Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753919AbbFAVX4 (ORCPT ); Mon, 1 Jun 2015 17:23:56 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48704 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751591AbbFAVXs (ORCPT ); Mon, 1 Jun 2015 17:23:48 -0400 Date: Mon, 1 Jun 2015 14:23:47 -0700 From: Andrew Morton To: Vasily Averin Cc: linux-kernel@vger.kernel.org, Kees Cook , Josh Boyer , Eric Paris Subject: Re: [PATCH v2] security_syslog() should be called once only Message-Id: <20150601142347.06b1b4ba00d7210ea4b6e3f6@linux-foundation.org> In-Reply-To: <5569C066.1010300@virtuozzo.com> References: <20150514150154.dbfb8ab275aa30d0fe93172b@linux-foundation.org> <5561F9E0.6050504@virtuozzo.com> <20150527164312.a22ad8bb748acaddbea3bf70@linux-foundation.org> <5569C066.1010300@virtuozzo.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1461 Lines: 46 On Sat, 30 May 2015 16:51:34 +0300 Vasily Averin wrote: > On 28.05.2015 02:43, Andrew Morton wrote: > > So we run security_syslog() for actions other than open() (of kmsg). > > Why? > Could you please clarify this question? > > Linux kernel have reasonable default security policy and it's great. > And at the same time kernel allows to override default behaviour > and set custom security policy. > For example, to prohibit work on Saturday. > QA can use it for random failures generation. > Why not? This change: : --- a/kernel/printk/printk.c~security_syslog-should-be-called-once-only : +++ a/kernel/printk/printk.c : @@ -496,11 +496,11 @@ int check_syslog_permissions(int type, b : * already done the capabilities checks at open time. : */ : if (from_file && type != SYSLOG_ACTION_OPEN) : - return 0; : + goto ok; : : ... : : } : return -EPERM; : } : +ok: : return security_syslog(type); : } Means that we will now call security_syslog() for SYSLOG_ACTION_CLOSE, SYSLOG_ACTION_READ, SYSLOG_ACTION_READ_ALL, etc. That's new behaviour and it may be wrong. Why should check_syslog_permissions() call security_syslog() for anything other than SYSLOG_ACTION_OPEN? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/