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=-23.3 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_IN_DEF_DKIM_WL autolearn=ham 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 7CC6DC433E6 for ; Fri, 22 Jan 2021 14:48:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 344C7239EE for ; Fri, 22 Jan 2021 14:48:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728930AbhAVOsM (ORCPT ); Fri, 22 Jan 2021 09:48:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728840AbhAVOrc (ORCPT ); Fri, 22 Jan 2021 09:47:32 -0500 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 874D2C06174A for ; Fri, 22 Jan 2021 06:46:49 -0800 (PST) Received: by mail-pj1-x1031.google.com with SMTP id kx7so3797538pjb.2 for ; Fri, 22 Jan 2021 06:46:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=V1AbIZrJERg8kpP9b2k7FTBNRitSl0TDoTbXm4ZySsk=; b=rpdT9oqcosb6A0f/AHspYPylqTLN9xsaGoioXlQCOaowJIvqbT1m4Nu/Xu7Br+6LuK 0lflK7FzE1pPlyLGtsC7nFAlqiSYWE/3Wt/a3GHnZcnE+UO300CcMMl1Whw2PR/24xFB 4yPPMyADS9/tPPx/McZ/u/gRF2wVOd3IIWdZH5zdPj30nysCNR27+ResbENic8F/ypGr EAQR7SvNUfmtFbpsoZNRBcSoqpvV0TdDK/XG45HKX4qPygkvQFPwRl3qKSB12hFPZ3n8 tFUX9NHmQ53EmTA5y2+1ZAyQAnF04TclP9NE2xnS3q3FhFPxC3VVvVpbsEVN6hyn9aAz qORg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=V1AbIZrJERg8kpP9b2k7FTBNRitSl0TDoTbXm4ZySsk=; b=TcXUACRwbNOHe9NKBZ7w3n9JyrJIp8vtAKRd1QVJrZToxijp1VH1VS/TdZOUSjtF2u isFsSAKxPU+hnwklockpV/O3HbrEQioV0/23VhztLrHcM2TKj9zXR7VA+4aC42Xzjrqf nOsOdybZevveO85uT8xIkANVyNOVnyDjoUinYTw29B687RvyTbPKeJH92axKgPrtWsSe U8yLvd/7V5hYXeZyMCUNEMiU0gxb7/xLcLQeBQSmThEFagD1s3GX2moCEgf6naD9Q3Ye PipdEutOT979dMrPP8mxnaB99iQ11SqbyBWAo/KQJgvXExrVHqj0fXwRYnQjsVo1IrCw KT8A== X-Gm-Message-State: AOAM531mqJJ9lgV9HI42K+72+0zeMafyeFqxF4Gakblg0L41RwqXznyk yNH2clOpgPoFa1RpRXNmr8rpiZ4N2cNLl82JjPmLpg== X-Google-Smtp-Source: ABdhPJzAkNme0Ln/dfT80F+KxHP9wbD5M2iWDo1O1wJQDetyIzu1vqcr/qB/WRL2sRiRaoATMkvNkYdzRT0gNx91jJM= X-Received: by 2002:a17:90a:ce10:: with SMTP id f16mr5863900pju.136.1611326808923; Fri, 22 Jan 2021 06:46:48 -0800 (PST) MIME-Version: 1.0 References: <20210122143748.50089-1-vincenzo.frascino@arm.com> <20210122143748.50089-3-vincenzo.frascino@arm.com> In-Reply-To: <20210122143748.50089-3-vincenzo.frascino@arm.com> From: Andrey Konovalov Date: Fri, 22 Jan 2021 15:46:37 +0100 Message-ID: Subject: Re: [PATCH v3 2/2] kasan: Add explicit preconditions to kasan_report() To: Vincenzo Frascino Cc: Linux ARM , LKML , kasan-dev , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Leon Romanovsky , Catalin Marinas , Will Deacon , Mark Rutland , "Paul E . McKenney" , Naresh Kamboju Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 22, 2021 at 3:38 PM Vincenzo Frascino wrote: > > With the introduction of KASAN_HW_TAGS, kasan_report() dereferences > the address passed as a parameter. It doesn't dereference the address, it accesses the metadata. And only when addr_has_metadata() succeeds. > > Add a comment to make sure that the preconditions to the function are > explicitly clarified. > > Note: An invalid address (e.g. NULL) passed to the function when, > KASAN_HW_TAGS is enabled, leads to a kernel panic. This is no longer true, right? Commit description needs to be updated. > > Cc: Andrey Ryabinin > Cc: Alexander Potapenko > Cc: Dmitry Vyukov > Cc: Leon Romanovsky > Cc: Andrey Konovalov > Signed-off-by: Vincenzo Frascino > --- > include/linux/kasan.h | 7 +++++++ > mm/kasan/kasan.h | 2 +- > 2 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > index fe1ae73ff8b5..0aea9e2a2a01 100644 > --- a/include/linux/kasan.h > +++ b/include/linux/kasan.h > @@ -333,6 +333,13 @@ static inline void *kasan_reset_tag(const void *addr) > return (void *)arch_kasan_reset_tag(addr); > } > > +/** > + * kasan_report - print a report about a bad memory access detected by KASAN > + * @addr: