Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull keyring ACL support from David Howells:
 "This changes the permissions model used by keys and keyrings to be
  based on an internal ACL by the following means:

   - Replace the permissions mask internally with an ACL that contains a
     list of ACEs, each with a specific subject with a permissions mask.
     Potted default ACLs are available for new keys and keyrings.

     ACE subjects can be macroised to indicate the UID and GID specified
     on the key (which remain). Future commits will be able to add
     additional subject types, such as specific UIDs or domain
     tags/namespaces.

     Also split a number of permissions to give finer control. Examples
     include splitting the revocation permit from the change-attributes
     permit, thereby allowing someone to be granted permission to revoke
     a key without allowing them to change the owner; also the ability
     to join a keyring is split from the ability to link to it, thereby
     stopping a process accessing a keyring by joining it and thus
     acquiring use of possessor permits.

   - Provide a keyctl to allow the granting or denial of one or more
     permits to a specific subject. Direct access to the ACL is not
     granted, and the ACL cannot be viewed"

* tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  keys: Provide KEYCTL_GRANT_PERMISSION
  keys: Replace uid/gid/perm permissions checking with an ACL

5 files changed, 40 insertions, 14 deletions

diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 1c811c74bfc0..38de80d01aae 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -306,7 +306,7 @@ static int get_secret(struct ceph_crypto_key *dst, const char *name) {
 	int err = 0;
 	struct ceph_crypto_key *ckey;
 
-	ukey = request_key(&key_type_ceph, name, NULL);
+	ukey = request_key(&key_type_ceph, name, NULL, NULL);
 	if (IS_ERR(ukey)) {
 		/* request_key errors don't map nicely to mount(2)
 		   errors; don't even try, but still printk */
diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
index 3e1a90669006..6b201531b165 100644
--- a/net/dns_resolver/dns_key.c
+++ b/net/dns_resolver/dns_key.c
@@ -46,6 +46,15 @@ const struct cred *dns_resolver_cache;
 
 #define	DNS_ERRORNO_OPTION	"dnserror"
 
+static struct key_acl dns_keyring_acl = {
+	.usage	= REFCOUNT_INIT(1),
+	.nr_ace	= 2,
+	.aces = {
+		KEY_POSSESSOR_ACE(KEY_ACE_SEARCH | KEY_ACE_WRITE),
+		KEY_OWNER_ACE(KEY_ACE_VIEW | KEY_ACE_READ | KEY_ACE_CLEAR),
+	}
+};
+
 /*
  * Preparse instantiation data for a dns_resolver key.
  *
@@ -343,8 +352,7 @@ static int __init init_dns_resolver(void)
 
 	keyring = keyring_alloc(".dns_resolver",
 				GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
-				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
-				KEY_USR_VIEW | KEY_USR_READ,
+				&dns_keyring_acl,
 				KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
 	if (IS_ERR(keyring)) {
 		ret = PTR_ERR(keyring);
diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c
index cab4e0df924f..236baf2bfa4c 100644
--- a/net/dns_resolver/dns_query.c
+++ b/net/dns_resolver/dns_query.c
@@ -47,6 +47,16 @@
 
 #include "internal.h"
 
+static struct key_acl dns_key_acl = {
+	.usage	= REFCOUNT_INIT(1),
+	.nr_ace	= 2,
+	.possessor_viewable = true,
+	.aces = {
+		KEY_POSSESSOR_ACE(KEY_ACE_VIEW | KEY_ACE_SEARCH | KEY_ACE_READ),
+		KEY_OWNER_ACE(KEY_ACE_VIEW | KEY_ACE_INVAL),
+	}
+};
+
 /**
  * dns_query - Query the DNS
  * @net: The network namespace to operate in.
@@ -125,7 +135,8 @@ int dns_query(struct net *net,
 	 * add_key() to preinstall malicious redirections
 	 */
 	saved_cred = override_creds(dns_resolver_cache);
-	rkey = request_key_net(&key_type_dns_resolver, desc, net, options);
+	rkey = request_key_net(&key_type_dns_resolver, desc, net, options,
+			       &dns_key_acl);
 	revert_creds(saved_cred);
 	kfree(desc);
 	if (IS_ERR(rkey)) {
@@ -135,8 +146,6 @@ int dns_query(struct net *net,
 
