Commit ce1fad27 authored Oct 20, 2015 by Linus Torvalds

linux-fs

Pull key handling fixes from David Howells:
 "Here are two patches, the first of which at least should go upstream
  immediately:

  (1) Prevent a user-triggerable crash in the keyrings destructor when a
      negatively instantiated keyring is garbage collected.  I have also
      seen this triggered for user type keys.

  (2) Prevent the user from using requesting that a keyring be created
      and instantiated through an upcall.  Doing so is probably safe
      since the keyring type ignores the arguments to its instantiation
      function - but we probably shouldn't let keyrings be created in
      this manner"

* 'keys-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  KEYS: Don't permit request_key() to construct a new keyring
  KEYS: Fix crash when attempt to garbage collect an uninstantiated keyring

parents 1099f860 911b79cd

security/keys/gc.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -134,8 +134,10 @@ static noinline void key_gc_unused_keys(struct list_head *keys)
		kdebug("- %u", key->serial);
		key_check(key);

		/* Throw away the key data */
		if (key->type->destroy)
		/* Throw away the key data if the key is instantiated */
		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags) &&
		!test_bit(KEY_FLAG_NEGATIVE, &key->flags) &&
		key->type->destroy)
		key->type->destroy(key);

		security_key_free(key);

security/keys/request_key.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -440,6 +440,9 @@ static struct key construct_key_and_link(struct keyring_search_context ctx,

		kenter("");

		if (ctx->index_key.type == &key_type_keyring)
		return ERR_PTR(-EPERM);

		user = key_user_lookup(current_fsuid());
		if (!user)
		return ERR_PTR(-ENOMEM);