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 DBB6FC433EF for ; Fri, 1 Jul 2022 14:28:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232683AbiGAO2q (ORCPT ); Fri, 1 Jul 2022 10:28:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232544AbiGAO1T (ORCPT ); Fri, 1 Jul 2022 10:27:19 -0400 Received: from mail-ej1-x649.google.com (mail-ej1-x649.google.com [IPv6:2a00:1450:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1144650729 for ; Fri, 1 Jul 2022 07:24:48 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id qa41-20020a17090786a900b00722f313a60eso835931ejc.13 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=mddypiYeilBDqhr/RVewhi4bp0SbNqxlo31/MVPV9f2iFpE0GH8NZ8tVFGik3u6Qwj RA5uaJkhWEz9bQLPgUP9IZYlS230N9TJSGwtiJrN3Fu2icsPcmSsmYwuH1lbcgy2lMD/ QsjXBDisvbkVft+YUwsf1K3a4SoNRVaVPfILpxR+xk0WCbtn6dVb8gMVJyAcfWHAMhVy 6uCicQXFJ8cszwO/842+WtuN48L5XjH1HGK6vAfKp3ggaQM38+lhDa0dVMc+oUJQQx2E pOo16cxpcGCJXCx+4pm0+F7CTf78Lwito/TwfzlfW9Kzi4MYa79GrmfJYUdQhG+RQf92 pmjQ== X-Gm-Message-State: AJIora+2B7lHZP+4ocG0KOJzgXKYGcL3UYo1c7jhmKyTm3gvz/IgPVsj BaVs7LaSXN1DLpJEpdFtrozTR3lim4E= 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-kernel@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