From patchwork Thu May 4 21:30:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael McCracken X-Patchwork-Id: 13231853 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5F3EC77B73 for ; Thu, 4 May 2023 21:30:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 74CF66B0075; Thu, 4 May 2023 17:30:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6FD2A6B0078; Thu, 4 May 2023 17:30:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5EBE66B007B; Thu, 4 May 2023 17:30:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f44.google.com (mail-ed1-f44.google.com [209.85.208.44]) by kanga.kvack.org (Postfix) with ESMTP id 1FD696B0075 for ; Thu, 4 May 2023 17:30:23 -0400 (EDT) Received: by mail-ed1-f44.google.com with SMTP id 4fb4d7f45d1cf-50bc4ba28cbso1874076a12.0 for ; Thu, 04 May 2023 14:30:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683235822; x=1685827822; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=dpDrHaDFb9uvY+Y5nUdaIxQKRWlMia3wPTlgfDNdf4c=; b=qwrCJncTbPjo7OVmLb6DC5CkyjhsTdxQEiYUjTISYeax0QnqJ+7w+fLvAGvuaJxaPp Biy+dpVNBJiWXPjTLS+Qjh7jTGnXGR054skBqurueUu4mQWWDFwk051N9sNmIVKpJlSm TtFoeRQKXeWTkPAParUiybl3T2AqyyLA+h36wqpHyuC/fQmynrFvoPnWeHhOkaJH1Jgj u9rNKsiyyy6gEYMZweRZ7GkEXNtSkiCyE7OhDcLiksv0RNr5Wlce5aK2IPjhGIYzVfJv S2Mmws/AseRyPGDs1Z8egoP2B3KfaGRUmRGMnwRjiF7GyKCb+bPVpN6/r4DPaYbQPKxw I93g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683235822; x=1685827822; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=dpDrHaDFb9uvY+Y5nUdaIxQKRWlMia3wPTlgfDNdf4c=; b=ez4hs07JWyLJ+bPcBjLqTRW3Sdyk2DGunbrsZkUMH4TxaVFboQXTmkoT6aFdbCUhH8 paiNsbqNkE6/8sjQFQpiuEKQf7NHl6mLruOIUjcYG5j3xpOFdxvp6uzUSN9m9mNkLCxZ 4KhG/DvN3/Hij0mlYP4L5u5MJgE+V+/YP3f6iu+WQE5axO+R/zFwMsJ9+dRyWFoQ/Ou/ p74Ksw1+nozv9HXbO655mh0kXwxb0Mh1eMFQkTs9wPpoBHS2QwlAFWEjndM/CFji72Ep 8s7hBvVYtCHnPalDOEobyYFSxZZA4VUpCSOktrlhERlvnX2KOyqmUWJr6PkCM1IEcTQF Phew== X-Gm-Message-State: AC+VfDyhKS3lua4TEVHOv13Ayrqc2ugZAhJitHq/jhB7VewylOi9Kwun rhsjLz8j518m5pSP2RHawXo= X-Google-Smtp-Source: ACHHUZ5Wn3isdXputF03nNuI/MZ3Uu+owH1nKZqePrOGnu81HEC8Zu53kDXxLbOPkyMXsTcPaUAMwg== X-Received: by 2002:a17:906:4785:b0:94a:7716:e649 with SMTP id cw5-20020a170906478500b0094a7716e649mr222144ejc.13.1683235822205; Thu, 04 May 2023 14:30:22 -0700 (PDT) Received: from MIKMCCRA-M-GY0W.cisco.com ([2001:420:c0c0:1001::d1]) by smtp.gmail.com with ESMTPSA id bz1-20020a1709070aa100b008f89953b761sm63289ejc.3.2023.05.04.14.30.20 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 04 May 2023 14:30:21 -0700 (PDT) From: Michael McCracken To: linux-kernel@vger.kernel.org Cc: kernel-hardening@lists.openwall.com, serge@hallyn.com, tycho@tycho.pizza, Michael McCracken , Luis Chamberlain , Kees Cook , Iurii Zaikin , Andrew Morton , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH] sysctl: add config to make randomize_va_space RO Date: Thu, 4 May 2023 14:30:02 -0700 Message-Id: <20230504213002.56803-1-michael.mccracken@gmail.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) MIME-Version: 1.0 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: Add config RO_RANDMAP_SYSCTL to set the mode of the randomize_va_space sysctl to 0444 to disallow all runtime changes. This will prevent accidental changing of this value by a root service. The config is disabled by default to avoid surprises. Signed-off-by: Michael McCracken --- kernel/sysctl.c | 4 ++++ mm/Kconfig | 7 +++++++ 2 files changed, 11 insertions(+) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index bfe53e835524..c5aafb734abe 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1913,7 +1913,11 @@ static struct ctl_table kern_table[] = { .procname = "randomize_va_space", .data = &randomize_va_space, .maxlen = sizeof(int), +#if defined(CONFIG_RO_RANDMAP_SYSCTL) + .mode = 0444, +#else .mode = 0644, +#endif .proc_handler = proc_dointvec, }, #endif diff --git a/mm/Kconfig b/mm/Kconfig index 7672a22647b4..91a4a86d70e0 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1206,6 +1206,13 @@ config PER_VMA_LOCK This feature allows locking each virtual memory area separately when handling page faults instead of taking mmap_lock. +config RO_RANDMAP_SYSCTL + bool "Make randomize_va_space sysctl 0444" + depends on MMU + default n + help + Set file mode of /proc/sys/kernel/randomize_va_space to 0444 to disallow runtime changes in ASLR. + source "mm/damon/Kconfig" endmenu