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 X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C93FC83010 for ; Mon, 23 Nov 2020 20:09:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2AD0A20717 for ; Mon, 23 Nov 2020 20:09:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="lgtA4NzR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730400AbgKWUIx (ORCPT ); Mon, 23 Nov 2020 15:08:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730196AbgKWUIr (ORCPT ); Mon, 23 Nov 2020 15:08:47 -0500 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAE7FC0613CF for ; Mon, 23 Nov 2020 12:08:47 -0800 (PST) Received: by mail-qv1-xf49.google.com with SMTP id dp12so13784854qvb.2 for ; Mon, 23 Nov 2020 12:08:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=VsAI4kIskvc7OgbGXOlaJf5U20hpa/63jMpnaocWLWM=; b=lgtA4NzRKL/sS7cId/OtSk8bpsKjz14BloPlYcl+E2erZjK92bXsA4p8a37FOE46k6 Zu2Mkr+TVz0sub5GN8es0wA2jSJpZKBjIyQGVbEq5lGruBJThs+asHBSMhEK+pipkSZq KtzRRfVyYJL1zFc1GtIZI3Ze4Fqlo7wHN/qS/h/mn88ZzkIm5pgf415vAnBEZLflSx0+ tpYAzbuveP5T6zeGoIEtqVfguTeqU5eTBcrDaKoUgMEFdl4/p0u2wxRnAkzPlpsfxxu4 uTMFqHXQyPRhTfOgud0hIITTPSbxXxkeyUSdnBa0yJHwDqVVa/RLBhopPo3S14gqLiHM GJOw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=VsAI4kIskvc7OgbGXOlaJf5U20hpa/63jMpnaocWLWM=; b=iDojtZpdFy4t/1qWi+82qJkDz0h4lBLOiK/JRK2qP0OrLj2bW42slJmqyEq5S3PNuk 12LvfJ+JMndNrZErDp1ZuoKU6xmMHWMvGvJbloSA5EqP1Q88cegBERTdneHMOtH66sXo lCEpLh+8hQ+xWgR7kmobbrjujAck33N7HbcLNALZTagNo9KtGgW/B3DRYshbrhmmOEms fgUtVVPiJuXFU4DEQbzxDURvIvpaD+qW2EszKMrbSkEcF0HC4SCcI3zP2NBtuD6LQ7/I XZU6dK4d5gTmMTIt0B5GS6JtEnjKgkwxpITAHUNnMFdMtWqAG39ixVeWfQ60XVt7aoQZ PF9A== X-Gm-Message-State: AOAM531QG8azK3SnsnC7sDGcURu6AFxjU0uVLJi6UDVAfQaM1FRpNJyZ K7O0rsZvxLUa8wAkEY0Jo5IS3DynP0Jm3g9b X-Google-Smtp-Source: ABdhPJzQ44VzGDQGjD82W9CmwEaWld7rLNdT6Y1+lJuUYaoCWdvd/M8e9RFhUQ1m43P7Ba8CtJwX2RPN19SUuUND Sender: "andreyknvl via sendgmr" X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:a0c:eac4:: with SMTP id y4mr1106877qvp.19.1606162126939; Mon, 23 Nov 2020 12:08:46 -0800 (PST) Date: Mon, 23 Nov 2020 21:07:36 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH mm v11 12/42] kasan: hide invalid free check implementation From: Andrey Konovalov To: Andrew Morton Cc: Catalin Marinas , Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode. For software KASAN modes the check is based on the value in the shadow memory. Hardware tag-based KASAN won't be using shadow, so hide the implementation of the check in check_invalid_free(). Also simplify the code for software tag-based mode. No functional changes for software modes. Signed-off-by: Andrey Konovalov Signed-off-by: Vincenzo Frascino Reviewed-by: Marco Elver Reviewed-by: Alexander Potapenko --- Change-Id: I5fae9531c9fc948eb4d4e0c589744032fc5a0789 --- mm/kasan/common.c | 19 +------------------ mm/kasan/generic.c | 7 +++++++ mm/kasan/kasan.h | 2 ++ mm/kasan/sw_tags.c | 9 +++++++++ 4 files changed, 19 insertions(+), 18 deletions(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index b3ebee6fcfca..ae55570b4d32 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -278,25 +278,9 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, return (void *)object; } -static inline bool shadow_invalid(u8 tag, s8 shadow_byte) -{ - if (IS_ENABLED(CONFIG_KASAN_GENERIC)) - return shadow_byte < 0 || - shadow_byte >= KASAN_GRANULE_SIZE; - - /* else CONFIG_KASAN_SW_TAGS: */ - if ((u8)shadow_byte == KASAN_TAG_INVALID) - return true; - if ((tag != KASAN_TAG_KERNEL) && (tag != (u8)shadow_byte)) - return true; - - return false; -} - static bool __kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip, bool quarantine) { - s8 shadow_byte; u8 tag; void *tagged_object; unsigned long rounded_up_size; @@ -318,8 +302,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) return false; - shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object)); - if (shadow_invalid(tag, shadow_byte)) { + if (check_invalid_free(tagged_object)) { kasan_report_invalid_free(tagged_object, ip); return true; } diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 754217c258a8..67642acafe92 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -188,6 +188,13 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, return check_memory_region_inline(addr, size, write, ret_ip); } +bool check_invalid_free(void *addr) +{ + s8 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr)); + + return shadow_byte < 0 || shadow_byte >= KASAN_GRANULE_SIZE; +} + void kasan_cache_shrink(struct kmem_cache *cache) { quarantine_remove_cache(cache); diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index eec88bf28c64..e5b5f60bc963 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -166,6 +166,8 @@ void unpoison_range(const void *address, size_t size); bool check_memory_region(unsigned long addr, size_t size, bool write, unsigned long ret_ip); +bool check_invalid_free(void *addr); + void *find_first_bad_addr(void *addr, size_t size); const char *get_bug_type(struct kasan_access_info *info); diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c index c0b3f327812b..64540109c461 100644 --- a/mm/kasan/sw_tags.c +++ b/mm/kasan/sw_tags.c @@ -121,6 +121,15 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, return true; } +bool check_invalid_free(void *addr) +{ + u8 tag = get_tag(addr); + u8 shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(reset_tag(addr))); + + return (shadow_byte == KASAN_TAG_INVALID) || + (tag != KASAN_TAG_KERNEL && tag != shadow_byte); +} + #define DEFINE_HWASAN_LOAD_STORE(size) \ void __hwasan_load##size##_noabort(unsigned long addr) \ { \ -- 2.29.2.454.gaff20da3a2-goog