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Message-ID: <20091227010650.GA12190@heat>
Date: Sat, 26 Dec 2009 20:06:50 -0500
From: Michael Stone <michael@...top.org>
To: linux-kernel@...r.kernel.org
Cc: netdev@...r.kernel.org, linux-security-module@...r.kernel.org,
Andi Kleen <andi@...stfloor.org>, David Lang <david@...g.hm>,
Oliver Hartkopp <socketcan@...tkopp.net>,
Alan Cox <alan@...rguk.ukuu.org.uk>,
Herbert Xu <herbert@...dor.apana.org.au>,
Valdis Kletnieks <Valdis.Kletnieks@...edu>,
Bryan Donlan <bdonlan@...il.com>,
Evgeniy Polyakov <zbr@...emap.net>,
"C. Scott Ananian" <cscott@...ott.net>,
James Morris <jmorris@...ei.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Bernie Innocenti <bernie@...ewiz.org>,
Mark Seaborn <mrs@...hic-beasts.com>,
Randy Dunlap <randy.dunlap@...cle.com>,
Américo Wang <xiyou.wangcong@...il.com>,
Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
Samir Bellabes <sam@...ack.fr>,
Casey Schaufler <casey@...aufler-ca.com>,
"Serge E. Hallyn" <serue@...ibm.com>, Pavel Machek <pavel@....cz>,
Michael Stone <michael@...top.org>
Subject: [PATCH 2/3] Security: Implement disablenetwork semantics. (v4)
Implement security_* hooks for socket_create, socket_bind, socket_connect,
socket_sendmsg, and ptrace_access_check which return -EPERM when called from a
process with networking restrictions. Exempt AF_UNIX sockets.
Signed-off-by: Michael Stone <michael@...top.org>
---
include/linux/disablenetwork.h | 22 +++++++++++
security/Makefile | 1 +
security/disablenetwork.c | 73 ++++++++++++++++++++++++++++++++++++++
security/security.c | 76 +++++++++++++++++++++++++++++++++++++---
4 files changed, 167 insertions(+), 5 deletions(-)
create mode 100644 include/linux/disablenetwork.h
create mode 100644 security/disablenetwork.c
diff --git a/include/linux/disablenetwork.h b/include/linux/disablenetwork.h
new file mode 100644
index 0000000..8a7bcc2
--- /dev/null
+++ b/include/linux/disablenetwork.h
@@ -0,0 +1,22 @@
+#ifndef __LINUX_DISABLENETWORK_H
+#define __LINUX_DISABLENETWORK_H
+
+#ifdef CONFIG_SECURITY_DISABLENETWORK
+
+int disablenetwork_security_socket_create(int family, int type,
+ int protocol, int kern);
+int disablenetwork_security_socket_bind(struct socket *sock,
+ struct sockaddr *address,
+ int addrlen);
+int disablenetwork_security_socket_connect(struct socket *sock,
+ struct sockaddr *address,
+ int addrlen);
+int disablenetwork_security_socket_sendmsg(struct socket *sock,
+ struct msghdr *msg,
+ int size);
+int disablenetwork_security_ptrace_access_check(struct task_struct *child,
+ unsigned int mode);
+
+#endif /* CONFIG_SECURITY_DISABLENETWORK */
+
+#endif /* ! __LINUX_DISABLENETWORK_H */
diff --git a/security/Makefile b/security/Makefile
index da20a19..2f23b60 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_SECURITY_SMACK) += smack/built-in.o
obj-$(CONFIG_AUDIT) += lsm_audit.o
obj-$(CONFIG_SECURITY_TOMOYO) += tomoyo/built-in.o
obj-$(CONFIG_CGROUP_DEVICE) += device_cgroup.o
+obj-$(CONFIG_SECURITY_DISABLENETWORK) += disablenetwork.o
# Object integrity file lists
subdir-$(CONFIG_IMA) += integrity/ima
diff --git a/security/disablenetwork.c b/security/disablenetwork.c
new file mode 100644
index 0000000..f45ddfc
--- /dev/null
+++ b/security/disablenetwork.c
@@ -0,0 +1,73 @@
+/*
+ * disablenetwork security hooks.
+ *
+ * Copyright (C) 2008-2009 Michael Stone <michael@...top.org>
+ *
+ * Implements the disablenetwork discretionary access control logic underlying
+ * the prctl(PRCTL_SET_NETWORK, PR_NETWORK_OFF) interface.
+ *
+ * See Documentation/disablenetwork.txt for more information.
