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 F382CECAAA1 for ; Thu, 15 Sep 2022 15:10:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230217AbiIOPKb (ORCPT ); Thu, 15 Sep 2022 11:10:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230376AbiIOPIv (ORCPT ); Thu, 15 Sep 2022 11:08:51 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89FFD98CBE for ; Thu, 15 Sep 2022 08:06:03 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id b18-20020a253412000000b006b0177978eeso4084951yba.21 for ; Thu, 15 Sep 2022 08:06:03 -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:subject:date; bh=mxKrKakNES2O6WNVUjUiVAG/aqg8NEyyXmfzwvDy3M8=; b=QcWSJZZkiYWs+sa+cokZ+5ih/3AigYwqha5oBzQKZX2ROZg6ZA3IUEgOs0eaSXO+su nynwTZxRJ3h5UK5bRt9ZIBKugOR9VD/wb2UQjdtResQ/B8p8IkXP6aGpAvmpsNj4uPDT g9XcO9t+eEd46cZjKpaZdtoo+KHYDdMPK4LApETzHxHqBUgFU1YKU7DIXGAmDZ5uwQk1 VZTeF44KqcNIcSibzQDkTi6BRiZq+KBK3WRtjsxy+OtraDYZ7O7tuXbkHApnF4hjaeSB xkP3yPUIvRQJsGMky0kNRvZS+Rc0renoCDGlUJjq1GKjAS9Q6aHVUEG99/PfpTuNweGG CY+w== 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:subject:date; bh=mxKrKakNES2O6WNVUjUiVAG/aqg8NEyyXmfzwvDy3M8=; b=1npfxDB4J0GDfKgw05kft7ab/UNP4KJOzHeXXjZQjACmhZZGC97qITCpdEVaSiEKi0 iHyz3YLiTaBQxTzC09zl9uISfgMirOTTb90H1d2DKS2BETnUkCbpYbq0AoahFn8m5kJ9 EEWHaACVlhwQShHDT/pl30S/ElynwXhn+e3LlnZOTgJ3xNXYsG6IHAugC29ybGMt/lfm yhOrag1PktuLuCP5Rg0EUimCOj+/vIegSg0NQAbewKvPUB5GD+RAmC90KktWvnq6CjfT GV7+H02Prz1/WPLAKcLOf7yrUHJC8Y9D8sctfziUa9nZyEj6E8UkR+rZNrW7/eAAsXh6 OdQw== X-Gm-Message-State: ACrzQf1F6PEZ+Rii2VP1NdI8EP5K5Yjr5kny+W2cIf+Pdd6L3C0EC3BS w5RB+dlCEoZlIn3RUMk8QB08gAtfN/E= X-Google-Smtp-Source: AMsMyM5QNy6iagLQZF5XlPAvUcWfp+eaYBogp+9cAeIdO1aa1vANNHLNyhp7U4YSK9OGDcBNDqZffj+MYXA= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:686d:27b5:495:85b7]) (user=glider job=sendgmr) by 2002:a81:a503:0:b0:349:f6c6:434 with SMTP id u3-20020a81a503000000b00349f6c60434mr248211ywg.70.1663254362758; Thu, 15 Sep 2022 08:06:02 -0700 (PDT) Date: Thu, 15 Sep 2022 17:04:05 +0200 In-Reply-To: <20220915150417.722975-1-glider@google.com> Mime-Version: 1.0 References: <20220915150417.722975-1-glider@google.com> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog Message-ID: <20220915150417.722975-32-glider@google.com> Subject: [PATCH v7 31/43] 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 Biggers , 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 , Stephen Rothwell , 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 e55fdf952a3a1..7c048c11ce7da 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1062,6 +1062,26 @@ 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", -- 2.37.2.789.g6183377224-goog