From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 24/54] mm/mmap.c: do not allow mappings outside of allowed limits Date: Sun, 07 Jun 2020 21:41:21 -0700 Message-ID: <20200608044121.stuEeVRhM%akpm@linux-foundation.org> References: <20200607212615.b050e41fac139a1e16fe00bd@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:37176 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726929AbgFHElW (ORCPT ); Mon, 8 Jun 2020 00:41:22 -0400 In-Reply-To: <20200607212615.b050e41fac139a1e16fe00bd@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: agordeev@linux.ibm.com, akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org From: Alexander Gordeev Subject: mm/mmap.c: do not allow mappings outside of allowed limits One can set a lowest possible address in /proc/sys/vm/mmap_min_addr and mmap below that bound nevertheless. It is possible to request a fixed mapping address below mmap_min_addr and succeed. This update adds early checks of mmap_min_addr and mmap_end boundaries and fixes the above issue. Apart from it is wrong I am not aware of any existing issue. Link: http://lkml.kernel.org/r/d6da1319114a331095052638f0ffa3ccb0be58f1.1584958099.git.agordeev@linux.ibm.com Signed-off-by: Alexander Gordeev Signed-off-by: Andrew Morton --- mm/mmap.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) --- a/mm/mmap.c~mm-mmapc-do-not-allow-mappings-outside-of-allowed-limits +++ a/mm/mmap.c @@ -62,6 +62,14 @@ #define arch_mmap_check(addr, len, flags) (0) #endif +#ifndef arch_get_mmap_end +#define arch_get_mmap_end(addr) (TASK_SIZE) +#endif + +#ifndef arch_get_mmap_base +#define arch_get_mmap_base(addr, base) (base) +#endif + #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN; const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX; @@ -1369,6 +1377,7 @@ unsigned long do_mmap(struct file *file, unsigned long pgoff, unsigned long *populate, struct list_head *uf) { + const unsigned long mmap_end = arch_get_mmap_end(addr); struct mm_struct *mm = current->mm; int pkey = 0; @@ -1391,8 +1400,12 @@ unsigned long do_mmap(struct file *file, if (flags & MAP_FIXED_NOREPLACE) flags |= MAP_FIXED; - if (!(flags & MAP_FIXED)) + if (flags & MAP_FIXED) { + if ((addr < mmap_min_addr) || (addr > mmap_end)) + return -ENOMEM; + } else { addr = round_hint_to_min(addr); + } /* Careful about overflows.. */ len = PAGE_ALIGN(len); @@ -2074,14 +2087,6 @@ unsigned long vm_unmapped_area(struct vm return addr; } -#ifndef arch_get_mmap_end -#define arch_get_mmap_end(addr) (TASK_SIZE) -#endif - -#ifndef arch_get_mmap_base -#define arch_get_mmap_base(addr, base) (base) -#endif 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 E11AEC433E1 for ; Mon, 8 Jun 2020 04:41:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A3248206D5 for ; 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Mon, 8 Jun 2020 04:41:22 +0000 (UTC) X-FDA: 76904795604.05.face32_180239226db7 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id AA773180E2F82 for ; Mon, 8 Jun 2020 04:41:22 +0000 (UTC) X-HE-Tag: face32_180239226db7 X-Filterd-Recvd-Size: 3664 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Mon, 8 Jun 2020 04:41:22 +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 7DA9820760; Mon, 8 Jun 2020 04:41:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591591281; bh=1KFdmdnCR7RRQ1buMaFVxzQoATGArKFSUx/DO2jMC68=; h=Date:From:To:Subject:In-Reply-To:From; b=rWC9Q3mXg1/FgcqjOtL9sbTP5QxvlggqelW4nBNdbjH18PcanWVguSLGrGS4VEld2 p5MEM7NXdujKLFjqIrqRhu9tI0JNGwovYzoMr55iiAeg9oPyh6E/RRvTySiAYKzLZC k53N/4kszGH/DVJ5paukJAtdzw5ZhMAWJEbXWpRc= Date: Sun, 07 Jun 2020 21:41:21 -0700 From: Andrew Morton To: agordeev@linux.ibm.com, akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 24/54] mm/mmap.c: do not allow mappings outside of allowed limits Message-ID: <20200608044121.stuEeVRhM%akpm@linux-foundation.org> In-Reply-To: <20200607212615.b050e41fac139a1e16fe00bd@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: AA773180E2F82 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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: Alexander Gordeev Subject: mm/mmap.c: do not allow mappings outside of allowed limits One can set a lowest possible address in /proc/sys/vm/mmap_min_addr and mmap below that bound nevertheless. It is possible to request a fixed mapping address below mmap_min_addr and succeed. This update adds early checks of mmap_min_addr and mmap_end boundaries and fixes the above issue. Apart from it is wrong I am not aware of any existing issue. Link: http://lkml.kernel.org/r/d6da1319114a331095052638f0ffa3ccb0be58f1.1584958099.git.agordeev@linux.ibm.com Signed-off-by: Alexander Gordeev Signed-off-by: Andrew Morton --- mm/mmap.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) --- a/mm/mmap.c~mm-mmapc-do-not-allow-mappings-outside-of-allowed-limits +++ a/mm/mmap.c @@ -62,6 +62,14 @@ #define arch_mmap_check(addr, len, flags) (0) #endif +#ifndef arch_get_mmap_end +#define arch_get_mmap_end(addr) (TASK_SIZE) +#endif + +#ifndef arch_get_mmap_base +#define arch_get_mmap_base(addr, base) (base) +#endif + #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN; const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX; @@ -1369,6 +1377,7 @@ unsigned long do_mmap(struct file *file, unsigned long pgoff, unsigned long *populate, struct list_head *uf) { + const unsigned long mmap_end = arch_get_mmap_end(addr); struct mm_struct *mm = current->mm; int pkey = 0; @@ -1391,8 +1400,12 @@ unsigned long do_mmap(struct file *file, if (flags & MAP_FIXED_NOREPLACE) flags |= MAP_FIXED; - if (!(flags & MAP_FIXED)) + if (flags & MAP_FIXED) { + if ((addr < mmap_min_addr) || (addr > mmap_end)) + return -ENOMEM; + } else { addr = round_hint_to_min(addr); + } /* Careful about overflows.. */ len = PAGE_ALIGN(len); @@ -2074,14 +2087,6 @@ unsigned long vm_unmapped_area(struct vm return addr; } -#ifndef arch_get_mmap_end -#define arch_get_mmap_end(addr) (TASK_SIZE) -#endif - -#ifndef arch_get_mmap_base -#define arch_get_mmap_base(addr, base) (base) -#endif - /* Get an address range which is currently unmapped. * For shmat() with addr=0. * _