From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B865FC433EF for ; Fri, 1 Jul 2022 14:28:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232536AbiGAO2l (ORCPT ); Fri, 1 Jul 2022 10:28:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232545AbiGAO1S (ORCPT ); Fri, 1 Jul 2022 10:27:18 -0400 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB3BE36B4B for ; Fri, 1 Jul 2022 07:24:47 -0700 (PDT) Received: by mail-ej1-x64a.google.com with SMTP id sg40-20020a170907a42800b00722faf0aacbso849332ejc.3 for ; Fri, 01 Jul 2022 07:24:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=z3bEqNJSKGgtE+5cRSN2oSZAKY283RHsG2GOYMoI00Y=; b=qnQCWjKq5yG4F3jPwXLMHLCDtYd3ls2GTNlYs9o6Wm5n9ZlXM2kcHIEFbE0tYS3KKn HmTASR9qhhcfDdychxG1CfugY/2EWvcCDInodoMg7RU0zMb9HYdN78o9NjljMlNc8rMd hIPR0zujO1oAwrMaZfThO3gQ6658HJ1jfgOwDhl9ZusUhjpUAC4OrXaLRqEtr0Uzsch/ DsH42O9o1nqIfH3L8cjBMMq0dkqxJiiaM9JZTR6pQdrxlRJnL8p1AzkkSc/He2avvllk IPUugX4/4fHGoOL5a8zYmVOjP0tM9Ig0OyWFD1/fv11wQ/OCoEsmw4o/l++EGmFeYma8 W7cw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=z3bEqNJSKGgtE+5cRSN2oSZAKY283RHsG2GOYMoI00Y=; b=gf9KLWzeT9yfP82+zq4cL51Cv3mnIZhx/cjI1f6B7LWxSIo7WRaLVzDkiuAcwYNUky 0g7MRlp3pawda4L4QfboTpvNNBDksIvIQXdy2rcAxFcKrFNvidja0lZ8QpqwOFcjPwQ3 trgu0GGkVNzRkw1wKRcQQxYavlPYGljFYWtxwcdUIBbePY1g2vBNfgqYQOMl3Y04nsXW fML2lxDXO+c3KlAciqb3UMReqjvqz7tEB8JGEVvI4KmwKipbW+CIXrly0A5k/MPeFt3A 5AieI/eiN3wnuhMbF7lqesCaAtTb4sqMrMNbka31Rve5qz7QBzdaeG9r/Yfb35wWrF5Q Zzbw== X-Gm-Message-State: AJIora+YuD6fluO1CKtVqnsdfLgO2KC2MZidVq0EwPMXZHVMSQY3ldtr Ek3cQIn2OQTrZipvJzgyAl1oPZMkDCw= X-Google-Smtp-Source: AGRyM1v3S88h3I8S3PNOLZJhMmyQhBUBhKM4ToewpYwCFFWW8Gw6EHSPC9ywT4YZ1DjScWDrCrHuxSVSgLc= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:a6f5:f713:759c:abb6]) (user=glider job=sendgmr) by 2002:a17:906:2086:b0:717:4e91:f1db with SMTP id 6-20020a170906208600b007174e91f1dbmr14229924ejq.345.1656685485180; Fri, 01 Jul 2022 07:24:45 -0700 (PDT) Date: Fri, 1 Jul 2022 16:22:57 +0200 In-Reply-To: <20220701142310.2188015-1-glider@google.com> Message-Id: <20220701142310.2188015-33-glider@google.com> Mime-Version: 1.0 References: <20220701142310.2188015-1-glider@google.com> X-Mailer: git-send-email 2.37.0.rc0.161.g10f37bed90-goog Subject: [PATCH v4 32/45] objtool: kmsan: list KMSAN API functions as uaccess-safe From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Alexei Starovoitov , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org KMSAN inserts API function calls in a lot of places (function entries and exits, local variables, memory accesses), so they may get called from the uaccess regions as well. KMSAN API functions are used to update the metadata (shadow/origin pages) for kernel memory accesses. The metadata pages for kernel pointers are also located in the kernel memory, so touching them is not a problem. For userspace pointers, no metadata is allocated. If an API function is supposed to read or modify the metadata, it does so for kernel pointers and ignores userspace pointers. If an API function is supposed to return a pair of metadata pointers for the instrumentation to use (like all __msan_metadata_ptr_for_TYPE_SIZE() functions do), it returns the allocated metadata for kernel pointers and special dummy buffers residing in the kernel memory for userspace pointers. As a result, none of KMSAN API functions perform userspace accesses, but since they might be called from UACCESS regions they use user_access_save/restore(). Signed-off-by: Alexander Potapenko --- v3: -- updated the patch description v4: -- add kmsan_unpoison_entry_regs() Link: https://linux-review.googlesource.com/id/I242bc9816273fecad4ea3d977393784396bb3c35 --- tools/objtool/check.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 864bb9dd35845..1cf260c966441 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1013,6 +1013,26 @@ static const char *uaccess_safe_builtin[] = { "__sanitizer_cov_trace_cmp4", "__sanitizer_cov_trace_cmp8", "__sanitizer_cov_trace_switch", + /* KMSAN */ + "kmsan_copy_to_user", + "kmsan_report", + "kmsan_unpoison_entry_regs", + "kmsan_unpoison_memory", + "__msan_chain_origin", + "__msan_get_context_state", + "__msan_instrument_asm_store", + "__msan_metadata_ptr_for_load_1", + "__msan_metadata_ptr_for_load_2", + "__msan_metadata_ptr_for_load_4", + "__msan_metadata_ptr_for_load_8", + "__msan_metadata_ptr_for_load_n", + "__msan_metadata_ptr_for_store_1", + "__msan_metadata_ptr_for_store_2", + "__msan_metadata_ptr_for_store_4", + "__msan_metadata_ptr_for_store_8", + "__msan_metadata_ptr_for_store_n", + "__msan_poison_alloca", + "__msan_warning", /* UBSAN */ "ubsan_type_mismatch_common", "__ubsan_handle_type_mismatch", -- 2.37.0.rc0.161.g10f37bed90-goog