[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>

12 files changed, 35 insertions, 34 deletions

diff --git a/include/linux/security.h b/include/linux/security.h
index 51805806f974..c7ea15716dce 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -67,7 +67,7 @@ struct xfrm_state;
 struct xfrm_user_sec_ctx;
 
 extern int cap_netlink_send(struct sock *sk, struct sk_buff *skb);
-extern int cap_netlink_recv(struct sk_buff *skb);
+extern int cap_netlink_recv(struct sk_buff *skb, int cap);
 
 /*
  * Values used in the task_security_ops calls
@@ -656,6 +656,7 @@ struct swap_info_struct;
  *      Check permission before processing the received netlink message in
  *      @skb.
  *      @skb contains the sk_buff structure for the netlink message.
+ *      @cap indicates the capability required
  *      Return 0 if permission is granted.
  *
  * Security hooks for Unix domain networking.
@@ -1266,7 +1267,7 @@ struct security_operations {
                           struct sembuf * sops, unsigned nsops, int alter);
 
         int (*netlink_send) (struct sock * sk, struct sk_buff * skb);
-        int (*netlink_recv) (struct sk_buff * skb);
+        int (*netlink_recv) (struct sk_buff * skb, int cap);
 
         /* allow module stacking */
         int (*register_security) (const char *name,
@@ -2032,9 +2033,9 @@ static inline int security_netlink_send(struct sock *sk, struct sk_buff * skb)
         return security_ops->netlink_send(sk, skb);
 }
 
-static inline int security_netlink_recv(struct sk_buff * skb)
+static inline int security_netlink_recv(struct sk_buff * skb, int cap)
 {
-        return security_ops->netlink_recv(skb);
+        return security_ops->netlink_recv(skb, cap);
 }
 
 /* prototypes */
@@ -2670,9 +2671,9 @@ static inline int security_netlink_send (struct sock *sk, struct sk_buff *skb)
         return cap_netlink_send (sk, skb);
 }
 
-static inline int security_netlink_recv (struct sk_buff *skb)
+static inline int security_netlink_recv (struct sk_buff *skb, int cap)
 {
-        return cap_netlink_recv (skb);
+        return cap_netlink_recv (skb, cap);
 }
 
 static inline struct dentry *securityfs_create_dir(const char *name,
diff --git a/kernel/audit.c b/kernel/audit.c
index 82443fb433ef..d417ca1db79b 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -445,7 +445,7 @@ void audit_send_reply(int pid, int seq, int type, int done, int multi,
  * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
  * control messages.
  */
-static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type)
+static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 {
         int err = 0;
 
@@ -459,13 +459,13 @@ static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type)
         case AUDIT_DEL:
         case AUDIT_DEL_RULE:
         case AUDIT_SIGNAL_INFO:
-                if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL))
+                if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
                         err = -EPERM;
                 break;
         case AUDIT_USER:
         case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
         case AUDIT_FIRST_USER_MSG2...AUDIT_LAST_USER_MSG2:
-                if (!cap_raised(eff_cap, CAP_AUDIT_WRITE))
+                if (security_netlink_recv(skb, CAP_AUDIT_WRITE))
                         err = -EPERM;
                 break;
         default:  /* bad msg */
@@ -488,7 +488,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
         char                    *ctx;
         u32                     len;
 
-        err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type);
+        err = audit_netlink_ok(skb, msg_type);
         if (err)
                 return err;
 
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 3fcfa9c59e1f..f25aac17497a 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -663,7 +663,7 @@ rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
         sz_idx = type>>2;
         kind = type&3;
 
-        if (kind != 2 && security_netlink_recv(skb)) {
+        if (kind != 2 && security_netlink_recv(skb, CAP_NET_ADMIN)) {
                 *errp = -EPERM;
                 return -1;
         }
diff --git a/net/decnet/netfilter/dn_rtmsg.c b/net/decnet/netfilter/dn_rtmsg.c
index 74133ecd7700..8b99bd33540d 100644
--- a/net/decnet/netfilter/dn_rtmsg.c
+++ b/net/decnet/netfilter/dn_rtmsg.c
@@ -107,7 +107,7 @@ static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
         if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
                 return;
 
-        if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))
+        if (security_netlink_recv(skb, CAP_NET_ADMIN))
                 RCV_SKB_FAIL(-EPERM);
 
         /* Eventually we might send routing messages too */
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index 213d116e5bb9..198ac36db861 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -515,7 +515,7 @@ ipq_rcv_skb(struct sk_buff *skb)
         if (type <= IPQM_BASE)
                 return;
                 
-        if (security_netlink_recv(skb))
+        if (security_netlink_recv(skb, CAP_NET_ADMIN))
                 RCV_SKB_FAIL(-EPERM);
         
         write_lock_bh(&queue_lock);
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index b4b7d441af25..968a14be0d05 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -505,7 +505,7 @@ ipq_rcv_skb(struct sk_buff *skb)
         if (type <= IPQM_BASE)
                 return;
         
-        if (security_netlink_recv(skb))
+        if (security_netlink_recv(skb, CAP_NET_ADMIN))
                 RCV_SKB_FAIL(-EPERM);   
 
         write_lock_bh(&queue_lock);
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index b88e82a1a987..ec9f0efea6bb 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -229,7 +229,7 @@ static int nfnetlink_rcv_msg(struct sk_buff *skb,
                  NFNL_SUBSYS_ID(nlh->nlmsg_type),
                  NFNL_MSG_TYPE(nlh->nlmsg_type));
 
-        if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN)) {
+        if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
                 DEBUGP("missing CAP_NET_ADMIN\n");
                 *errp = -EPERM;
                 return -1;
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index f329b72578f5..edf084becd5e 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -320,7 +320,7 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
                 goto errout;
         }
 
-        if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb)) {
+        if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb, CAP_NET_ADMIN)) {
                 err = -EPERM;
                 goto errout;
         }
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index c21dc26141ea..3e6a722d072e 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1435,7 +1435,7 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *err
         link = &xfrm_dispatch[type];
 
         /* All operations require privileges, even GET */
-        if (security_netlink_recv(skb)) {
+        if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
                 *errp = -EPERM;
                 return -1;
         }
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,