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 BF793ECAAD4 for ; Fri, 26 Aug 2022 15:14:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245143AbiHZPOs (ORCPT ); Fri, 26 Aug 2022 11:14:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344196AbiHZPNm (ORCPT ); Fri, 26 Aug 2022 11:13:42 -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 8248410B4 for ; Fri, 26 Aug 2022 08:09:47 -0700 (PDT) Received: by mail-ej1-x649.google.com with SMTP id gt9-20020a1709072d8900b0073d82402ea6so732600ejc.21 for ; Fri, 26 Aug 2022 08:09:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=wnBRr6RijpcrZwDY4IvPeedZIJ4FbGOivCI4jGGTq68=; b=Q2dLT3h7TWqrdhr9cKJaZHS7iaLiqYTtydJ8WFBafxLMcKO+tWNvB/c1oHlNA44pJ7 /OXz8Sr59WCHZVNiYq5ZO1SudMDbRYsAoPTTGJZwqRehknAE2rlYQmFGjPCW+F59/jA8 4CGBdHbeqGVMdW2YUIUBHbdr0K3ckRBLlyr7LkOy1/yf2HWblMEVwWDcc4r9h7xID/vX XMqQsXajhwumZ46fKGFKaccQ9fQsrPuYa0ruT4rNz0CxhrMmw4c71iIpLPuYx4UZ7eQv mqdpWuXSHPVCrwsBJhHLWeKUt/81aDaMfsn199V9hC6WQQ+JcGqn5dar3vI5lIw7PM1Z VyHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=wnBRr6RijpcrZwDY4IvPeedZIJ4FbGOivCI4jGGTq68=; b=s9iD37XMSlC4y/4O8otHUF2vE07ivwjnA/7IScZSC6pkP9jaunsQ1ACfW5FjAt3He6 4hkq1NUGkoQ/B+BfG0npQElPJU0MCGYOLHBuHp+swDeJgmW25bIQcEitfAh7OQ+r9M3A 71dObqW61NZ5Q12rxoIyiJXYqOiXI/D5Mx6QaNKYcKoXVHy8C07YQYvC3jpZA6IY/Aef yh/9MaM9p1UqkpFcM4rSdotFhL0deHaS5B3xWyWDW9fpRvJe5sucdEaVsria48xplkqm dxfLR6NGc4A2qmITupQVcBJvOgIt4cVl0ONWUPAjY+EOPzjjkoc/p7GdP5xUCGBA727V boVQ== X-Gm-Message-State: ACgBeo1+lpLsZGwcCTMdV3+nR16K92U92ToknKvLhr+d4gTrvpqAjbkK iUnZhyFM3AV8DHzMlD6CcHkX3x54dpA= X-Google-Smtp-Source: AA6agR5Cviceae2TWrL6o3zdALqTpxVHsH33a+v7kdsRPAsBV/Ys+W35Cv65k+Ev6zMJg2mViJephdzVroE= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:5207:ac36:fdd3:502d]) (user=glider job=sendgmr) by 2002:a05:6402:268d:b0:43d:b9d0:9efc with SMTP id w13-20020a056402268d00b0043db9d09efcmr7340129edd.92.1661526582428; Fri, 26 Aug 2022 08:09:42 -0700 (PDT) Date: Fri, 26 Aug 2022 17:07:55 +0200 In-Reply-To: <20220826150807.723137-1-glider@google.com> Mime-Version: 1.0 References: <20220826150807.723137-1-glider@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220826150807.723137-33-glider@google.com> Subject: [PATCH v5 32/44] 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 91678252a9b67..577dfdca635e8 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1060,6 +1060,26 @@ 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", -- 2.37.2.672.g94769d06f0-goog