Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752401AbdFAPtm (ORCPT ); Thu, 1 Jun 2017 11:49:42 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33815 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752381AbdFAPpW (ORCPT ); Thu, 1 Jun 2017 11:45:22 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Mimi Zohar" , "Dmitry Kasatkin" , "David Howells" Date: Thu, 01 Jun 2017 16:43:16 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 182/212] KEYS: special dot prefixed keyring name bug fix In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1518 Lines: 52 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Mimi Zohar commit a4e3b8d79a5c6d40f4a9703abf7fe3abcc6c3b8d upstream. Dot prefixed keyring names are supposed to be reserved for the kernel, but add_key() calls key_get_type_from_user(), which incorrectly verifies the 'type' field, not the 'description' field. This patch verifies the 'description' field isn't dot prefixed, when creating a new keyring, and removes the dot prefix test in key_get_type_from_user(). Changelog v6: - whitespace and other cleanup Changelog v5: - Only prevent userspace from creating a dot prefixed keyring, not regular keys - Dmitry Reported-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar Acked-by: David Howells Signed-off-by: Ben Hutchings --- security/keys/keyctl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -37,8 +37,6 @@ static int key_get_type_from_user(char * return ret; if (ret == 0 || ret >= len) return -EINVAL; - if (type[0] == '.') - return -EPERM; type[len - 1] = '\0'; return 0; } @@ -86,6 +84,10 @@ SYSCALL_DEFINE5(add_key, const char __us if (!*description) { kfree(description); description = NULL; + } else if ((description[0] == '.') && + (strncmp(type, "keyring", 7) == 0)) { + ret = -EPERM; + goto error2; } }