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, 15 insertions, 1 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3ec7ac70c313..4ed83d869084 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6502,6 +6502,7 @@ static int selinux_key_permission(key_ref_t key_ref,
 {
         struct key *key;
         struct key_security_struct *ksec;
+        unsigned oldstyle_perm;
         u32 sid;
 
         /* if no specific permissions are requested, we skip the
@@ -6510,13 +6511,26 @@ static int selinux_key_permission(key_ref_t key_ref,
         if (perm == 0)
                 return 0;
 
+        oldstyle_perm = perm & (KEY_NEED_VIEW | KEY_NEED_READ | KEY_NEED_WRITE |
+                                KEY_NEED_SEARCH | KEY_NEED_LINK);
+        if (perm & KEY_NEED_SETSEC)
+                oldstyle_perm |= OLD_KEY_NEED_SETATTR;
+        if (perm & KEY_NEED_INVAL)
+                oldstyle_perm |= KEY_NEED_SEARCH;
+        if (perm & KEY_NEED_REVOKE && !(perm & OLD_KEY_NEED_SETATTR))
+                oldstyle_perm |= KEY_NEED_WRITE;
+        if (perm & KEY_NEED_JOIN)
+                oldstyle_perm |= KEY_NEED_SEARCH;
+        if (perm & KEY_NEED_CLEAR)
+                oldstyle_perm |= KEY_NEED_WRITE;
+
         sid = cred_sid(cred);
 
         key = key_ref_to_ptr(key_ref);
         ksec = key->security;
 
         return avc_has_perm(&selinux_state,
-                            sid, ksec->sid, SECCLASS_KEY, perm, NULL);
+                            sid, ksec->sid, SECCLASS_KEY, oldstyle_perm, NULL);
 }
 
 static int selinux_key_getsecurity(struct key *key, char **_buffer)