TUN_SOCKET__RELABELTO, NULL);
+ if (err)
+ return err;
+ tun_sksec->sid = sid;
+
+ return 0;
+}
+
static int selinux_nlmsg_perm(struct sock *sk, struct sk_buff *skb)
{
int err = 0;
@@ -5464,6 +5533,9 @@ static struct security_operations selinux_ops = {
.inet_csk_clone = selinux_inet_csk_clone,
.inet_conn_established = selinux_inet_conn_established,
.req_classify_flow = selinux_req_classify_flow,
+ .tun_dev_create = selinux_tun_dev_create,
+ .tun_dev_post_create = selinux_tun_dev_post_create,
+ .tun_dev_attach = selinux_tun_dev_attach,
#ifdef CONFIG_SECURITY_NETWORK_XFRM
.xfrm_policy_alloc_security = selinux_xfrm_policy_alloc,
diff --git a/security/selinux/include/av_inherit.h b/security/selinux/include/av_inherit.h
index 8377a4b..abedcd7 100644
--- a/security/selinux/include/av_inherit.h
+++ b/security/selinux/include/av_inherit.h
@@ -15,6 +15,7 @@
S_(SECCLASS_KEY_SOCKET, socket, 0x00400000UL)
S_(SECCLASS_UNIX_STREAM_SOCKET, socket, 0x00400000UL)
S_(SECCLASS_UNIX_DGRAM_SOCKET, socket, 0x00400000UL)
+ S_(SECCLASS_TUN_SOCKET, socket, 0x00400000UL)
S_(SECCLASS_IPC, ipc, 0x00000200UL)
S_(SECCLASS_SEM, ipc, 0x00000200UL)
S_(SECCLASS_MSGQ, ipc, 0x00000200UL)
diff --git a/security/selinux/include/av_permissions.h b/security/selinux/include/av_permissions.h
index d645192..0b41ad5 100644
--- a/security/selinux/include/av_permissions.h
+++ b/security/selinux/include/av_permissions.h
@@ -423,6 +423,28 @@
#define UNIX_DGRAM_SOCKET__RECV_MSG 0x00080000UL
#define UNIX_DGRAM_SOCKET__SEND_MSG 0x00100000UL
#define UNIX_DGRAM_SOCKET__NAME_BIND 0x00200000UL
+#define TUN_SOCKET__IOCTL 0x00000001UL
+#define TUN_SOCKET__READ 0x00000002UL
+#define TUN_SOCKET__WRITE 0x00000004UL
+#define TUN_SOCKET__CREATE 0x00000008UL
+#define TUN_SOCKET__GETATTR 0x00000010UL
+#define TUN_SOCKET__SETATTR 0x00000020UL
+#define TUN_SOCKET__LOCK 0x00000040UL
+#define TUN_SOCKET__RELABELFROM 0x00000080UL
+#define TUN_SOCKET__RELABELTO 0x00000100UL
+#define TUN_SOCKET__APPEND 0x00000200UL
+#define TUN_SOCKET__BIND 0x00000400UL
+#define TUN_SOCKET__CONNECT 0x00000800UL
+#define TUN_SOCKET__LISTEN 0x00001000UL
+#define TUN_SOCKET__ACCEPT 0x00002000UL
+#define TUN_SOCKET__GETOPT 0x00004000UL
+#define TUN_SOCKET__SETOPT 0x00008000UL
+#define TUN_SOCKET__SHUTDOWN 0x00010000UL
+#define TUN_SOCKET__RECVFROM 0x00020000UL
+#define TUN_SOCKET__SENDTO 0x00040000UL
+#define TUN_SOCKET__RECV_MSG 0x00080000UL
+#define TUN_SOCKET__SEND_MSG 0x00100000UL
+#define TUN_SOCKET__NAME_BIND 0x00200000UL
#define PROCESS__FORK 0x00000001UL
#define PROCESS__TRANSITION 0x00000002UL
#define PROCESS__SIGCHLD 0x00000004UL
diff --git a/security/selinux/include/class_to_string.h b/security/selinux/include/class_to_string.h
index 21ec786..7ab9299 100644
--- a/security/selinux/include/class_to_string.h
+++ b/security/selinux/include/class_to_string.h
@@ -77,3 +77,4 @@
S_(NULL)
S_(NULL)
S_("kernel_service")
+ S_("tun_socket")
diff --git a/security/selinux/include/flask.h b/security/selinux/include/flask.h
index 882f27d..f248500 100644
--- a/security/selinux/include/flask.h
+++ b/security/selinux/include/flask.h
@@ -53,6 +53,7 @@
#define SECCLASS_PEER 68
#define SECCLASS_CAPABILITY2 69
#define SECCLASS_KERNEL_SERVICE 74
+#define SECCLASS_TUN_SOCKET 75
/*
* Security identifier indices for initial entities
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index ca83579..188af8d 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -63,12 +63,14 @@ extern int selinux_mls_enabled;
enum {
POLICYDB_CAPABILITY_NETPEER,
POLICYDB_CAPABILITY_OPENPERM,
+ POLICYDB_CAPABILITY_TUNPERM,
__POLICYDB_CAPABILITY_MAX
};
#define POLICYDB_CAPABILITY_MAX (__POLICYDB_CAPABILITY_MAX - 1)
extern int selinux_policycap_netpeer;
extern int selinux_policycap_openperm;
+extern int selinux_policycap_tunperm;
/*
* type_datum properties
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index b4fc506..770e059 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -42,7 +42,8 @@
/* Policy capability filenames */
static char *policycap_names[] = {
"network_peer_controls",
- "open_perms"
+ "open_perms",
+ "tun_perms"
};
unsigned int selinux_checkreqprot = CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE;
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 500e6f7..adbe6d5 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -64,6 +64,7 @@ unsigned int policydb_loaded_version;
int selinux_policycap_netpeer;
int selinux_policycap_openperm;
+int selinux_policycap_tunperm;
/*
* This is declared in avc.c
@@ -1593,6 +1594,8 @@ static void security_load_policycaps(void)
POLICYDB_CAPABILITY_NETPEER);
selinux_policycap_openperm = ebitmap_get_bit(&policydb.policycaps,
POLICYDB_CAPABILITY_OPENPERM);
+ selinux_policycap_tunperm = ebitmap_get_bit(&policydb.policycaps,
+ POLICYDB_CAPABILITY_TUNPERM);
}
extern void selinux_complete_init(void);
--
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