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>
This commit is contained in:
David Howells
2013-08-30 16:07:37 +01:00
parent b56e5a17b6
commit 008643b86c
5 changed files with 19 additions and 1 deletions

View File

@@ -300,6 +300,8 @@ struct key *key_alloc(struct key_type *type, const char *desc,
if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
key->flags |= 1 << KEY_FLAG_IN_QUOTA;
if (flags & KEY_ALLOC_TRUSTED)
key->flags |= 1 << KEY_FLAG_TRUSTED;
memset(&key->type_data, 0, sizeof(key->type_data));
@@ -813,6 +815,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
prep.data = payload;
prep.datalen = plen;
prep.quotalen = index_key.type->def_datalen;
prep.trusted = flags & KEY_ALLOC_TRUSTED;
if (index_key.type->preparse) {
ret = index_key.type->preparse(&prep);
if (ret < 0) {
@@ -827,6 +830,11 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
}
index_key.desc_len = strlen(index_key.description);
key_ref = ERR_PTR(-EPERM);
if (!prep.trusted && test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags))
goto error_free_prep;
flags |= prep.trusted ? KEY_ALLOC_TRUSTED : 0;
ret = __key_link_begin(keyring, &index_key, &edit);
if (ret < 0) {
key_ref = ERR_PTR(ret);

View File

@@ -1183,6 +1183,10 @@ int key_link(struct key *keyring, struct key *key)
key_check(keyring);
key_check(key);
if (test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags) &&
!test_bit(KEY_FLAG_TRUSTED, &key->flags))
return -EPERM;
ret = __key_link_begin(keyring, &key->index_key, &edit);
if (ret == 0) {
kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage));