From patchwork Wed Dec 19 21:33:29 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Stoppa X-Patchwork-Id: 10738179 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CD9E414E5 for ; Wed, 19 Dec 2018 21:34:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BE57F286B2 for ; Wed, 19 Dec 2018 21:34:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B25E9286CB; Wed, 19 Dec 2018 21:34:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.0 required=2.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 0F229286B2 for ; Wed, 19 Dec 2018 21:34:45 +0000 (UTC) Received: (qmail 30534 invoked by uid 550); 19 Dec 2018 21:34:21 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 30445 invoked from network); 19 Dec 2018 21:34:21 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references:reply-to :mime-version:content-transfer-encoding; bh=a4GARTJCVW7jLG2/Ght7MRyZWVbd6ovvI1Dj2egfwMc=; b=dbfUXW85OwLBh0AWXRb7Rg53FgFGDptikU6zcwkC+hhGhlsvpnutIHcDEd/wtdlKpa gX4MH/CHsn+jl14fjNwSWhH36kcHsblgTScMVGeqR/Lgo1ExI/W0l9l7t+8qgqxb6Lxs 9uLAWe2buKqBOxAkBxX5nLxALwdD06Yl594SWveM3vgTFfO4gUope5PRrGDknnG9XqeE Kmdl/DM/nI/lCQDdMxff3p8gPyWkDpLeVtUYmL0tQyKe0KoyjpvtXCaiaDXkpq7YlZ+9 MRYHuQ5JpqIQdly6QAUrhwsalzo9T7OqVtc0VOq3rEevctvQTMJtK4wivWhqFOt0qfqd UJvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:reply-to:mime-version:content-transfer-encoding; bh=a4GARTJCVW7jLG2/Ght7MRyZWVbd6ovvI1Dj2egfwMc=; b=kBlAavRDWc52r4FZ5J06W9EQu/+y8Hy3lAljfK4EG6BY0oIsudOMbFte+Dpu0l/vFn LO6nudfuh0H+YeU+vGfOj5ow7dzvXHz4/FEW+8OJfMq+JgMhiOd0Q5xbUrcRegRIBEqT d4IcCznnY6St+DtbDzuPLq7ybBfRJ6qVZYoIPHnckEV6tlwQr0wI1R1YVSak6obPktAs aL2lDzK3lLHmrbLYYukmmYV99jPBYeCSPXcFEJctaAGh4LpxkJT4VXZVL/pEhDDGWZU2 LPLlZpc8HlHE5xGin7OzP8/R8/vD5O5IYm+9EwDCx38c3bv2XwND6iZSu8BEKOBMziv/ C3Pg== X-Gm-Message-State: AA+aEWY3Oh8+j39P0tS2jwBHbwmmb9Kec3VBttmyBLjRDfl6tDvef1Np kbK9F9U5z2d1GDxm9H68Bm4= X-Google-Smtp-Source: AFSGD/VZbcj5I0PidtfgNZ3Lh1artAeHuFU5euFIwEOUPsXo/4L+9qvccqJSpUN7B7uqhIGBhtnvLA== X-Received: by 2002:a19:cc46:: with SMTP id c67mr13252319lfg.145.1545255249984; Wed, 19 Dec 2018 13:34:09 -0800 (PST) From: Igor Stoppa X-Google-Original-From: Igor Stoppa To: Andy Lutomirski , Matthew Wilcox , Peter Zijlstra , Dave Hansen , Mimi Zohar Cc: igor.stoppa@huawei.com, Nadav Amit , Kees Cook , linux-integrity@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 03/12] __wr_after_init: generic header Date: Wed, 19 Dec 2018 23:33:29 +0200 Message-Id: <20181219213338.26619-4-igor.stoppa@huawei.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181219213338.26619-1-igor.stoppa@huawei.com> References: <20181219213338.26619-1-igor.stoppa@huawei.com> MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP The header provides: - the generic part of the write rare functionality for static data - the dummy functionality, in case an arch doesn't support write rare or the functionality is disabled The basic functions are: - wr_memset(): write rare counterpart of memset() - wr_memcpy(): write rare counterpart of memcpy() - wr_assign(): write rare counterpart of the assignment ('=') operator - wr_rcu_assign_pointer(): write rare counterpart of rcu_assign_pointer() Signed-off-by: Igor Stoppa CC: Andy Lutomirski CC: Nadav Amit CC: Matthew Wilcox CC: Peter Zijlstra CC: Kees Cook CC: Dave Hansen CC: Mimi Zohar CC: linux-integrity@vger.kernel.org CC: kernel-hardening@lists.openwall.com CC: linux-mm@kvack.org CC: linux-kernel@vger.kernel.org --- include/linux/prmem.h | 142 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 142 insertions(+) create mode 100644 include/linux/prmem.h diff --git a/include/linux/prmem.h b/include/linux/prmem.h new file mode 100644 index 000000000000..7b8f3a054d97 --- /dev/null +++ b/include/linux/prmem.h @@ -0,0 +1,142 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * prmem.h: Header for memory protection library + * + * (C) Copyright 2018 Huawei Technologies Co. Ltd. + * Author: Igor Stoppa + * + * Support for: + * - statically allocated write rare data + */ + +#ifndef _LINUX_PRMEM_H +#define _LINUX_PRMEM_H + +#include +#include +#include +#include +#include +#include +#include +#include + +/** + * memtst() - test n bytes of the source to match the c value + * @p: beginning of the memory to test + * @c: byte to compare against + * @len: amount of bytes to test + * + * Returns 0 on success, non-zero otherwise. + */ +static inline int memtst(void *p, int c, __kernel_size_t len) +{ + __kernel_size_t i; + + for (i = 0; i < len; i++) { + u8 d = *(i + (u8 *)p) - (u8)c; + + if (unlikely(d)) + return d; + } + return 0; +} + + +#ifndef CONFIG_PRMEM + +static inline void *wr_memset(void *p, int c, __kernel_size_t len) +{ + return memset(p, c, len); +} + +static inline void *wr_memcpy(void *p, const void *q, __kernel_size_t size) +{ + return memcpy(p, q, size); +} + +#define wr_assign(var, val) ((var) = (val)) + +#define wr_rcu_assign_pointer(p, v) \ + rcu_assign_pointer(p, v) + +#else + +/* + * If CONFIG_PRMEM is enabled, the ARCH code must provide an + * implementation for __wr_op() + */ + +enum wr_op_type { + WR_MEMCPY, + WR_MEMSET, + WR_OPS_NUMBER, +}; + +void *__wr_op(unsigned long dst, unsigned long src, __kernel_size_t len, + enum wr_op_type op); + +/** + * wr_memset() - sets n bytes of the destination to the c value + * @p: beginning of the memory to write to + * @c: byte to replicate + * @len: amount of bytes to copy + * + * Returns true on success, false otherwise. + */ +static inline void *wr_memset(void *p, int c, __kernel_size_t len) +{ + return __wr_op((unsigned long)p, (unsigned long)c, len, WR_MEMSET); +} + +/** + * wr_memcpy() - copyes n bytes from source to destination + * @dst: beginning of the memory to write to + * @src: beginning of the memory to read from + * @n_bytes: amount of bytes to copy + * + * Returns pointer to the destination + */ +static inline void *wr_memcpy(void *p, const void *q, __kernel_size_t size) +{ + return __wr_op((unsigned long)p, (unsigned long)q, size, WR_MEMCPY); +} + +/** + * wr_assign() - sets a write-rare variable to a specified value + * @var: the variable to set + * @val: the new value + * + * Returns: the variable + * + * Note: it might be possible to optimize this, to use wr_memset in some + * cases (maybe with NULL?). + */ + +#define wr_assign(var, val) ({ \ + typeof(var) tmp = (typeof(var))val; \ + \ + wr_memcpy(&var, &tmp, sizeof(var)); \ + var; \ +}) + +/** + * wr_rcu_assign_pointer() - initialize a pointer in rcu mode + * @p: the rcu pointer - it MUST be aligned to a machine word + * @v: the new value + * + * Returns the value assigned to the rcu pointer. + * + * It is provided as macro, to match rcu_assign_pointer() + * The rcu_assign_pointer() is implemented as equivalent of: + * + * smp_mb(); + * WRITE_ONCE(); + */ +#define wr_rcu_assign_pointer(p, v) ({ \ + smp_mb(); \ + wr_assign(p, v); \ + p; \ +}) +#endif +#endif