From patchwork Wed Sep 19 18:54:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10606281 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 402EE1390 for ; Wed, 19 Sep 2018 18:56:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 311382B5EA for ; Wed, 19 Sep 2018 18:56:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 243882B840; Wed, 19 Sep 2018 18:56:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7B0F42C862 for ; Wed, 19 Sep 2018 18:56:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732738AbeITAfj (ORCPT ); Wed, 19 Sep 2018 20:35:39 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:39147 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387588AbeITAeo (ORCPT ); Wed, 19 Sep 2018 20:34:44 -0400 Received: by mail-wr1-f65.google.com with SMTP id s14-v6so6866286wrw.6 for ; Wed, 19 Sep 2018 11:55:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Jw2K2wpnoqMaSJ8uFP7eR1+4k/u8wFMFa7zpsX+OS5g=; b=t7EHud3XKEEXHDP922lt6sPMiqiq9nM2wcysZV32bKKA1SE+nz61EfGYmywA1dXGit 9WZxK/jaky0AAHf/Q6UOKXR5Kur6KkoFTcmsu+txVR4FQcO9l/Ee4ZKGyG4SVKgKZ8Pr gYbk8tgvInAzpi+VcB79/1ciBId2DICtjZ+aYyMoPKjrOYnoNBiixC93kom5kXKCYhEe 0JMJ//F5JrWOkDp90btk9Y/UYEEPbE6tKBEF/1CfqofBG+B3HyRtIgsNurICxD8aSZfZ s5GmYCRmAzHs56Vzv0hzONIay3tzghXLGoIPgwqN5VVUl3mfq9UBAe02fcgir1cBUSJD QWCw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Jw2K2wpnoqMaSJ8uFP7eR1+4k/u8wFMFa7zpsX+OS5g=; b=lar+aAKsD/iaY0m6EKs6wdE6g4cj9iPngC5mxM3jq0yf6/vKDBV0JgUDkY795IB05Q iGogvJpTBHwDoXeweh65xqZBb8EpcEeGiusXQDxlTFHOVDGl/a0HHB9Za/zKsedzd5uQ 6Ym3WdQxGMlRyjZ2b1OJkJFPwBDNJwsw96fUqna45qV/UwNr5VeI/1mJU7JWOj8UWIEW Cr/76A9FlfHn8vX5LfLLlpOCH7oDU2TDvLirAg1R/zyDZXbw2d0TjxEYn/LSxe+az0WV eXqh/Uz6/zhHHSng5f5/eNzaM6uouekkrodGlkhrM0IV56qR3oaFlYtLjtL4XByfltO3 gxxA== X-Gm-Message-State: APzg51AnMhvXoKMRRz15691mFXlPP4zz//MwlXFm7pIvhRR2TYdnKXj+ miqIRACXQORgjzJWdmoEdwvtyQ== X-Google-Smtp-Source: ANB0VdaWHDHKIKf2dppTPO9LjYtesdjVa9cdxTmnTRNARXTenV2GUf/zFzuR7wLZwBB2m8drdztEog== X-Received: by 2002:a5d:4089:: with SMTP id o9-v6mr30434186wrp.133.1537383327612; Wed, 19 Sep 2018 11:55:27 -0700 (PDT) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id b10-v6sm8510065wmc.28.2018.09.19.11.55.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 19 Sep 2018 11:55:27 -0700 (PDT) From: Andrey Konovalov To: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Catalin Marinas , Will Deacon , Christoph Lameter , Andrew Morton , Mark Rutland , Nick Desaulniers , Marc Zyngier , Dave Martin , Ard Biesheuvel , "Eric W . Biederman" , Ingo Molnar , Paul Lawrence , Geert Uytterhoeven , Arnd Bergmann , "Kirill A . Shutemov" , Greg Kroah-Hartman , Kate Stewart , Mike Rapoport , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sparse@vger.kernel.org, linux-mm@kvack.org, linux-kbuild@vger.kernel.org Cc: Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Jann Horn , Mark Brand , Chintan Pandya , Vishwath Mohan , Andrey Konovalov Subject: [PATCH v8 15/20] kasan: add bug reporting routines for tag-based mode Date: Wed, 19 Sep 2018 20:54:54 +0200 Message-Id: <3da501714f11f558ccb2f3e9ca1fa32ebe69b3c1.1537383101.git.andreyknvl@google.com> X-Mailer: git-send-email 2.19.0.397.gdd90340f6a-goog In-Reply-To: References: MIME-Version: 1.0 Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This commit adds rountines, that print tag-based KASAN error reports. Those are quite similar to generic KASAN, the difference is: 1. The way tag-based KASAN finds the first bad shadow cell (with a mismatching tag). Tag-based KASAN compares memory tags from the shadow memory to the pointer tag. 2. Tag-based KASAN reports all bugs with the "KASAN: invalid-access" header. Also simplify generic KASAN find_first_bad_addr. Signed-off-by: Andrey Konovalov --- mm/kasan/generic_report.c | 16 ++++------- mm/kasan/kasan.h | 5 ++++ mm/kasan/report.c | 57 +++++++++++++++++++++------------------ mm/kasan/tags_report.c | 18 +++++++++++++ 4 files changed, 59 insertions(+), 37 deletions(-) diff --git a/mm/kasan/generic_report.c b/mm/kasan/generic_report.c index 5201d1770700..a4604cceae59 100644 --- a/mm/kasan/generic_report.c +++ b/mm/kasan/generic_report.c @@ -33,16 +33,13 @@ #include "kasan.h" #include "../slab.h" -static const void *find_first_bad_addr(const void *addr, size_t size) +void *find_first_bad_addr(void *addr, size_t size) { - u8 shadow_val = *(u8 *)kasan_mem_to_shadow(addr); - const void *first_bad_addr = addr; + void *p = addr; - while (!shadow_val && first_bad_addr < addr + size) { - first_bad_addr += KASAN_SHADOW_SCALE_SIZE; - shadow_val = *(u8 *)kasan_mem_to_shadow(first_bad_addr); - } - return first_bad_addr; + while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p))) + p += KASAN_SHADOW_SCALE_SIZE; + return p; } static const char *get_shadow_bug_type(struct kasan_access_info *info) @@ -50,9 +47,6 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info) const char *bug_type = "unknown-crash"; u8 *shadow_addr; - info->first_bad_addr = find_first_bad_addr(info->access_addr, - info->access_size); - shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr); /* diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 31efc4ee3ddd..a2533b890248 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -119,6 +119,7 @@ void kasan_poison_shadow(const void *address, size_t size, u8 value); void check_memory_region(unsigned long addr, size_t size, bool write, unsigned long ret_ip); +void *find_first_bad_addr(void *addr, size_t size); const char *get_bug_type(struct kasan_access_info *info); void kasan_report(unsigned long addr, size_t size, @@ -139,6 +140,8 @@ static inline void quarantine_remove_cache(struct kmem_cache *cache) { } #ifdef CONFIG_KASAN_SW_TAGS +void print_tags(u8 addr_tag, const void *addr); + #define KASAN_TAG_SHIFT 56 #define KASAN_TAG_MASK (0xFFUL << KASAN_TAG_SHIFT) @@ -166,6 +169,8 @@ static inline void *reset_tag(const void *addr) #else /* CONFIG_KASAN_SW_TAGS */ +static inline void print_tags(u8 addr_tag, const void *addr) { } + static inline u8 random_tag(void) { return 0; diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 64a74f334c45..214d85035f99 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -64,11 +64,10 @@ static int __init kasan_set_multi_shot(char *str) } __setup("kasan_multi_shot", kasan_set_multi_shot); -static void print_error_description(struct kasan_access_info *info, - const char *bug_type) +static void print_error_description(struct kasan_access_info *info) { pr_err("BUG: KASAN: %s in %pS\n", - bug_type, (void *)info->ip); + get_bug_type(info), (void *)info->ip); pr_err("%s of size %zu at addr %px by task %s/%d\n", info->is_write ? "Write" : "Read", info->access_size, info->access_addr, current->comm, task_pid_nr(current)); @@ -272,6 +271,8 @@ void kasan_report_invalid_free(void *object, unsigned long ip) start_report(&flags); pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", (void *)ip); + print_tags(get_tag(object), reset_tag(object)); + object = reset_tag(object); pr_err("\n"); print_address_description(object); pr_err("\n"); @@ -279,41 +280,45 @@ void kasan_report_invalid_free(void *object, unsigned long ip) end_report(&flags); } -static void kasan_report_error(struct kasan_access_info *info) -{ - unsigned long flags; - - start_report(&flags); - - print_error_description(info, get_bug_type(info)); - pr_err("\n"); - - if (!addr_has_shadow(info->access_addr)) { - dump_stack(); - } else { - print_address_description((void *)info->access_addr); - pr_err("\n"); - print_shadow_for_address(info->first_bad_addr); - } - - end_report(&flags); -} - void kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip) { struct kasan_access_info info; + void *tagged_addr; + void *untagged_addr; + unsigned long flags; if (likely(!report_enabled())) return; disable_trace_on_warning(); - info.access_addr = (void *)addr; - info.first_bad_addr = (void *)addr; + tagged_addr = (void *)addr; + untagged_addr = reset_tag(tagged_addr); + + info.access_addr = tagged_addr; + if (addr_has_shadow(untagged_addr)) + info.first_bad_addr = find_first_bad_addr(tagged_addr, size); + else + info.first_bad_addr = untagged_addr; info.access_size = size; info.is_write = is_write; info.ip = ip; - kasan_report_error(&info); + start_report(&flags); + + print_error_description(&info); + if (addr_has_shadow(untagged_addr)) + print_tags(get_tag(tagged_addr), info.first_bad_addr); + pr_err("\n"); + + if (addr_has_shadow(untagged_addr)) { + print_address_description(untagged_addr); + pr_err("\n"); + print_shadow_for_address(info.first_bad_addr); + } else { + dump_stack(); + } + + end_report(&flags); } diff --git a/mm/kasan/tags_report.c b/mm/kasan/tags_report.c index 8af15e87d3bc..573c51d20d09 100644 --- a/mm/kasan/tags_report.c +++ b/mm/kasan/tags_report.c @@ -37,3 +37,21 @@ const char *get_bug_type(struct kasan_access_info *info) { return "invalid-access"; } + +void *find_first_bad_addr(void *addr, size_t size) +{ + u8 tag = get_tag(addr); + void *p = reset_tag(addr); + void *end = p + size; + + while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p)) + p += KASAN_SHADOW_SCALE_SIZE; + return p; +} + +void print_tags(u8 addr_tag, const void *addr) +{ + u8 *shadow = (u8 *)kasan_mem_to_shadow(addr); + + pr_err("Pointer tag: [%02x], memory tag: [%02x]\n", addr_tag, *shadow); +}