From patchwork Tue Nov 30 22:08:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 12648291 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83B5AC433F5 for ; Tue, 30 Nov 2021 22:14:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6C7356B0089; Tue, 30 Nov 2021 17:08:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6770F6B008A; Tue, 30 Nov 2021 17:08:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 598836B008C; Tue, 30 Nov 2021 17:08:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0235.hostedemail.com [216.40.44.235]) by kanga.kvack.org (Postfix) with ESMTP id 48CDD6B0089 for ; Tue, 30 Nov 2021 17:08:30 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id F34C5180E4EC1 for ; Tue, 30 Nov 2021 22:08:19 +0000 (UTC) X-FDA: 78866985960.26.D0B69F5 Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by imf09.hostedemail.com (Postfix) with ESMTP id 2E31E3000105 for ; Tue, 30 Nov 2021 22:08:14 +0000 (UTC) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1638310098; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I6urKhfqw7JpSyBvAL9pvvA3mZVZS1PNduDQn1CKZuM=; b=HD4yVRk27K6f2rQWGp63xAG0X0mfcmtNgAo0K7uajS5HSkNW21AwhF3QnkABi1A/1bR+0k qhMS2T49GgEx4G5CpL5MK9B6CqBMeJCaYPu0ffoDTN/DPZpB0wdpOZHYrS1uC+3hq+u8i0 uOrS8K4kGamVMhKji5oRyp2OBseMnAU= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Vincenzo Frascino , Catalin Marinas , Peter Collingbourne Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Andrew Morton , linux-mm@kvack.org, Will Deacon , linux-arm-kernel@lists.infradead.org, Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH 28/31] kasan: add kasan.vmalloc command line flag Date: Tue, 30 Nov 2021 23:08:16 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2E31E3000105 X-Stat-Signature: zdgg7c94hc5m5uizuf8jtieo9r5uiocq Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=HD4yVRk2; spf=pass (imf09.hostedemail.com: domain of andrey.konovalov@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-HE-Tag: 1638310094-310601 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Andrey Konovalov Allow disabling vmalloc() tagging for HW_TAGS KASAN via a kasan.vmalloc command line switch. This is a fail-safe switch intended for production systems that enable HW_TAGS KASAN. In case vmalloc() tagging ends up having an issue not detected during testing but that manifests in production, kasan.vmalloc allows to turn vmalloc() tagging off while leaving page_alloc/slab tagging on. Signed-off-by: Andrey Konovalov --- mm/kasan/hw_tags.c | 46 +++++++++++++++++++++++++++++++++++++++++++++- mm/kasan/kasan.h | 6 ++++++ 2 files changed, 51 insertions(+), 1 deletion(-) diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index fd3a93dfca42..2da9ad051cdd 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -32,6 +32,12 @@ enum kasan_arg_mode { KASAN_ARG_MODE_ASYMM, }; +enum kasan_arg_vmalloc { + KASAN_ARG_VMALLOC_DEFAULT, + KASAN_ARG_VMALLOC_OFF, + KASAN_ARG_VMALLOC_ON, +}; + enum kasan_arg_stacktrace { KASAN_ARG_STACKTRACE_DEFAULT, KASAN_ARG_STACKTRACE_OFF, @@ -40,6 +46,7 @@ enum kasan_arg_stacktrace { static enum kasan_arg kasan_arg __ro_after_init; static enum kasan_arg_mode kasan_arg_mode __ro_after_init; +static enum kasan_arg_vmalloc kasan_arg_vmalloc __ro_after_init; static enum kasan_arg_stacktrace kasan_arg_stacktrace __ro_after_init; /* Whether KASAN is enabled at all. */ @@ -50,6 +57,9 @@ EXPORT_SYMBOL(kasan_flag_enabled); enum kasan_mode kasan_mode __ro_after_init; EXPORT_SYMBOL_GPL(kasan_mode); +/* Whether to enable vmalloc tagging. */ +DEFINE_STATIC_KEY_FALSE(kasan_flag_vmalloc); + /* Whether to collect alloc/free stack traces. */ DEFINE_STATIC_KEY_FALSE(kasan_flag_stacktrace); @@ -89,6 +99,23 @@ static int __init early_kasan_mode(char *arg) } early_param("kasan.mode", early_kasan_mode); +/* kasan.vmalloc=off/on */ +static int __init early_kasan_flag_vmalloc(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "off")) + kasan_arg_vmalloc = KASAN_ARG_VMALLOC_OFF; + else if (!strcmp(arg, "on")) + kasan_arg_vmalloc = KASAN_ARG_VMALLOC_ON; + else + return -EINVAL; + + return 0; +} +early_param("kasan.vmalloc", early_kasan_flag_vmalloc); + /* kasan.stacktrace=off/on */ static int __init early_kasan_flag_stacktrace(char *arg) { @@ -174,6 +201,19 @@ void __init kasan_init_hw_tags(void) break; } + switch (kasan_arg_vmalloc) { + case KASAN_ARG_VMALLOC_DEFAULT: + /* Default to enabling vmalloc tagging. */ + static_branch_enable(&kasan_flag_vmalloc); + break; + case KASAN_ARG_VMALLOC_OFF: + /* Do nothing, kasan_flag_vmalloc keeps its default value. */ + break; + case KASAN_ARG_VMALLOC_ON: + static_branch_enable(&kasan_flag_vmalloc); + break; + } + switch (kasan_arg_stacktrace) { case KASAN_ARG_STACKTRACE_DEFAULT: /* Default to enabling stack trace collection. */ @@ -187,8 +227,9 @@ void __init kasan_init_hw_tags(void) break; } - pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, stacktrace=%s)\n", + pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, vmalloc=%s, stacktrace=%s)\n", kasan_mode_info(), + kasan_vmalloc_enabled() ? "on" : "off", kasan_stack_collection_enabled() ? "on" : "off"); } @@ -221,6 +262,9 @@ void *__kasan_unpoison_vmalloc(const void *start, unsigned long size, u8 tag; unsigned long redzone_start, redzone_size; + if (!kasan_vmalloc_enabled()) + return (void *)start; + if (!is_vmalloc_or_module_addr(start)) return (void *)start; diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 0827d74d0d87..b58a4547ec5a 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -12,6 +12,7 @@ #include #include "../slab.h" +DECLARE_STATIC_KEY_FALSE(kasan_flag_vmalloc); DECLARE_STATIC_KEY_FALSE(kasan_flag_stacktrace); enum kasan_mode { @@ -22,6 +23,11 @@ enum kasan_mode { extern enum kasan_mode kasan_mode __ro_after_init; +static inline bool kasan_vmalloc_enabled(void) +{ + return static_branch_likely(&kasan_flag_vmalloc); +} + static inline bool kasan_stack_collection_enabled(void) { return static_branch_unlikely(&kasan_flag_stacktrace);