Just so everyone knows... ---------- Forwarded Message ---------- Subject: [PATCH] SELinux: add finer grained permissions to Netlink audit processing Date: Tuesday 19 April 2005 11:29 From: James Morris <jmorris(a)redhat.com&gt; To: Andrew Morton <akpm(a)osdl.org&gt; Cc: linux-kernel(a)vger.kernel.org, Stephen Smalley <sds(a)epoch.ncsc.mil&gt;, Steve Grubb <sgrubb(a)redhat.com&gt; This patch provides finer grained permissions for the audit family of Netlink sockets under SELinux. 1. We need a way to differentiate between privileged and unprivileged reads of kernel data maintained by the audit subsystem. The AUDIT_GET operation is unprivileged: it returns the current status of the audit subsystem (e.g. whether it's enabled etc.). The AUDIT_LIST operation however returns a list of the current audit ruleset, which is considered privileged by the audit folk. To deal with this, a new SELinux permission has been implemented and applied to the operation: nlmsg_readpriv, which can be allocated to appropriately privileged domains. Unprivileged domains would only be allocated nlmsg_read. 2. There is a requirement for certain domains to generate audit events from userspace. These events need to be collected by the kernel, collated and transmitted sequentially back to the audit daemon. An example is user level login, an auditable event under CAPP, where login-related domains generate AUDIT_USER messages via PAM which are relayed back to auditd via the kernel. To prevent handing out nlmsg_write permissions to such domains, a new permission has been added, nlmsg_relay, which is intended for this type of purpose: data is passed via the kernel back to userspace but no privileged information is written to the kernel. Also, AUDIT_LOGIN messages are now valid only for kernel->user messaging, so this value has been removed from the SELinux nlmsgtab (which is only used to check user->kernel messages). Please apply. Signed-off-by: James Morris <jmorris(a)redhat.com&gt; Signed-off-by: Stephen Smalley <sds(a)tycho.nsa.gov&gt; --- security/selinux/include/av_perm_to_string.h | 2 ++ security/selinux/include/av_permissions.h | 2 ++ security/selinux/nlmsgtab.c | 13 ++++++------- 3 files changed, 10 insertions(+), 7 deletions(-) diff -purN -X dontdiff linux-2.6.12-rc2-mm3.o/security/selinux/include/av_permissions.h linux-2.6.12-rc2-mm3.w1/security/selinux/include/av_permissions.h --- linux-2.6.12-rc2-mm3.o/security/selinux/include/av_permissions.h 2005-04-14 21:02:39.000000000 -0400 +++ linux-2.6.12-rc2-mm3.w1/security/selinux/include/av_permissions.h 2005-04-15 15:32:36.000000000 -0400 @@ -840,6 +840,8 @@ #define NETLINK_AUDIT_SOCKET__NLMSG_READ 0x00400000UL #define NETLINK_AUDIT_SOCKET__NLMSG_WRITE 0x00800000UL +#define NETLINK_AUDIT_SOCKET__NLMSG_RELAY 0x01000000UL +#define NETLINK_AUDIT_SOCKET__NLMSG_READPRIV 0x02000000UL #define NETLINK_IP6FW_SOCKET__IOCTL 0x00000001UL #define NETLINK_IP6FW_SOCKET__READ 0x00000002UL diff -purN -X dontdiff linux-2.6.12-rc2-mm3.o/security/selinux/include/av_perm_to_string.h linux-2.6.12-rc2-mm3.w1/security/selinux/include/av_perm_to_string.h --- linux-2.6.12-rc2-mm3.o/security/selinux/include/av_perm_to_string.h 2005-04- 14 21:02:39.000000000 -0400 +++ linux-2.6.12-rc2-mm3.w1/security/selinux/include/av_perm_to_string.h 2005-04 -15 15:32:00.000000000 -0400 @@ -220,6 +220,8 @@ S_(SECCLASS_NETLINK_XFRM_SOCKET, NETLINK_XFRM_SOCKET__NLMSG_WRITE, "nlmsg_write") S_(SECCLASS_NETLINK_AUDIT_SOCKET, NETLINK_AUDIT_SOCKET__NLMSG_READ, "nlmsg_read") S_(SECCLASS_NETLINK_AUDIT_SOCKET, NETLINK_AUDIT_SOCKET__NLMSG_WRITE, "nlmsg_write") + S_(SECCLASS_NETLINK_AUDIT_SOCKET, NETLINK_AUDIT_SOCKET__NLMSG_RELAY, "nlmsg_relay") + S_(SECCLASS_NETLINK_AUDIT_SOCKET, NETLINK_AUDIT_SOCKET__NLMSG_READPRIV, "nlmsg_readpriv") S_(SECCLASS_NETLINK_IP6FW_SOCKET, NETLINK_IP6FW_SOCKET__NLMSG_READ, "nlmsg_read") S_(SECCLASS_NETLINK_IP6FW_SOCKET, NETLINK_IP6FW_SOCKET__NLMSG_WRITE, "nlmsg_write") S_(SECCLASS_DBUS, DBUS__ACQUIRE_SVC, "acquire_svc") diff -purN -X dontdiff linux-2.6.12-rc2-mm3.o/security/selinux/nlmsgtab.c linux-2.6.12-rc2-mm3.w1/security/selinux/nlmsgtab.c --- linux-2.6.12-rc2-mm3.o/security/selinux/nlmsgtab.c 2005-04-14 21:02:39.000000000 -0400 +++ linux-2.6.12-rc2-mm3.w1/security/selinux/nlmsgtab.c 2005-04-15 16:42:33.000000000 -0400 @@ -91,13 +91,12 @@ static struct nlmsg_perm nlmsg_xfrm_perm static struct nlmsg_perm nlmsg_audit_perms[] = { - { AUDIT_GET, NETLINK_AUDIT_SOCKET__NLMSG_READ }, - { AUDIT_SET, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, - { AUDIT_LIST, NETLINK_AUDIT_SOCKET__NLMSG_READ }, - { AUDIT_ADD, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, - { AUDIT_DEL, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, - { AUDIT_USER, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, - { AUDIT_LOGIN, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, + { AUDIT_GET, NETLINK_AUDIT_SOCKET__NLMSG_READ }, + { AUDIT_SET, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, + { AUDIT_LIST, NETLINK_AUDIT_SOCKET__NLMSG_READPRIV }, + { AUDIT_ADD, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, + { AUDIT_DEL, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, + { AUDIT_USER, NETLINK_AUDIT_SOCKET__NLMSG_RELAY }, }; -------------------------------------------------------