From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753052AbaBNOP1 (ORCPT ); Fri, 14 Feb 2014 09:15:27 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:35465 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752596AbaBNOPX (ORCPT ); Fri, 14 Feb 2014 09:15:23 -0500 From: Andrey Vagin To: linux-kernel@vger.kernel.org Cc: criu@openvz.org, Andrey Vagin , Andrew Morton , Oleg Nesterov , Al Viro , Kees Cook , "Eric W. Biederman" , Stephen Rothwell , Pavel Emelyanov , Aditya Kali Subject: [PATCH 1/3] prctl: reduce permissions to change boundaries of data, brk and stack Date: Fri, 14 Feb 2014 18:13:27 +0400 Message-Id: <1392387209-330-2-git-send-email-avagin@openvz.org> X-Mailer: git-send-email 1.8.5.3 In-Reply-To: <1392387209-330-1-git-send-email-avagin@openvz.org> References: <1392387209-330-1-git-send-email-avagin@openvz.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently this operation requires the global CAP_SYS_RESOURCE. It's required, because a task can exceed limits (RLIMIT_DATA, RLIMIT_STACK). So let's allow task to change these parameters if a proper limit is unlimited. When we restore a task we need to set up text, data and data heap sizes from userspace to the values a task had at checkpoint time. Currently we can not restore these parameters, if a task lives in a non-root user name space, because it has no capabilities in the parent namespace. Cc: Andrew Morton Cc: Oleg Nesterov Cc: Al Viro Cc: Kees Cook Cc: "Eric W. Biederman" Cc: Stephen Rothwell Cc: Pavel Emelyanov Cc: Aditya Kali Signed-off-by: Andrey Vagin --- kernel/sys.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/kernel/sys.c b/kernel/sys.c index c0a58be..939370c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1701,8 +1701,23 @@ static int prctl_set_mm(int opt, unsigned long addr, if (arg5 || (arg4 && opt != PR_SET_MM_AUXV)) return -EINVAL; - if (!capable(CAP_SYS_RESOURCE)) - return -EPERM; + if (!capable(CAP_SYS_RESOURCE)) { + switch (opt) { + case PR_SET_MM_START_DATA: + case PR_SET_MM_END_DATA: + case PR_SET_MM_START_BRK: + case PR_SET_MM_BRK: + if (rlim < RLIM_INFINITY) + return -EPERM; + break; + case PR_SET_MM_START_STACK: + if (rlimit(RLIMIT_STACK) < RLIM_INFINITY) + return -EPERM; + break; + default: + return -EPERM; + } + } if (opt == PR_SET_MM_EXE_FILE) return prctl_set_mm_exe_file(mm, (unsigned int)addr); -- 1.8.5.3