+ *
+ * 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 <linux/errno.h>
+#include <linux/sched.h>
+#include <net/sock.h>
+#include <linux/socket.h>
+#include <linux/disablenetwork.h>
+
+static inline int maybe_allow(void)
+{
+ if (current->network)
+ return -EPERM;
+ return 0;
+}
+
+int disablenetwork_security_socket_create(int family, int type,
+ int protocol, int kern)
+{
+ if (family == AF_UNIX)
+ return 0;
+ return maybe_allow();
+}
+
+int disablenetwork_security_socket_bind(struct socket * sock,
+ struct sockaddr * address,
+ int addrlen)
+{
+ if (address->sa_family == AF_UNIX)
+ return 0;
+ return maybe_allow();
+}
+
+int disablenetwork_security_socket_connect(struct socket * sock,
+ struct sockaddr * address,
+ int addrlen)
+{
+ if (address->sa_family == AF_UNIX)
+ return 0;
+ return maybe_allow();
+}
+
+int disablenetwork_security_socket_sendmsg(struct socket * sock,
+ struct msghdr * msg, int size)
+{
+ if (sock->sk->sk_family != PF_UNIX &&
+ current->network &&
+ (msg->msg_name != NULL || msg->msg_namelen != 0))
+ return -EPERM;
+ return 0;
+}
+
+int disablenetwork_security_ptrace_access_check(struct task_struct *child,
+ unsigned int mode)
+{
+ /* does current have networking restrictions not shared by child? */
+ if (current->network & ~child->network)
+ return -EPERM;
+ return 0;
+}
diff --git a/security/security.c b/security/security.c
index 24e060b..40ac615 100644
--- a/security/security.c
+++ b/security/security.c
@@ -17,6 +17,7 @@
#include <linux/kernel.h>
#include <linux/security.h>
#include <linux/ima.h>
+#include <linux/disablenetwork.h>
/* Boot-time LSM user choice */
static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
@@ -130,7 +131,20 @@ int register_security(struct security_operations *ops)
int security_ptrace_access_check(struct task_struct *child, unsigned int mode)
{
- return security_ops->ptrace_access_check(child, mode);
+ int ret = 0;
+
+ ret = security_ops->ptrace_access_check(child, mode);
+ if (ret)
+ goto out;
+
+#ifdef CONFIG_SECURITY_DISABLENETWORK
+ ret = disablenetwork_security_ptrace_access_check(child, mode);
+ if (ret)
+ goto out;
+#endif
+
+out:
+ return ret;
}
int security_ptrace_traceme(struct task_struct *parent)
@@ -1054,7 +1068,20 @@ EXPORT_SYMBOL(security_unix_may_send);
int security_socket_create(int family, int type, int protocol, int kern)
{
- return security_ops->socket_create(family, type, protocol, kern);
+ int ret = 0;
+
+ ret = security_ops->socket_create(family, type, protocol, kern);
+ if (ret)
+ goto out;
+
+#ifdef CONFIG_SECURITY_DISABLENETWORK
+ ret = disablenetwork_security_socket_create(family, type, protocol, kern);
+ if (ret)
+ goto out;
+#endif
+
+out:
+ return ret;
}
int security_socket_post_create(struct socket *sock, int family,
@@ -1066,12 +1093,38 @@ int security_socket_post_create(struct socket *sock, int family,
int security_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
{
- return security_ops->socket_bind(sock, address, addrlen);
+ int ret = 0;
+
+ ret = security_ops->socket_bind(sock, address, addrlen);
+ if (ret)
+ goto out;
+
+#ifdef CONFIG_SECURITY_DISABLENETWORK
+ ret = disablenetwork_security_socket_bind(sock, address, addrlen);
+ if (ret)
+ goto out;
+#endif
+
+out:
+ return ret;
}
int security_socket_connect(struct socket *sock, struct sockaddr *address, int addrlen)
{
- return security_ops->socket_connect(sock, address, addrlen);
+ int ret = 0;
+
+ ret = security_ops->socket_connect(sock, address, addrlen);
+ if (ret)
+ goto out;
+
+#ifdef CONFIG_SECURITY_DISABLENETWORK
+ ret = disablenetwork_security_socket_connect(sock, address, addrlen);
+ if (ret)
+ goto out;
+#endif
+
+out:
+ return ret;
}
int security_socket_listen(struct socket *sock, int backlog)
@@ -1086,7 +1139,20 @@ int security_socket_accept(struct socket *sock, struct socket *newsock)
int security_socket_sendmsg(struct socket *sock, struct msghdr *msg, int size)
{
- return security_ops->socket_sendmsg(sock, msg, size);
+ int ret = 0;
+
+ ret = security_ops->socket_sendmsg(sock, msg, size);
+ if (ret)
+ goto out;
+
+#ifdef CONFIG_SECURITY_DISABLENETWORK
+ ret = disablenetwork_security_socket_sendmsg(sock, msg, size);
+ if (ret)
+ goto out;
+#endif
+
+out:
+ return ret;
}
int security_socket_recvmsg(struct socket *sock, struct msghdr *msg,
--
1.6.6.rc2
--
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