security: remove the security_netlink_recv hook as it is equivalent to capable()

Once upon a time netlink was not sync and we had to get the effective
capabilities from the skb that was being received.  Today we instead get
the capabilities from the current task.  This has rendered the entire
purpose of the hook moot as it is now functionally equivalent to the
capable() call.

Signed-off-by: Eric Paris <eparis@redhat.com>

14 files changed, 10 insertions, 58 deletions

diff --git a/drivers/scsi/scsi_netlink.c b/drivers/scsi/scsi_netlink.c
index 26a8a45..feee1cc 100644
--- a/drivers/scsi/scsi_netlink.c
+++ b/drivers/scsi/scsi_netlink.c
@@ -111,7 +111,7 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
 			goto next_msg;
 		}
 
-		if (security_netlink_recv(skb, CAP_SYS_ADMIN)) {
+		if (!capable(CAP_SYS_ADMIN)) {
 			err = -EPERM;
 			goto next_msg;
 		}
diff --git a/include/linux/security.h b/include/linux/security.h
index cd04d6f..93fa9ae 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -95,7 +95,6 @@ struct xfrm_user_sec_ctx;
 struct seq_file;
 
 extern int cap_netlink_send(struct sock *sk, struct sk_buff *skb);
-extern int cap_netlink_recv(struct sk_buff *skb, int cap);
 
 void reset_security_ops(void);
 
@@ -792,12 +791,6 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *	@skb contains the sk_buff structure for the netlink message.
  *	Return 0 if the information was successfully saved and message
  *	is allowed to be transmitted.
- * @netlink_recv:
- *	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.
  *
@@ -1561,7 +1554,6 @@ 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 cap);
 
 	void (*d_instantiate) (struct dentry *dentry, struct inode *inode);
 
@@ -1815,7 +1807,6 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode);
 int security_getprocattr(struct task_struct *p, char *name, char **value);
 int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
-int security_netlink_recv(struct sk_buff *skb, int cap);
 int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
 int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
 void security_release_secctx(char *secdata, u32 seclen);
@@ -2532,11 +2523,6 @@ 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, int cap)
-{
-	return cap_netlink_recv(skb, cap);
-}
-
 static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
 {
 	return -EOPNOTSUPP;
diff --git a/kernel/audit.c b/kernel/audit.c
index 9395003..76177c7 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -598,13 +598,13 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 	case AUDIT_TTY_SET:
 	case AUDIT_TRIM:
 	case AUDIT_MAKE_EQUIV:
-		if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
+		if (!capable(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 (security_netlink_recv(skb, CAP_AUDIT_WRITE))
+		if (!capable(CAP_AUDIT_WRITE))
 			err = -EPERM;
 		break;
 	default:  /* bad msg */
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index b6aaa7a..4698e7c 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1976,7 +1976,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	sz_idx = type>>2;
 	kind = type&3;
 
-	if (kind != 2 && security_netlink_recv(skb, CAP_NET_ADMIN))
+	if (kind != 2 && !capable(CAP_NET_ADMIN))
 		return -EPERM;
 
 	if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {
diff --git a/net/decnet/netfilter/dn_rtmsg.c b/net/decnet/netfilter/dn_rtmsg.c
index 64a7f39..5524726 100644
--- a/net/decnet/netfilter/dn_rtmsg.c
+++ b/net/decnet/netfilter/dn_rtmsg.c
@@ -108,7 +108,7 @@ static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
 	if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
 		return;
 
-	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+	if (!capable(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 5c9b9d9..6a9b7c8 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -432,7 +432,7 @@ __ipq_rcv_skb(struct sk_buff *skb)
 	if (type <= IPQM_BASE)
 		return;
 
-	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+	if (!capable(CAP_NET_ADMIN))
 		RCV_SKB_FAIL(-EPERM);
 
 	spin_lock_bh(&queue_lock);
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index 2493948..8c8c326 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -433,7 +433,7 @@ __ipq_rcv_skb(struct sk_buff *skb)
 	if (type <= IPQM_BASE)
 		return;
 
