From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935359AbcJ2NVg (ORCPT ); Sat, 29 Oct 2016 09:21:36 -0400 Received: from mail-lf0-f68.google.com ([209.85.215.68]:34623 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932372AbcJ2NVf (ORCPT ); Sat, 29 Oct 2016 09:21:35 -0400 Date: Sat, 29 Oct 2016 18:21:24 +0300 From: Alexey Dobriyan To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, keescook@chromium.org Subject: [PATCH] coredump: clarify "unsafe core_pattern" warning Message-ID: <20161029152124.GA1258@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I was amused to find "unsafe core_pattern" warning having these lines in /etc/sysctl.conf: fs.suid_dumpable=2 kernel.core_pattern=/core/core-%e-%p-%E kernel.core_uses_pid=0 Turns out kernel is formally right. Default core_pattern is just "core", which doesn't qualify for secure path while setting suid.dumpable. Hint admins about solution, clarify sysctl names, delete unnecessary '\' characters (string literals are concatenated regardless) and reformat for easier grepping. Signed-off-by: Alexey Dobriyan --- kernel/sysctl.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) commit ba93b14a4f61e4563134abab5d81bb8b53c60df9 Author: Alexey Dobriyan Date: Sat Oct 29 18:13:57 2016 +0300 kernel.core_dump --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2403,9 +2403,11 @@ static void validate_coredump_safety(void) #ifdef CONFIG_COREDUMP if (suid_dumpable == SUID_DUMP_ROOT && core_pattern[0] != '/' && core_pattern[0] != '|') { - printk(KERN_WARNING "Unsafe core_pattern used with "\ - "suid_dumpable=2. Pipe handler or fully qualified "\ - "core dump path required.\n"); + printk(KERN_WARNING +"Unsafe core_pattern used with fs.suid_dumpable=2.\n" +"Pipe handler or fully qualified core dump path required.\n" +"Set kernel.core_pattern before fs.suid_dumpable.\n" + ); } #endif }