From 504b69eb3c95180bc59f1ae9096ad4b10bbbf254 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 19 Jun 2019 16:10:15 +0100 Subject: keys: Fix request_key() lack of Link perm check on found key The request_key() syscall allows a process to gain access to the 'possessor' permits of any key that grants it Search permission by virtue of request_key() not checking whether a key it finds grants Link permission to the caller. Signed-off-by: David Howells --- security/keys/request_key.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'security') diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 857da65e1940..a6543ed98b1f 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -564,6 +564,16 @@ struct key *request_key_and_link(struct key_type *type, key_ref = search_process_keyrings(&ctx); if (!IS_ERR(key_ref)) { + if (dest_keyring) { + ret = key_task_permission(key_ref, current_cred(), + KEY_NEED_LINK); + if (ret < 0) { + key_ref_put(key_ref); + key = ERR_PTR(ret); + goto error_free; + } + } + key = key_ref_to_ptr(key_ref); if (dest_keyring) { ret = key_link(dest_keyring, key); -- cgit v1.2.3-55-g7522