From patchwork Thu Apr 14 13:12:28 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: 561768 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 F054DC35273 for ; Thu, 14 Apr 2022 13:43:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245142AbiDNNnK (ORCPT ); Thu, 14 Apr 2022 09:43:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344070AbiDNNaR (ORCPT ); Thu, 14 Apr 2022 09:30:17 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06471D64; Thu, 14 Apr 2022 06:27:36 -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 A9C07B82941; Thu, 14 Apr 2022 13:27:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3A1BC385A5; Thu, 14 Apr 2022 13:27:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649942853; bh=3iLHWJ9oMVew3w5dKq0ip6r7rm2TZisUU8LmVzgiauw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G7k3P2BWe17RxE0zu+J5sdXgINRDGXvMbcZNgvGD2JF7pBy03W/Ii1bpn0C3bJVXU 2Rxr4e+NU3X0+5svb+4Z+NU3eTS130Ho8phge3y7vjvpYHNAH3aIt6NCdmyTLSVWid qpmoXv3ioH7Y1E+sCZGtqht+nCEjqS+rQfT9Zqds= 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 4.19 245/338] mm/mmap: return 1 from stack_guard_gap __setup() handler Date: Thu, 14 Apr 2022 15:12:28 +0200 Message-Id: <20220414110845.864034268@linuxfoundation.org> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220414110838.883074566@linuxfoundation.org> References: <20220414110838.883074566@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 @@ -2469,7 +2469,7 @@ 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);