From patchwork Mon Feb 27 20:43:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9594191 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 89FE760471 for ; Mon, 27 Feb 2017 20:44:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7C43727F9F for ; Mon, 27 Feb 2017 20:44:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 714C52832D; Mon, 27 Feb 2017 20:44:23 +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=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID 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 7911A27F9F for ; Mon, 27 Feb 2017 20:44:22 +0000 (UTC) Received: (qmail 7923 invoked by uid 550); 27 Feb 2017 20:43:57 -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 6116 invoked from network); 27 Feb 2017 20:43:45 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=NCk3urdNb66R0P1cFray4uKeTyDIuZQ1Wb4V62NaG9I=; b=XQKDSQboaUDi24FRr5tu3NUOVQJ4XnUq5WJrPzdtWTPEZZ6u8tpRxgNG+kXxS8pIpr M413OvNp7Kjvqpc3n6CUpy+agkCl5YsJPGrPLUxGIlpgG8dssnZ55fBT3PrYII8dtSKV XZrcqMc4lHaUC0eULXxJPMWqrAOsg8wP6/dd8= 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; bh=NCk3urdNb66R0P1cFray4uKeTyDIuZQ1Wb4V62NaG9I=; b=paatX+29yRmSvSvSc9NhlgfqpF3XXunLuLlDDFNa9bYV1WfG9vBI0Vh8tktJdx03Tc WiiWoKDkkVCGL/6DZKGV7rWLPOdA3pSN0P4F97gqjXYpbdjfhi0Jh+Op4G6ApjuzWr0F qMEAAcO90JMZoc7hUIoTemLD7fKKEHa1p45YEljWXNsc+ax9mwcG1hUyGb9cw2DIwhmm yMRyBrUoVafruda2iWpCEJacHi56NKYnZ7X52WZo3PkUheJppG8lOdMWwmAwvsIEckfc nLq9SFXdGOosioP/aho/CCQgpMcWuum2EuZsRAbDbR3yhAgJXaGzdGMx8Ns09J+DUW36 uSLA== X-Gm-Message-State: AMke39lKbYGVvYek8rr42OprURmwDqAJU4Puv/Z2tkuwjPuElGYutrXgXKHVQaSE1Lfxmf5j X-Received: by 10.99.140.29 with SMTP id m29mr10450540pgd.174.1488228213976; Mon, 27 Feb 2017 12:43:33 -0800 (PST) From: Kees Cook To: kernel-hardening@lists.openwall.com Cc: Kees Cook , Mark Rutland , Andy Lutomirski , Hoeun Ryu , PaX Team , Emese Revfy , Russell King , x86@kernel.org Date: Mon, 27 Feb 2017 12:43:04 -0800 Message-Id: <1488228186-110679-7-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488228186-110679-1-git-send-email-keescook@chromium.org> References: <1488228186-110679-1-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] [RFC][PATCH 6/8] list: add rare_write() list helpers X-Virus-Scanned: ClamAV using ClamSMTP Some structures that are intended to be made write-rarely are designed to be linked by lists. As a result, there need to be rare_write()-supported linked list primitives. As found in PaX, this adds list management helpers for doing updates to rarely-changed lists. Signed-off-by: Kees Cook --- include/linux/list.h | 17 +++++++++++++++++ lib/Makefile | 2 +- lib/list_debug.c | 34 ++++++++++++++++++++++++++++++++++ 3 files changed, 52 insertions(+), 1 deletion(-) diff --git a/include/linux/list.h b/include/linux/list.h index d1039ecaf94f..548b95546793 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -126,6 +126,23 @@ static inline void list_del(struct list_head *entry) entry->prev = LIST_POISON2; } +extern void __rare_list_add(struct list_head *new, + struct list_head *prev, + struct list_head *next); + +static inline void +rare_list_add(__wr_rare_type struct list_head *new, struct list_head *head) +{ + __rare_list_add((struct list_head *)new, head, head->next); +} +static inline void +rare_list_add_tail(__wr_rare_type struct list_head *new, struct list_head *head) +{ + __rare_list_add((struct list_head *)new, head->prev, head); +} + +extern void rare_list_del(__wr_rare_type struct list_head *entry); + /** * list_replace - replace old entry by new one * @old : the element to be replaced diff --git a/lib/Makefile b/lib/Makefile index bc4073a8cd08..edee0bcc660a 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -76,7 +76,7 @@ obj-$(CONFIG_BTREE) += btree.o obj-$(CONFIG_INTERVAL_TREE) += interval_tree.o obj-$(CONFIG_ASSOCIATIVE_ARRAY) += assoc_array.o obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o -obj-$(CONFIG_DEBUG_LIST) += list_debug.o +obj-y += list_debug.o obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o ifneq ($(CONFIG_HAVE_DEC_LOCK),y) diff --git a/lib/list_debug.c b/lib/list_debug.c index 7f7bfa55eb6d..1ff3c5bb926a 100644 --- a/lib/list_debug.c +++ b/lib/list_debug.c @@ -10,7 +10,9 @@ #include #include #include +#include +#ifdef CONFIG_DEBUG_LIST /* * Check that the data structures for the list manipulations are reasonably * valid. Failures here indicate memory corruption (and possibly an exploit @@ -57,3 +59,35 @@ bool __list_del_entry_valid(struct list_head *entry) } EXPORT_SYMBOL(__list_del_entry_valid); + +#endif /* CONFIG_DEBUG_LIST */ + +void __rare_list_add(struct list_head *new, struct list_head *prev, + struct list_head *next) +{ + if (!__list_add_valid(new, prev, next)) + return; + + rare_write_enable(); + next->prev = new; + new->next = next; + new->prev = prev; + prev->next = new; + rare_write_disable(); +} +EXPORT_SYMBOL(__rare_list_add); + +void rare_list_del(__wr_rare_type struct list_head *entry_const) +{ + struct list_head *entry = (struct list_head *)entry_const; + + if (!__list_del_entry_valid(entry)) + return; + + rare_write_enable(); + __list_del(entry->prev, entry->next); + entry->next = LIST_POISON1; + entry->prev = LIST_POISON2; + rare_write_disable(); +} +EXPORT_SYMBOL(rare_list_del);