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

1 files changed, 13 insertions, 18 deletions

diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 4582bc26770a..ceb10553a6ba 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -47,7 +47,8 @@ int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
 
 	if (!keyring[id]) {
 		keyring[id] =
-			request_key(&key_type_keyring, keyring_name[id], NULL);
+			request_key(&key_type_keyring, keyring_name[id],
+				    NULL, NULL);
 		if (IS_ERR(keyring[id])) {
 			int err = PTR_ERR(keyring[id]);
 			pr_err("no %s keyring: %d\n", keyring_name[id], err);
@@ -69,14 +70,14 @@ int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
 	return -EOPNOTSUPP;
 }
 
-static int __integrity_init_keyring(const unsigned int id, key_perm_t perm,
+static int __integrity_init_keyring(const unsigned int id, struct key_acl *acl,
 				    struct key_restriction *restriction)
 {
 	const struct cred *cred = current_cred();
 	int err = 0;
 
 	keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
-				    KGIDT_INIT(0), cred, perm,
+				    KGIDT_INIT(0), cred, acl,
 				    KEY_ALLOC_NOT_IN_QUOTA, restriction, NULL);
 	if (IS_ERR(keyring[id])) {
 		err = PTR_ERR(keyring[id]);
@@ -94,10 +95,7 @@ static int __integrity_init_keyring(const unsigned int id, key_perm_t perm,
 int __init integrity_init_keyring(const unsigned int id)
 {
 	struct key_restriction *restriction;
-	key_perm_t perm;
-
-	perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
-		| KEY_USR_READ | KEY_USR_SEARCH;
+	struct key_acl *acl = &internal_keyring_acl;
 
 	if (id == INTEGRITY_KEYRING_PLATFORM) {
 		restriction = NULL;
@@ -112,14 +110,14 @@ int __init integrity_init_keyring(const unsigned int id)
 		return -ENOMEM;
 
 	restriction->check = restrict_link_to_ima;
-	perm |= KEY_USR_WRITE;
+	acl = &internal_writable_keyring_acl;
 
 out:
-	return __integrity_init_keyring(id, perm, restriction);
+	return __integrity_init_keyring(id, acl, restriction);
 }
 
-int __init integrity_add_key(const unsigned int id, const void *data,
-			     off_t size, key_perm_t perm)
+static int __init integrity_add_key(const unsigned int id, const void *data,
+				    off_t size, struct key_acl *acl)
 {
 	key_ref_t key;
 	int rc = 0;
@@ -128,7 +126,7 @@ int __init integrity_add_key(const unsigned int id, const void *data,
 		return -EINVAL;
 
 	key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
-				   NULL, data, size, perm,
+				   NULL, data, size, acl ?: &internal_key_acl,
 				   KEY_ALLOC_NOT_IN_QUOTA);
 	if (IS_ERR(key)) {
 		rc = PTR_ERR(key);
@@ -148,7 +146,6 @@ int __init integrity_load_x509(const unsigned int id, const char *path)
 	void *data;
 	loff_t size;
 	int rc;
-	key_perm_t perm;
 
 	rc = kernel_read_file_from_path(path, &data, &size, 0,
 					READING_X509_CERTIFICATE);
@@ -157,21 +154,19 @@ int __init integrity_load_x509(const unsigned int id, const char *path)
 		return rc;
 	}
 
-	perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
-
 	pr_info("Loading X.509 certificate: %s\n", path);
-	rc = integrity_add_key(id, (const void *)data, size, perm);
+	rc = integrity_add_key(id, data, size, NULL);
 
 	vfree(data);
 	return rc;
 }
 
 int __init integrity_load_cert(const unsigned int id, const char *source,
-			       const void *data, size_t len, key_perm_t perm)
+			       const void *data, size_t len, struct key_acl *acl)
 {
 	if (!data)
 		return -EINVAL;
 
 	pr_info("Loading X.509 certificate: %s\n", source);
-	return integrity_add_key(id, data, len, perm);
+	return integrity_add_key(id, data, len, acl);
 }