From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by kanga.kvack.org (Postfix) with ESMTP id D15036B6D8F for ; Tue, 4 Dec 2018 02:37:27 -0500 (EST) Received: by mail-pl1-f198.google.com with SMTP id j8so2280512plb.1 for ; Mon, 03 Dec 2018 23:37:27 -0800 (PST) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTPS id s13si14970777pgc.509.2018.12.03.23.37.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Dec 2018 23:37:26 -0800 (PST) From: Alison Schofield Subject: [RFC v2 09/13] mm: Restrict memory encryption to anonymous VMA's Date: Mon, 3 Dec 2018 23:39:56 -0800 Message-Id: <0b294e74f06a0d6bee51efcd7b0eb1f20b00babe.1543903910.git.alison.schofield@intel.com> In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: dhowells@redhat.com, tglx@linutronix.de Cc: jmorris@namei.org, mingo@redhat.com, hpa@zytor.com, bp@alien8.de, luto@kernel.org, peterz@infradead.org, kirill.shutemov@linux.intel.com, dave.hansen@intel.com, kai.huang@intel.com, jun.nakajima@intel.com, dan.j.williams@intel.com, jarkko.sakkinen@intel.com, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Memory encryption is only supported for mappings that are ANONYMOUS. Test the entire range of VMA's in an encrypt_mprotect() request to make sure they all meet that requirement before encrypting any. The encrypt_mprotect syscall will return -EINVAL and will not encrypt any VMA's if this check fails. Signed-off-by: Alison Schofield Signed-off-by: Kirill A. Shutemov --- mm/mprotect.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/mm/mprotect.c b/mm/mprotect.c index ad8127dc9aac..f1c009409134 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -345,6 +345,24 @@ static int prot_none_walk(struct vm_area_struct *vma, unsigned long start, return walk_page_range(start, end, &prot_none_walk); } +/* + * Encrypted mprotect is only supported on anonymous mappings. + * All VMA's in the requested range must be anonymous. If this + * test fails on any single VMA, the entire mprotect request fails. + */ +bool mem_supports_encryption(struct vm_area_struct *vma, unsigned long end) +{ + struct vm_area_struct *test_vma = vma; + + do { + if (!vma_is_anonymous(test_vma)) + return false; + + test_vma = test_vma->vm_next; + } while (test_vma && test_vma->vm_start < end); + return true; +} + int mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, unsigned long start, unsigned long end, unsigned long newflags, @@ -531,6 +549,12 @@ static int do_mprotect_ext(unsigned long start, size_t len, goto out; } } + + if (keyid > 0 && !mem_supports_encryption(vma, end)) { + error = -EINVAL; + goto out; + } + if (start > vma->vm_start) prev = vma; -- 2.14.1