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, 65 insertions, 0 deletions

diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h
index ed3d5893830d..1f7a4e737214 100644
--- a/include/uapi/linux/keyctl.h
+++ b/include/uapi/linux/keyctl.h
@@ -15,6 +15,69 @@
 
 #include <linux/types.h>
 
+/*
+ * Keyring permission grant definitions
+ */
+enum key_ace_subject_type {
+	KEY_ACE_SUBJ_STANDARD	= 0,	/* subject is one of key_ace_standard_subject */
+	nr__key_ace_subject_type
+};
+
+enum key_ace_standard_subject {
+	KEY_ACE_EVERYONE	= 0,	/* Everyone, including owner and group */
+	KEY_ACE_GROUP		= 1,	/* The key's group */
+	KEY_ACE_OWNER		= 2,	/* The owner of the key */
+	KEY_ACE_POSSESSOR	= 3,	/* Any process that possesses of the key */
+	nr__key_ace_standard_subject
+};
+
+#define KEY_ACE_VIEW		0x00000001 /* Can describe the key */
+#define KEY_ACE_READ		0x00000002 /* Can read the key content */
+#define KEY_ACE_WRITE		0x00000004 /* Can update/modify the key content */
+#define KEY_ACE_SEARCH		0x00000008 /* Can find the key by search */
+#define KEY_ACE_LINK		0x00000010 /* Can make a link to the key */
+#define KEY_ACE_SET_SECURITY	0x00000020 /* Can set owner, group, ACL */
+#define KEY_ACE_INVAL		0x00000040 /* Can invalidate the key */
+#define KEY_ACE_REVOKE		0x00000080 /* Can revoke the key */
+#define KEY_ACE_JOIN		0x00000100 /* Can join keyring */
+#define KEY_ACE_CLEAR		0x00000200 /* Can clear keyring */
+#define KEY_ACE__PERMS		0xffffffff
+
+/*
+ * Old-style permissions mask, deprecated in favour of ACL.
+ */
+#define KEY_POS_VIEW	0x01000000	/* possessor can view a key's attributes */
+#define KEY_POS_READ	0x02000000	/* possessor can read key payload / view keyring */
+#define KEY_POS_WRITE	0x04000000	/* possessor can update key payload / add link to keyring */
+#define KEY_POS_SEARCH	0x08000000	/* possessor can find a key in search / search a keyring */
+#define KEY_POS_LINK	0x10000000	/* possessor can create a link to a key/keyring */
+#define KEY_POS_SETATTR	0x20000000	/* possessor can set key attributes */
+#define KEY_POS_ALL	0x3f000000
+
+#define KEY_USR_VIEW	0x00010000	/* user permissions... */
+#define KEY_USR_READ	0x00020000
+#define KEY_USR_WRITE	0x00040000
+#define KEY_USR_SEARCH	0x00080000
+#define KEY_USR_LINK	0x00100000
+#define KEY_USR_SETATTR	0x00200000
+#define KEY_USR_ALL	0x003f0000
+
+#define KEY_GRP_VIEW	0x00000100	/* group permissions... */
+#define KEY_GRP_READ	0x00000200
+#define KEY_GRP_WRITE	0x00000400
+#define KEY_GRP_SEARCH	0x00000800
+#define KEY_GRP_LINK	0x00001000
+#define KEY_GRP_SETATTR	0x00002000
+#define KEY_GRP_ALL	0x00003f00
+
+#define KEY_OTH_VIEW	0x00000001	/* third party permissions... */
+#define KEY_OTH_READ	0x00000002
+#define KEY_OTH_WRITE	0x00000004
+#define KEY_OTH_SEARCH	0x00000008
+#define KEY_OTH_LINK	0x00000010
+#define KEY_OTH_SETATTR	0x00000020
+#define KEY_OTH_ALL	0x0000003f
+
 /* special process keyring shortcut IDs */
 #define KEY_SPEC_THREAD_KEYRING		-1	/* - key ID for thread-specific keyring */
 #define KEY_SPEC_PROCESS_KEYRING	-2	/* - key ID for process-specific keyring */
@@ -69,6 +132,7 @@
 #define KEYCTL_RESTRICT_KEYRING		29	/* Restrict keys allowed to link to a keyring */
 #define KEYCTL_MOVE			30	/* Move keys between keyrings */
 #define KEYCTL_CAPABILITIES		31	/* Find capabilities of keyrings subsystem */
+#define KEYCTL_GRANT_PERMISSION		32	/* Grant a permit to a key */
 
 /* keyctl structures */
 struct keyctl_dh_params {
@@ -130,5 +194,6 @@ struct keyctl_pkey_params {
 #define KEYCTL_CAPS0_MOVE		0x80 /* KEYCTL_MOVE supported */
 #define KEYCTL_CAPS1_NS_KEYRING_NAME	0x01 /* Keyring names are per-user_namespace */
 #define KEYCTL_CAPS1_NS_KEY_TAG		0x02 /* Key indexing can include a namespace tag */
+#define KEYCTL_CAPS1_ACL_ALTERABLE	0x04 /* Keys have internal ACL that can be altered */
 
 #endif /*  _LINUX_KEYCTL_H */