Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752557AbaBLPor (ORCPT ); Wed, 12 Feb 2014 10:44:47 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:28345 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751883AbaBLPoq (ORCPT ); Wed, 12 Feb 2014 10:44:46 -0500 From: Andrey Vagin To: linux-kernel@vger.kernel.org Cc: criu@openvz.org, Andrey Vagin , Andrew Morton , Oleg Nesterov , Robin Holt , Al Viro , Kees Cook , "Eric W. Biederman" , Chen Gang , Stephen Rothwell , Pavel Emelyanov , Aditya Kali , security@kernel.org Subject: [PATCH] kernel: reduce required permission for prctl_set_mm Date: Wed, 12 Feb 2014 19:40:11 +0400 Message-Id: <1392219611-13260-1-git-send-email-avagin@openvz.org> X-Mailer: git-send-email 1.8.5.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently prctl_set_mm requires the global CAP_SYS_RESOURCE, this patch reduce requiremence to CAP_SYS_RESOURCE in the current namespace. 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. prctl_set_mm() changes parameters of the current task and doesn't affect other tasks. This patch affects the RLIMIT_DATA limit, because a consumtiuon is calculated relatively to mm->end_data, mm->start_data, mm->start_brk. rlim = rlimit(RLIMIT_DATA); if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + (mm->end_data - mm->start_data) > rlim) goto out; This limit affects calls to brk() and sbrk(), but it doesn't affect mmap. So I think requirement of CAP_SYS_RESOURCE in the current namespace is enough for this limit. Cc: Andrew Morton Cc: Oleg Nesterov Cc: Robin Holt Cc: Al Viro Cc: Kees Cook Cc: "Eric W. Biederman" Cc: Chen Gang Cc: Stephen Rothwell Cc: Pavel Emelyanov Cc: Aditya Kali Cc: security@kernel.org Signed-off-by: Andrey Vagin --- kernel/sys.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sys.c b/kernel/sys.c index c0a58be..6f36fb3 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1701,7 +1701,7 @@ 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)) + if (!ns_capable(current_user_ns(), CAP_SYS_RESOURCE)) return -EPERM; if (opt == PR_SET_MM_EXE_FILE) -- 1.8.5.3 -- 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/