[NETLINK]: Encapsulate eff_cap usage within security framework.

This patch encapsulates the usage of eff_cap (in netlink_skb_params) within
the security framework by extending security_netlink_recv to include a required
capability parameter and converting all direct usage of eff_caps outside
of the lsm modules to use the interface.  It also updates the SELinux
implementation of the security_netlink_send and security_netlink_recv
hooks to take advantage of the sid in the netlink_skb_params struct.
This also enables SELinux to perform auditing of netlink capability checks.
Please apply, for 2.6.18 if possible.

Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by:  James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 17 insertions, 17 deletions

diff --git a/security/commoncap.c b/security/commoncap.c
index 841eb4e5c62b..57673ee07ceb 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -33,9 +33,9 @@ int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
 
 EXPORT_SYMBOL(cap_netlink_send);
 
-int cap_netlink_recv(struct sk_buff *skb)
+int cap_netlink_recv(struct sk_buff *skb, int cap)
 {
-        if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))
+        if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))
                 return -EPERM;
         return 0;
 }
diff --git a/security/dummy.c b/security/dummy.c
index 310fcdf7b749..913540808577 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -675,9 +675,9 @@ static int dummy_netlink_send (struct sock *sk, struct sk_buff *skb)
         return 0;
 }
 
-static int dummy_netlink_recv (struct sk_buff *skb)
+static int dummy_netlink_recv (struct sk_buff *skb, int cap)
 {
-        if (!cap_raised (NETLINK_CB (skb).eff_cap, CAP_NET_ADMIN))
+        if (!cap_raised (NETLINK_CB (skb).eff_cap, cap))
                 return -EPERM;
         return 0;
 }
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 28832e689800..b6c378dd4f12 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3641,32 +3641,32 @@ static unsigned int selinux_ipv6_postroute_last(unsigned int hooknum,
 
 static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
 {
-        struct task_security_struct *tsec;
-        struct av_decision avd;
         int err;
 
         err = secondary_ops->netlink_send(sk, skb);
         if (err)
                 return err;
 
-        tsec = current->security;
-
-        avd.allowed = 0;
-        avc_has_perm_noaudit(tsec->sid, tsec->sid,
-                                SECCLASS_CAPABILITY, ~0, &avd);
-        cap_mask(NETLINK_CB(skb).eff_cap, avd.allowed);
-
         if (policydb_loaded_version >= POLICYDB_VERSION_NLCLASS)
                 err = selinux_nlmsg_perm(sk, skb);
 
         return err;
 }
 
-static int selinux_netlink_recv(struct sk_buff *skb)
+static int selinux_netlink_recv(struct sk_buff *skb, int capability)
 {
-        if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))
-                return -EPERM;
-        return 0;
+        int err;
+        struct avc_audit_data ad;
+
+        err = secondary_ops->netlink_recv(skb, capability);
+        if (err)
+                return err;
+
+        AVC_AUDIT_DATA_INIT(&ad, CAP);
+        ad.u.cap = capability;
+
+        return avc_has_perm(NETLINK_CB(skb).sid, NETLINK_CB(skb).sid,
+                            SECCLASS_CAPABILITY, CAP_TO_MASK(capability), &ad);
 }
 
 static int ipc_alloc_security(struct task_struct *task,