-	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+	if (!capable(CAP_NET_ADMIN))
 		RCV_SKB_FAIL(-EPERM);
 
 	spin_lock_bh(&queue_lock);
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index b4a4532..503daca 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -130,7 +130,7 @@ static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	const struct nfnetlink_subsystem *ss;
 	int type, err;
 
-	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
 
 	/* All the messages must at least contain nfgenmsg */
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 874f8ff..51d7cc9 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -517,7 +517,7 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		return -EOPNOTSUPP;
 
 	if ((ops->flags & GENL_ADMIN_PERM) &&
-	    security_netlink_recv(skb, CAP_NET_ADMIN))
+	    !capable(CAP_NET_ADMIN))
 		return -EPERM;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 9bbe858..e0349ea 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2317,7 +2317,7 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	link = &xfrm_dispatch[type];
 
 	/* All operations require privileges, even GET */
-	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
 
 	if ((type == (XFRM_MSG_GETSA - XFRM_MSG_BASE) ||
diff --git a/security/capability.c b/security/capability.c
index ac5793c..755aebc 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -1023,7 +1023,6 @@ void __init security_fixup_ops(struct security_operations *ops)
 	set_to_cap_if_null(ops, sem_semctl);
 	set_to_cap_if_null(ops, sem_semop);
 	set_to_cap_if_null(ops, netlink_send);
-	set_to_cap_if_null(ops, netlink_recv);
 	set_to_cap_if_null(ops, d_instantiate);
 	set_to_cap_if_null(ops, getprocattr);
 	set_to_cap_if_null(ops, setprocattr);
diff --git a/security/commoncap.c b/security/commoncap.c
index 02b69b0..0a80697 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -61,14 +61,6 @@ int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
 	return 0;
 }
 
-int cap_netlink_recv(struct sk_buff *skb, int cap)
-{
-	if (!cap_raised(current_cap(), cap))
-		return -EPERM;
-	return 0;
-}
-EXPORT_SYMBOL(cap_netlink_recv);
-
 /**
  * cap_capable - Determine whether a task has a particular effective capability
  * @cred: The credentials to use
diff --git a/security/security.c b/security/security.c
index 0de3679..b668e1c 100644
--- a/security/security.c
+++ b/security/security.c
@@ -967,12 +967,6 @@ int security_netlink_send(struct sock *sk, struct sk_buff *skb)
 	return security_ops->netlink_send(sk, skb);
 }
 
-int security_netlink_recv(struct sk_buff *skb, int cap)
-{
-	return security_ops->netlink_recv(skb, cap);
-}
-EXPORT_SYMBOL(security_netlink_recv);
-
 int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
 {
 	return security_ops->secid_to_secctx(secid, secdata, seclen);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 7db421c..382af56 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4839,24 +4839,6 @@ static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
 	return selinux_nlmsg_perm(sk, skb);
 }
 
-static int selinux_netlink_recv(struct sk_buff *skb, int capability)
-{
-	int err;
-	struct common_audit_data ad;
-	u32 sid;
-
-	err = cap_netlink_recv(skb, capability);
-	if (err)
-		return err;
-
-	COMMON_AUDIT_DATA_INIT(&ad, CAP);
-	ad.u.cap = capability;
-
-	security_task_getsecid(current, &sid);
-	return avc_has_perm(sid, sid, SECCLASS_CAPABILITY,
-			    CAP_TO_MASK(capability), &ad);
-}
-
 static int ipc_alloc_security(struct task_struct *task,
 			      struct kern_ipc_perm *perm,
 			      u16 sclass)
@@ -5590,7 +5572,6 @@ static struct security_operations selinux_ops = {
 	.vm_enough_memory =		selinux_vm_enough_memory,
 
 	.netlink_send =			selinux_netlink_send,
-	.netlink_recv =			selinux_netlink_recv,
 
 	.bprm_set_creds =		selinux_bprm_set_creds,
 	.bprm_committing_creds =	selinux_bprm_committing_creds,