 	down_read(&rkey->sem);
 	set_bit(KEY_FLAG_ROOT_CAN_INVAL, &rkey->flags);
-	rkey->perm |= KEY_USR_VIEW;
-
 	ret = key_validate(rkey);
 	if (ret < 0)
 		goto put;
diff --git a/net/rxrpc/key.c b/net/rxrpc/key.c
index 6c3f35fac42d..2032f6a8225e 100644
--- a/net/rxrpc/key.c
+++ b/net/rxrpc/key.c
@@ -23,6 +23,14 @@
 #include <keys/user-type.h>
 #include "ar-internal.h"
 
+static struct key_acl rxrpc_null_key_acl = {
+	.usage	= REFCOUNT_INIT(1),
+	.nr_ace	= 1,
+	.aces = {
+		KEY_POSSESSOR_ACE(KEY_ACE_SEARCH | KEY_ACE_READ),
+	}
+};
+
 static int rxrpc_vet_description_s(const char *);
 static int rxrpc_preparse(struct key_preparsed_payload *);
 static int rxrpc_preparse_s(struct key_preparsed_payload *);
@@ -910,7 +918,8 @@ int rxrpc_request_key(struct rxrpc_sock *rx, char __user *optval, int optlen)
 	if (IS_ERR(description))
 		return PTR_ERR(description);
 
-	key = request_key_net(&key_type_rxrpc, description, sock_net(&rx->sk), NULL);
+	key = request_key_net(&key_type_rxrpc, description, sock_net(&rx->sk),
+			      NULL, NULL);
 	if (IS_ERR(key)) {
 		kfree(description);
 		_leave(" = %ld", PTR_ERR(key));
@@ -941,7 +950,8 @@ int rxrpc_server_keyring(struct rxrpc_sock *rx, char __user *optval,
 	if (IS_ERR(description))
 		return PTR_ERR(description);
 
-	key = request_key_net(&key_type_keyring, description, sock_net(&rx->sk), NULL);
+	key = request_key_net(&key_type_keyring, description, sock_net(&rx->sk),
+			      NULL, NULL);
 	if (IS_ERR(key)) {
 		kfree(description);
 		_leave(" = %ld", PTR_ERR(key));
@@ -974,7 +984,8 @@ int rxrpc_get_server_data_key(struct rxrpc_connection *conn,
 	_enter("");
 
 	key = key_alloc(&key_type_rxrpc, "x",
-			GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred, 0,
+			GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
+			&internal_key_acl,
 			KEY_ALLOC_NOT_IN_QUOTA, NULL);
 	if (IS_ERR(key)) {
 		_leave(" = -ENOMEM [alloc %ld]", PTR_ERR(key));
@@ -1022,7 +1033,7 @@ struct key *rxrpc_get_null_key(const char *keyname)
 
 	key = key_alloc(&key_type_rxrpc, keyname,
 			GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
-			KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA, NULL);
+			&rxrpc_null_key_acl, KEY_ALLOC_NOT_IN_QUOTA, NULL);
 	if (IS_ERR(key))
 		return key;
 
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 4831ad745f91..298fe91557f7 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -741,8 +741,7 @@ static void __init load_keys_from_buffer(const u8 *p, unsigned int buflen)
 
 		key = key_create_or_update(make_key_ref(builtin_regdb_keys, 1),
 					   "asymmetric", NULL, p, plen,
-					   ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
-					    KEY_USR_VIEW | KEY_USR_READ),
+					   &internal_key_acl, 
 					   KEY_ALLOC_NOT_IN_QUOTA |
 					   KEY_ALLOC_BUILT_IN |
 					   KEY_ALLOC_BYPASS_RESTRICTION);
@@ -768,8 +767,7 @@ static int __init load_builtin_regdb_keys(void)
 	builtin_regdb_keys =
 		keyring_alloc(".builtin_regdb_keys",
 			      KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
-			      ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
-			      KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
+			      &internal_keyring_acl, 
 			      KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
 	if (IS_ERR(builtin_regdb_keys))
 		return PTR_ERR(builtin_regdb_keys);