From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A49A6C433E0 for ; Mon, 8 Jun 2020 04:40:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 68F8920760 for ; Mon, 8 Jun 2020 04:40:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="mwbLhBOh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68F8920760 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 16EDE6B0033; Mon, 8 Jun 2020 00:40:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0F88A6B0036; Mon, 8 Jun 2020 00:40:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E8D4D6B0037; Mon, 8 Jun 2020 00:40:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id AF47B6B0033 for ; Mon, 8 Jun 2020 00:40:54 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 7AFE9804C45A for ; Mon, 8 Jun 2020 04:40:54 +0000 (UTC) X-FDA: 76904794428.19.queen11_140defc26db7 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id 55AF97487E for ; Mon, 8 Jun 2020 04:40:54 +0000 (UTC) X-HE-Tag: queen11_140defc26db7 X-Filterd-Recvd-Size: 3029 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Mon, 8 Jun 2020 04:40:53 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C7D1B206D5; Mon, 8 Jun 2020 04:40:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591591253; bh=WViusVnlw6268x0BWourLui/Cjl6Sjj3Fe1gOw+50fY=; h=Date:From:To:Subject:In-Reply-To:From; b=mwbLhBOh5TiGNvQJtaSKNDRZIfRJtIzO7k6HAqcjL39hBop6Igv36O78SvWwlgeq7 xtHgOJv2Yc7ehyiIN0E/jJYSZ1ryOGWz1KzIemWVe/WAMVdKrRm1UVa26bHpeRcKL6 W3f6Y/kg15CzqdzrZm2fqOoN0LA+8NViKiuPC8vM= Date: Sun, 07 Jun 2020 21:40:51 -0700 From: Andrew Morton To: akpm@linux-foundation.org, aquini@redhat.com, keescook@chromium.org, linux-mm@kvack.org, mcgrof@kernel.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, tytso@mit.edu, yzaikin@google.com Subject: [patch 15/54] kernel/sysctl.c: ignore out-of-range taint bits introduced via kernel.tainted Message-ID: <20200608044051.A6fYnLhbQ%akpm@linux-foundation.org> In-Reply-To: <20200607212615.b050e41fac139a1e16fe00bd@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 55AF97487E X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Rafael Aquini Subject: kernel/sysctl.c: ignore out-of-range taint bits introduced via kernel.tainted Users with SYS_ADMIN capability can add arbitrary taint flags to the running kernel by writing to /proc/sys/kernel/tainted or issuing the command 'sysctl -w kernel.tainted=...'. This interface, however, is open for any integer value and this might cause an invalid set of flags being committed to the tainted_mask bitset. This patch introduces a simple way for proc_taint() to ignore any eventual invalid bit coming from the user input before committing those bits to the kernel tainted_mask. Link: http://lkml.kernel.org/r/20200512223946.888020-1-aquini@redhat.com Signed-off-by: Rafael Aquini Reviewed-by: Luis Chamberlain Cc: Kees Cook Cc: Iurii Zaikin Cc: "Theodore Ts'o" Signed-off-by: Andrew Morton --- kernel/sysctl.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/kernel/sysctl.c~kernel-sysctl-ignore-out-of-range-taint-bits-introduced-via-kerneltainted +++ a/kernel/sysctl.c @@ -880,10 +880,9 @@ static int proc_taint(struct ctl_table * * Poor man's atomic or. Not worth adding a primitive * to everyone's atomic.h for this */ - for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) { - if ((tmptaint >> i) & 1) + for (i = 0; i < TAINT_FLAGS_COUNT; i++) + if ((1UL << i) & tmptaint) add_taint(i, LOCKDEP_STILL_OK); - } } return err; _