KEYS: Add a 'trusted' flag and a 'trusted only' flag

Add KEY_FLAG_TRUSTED to indicate that a key either comes from a trusted source
or had a cryptographic signature chain that led back to a trusted key the
kernel already possessed.

Add KEY_FLAGS_TRUSTED_ONLY to indicate that a keyring will only accept links to
keys marked with KEY_FLAGS_TRUSTED.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

2 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/key-type.h b/include/linux/key-type.h
index f58737bcb050..a74c3a84dfdd 100644
--- a/include/linux/key-type.h
+++ b/include/linux/key-type.h
@@ -45,6 +45,7 @@ struct key_preparsed_payload {
         const void      *data;          /* Raw data */
         size_t          datalen;        /* Raw datalen */
         size_t          quotalen;       /* Quota length for proposed payload */
+        bool            trusted;        /* True if key is trusted */
 };
 
 typedef int (*request_key_actor_t)(struct key_construction *key,
diff --git a/include/linux/key.h b/include/linux/key.h
index 010dbb618aca..80d677483e31 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -168,6 +168,8 @@ struct key {
 #define KEY_FLAG_NEGATIVE       5       /* set if key is negative */
 #define KEY_FLAG_ROOT_CAN_CLEAR 6       /* set if key can be cleared by root without permission */
 #define KEY_FLAG_INVALIDATED    7       /* set if key has been invalidated */
+#define KEY_FLAG_TRUSTED        8       /* set if key is trusted */
+#define KEY_FLAG_TRUSTED_ONLY   9       /* set if keyring only accepts links to trusted keys */
 
         /* the key type and key description string
          * - the desc is used to match a key against search criteria
@@ -218,6 +220,7 @@ extern struct key *key_alloc(struct key_type *type,
 #define KEY_ALLOC_IN_QUOTA      0x0000  /* add to quota, reject if would overrun */
 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001  /* add to quota, permit even if overrun */
 #define KEY_ALLOC_NOT_IN_QUOTA  0x0002  /* not in quota */
+#define KEY_ALLOC_TRUSTED       0x0004  /* Key should be flagged as trusted */
 
 extern void key_revoke(struct key *key);
 extern void key_invalidate(struct key *key);