address of the bad access > + * @size: size of the bad access > + * @is_write: whether the bad access is a write or a read > + * @ip: instruction pointer for the accessibility check or the bad access itself > + */ Looks good, thanks! > bool kasan_report(unsigned long addr, size_t size, > bool is_write, unsigned long ip); > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index cc4d9e1d49b1..8c706e7652f2 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -209,7 +209,7 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, > > static inline bool addr_has_metadata(const void *addr) > { > - return true; > + return (is_vmalloc_addr(addr) || virt_addr_valid(addr)); > } Let's put this change into a separate patch. > > #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ > -- > 2.30.0 > 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=-13.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 90B6EC433E0 for ; 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Fri, 22 Jan 2021 06:46:48 -0800 (PST) MIME-Version: 1.0 References: <20210122143748.50089-1-vincenzo.frascino@arm.com> <20210122143748.50089-3-vincenzo.frascino@arm.com> In-Reply-To: <20210122143748.50089-3-vincenzo.frascino@arm.com> From: Andrey Konovalov Date: Fri, 22 Jan 2021 15:46:37 +0100 Message-ID: Subject: Re: [PATCH v3 2/2] kasan: Add explicit preconditions to kasan_report() To: Vincenzo Frascino X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210122_094651_320654_67ACA196 X-CRM114-Status: GOOD ( 24.32 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , "Paul E . McKenney" , Catalin Marinas , Naresh Kamboju , LKML , kasan-dev , Leon Romanovsky , Alexander Potapenko , Linux ARM , Andrey Ryabinin , Will Deacon , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jan 22, 2021 at 3:38 PM Vincenzo Frascino wrote: > > With the introduction of KASAN_HW_TAGS, kasan_report() dereferences > the address passed as a parameter. It doesn't dereference the address, it accesses the metadata. And only when addr_has_metadata() succeeds. > > Add a comment to make sure that the preconditions to the function are > explicitly clarified. > > Note: An invalid address (e.g. NULL) passed to the function when, > KASAN_HW_TAGS is enabled, leads to a kernel panic. This is no longer true, right? Commit description needs to be updated. > > Cc: Andrey Ryabinin > Cc: Alexander Potapenko > Cc: Dmitry Vyukov > Cc: Leon Romanovsky > Cc: Andrey Konovalov > Signed-off-by: Vincenzo Frascino > --- > include/linux/kasan.h | 7 +++++++ > mm/kasan/kasan.h | 2 +- > 2 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > index fe1ae73ff8b5..0aea9e2a2a01 100644 > --- a/include/linux/kasan.h > +++ b/include/linux/kasan.h > @@ -333,6 +333,13 @@ static inline void *kasan_reset_tag(const void *addr) > return (void *)arch_kasan_reset_tag(addr); > } > > +/** > + * kasan_report - print a report about a bad memory access detected by KASAN > + * @addr: address of the bad access > + * @size: size of the bad access > + * @is_write: whether the bad access is a write or a read > + * @ip: instruction pointer for the accessibility check or the bad access itself > + */ Looks good, thanks! > bool kasan_report(unsigned long addr, size_t size, > bool is_write, unsigned long ip); > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index cc4d9e1d49b1..8c706e7652f2 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -209,7 +209,7 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, > > static inline bool addr_has_metadata(const void *addr) > { > - return true; > + return (is_vmalloc_addr(addr) || virt_addr_valid(addr)); > } Let's put this change into a separate patch. > > #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ > -- > 2.30.0 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel