From patchwork Mon Feb 7 12:17:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Michal_Koutn=C3=BD?= X-Patchwork-Id: 12737175 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39570C433FE for ; Mon, 7 Feb 2022 12:32:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1382629AbiBGM20 (ORCPT ); Mon, 7 Feb 2022 07:28:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1382733AbiBGMYW (ORCPT ); Mon, 7 Feb 2022 07:24:22 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07E93C002B4D; Mon, 7 Feb 2022 04:18:13 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 9B090210E7; Mon, 7 Feb 2022 12:18:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1644236292; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=i4aAhbDoTDfRME9edOXYN8Xd3j7KeUJo6FCdttuCi7Q=; b=qcuQVmPAKpuli8d8JKcy9s2e+6GX/jOzZeZJNIji/24oWaLjPX8+Cz2+qzRBS1bRUmJPDe pYqkF0kg059Fuh0emCFA3zwXUDfANmYFDp+aiQv2AFBdtdSYZWeY8qy3+mQ+BfgWCYW2ra eFvrMzdhrvh2BOyfRa+Pli1YwbUwxbk= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 781D913BE6; Mon, 7 Feb 2022 12:18:12 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id AInNHAQOAWLMegAAMHmgww (envelope-from ); Mon, 07 Feb 2022 12:18:12 +0000 From: =?utf-8?q?Michal_Koutn=C3=BD?= To: Eric Biederman , Alexey Gladkov Cc: Kees Cook , Shuah Khan , Christian Brauner , Solar Designer , Ran Xiaokai , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Linux Containers Subject: [RFC PATCH 1/6] set_user: Perform RLIMIT_NPROC capability check against new user credentials Date: Mon, 7 Feb 2022 13:17:55 +0100 Message-Id: <20220207121800.5079-2-mkoutny@suse.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220207121800.5079-1-mkoutny@suse.com> References: <20220207121800.5079-1-mkoutny@suse.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org The check is currently against the current->cred but since those are going to change and we want to check RLIMIT_NPROC condition after the switch, supply the capability check with the new cred. But since we're checking new_user being INIT_USER any new cred's capability-based allowance may be redundant when the check fails and the alternative solution would be revert of the commit 2863643fb8b9 ("set_user: add capability check when rlimit(RLIMIT_NPROC) exceeds") Fixes: 2863643fb8b9 ("set_user: add capability check when rlimit(RLIMIT_NPROC) exceeds") Cc: Solar Designer Cc: Christian Brauner Signed-off-by: Michal Koutný --- kernel/sys.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sys.c b/kernel/sys.c index 8ea20912103a..48c90dcceff3 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -481,7 +481,8 @@ static int set_user(struct cred *new) */ if (ucounts_limit_cmp(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) >= 0 && new_user != INIT_USER && - !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) + !security_capable(new, &init_user_ns, CAP_SYS_RESOURCE, CAP_OPT_NONE) && + !security_capable(new, &init_user_ns, CAP_SYS_ADMIN, CAP_OPT_NONE)) current->flags |= PF_NPROC_EXCEEDED; else current->flags &= ~PF_NPROC_EXCEEDED;