From patchwork Fri Mar 13 15:20:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 11437085 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 08D3E1668 for ; Fri, 13 Mar 2020 15:21:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DCC8020724 for ; Fri, 13 Mar 2020 15:21:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WF8FLIJK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726420AbgCMPV3 (ORCPT ); Fri, 13 Mar 2020 11:21:29 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:46432 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726534AbgCMPV3 (ORCPT ); Fri, 13 Mar 2020 11:21:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584112888; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=PNyjHm+IZ1fvNEx5HMZqidw/J156+wuo7jGfMRKY4Vs=; b=WF8FLIJKWv/vKm+YOyfldSYv9aXAViQKDgagKONhRdA/BRoZWDl5NlRARGlkDIUXuj5HXk bV1isMtDqzhshadAlfm9BU8ej4YO6u+7riYgd37e00bk+Y3ciDjJRAo7NxIy83iKquxILw nog94lM4NEifVPkqKMG3V380Aw6IjKA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-264-7lRX4n-MPCaBRrVDLTE9Ag-1; Fri, 13 Mar 2020 11:21:25 -0400 X-MC-Unique: 7lRX4n-MPCaBRrVDLTE9Ag-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 879888026B1; Fri, 13 Mar 2020 15:21:23 +0000 (UTC) Received: from llong.com (ovpn-125-21.rdu2.redhat.com [10.10.125.21]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9B39A91D61; Fri, 13 Mar 2020 15:21:18 +0000 (UTC) From: Waiman Long To: David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Mimi Zohar Cc: keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, Sumit Garg , Jerry Snitselaar , Roberto Sassu , Eric Biggers , Chris von Recklinghausen , Waiman Long Subject: [PATCH v3 0/3] KEYS: Read keys to internal buffer & then copy to userspace Date: Fri, 13 Mar 2020 11:20:59 -0400 Message-Id: <20200313152102.1707-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: keyrings-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org v3: - Reorganize the keyctl_read_key() code to make it more readable as suggested by Jarkko Sakkinen. - Add patch 3 to use kvmalloc() for safer large buffer allocation as suggested by David Howells. v2: - Handle NULL buffer and buflen properly in patch 1. - Fix a bug in big_key.c. - Add patch 2 to handle arbitrary large user-supplied buflen. The current security key read methods are called with the key semaphore held. The methods then copy out the key data to userspace which is subjected to page fault and may acquire the mmap semaphore. That can result in circular lock dependency and hence a chance to get into deadlock. To avoid such a deadlock, an internal buffer is now allocated for getting out the necessary data first. After releasing the key semaphore, the key data are then copied out to userspace sidestepping the circular lock dependency. The keyutils test suite was run and the test passed with these patchset applied without any falure. Waiman Long (3): KEYS: Don't write out to userspace while holding key semaphore KEYS: Avoid false positive ENOMEM error on key read KEYS: Use kvmalloc() to better handle large buffer allocation include/linux/key-type.h | 2 +- security/keys/big_key.c | 11 ++- security/keys/encrypted-keys/encrypted.c | 7 +- security/keys/internal.h | 14 ++++ security/keys/keyctl.c | 87 ++++++++++++++++++++--- security/keys/keyring.c | 6 +- security/keys/request_key_auth.c | 7 +- security/keys/trusted-keys/trusted_tpm1.c | 14 +--- security/keys/user_defined.c | 5 +- 9 files changed, 107 insertions(+), 46 deletions(-)