From 5dbbaf2de89613d19a9286d4db0a535ca2735d26 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Mon, 14 Jan 2013 07:12:19 +0000 Subject: tun: fix LSM/SELinux labeling of tun/tap devices This patch corrects some problems with LSM/SELinux that were introduced with the multiqueue patchset. The problem stems from the fact that the multiqueue work changed the relationship between the tun device and its associated socket; before the socket persisted for the life of the device, however after the multiqueue changes the socket only persisted for the life of the userspace connection (fd open). For non-persistent devices this is not an issue, but for persistent devices this can cause the tun device to lose its SELinux label. We correct this problem by adding an opaque LSM security blob to the tun device struct which allows us to have the LSM security state, e.g. SELinux labeling information, persist for the lifetime of the tun device. In the process we tweak the LSM hooks to work with this new approach to TUN device/socket labeling and introduce a new LSM hook, security_tun_dev_attach_queue(), to approve requests to attach to a TUN queue via TUNSETQUEUE. The SELinux code has been adjusted to match the new LSM hooks, the other LSMs do not make use of the LSM TUN controls. This patch makes use of the recently added "tun_socket:attach_queue" permission to restrict access to the TUNSETQUEUE operation. On older SELinux policies which do not define the "tun_socket:attach_queue" permission the access control decision for TUNSETQUEUE will be handled according to the SELinux policy's unknown permission setting. Signed-off-by: Paul Moore Acked-by: Eric Paris Tested-by: Jason Wang Signed-off-by: David S. Miller --- security/capability.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) (limited to 'security/capability.c') diff --git a/security/capability.c b/security/capability.c index 0fe5a026aef..57977508896 100644 --- a/security/capability.c +++ b/security/capability.c @@ -709,16 +709,31 @@ static void cap_req_classify_flow(const struct request_sock *req, { } +static int cap_tun_dev_alloc_security(void **security) +{ + return 0; +} + +static void cap_tun_dev_free_security(void *security) +{ +} + static int cap_tun_dev_create(void) { return 0; } -static void cap_tun_dev_post_create(struct sock *sk) +static int cap_tun_dev_attach_queue(void *security) +{ + return 0; +} + +static int cap_tun_dev_attach(struct sock *sk, void *security) { + return 0; } -static int cap_tun_dev_attach(struct sock *sk) +static int cap_tun_dev_open(void *security) { return 0; } @@ -1050,8 +1065,11 @@ void __init security_fixup_ops(struct security_operations *ops) set_to_cap_if_null(ops, secmark_refcount_inc); set_to_cap_if_null(ops, secmark_refcount_dec); set_to_cap_if_null(ops, req_classify_flow); + set_to_cap_if_null(ops, tun_dev_alloc_security); + set_to_cap_if_null(ops, tun_dev_free_security); set_to_cap_if_null(ops, tun_dev_create); - set_to_cap_if_null(ops, tun_dev_post_create); + set_to_cap_if_null(ops, tun_dev_open); + set_to_cap_if_null(ops, tun_dev_attach_queue); set_to_cap_if_null(ops, tun_dev_attach); #endif /* CONFIG_SECURITY_NETWORK */ #ifdef CONFIG_SECURITY_NETWORK_XFRM -- cgit v1.2.3