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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AA07CDB483 for ; Mon, 16 Oct 2023 14:39:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233487AbjJPOjN (ORCPT ); Mon, 16 Oct 2023 10:39:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232536AbjJPOjE (ORCPT ); Mon, 16 Oct 2023 10:39:04 -0400 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B713EE for ; Mon, 16 Oct 2023 07:39:02 -0700 (PDT) Received: by mail-pl1-x631.google.com with SMTP id d9443c01a7336-1c88b467ef8so30750115ad.0 for ; Mon, 16 Oct 2023 07:39:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1697467142; x=1698071942; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Xej43+CxxYh9a3blA/g52Ig4N3aDI9kSsEpUlToUGyY=; b=LwyrXl3vTxEDzbakDcTvG61WdDGcXTTnloGXmbWRhKmUm3qPzWzDAYM16vBObq/pc5 2oxGoOIBvqBsRWNfoJ12MqAPYo2DUq9eYoEFrVFogm5YiLsMajMzJdm5UHCMnCKQmzw6 YK/8I3KFIKpiCJvPwMlTyO6aIQ6/2HuWpkTOc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697467142; x=1698071942; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Xej43+CxxYh9a3blA/g52Ig4N3aDI9kSsEpUlToUGyY=; b=qXVRdiNV2ajj0aOmT1yQFu7VHHCk6rR0QpZkInSSsg5JxUbQldTg+97yFDIt2Q4zSi boAo7i0D2GwqYnPg70BN2WPvy8OkfSZ+taPvfQ2LdR+TqlrQ9YKJB8lBGM1GYpWb3byC uHepaEO1h0OFZoK5qnzhEDxyYpPuQs2UaNEx1WSOPsvsp/1ywTzi21yN0SblEWiIDLDO IjCKOMKssZzvdUm75fGHC4QOBdbSAmh9lgVwKDBwUYSgKZQauKCYr+bFSSPi8nnEdxU7 Kup66cZvCm4GYFYhcB0kryHuZ1P0s8eXmE58aqSo65VUgV6uxUQ8LKIYjMgtxpukajxA 5UGg== X-Gm-Message-State: AOJu0YxSETX3KhQtWzGWV+q8amogmnX/Mx9yVOPTjDmIfldxwL1PAVO7 ae4tQofgoypKm2dcjZ3scQkQdw== X-Google-Smtp-Source: AGHT+IGUzUb5v0t/3MkBLk3yxGa4HPz1kX3xlLqN5hhkqcb5wVyzEHQXpSYW2jltVLkxXX+Emd4ILg== X-Received: by 2002:a17:903:294b:b0:1c9:d143:e9e with SMTP id li11-20020a170903294b00b001c9d1430e9emr10728383plb.18.1697467141766; Mon, 16 Oct 2023 07:39:01 -0700 (PDT) Received: from localhost (9.184.168.34.bc.googleusercontent.com. [34.168.184.9]) by smtp.gmail.com with UTF8SMTPSA id ju1-20020a170903428100b001b9d335223csm8556065plb.26.2023.10.16.07.39.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Oct 2023 07:39:01 -0700 (PDT) From: jeffxu@chromium.org To: akpm@linux-foundation.org, keescook@chromium.org, sroettger@google.com Cc: jeffxu@google.com, jorgelo@chromium.org, groeck@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, jannh@google.com, surenb@google.com, alex.sierra@amd.com, apopple@nvidia.com, aneesh.kumar@linux.ibm.com, axelrasmussen@google.com, ben@decadent.org.uk, catalin.marinas@arm.com, david@redhat.com, dwmw@amazon.co.uk, ying.huang@intel.com, hughd@google.com, joey.gouly@arm.com, corbet@lwn.net, wangkefeng.wang@huawei.com, Liam.Howlett@oracle.com, torvalds@linux-foundation.org, lstoakes@gmail.com, willy@infradead.org, mawupeng1@huawei.com, linmiaohe@huawei.com, namit@vmware.com, peterx@redhat.com, peterz@infradead.org, ryan.roberts@arm.com, shr@devkernel.io, vbabka@suse.cz, xiujianfeng@huawei.com, yu.ma@intel.com, zhangpeng362@huawei.com, dave.hansen@intel.com, luto@kernel.org, linux-hardening@vger.kernel.org Subject: [RFC PATCH v1 3/8] mseal: add can_modify_mm and can_modify_vma Date: Mon, 16 Oct 2023 14:38:22 +0000 Message-ID: <20231016143828.647848-4-jeffxu@chromium.org> X-Mailer: git-send-email 2.42.0.655.g421f12c284-goog In-Reply-To: <20231016143828.647848-1-jeffxu@chromium.org> References: <20231016143828.647848-1-jeffxu@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jeff Xu can_modify_mm: checks sealing flags for given memory range. can_modify_vma: checks sealing flags for given vma. Signed-off-by: Jeff Xu --- include/linux/mm.h | 34 ++++++++++++++++++++++++++ mm/mseal.