From patchwork Tue Apr 5 07:31:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 557280 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 6DC6BC43217 for ; Tue, 5 Apr 2022 10:28:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355810AbiDEKWG (ORCPT ); Tue, 5 Apr 2022 06:22:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347843AbiDEJ2e (ORCPT ); Tue, 5 Apr 2022 05:28:34 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BD6DDFDF9; Tue, 5 Apr 2022 02:15:49 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 25D81B81C14; Tue, 5 Apr 2022 09:15:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7610BC385A2; Tue, 5 Apr 2022 09:15:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649150144; bh=Ob6Qc/Tu2bMLO6pSa2/DGEYux6T8HjO/eIMbj+L/fFo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dq/JWBps+j9KPOfjzvVwElEC1fl4MqYlilQGk3R9CuzcjIfzY5ubDzDkBmxlI7qnq npfJLRxdEZAlTty0+qBqfDbdNDq9CR1ZPi7a/pQCgKfCJYWGrL+8CIoJvfIHRjUcjq q5UxgP5WSD1EqsuLiz+EqRO2Gaxlb3YhyVNsOK1I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Randy Dunlap , Igor Zhbanov , Hugh Dickins , Andrew Morton , Linus Torvalds Subject: [PATCH 5.16 0971/1017] mm/mmap: return 1 from stack_guard_gap __setup() handler Date: Tue, 5 Apr 2022 09:31:24 +0200 Message-Id: <20220405070423.027891655@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070354.155796697@linuxfoundation.org> References: <20220405070354.155796697@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Randy Dunlap commit e6d094936988910ce6e8197570f2753898830081 upstream. __setup() handlers should return 1 if the command line option is handled and 0 if not (or maybe never return 0; it just pollutes init's environment). This prevents: Unknown kernel command line parameters \ "BOOT_IMAGE=/boot/bzImage-517rc5 stack_guard_gap=100", will be \ passed to user space. Run /sbin/init as init process with arguments: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc5 stack_guard_gap=100 Return 1 to indicate that the boot option has been handled. Note that there is no warning message if someone enters: stack_guard_gap=anything_invalid and 'val' and stack_guard_gap are both set to 0 due to the use of simple_strtoul(). This could be improved by using kstrtoxxx() and checking for an error. It appears that having stack_guard_gap == 0 is valid (if unexpected) since using "stack_guard_gap=0" on the kernel command line does that. Link: https://lkml.kernel.org/r/20220222005817.11087-1-rdunlap@infradead.org Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Fixes: 1be7107fbe18e ("mm: larger stack guard gap, between vmas") Signed-off-by: Randy Dunlap Reported-by: Igor Zhbanov Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2550,7 +2550,7 @@ static int __init cmdline_parse_stack_gu if (!*endptr) stack_guard_gap = val << PAGE_SHIFT; - return 0; + return 1; } __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);