From nobody Mon Sep 29 21:12:44 2025 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 2A5F6C25B0D for ; Tue, 16 Aug 2022 04:40:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230389AbiHPEkI (ORCPT ); Tue, 16 Aug 2022 00:40:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230053AbiHPEje (ORCPT ); Tue, 16 Aug 2022 00:39:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F43ECD7AE; Mon, 15 Aug 2022 13:30:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6DA7C60EE9; Mon, 15 Aug 2022 20:30:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 799ABC433C1; Mon, 15 Aug 2022 20:30:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660595444; bh=h1c5kmFWQCXORLtYNwoZ9HDkuyhJMikKoqEajH9jiWY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jOJKdQAkirI5kRtuhhvi/QrwS4sK7GBNA1RgYyVMnHmVgj3euO6bHgD9hfTwJKM9X FyMPIjy+SmURy+4Hs+NZOFIESqZt9Ira2RLWEbG7R/UPBQLuqVH1Gx8pRy5IlwQFxf AYu4RctxKzVoALH0bd5g7BKa5DuevfHEnPGuIxOc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrey Konovalov , Marco Elver , Alexander Potapenko , Dmitry Vyukov , Andrey Ryabinin , Andrew Morton , Sasha Levin Subject: [PATCH 5.19 0767/1157] kasan: fix zeroing vmalloc memory with HW_TAGS Date: Mon, 15 Aug 2022 20:02:03 +0200 Message-Id: <20220815180510.173732661@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180439.416659447@linuxfoundation.org> References: <20220815180439.416659447@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Andrey Konovalov [ Upstream commit 6c2f761dad7851d8088b91063ccaea3c970efe78 ] HW_TAGS KASAN skips zeroing page_alloc allocations backing vmalloc mappings via __GFP_SKIP_ZERO. Instead, these pages are zeroed via kasan_unpoison_vmalloc() by passing the KASAN_VMALLOC_INIT flag. The problem is that __kasan_unpoison_vmalloc() does not zero pages when either kasan_vmalloc_enabled() or is_vmalloc_or_module_addr() fail. Thus: 1. Change __vmalloc_node_range() to only set KASAN_VMALLOC_INIT when __GFP_SKIP_ZERO is set. 2. Change __kasan_unpoison_vmalloc() to always zero pages when the KASAN_VMALLOC_INIT flag is set. 3. Add WARN_ON() asserts to check that KASAN_VMALLOC_INIT cannot be set in other early return paths of __kasan_unpoison_vmalloc(). Also clean up the comment in __kasan_unpoison_vmalloc. Link: https://lkml.kernel.org/r/4bc503537efdc539ffc3f461c1b70162eea31cf6.16= 54798516.git.andreyknvl@google.com Fixes: 23689e91fb22 ("kasan, vmalloc: add vmalloc tagging for HW_TAGS") Signed-off-by: Andrey Konovalov Cc: Marco Elver Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- mm/kasan/hw_tags.c | 32 +++++++++++++++++++++++--------- mm/vmalloc.c | 10 +++++----- 2 files changed, 28 insertions(+), 14 deletions(-) diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 9e1b6544bfa8..9ad8eff71b28 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -257,27 +257,37 @@ static void unpoison_vmalloc_pages(const void *addr, = u8 tag) } } =20 +static void init_vmalloc_pages(const void *start, unsigned long size) +{ + const void *addr; + + for (addr =3D start; addr < start + size; addr +=3D PAGE_SIZE) { + struct page *page =3D virt_to_page(addr); + + clear_highpage_kasan_tagged(page); + } +} + void *__kasan_unpoison_vmalloc(const void *start, unsigned long size, kasan_vmalloc_flags_t flags) { u8 tag; unsigned long redzone_start, redzone_size; =20 - if (!kasan_vmalloc_enabled()) - return (void *)start; - - if (!is_vmalloc_or_module_addr(start)) + if (!kasan_vmalloc_enabled() || !is_vmalloc_or_module_addr(start)) { + if (flags & KASAN_VMALLOC_INIT) + init_vmalloc_pages(start, size); return (void *)start; + } =20 /* - * Skip unpoisoning and assigning a pointer tag for non-VM_ALLOC - * mappings as: + * Don't tag non-VM_ALLOC mappings, as: * * 1. Unlike the software KASAN modes, hardware tag-based KASAN only * supports tagging physical memory. Therefore, it can only tag a * single mapping of normal physical pages. * 2. Hardware tag-based KASAN can only tag memory mapped with special - * mapping protection bits, see arch_vmalloc_pgprot_modify(). + * mapping protection bits, see arch_vmap_pgprot_tagged(). * As non-VM_ALLOC mappings can be mapped outside of vmalloc code, * providing these bits would require tracking all non-VM_ALLOC * mappers. @@ -289,15 +299,19 @@ void *__kasan_unpoison_vmalloc(const void *start, uns= igned long size, * * For non-VM_ALLOC allocations, page_alloc memory is tagged as usual. */ - if (!(flags & KASAN_VMALLOC_VM_ALLOC)) + if (!(flags & KASAN_VMALLOC_VM_ALLOC)) { + WARN_ON(flags & KASAN_VMALLOC_INIT); return (void *)start; + } =20 /* * Don't tag executable memory. * The kernel doesn't tolerate having the PC register tagged. */ - if (!(flags & KASAN_VMALLOC_PROT_NORMAL)) + if (!(flags & KASAN_VMALLOC_PROT_NORMAL)) { + WARN_ON(flags & KASAN_VMALLOC_INIT); return (void *)start; + } =20 tag =3D kasan_random_tag(); start =3D set_tag(start, tag); diff --git a/mm/vmalloc.c b/mm/vmalloc.c index effd1ff6a4b4..a1ab9b472571 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3168,15 +3168,15 @@ void *__vmalloc_node_range(unsigned long size, unsi= gned long align, =20 /* * Mark the pages as accessible, now that they are mapped. - * The init condition should match the one in post_alloc_hook() - * (except for the should_skip_init() check) to make sure that memory - * is initialized under the same conditions regardless of the enabled - * KASAN mode. + * The condition for setting KASAN_VMALLOC_INIT should complement the + * one in post_alloc_hook() with regards to the __GFP_SKIP_ZERO check + * to make sure that memory is initialized under the same conditions. * Tag-based KASAN modes only assign tags to normal non-executable * allocations, see __kasan_unpoison_vmalloc(). */ kasan_flags |=3D KASAN_VMALLOC_VM_ALLOC; - if (!want_init_on_free() && want_init_on_alloc(gfp_mask)) + if (!want_init_on_free() && want_init_on_alloc(gfp_mask) && + (gfp_mask & __GFP_SKIP_ZERO)) kasan_flags |=3D KASAN_VMALLOC_INIT; /* KASAN_VMALLOC_PROT_NORMAL already set if required. */ area->addr =3D kasan_unpoison_vmalloc(area->addr, real_size, kasan_flags); --=20 2.35.1