From patchwork Mon Dec 20 22:02:07 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: 12696940 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E0542C433F5 for ; Mon, 20 Dec 2021 22:23:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=bYCy9vdJ6XcmYpZ9AeF/14/Uu3T43svHB0MZ6Way0iQ=; b=ADIrVzeDkxNFdQ 9jxQ4H1qY83HCxc9Kvn/VxIaKTc1Slnqq5ulNwg8oifFB+Bp8yLk9zOYbGFxwFoS7C3c/kkBsZ8J/ eFqOQLJ07FBe5rOaWNc/JIEogSXm8Vh9E+cFlUhh2KfNK5nAQvtc+BEAPnxiaHty1/yf8Z1XGPqmG xMj8PUvQ84zTDSoHBeO9HDOyw8au+NTV0CuvnY2YczrjoX00b8gFfJwdUxW/hVOr5bshqfKTbwAFK zwKJy2bW6MVknK1s87EnR36csNUsKisnrHOU4e8YAbgU2bUXYSfrniMCZACW6J2A4UcyFRg5vRGcU zu/t93vt3oknQEsDDYEg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mzR2W-004mxp-VU; Mon, 20 Dec 2021 22:21:53 +0000 Received: from out1.migadu.com ([91.121.223.63]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mzQjv-004cvB-M8 for linux-arm-kernel@lists.infradead.org; Mon, 20 Dec 2021 22:02:41 +0000 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=1640037758; 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=HpThRSGWdOarJjOAX9kfY3aMgIuincihYZTBngAmaBg=; b=FynG3w6VPB3ZC4gxJzZsXQ2ABabdRUonUws/lP+iBrh6Apw80mC1TQ3suoDzqBTMYzubWZ Me6BSrknjcquBKDP5tT91zLfGFxwKWXuyFEMpK+91XOMYp1z4egfI+/vu3cDrC/lxaCKg0 VfYRQNbVFZ9Ik4Iuz27iJrZRtdYRm7Y= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Andrew Morton Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino , Catalin Marinas , Will Deacon , Mark Rutland , linux-arm-kernel@lists.infradead.org, Peter Collingbourne , Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH mm v4 35/39] kasan: add kasan.vmalloc command line flag Date: Mon, 20 Dec 2021 23:02:07 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211220_140240_074346_4497FC02 X-CRM114-Status: GOOD ( 14.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 --- Changes v1->v2: - Mark kasan_arg_stacktrace as __initdata instead of __ro_after_init. - Combine KASAN_ARG_VMALLOC_DEFAULT and KASAN_ARG_VMALLOC_ON switch cases. --- mm/kasan/hw_tags.c | 45 ++++++++++++++++++++++++++++++++++++++++++++- mm/kasan/kasan.h | 6 ++++++ 2 files changed, 50 insertions(+), 1 deletion(-) diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 99230e666c1b..657b23cebe28 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 __initdata; static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata; /* 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) { @@ -172,6 +199,18 @@ void __init kasan_init_hw_tags(void) break; } + switch (kasan_arg_vmalloc) { + case KASAN_ARG_VMALLOC_DEFAULT: + /* Default to enabling vmalloc tagging. */ + fallthrough; + case KASAN_ARG_VMALLOC_ON: + static_branch_enable(&kasan_flag_vmalloc); + break; + case KASAN_ARG_VMALLOC_OFF: + /* Do nothing, kasan_flag_vmalloc keeps its default value. */ + break; + } + switch (kasan_arg_stacktrace) { case KASAN_ARG_STACKTRACE_DEFAULT: /* Default to enabling stack trace collection. */ @@ -184,8 +223,9 @@ 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"); } @@ -218,6 +258,9 @@ 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 020f3e57a03f..49a5d5e2e948 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);