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 94 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index e790b91a0cd4..aafdb68950f8 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -257,6 +257,18 @@ extern struct rw_semaphore nommu_region_sem; extern unsigned int kobjsize(const void *objp); #endif +enum caller_origin { + ON_BEHALF_OF_KERNEL = 0, + ON_BEHALF_OF_USERSPACE, +}; + +enum mm_action { + MM_ACTION_MPROTECT, + MM_ACTION_MUNMAP, + MM_ACTION_MREMAP, + MM_ACTION_MMAP, +}; + /* * vm_seals in vm_area_struct, see mm_types.h. */ @@ -3302,6 +3314,28 @@ static inline void mm_populate(unsigned long addr, unsigned long len) static inline void mm_populate(unsigned long addr, unsigned long len) {} #endif +#ifdef CONFIG_MSEAL +extern bool can_modify_mm(struct mm_struct *mm, unsigned long start, + unsigned long end, enum mm_action action, + enum caller_origin called); + +extern bool can_modify_vma(struct vm_area_struct *vma, enum mm_action action, + enum caller_origin called); +#else +static inline bool can_modify_mm(struct mm_struct *mm, unsigned long start, + unsigned long end, enum mm_action action, + enum caller_origin called) +{ + return true; +} + +static inline bool can_modify_vma(struct vm_area_struct *vma, enum mm_action action, + enum caller_origin called) +{ + return true; +} +#endif + /* These take the mm semaphore themselves */ extern int __must_check vm_brk(unsigned long, unsigned long); extern int __must_check vm_brk_flags(unsigned long, unsigned long, unsigned long); diff --git a/mm/mseal.c b/mm/mseal.c index 615b6e06ab44..3285ef6b95a6 100644 --- a/mm/mseal.c +++ b/mm/mseal.c @@ -36,6 +36,66 @@ static bool can_do_mseal(unsigned int types, unsigned int flags) return true; } +/* + * check if a vma is sealed for modification. + * return true, if modification is allowed. + */ +bool can_modify_vma(struct vm_area_struct *vma, enum mm_action action, + enum caller_origin called) +{ + if (called == ON_BEHALF_OF_KERNEL) + return true; + + switch (action) { + case MM_ACTION_MPROTECT: + if (vma->vm_seals & VM_SEAL_MPROTECT) + return false; + break; + + case MM_ACTION_MUNMAP: + if (vma->vm_seals & VM_SEAL_MUNMAP) + return false; + break; + + case MM_ACTION_MREMAP: + if (vma->vm_seals & VM_SEAL_MREMAP) + return false; + break; + + case MM_ACTION_MMAP: + if (vma->vm_seals & VM_SEAL_MMAP) + return false; + break; + } + + return true; +} + +/* + * Check if the vmas of a memory range are allowed to be modified. + * the memory ranger can have a gap (unallocated memory). + * return true, if it is allowed. + */ +bool can_modify_mm(struct mm_struct *mm, unsigned long start, unsigned long end, + enum mm_action action, enum caller_origin called) +{ + struct vm_area_struct *vma; + + VMA_ITERATOR(vmi, mm, start); + + if (called == ON_BEHALF_OF_KERNEL) + return true; + + /* going through each vma to check */ + for_each_vma_range(vmi, vma, end) { + if (!can_modify_vma(vma, action, called)) + return false; + } + + /* Allow by default. */ + return true; +} + /* * Check if a seal type can be added to VMA. */ -- 2.42.0.609.gbb76f46606-goog