From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 03 Jan 2024 11:21:02 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rKyMw-001mmM-23 for lore@lore.pengutronix.de; Wed, 03 Jan 2024 11:21:02 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rKyMv-0004Kd-EU for lore@pengutronix.de; Wed, 03 Jan 2024 11:21:02 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ROoGrFP3h9Kmyoaw7A7L4mQ0bkNMcbsNoxd8/o5Y+Ho=; b=J1qMjf14Fdvqc2ihaW99V3hAgO oEVKpcApzEUltnz/79IE8ks+AryZR8Pi1qfLE6lsvnFIdrgRkvLSDgU71b4frRuMBV3Sk84LVHdgQ dGdfdFHKv5+2u276lPrexIL96Gu3C/jcNG3xQIYpBC2WsGuhDdLvtKGDATPc6WLGmRYtOfsILCfpE wJ2GdpOSSjbNliloL0vMmq9ksCBJRT42iil0ytUxYqUXrwcr8iaPPgla1SmAv9lVpDlG4WiZO43d0 cixrcVSoIiBEy4v5zh95TTkzFvXB5r58j/SiqPcPd1XIsArDC/QnGR6wqLzEekkkyklGeVbMOKnrR UYIjJx1A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rKyLv-00ANN9-0L; Wed, 03 Jan 2024 10:19:59 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rKyLo-00ANLx-1I for barebox@lists.infradead.org; Wed, 03 Jan 2024 10:19:56 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rKyLm-000422-Vv; Wed, 03 Jan 2024 11:19:51 +0100 Received: from [2a0a:edc0:0:1101:1d::54] (helo=dude05.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rKyLm-0005x1-Jd; Wed, 03 Jan 2024 11:19:50 +0100 Received: from localhost ([::1] helo=dude05.red.stw.pengutronix.de) by dude05.red.stw.pengutronix.de with esmtp (Exim 4.96) (envelope-from ) id 1rKyLm-00B2JG-1g; Wed, 03 Jan 2024 11:19:50 +0100 From: Ahmad Fatoum To: barebox@lists.infradead.org Cc: Ahmad Fatoum Date: Wed, 3 Jan 2024 11:19:48 +0100 Message-Id: <20240103101948.2630473-2-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240103101948.2630473-1-a.fatoum@pengutronix.de> References: <20240103101948.2630473-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240103_021955_168029_FC3C3570 X-CRM114-Status: GOOD ( 19.70 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-6.3 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH 2/2] lib: add optional linked list debugging X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) When enabled, this outputs messages like: list_del corruption, 000000005fe4a9d0->next is LIST_POISON1 (0000000000000100) which can be useful when debugging. Signed-off-by: Ahmad Fatoum --- common/Kconfig | 8 +++++ include/linux/bug.h | 17 +++++++++++ lib/Kconfig.hardening | 10 +++++++ lib/Makefile | 1 + lib/list_debug.c | 68 +++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 104 insertions(+) create mode 100644 lib/list_debug.c diff --git a/common/Kconfig b/common/Kconfig index c8c23a8e03a2..18ad01713293 100644 --- a/common/Kconfig +++ b/common/Kconfig @@ -1704,6 +1704,14 @@ config DMA_API_DEBUG If unsure, say N. +config DEBUG_LIST + bool "Debug linked list manipulation" + help + Enable this to turn on extended checks in the linked-list + walking routines. + + If unsure, say N. + config PBL_BREAK bool "Execute software break on pbl start" depends on ARM && (!CPU_32v4T && !ARCH_TEGRA) diff --git a/include/linux/bug.h b/include/linux/bug.h index d8fc328a0706..8ea5f8d1b260 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -6,4 +6,21 @@ #include #include +/* + * Since detected data corruption should stop operation on the affected + * structures. Return value must be checked and sanely acted on by caller. + */ +static inline __must_check bool check_data_corruption(bool v) { return v; } +#define CHECK_DATA_CORRUPTION(condition, fmt, ...) \ + check_data_corruption(({ \ + bool corruption = unlikely(condition); \ + if (corruption) { \ + if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \ + panic(fmt, ##__VA_ARGS__); \ + } else \ + WARN(1, fmt, ##__VA_ARGS__); \ + } \ + corruption; \ + })) + #endif /* _LINUX_BUG_H */ diff --git a/lib/Kconfig.hardening b/lib/Kconfig.hardening index 7f74d0d98a9c..28be42a27465 100644 --- a/lib/Kconfig.hardening +++ b/lib/Kconfig.hardening @@ -1,5 +1,15 @@ menu "Hardening options" +config BUG_ON_DATA_CORRUPTION + bool "Trigger a BUG when data corruption is detected" + select DEBUG_LIST + help + Select this option if barebox should BUG when it encounters + data corruption in its memory structures when they get checked + for validity. + + If unsure, say N. + config STACK_GUARD_PAGE bool "Place guard page to catch stack overflows" depends on ARM && MMU diff --git a/lib/Makefile b/lib/Makefile index 38204c8273e5..853d8870fe14 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -71,6 +71,7 @@ obj-$(CONFIG_FONTS) += fonts/ obj-$(CONFIG_BAREBOX_LOGO) += logo/ obj-y += reed_solomon/ obj-$(CONFIG_RATP) += ratp.o +obj-$(CONFIG_DEBUG_LIST) += list_debug.o obj-y += list_sort.o obj-y += refcount.o obj-y += int_sqrt.o diff --git a/lib/list_debug.c b/lib/list_debug.c new file mode 100644 index 000000000000..7de4c709a391 --- /dev/null +++ b/lib/list_debug.c @@ -0,0 +1,68 @@ +/* + * Copyright 2006, Red Hat, Inc., Dave Jones + * Released under the General Public License (GPL). + * + * This file contains the linked list validation for DEBUG_LIST. + */ + +#include +#include +#include +#include + +/* + * Check that the data structures for the list manipulations are reasonably + * valid. Failures here indicate memory corruption (and possibly an exploit + * attempt). + */ + +bool __list_add_valid_or_report(struct list_head *new, struct list_head *prev, + struct list_head *next) +{ + if (CHECK_DATA_CORRUPTION(prev == NULL, + "list_add corruption. prev is NULL.\n") || + CHECK_DATA_CORRUPTION(next == NULL, + "list_add corruption. next is NULL.\n") || + CHECK_DATA_CORRUPTION(next->prev != prev, + "list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n", + prev, next->prev, next) || + CHECK_DATA_CORRUPTION(prev->next != next, + "list_add corruption. prev->next should be next (%px), but was %px. (prev=%px).\n", + next, prev->next, prev) || + CHECK_DATA_CORRUPTION(new == prev || new == next, + "list_add double add: new=%px, prev=%px, next=%px.\n", + new, prev, next)) + return false; + + return true; +} +EXPORT_SYMBOL(__list_add_valid_or_report); + +bool __list_del_entry_valid_or_report(struct list_head *entry) +{ + struct list_head *prev, *next; + + prev = entry->prev; + next = entry->next; + + if (CHECK_DATA_CORRUPTION(next == NULL, + "list_del corruption, %px->next is NULL\n", entry) || + CHECK_DATA_CORRUPTION(prev == NULL, + "list_del corruption, %px->prev is NULL\n", entry) || + CHECK_DATA_CORRUPTION(next == LIST_POISON1, + "list_del corruption, %px->next is LIST_POISON1 (%px)\n", + entry, LIST_POISON1) || + CHECK_DATA_CORRUPTION(prev == LIST_POISON2, + "list_del corruption, %px->prev is LIST_POISON2 (%px)\n", + entry, LIST_POISON2) || + CHECK_DATA_CORRUPTION(prev->next != entry, + "list_del corruption. prev->next should be %px, but was %px. (prev=%px)\n", + entry, prev->next, prev) || + CHECK_DATA_CORRUPTION(next->prev != entry, + "list_del corruption. next->prev should be %px, but was %px. (next=%px)\n", + entry, next->prev, next)) + return false; + + return true; +} +EXPORT_SYMBOL(__list_del_entry_valid_or_report); -- 2.39.2