Re: [RFC PATCH 22/27] KEYS: Replace uid/gid/perm permissions checking with an ACL

Stephen Smalley [off-list ref] wrote:

quoted

--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c

@@ -6560,6 +6560,7 @@ 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

@@ -6568,13 +6569,26 @@ 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);

This might be ok temporarily for compatibility but we'll want to ultimately
define the new permissions in SELinux and switch over to using them if a new
policy capability bit is set to indicate that the policy supports them.  We
should probably decouple the SELinux permission bits from the KEY_NEED_*
values and explicitly map them all at the same time.

Sounds reasonable.  I should probably detach the first two ACL patches from
the set and push them separately.

David