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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 1AB43C4727F for ; Thu, 1 Oct 2020 21:56:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D12912075F for ; Thu, 1 Oct 2020 21:56:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="mGj4QqCg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733196AbgJAV4i (ORCPT ); Thu, 1 Oct 2020 17:56:38 -0400 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 S1726731AbgJAV4h (ORCPT ); Thu, 1 Oct 2020 17:56:37 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0807EC0613D0 for ; Thu, 1 Oct 2020 14:56:36 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id b124so5923526pfg.13 for ; Thu, 01 Oct 2020 14:56:36 -0700 (PDT) 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=lYN4Jo8znVBvexmXtOTq7Vyw02r7hMLAu1E79NO6g4Y=; b=mGj4QqCgUizMudIE9ro10wk616UWhcqWMnlmP/5Brlok2KQYI29mdFoZlyD5FuhZwQ JllnqWV9L+UwChyXuSeU2kelgLRStwVfSZi0sCBk5l3/6m0ljmL+heaCBlU+XbgUJLJq yhzJFFdISquAOlkwShM/RroZ8Yf9MiVCLq6POYZv4BTECBw6Ww+KOoueqyBwBUH1EVAp Y27OKSSzIxcH5u7iyHQmi0bPsXlI3NXlry8DhLOW0zG5MgYa2C0LGzYX0o90KyVacnsk Krmx5iqpudereHXhLCQsAh0F+jFSpSDqkLo+CFm5F/sXnL2hi2wxTJCImEy/hi/Xl/WP +V0w== 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=lYN4Jo8znVBvexmXtOTq7Vyw02r7hMLAu1E79NO6g4Y=; b=dv1ZyJ7j0HSNjiG2IJDSbGR6BMyTxKzLvmdtqOCk2l3OM4VLGTjwQeXqllkYG2hXk/ KFs6EBhTUNM6VBlvFfWr+BdPojeY4gGX0o6UdZjFnA/na9qXHz9mX+VeVa3yH8zJc4ta K8lPZ2OhkJ4Fh/3xoDVGGnFaauXamYbcpWiYYSE+yJUhInzxlBmjNwFMkFlTwztp6V9g hS2eL0QliGRopTDhsebNIFJuqM4+wp6rHV+3jdvM/YZaDyz7ZTC3fwOmhu6jU9LJCaqg BrasNFogymdLuy+e35y2lo2d4frY3ul9PgW/UT5r6g0SIJAXidV6QNw1fgcQHzxRwjA+ QAMw== X-Gm-Message-State: AOAM531ixbG9EcVAaDYd600JjJFNRPVcQWRSMJJTcbduY/vr3QoDbBSU +Gja+iXyeHIW4w0owoT1RgnesjdiNJFzv960fgsfRA== X-Google-Smtp-Source: ABdhPJxYUpKcj6UaxygvMWUbW4f2EntDeZNwix3KAhCgYDPQEpkY6t+bQ0VA6jtlFLf5ATMLr/wDCD2h89mtjTs7RaY= X-Received: by 2002:a63:2209:: with SMTP id i9mr7781306pgi.130.1601589395167; Thu, 01 Oct 2020 14:56:35 -0700 (PDT) MIME-Version: 1.0 References: <494045645c31b7f9298851118cb0b7f8964ac0f4.1600987622.git.andreyknvl@google.com> <20201001175402.GP4162920@elver.google.com> In-Reply-To: <20201001175402.GP4162920@elver.google.com> From: Andrey Konovalov Date: Thu, 1 Oct 2020 23:56:24 +0200 Message-ID: Subject: Re: [PATCH v3 20/39] kasan: separate metadata_fetch_row for each mode To: Marco Elver Cc: Dmitry Vyukov , Vincenzo Frascino , Catalin Marinas , kasan-dev , Andrey Ryabinin , Alexander Potapenko , Evgenii Stepanov , Elena Petrova , Branislav Rankov , Kevin Brodsky , Will Deacon , Andrew Morton , Linux ARM , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 1, 2020 at 7:54 PM wrote: > > On Fri, Sep 25, 2020 at 12:50AM +0200, Andrey Konovalov wrote: > > This is a preparatory commit for the upcoming addition of a new hardware > > tag-based (MTE-based) KASAN mode. > > Not sure why I've only noticed this now, but all these patches seem to > say "This is a preparatory commit" -- I don't think "commit" is > applicable, and "This .. patch" is discouraged. "This commit" is used all over the place if you do git log, so it should be fine. > > Maybe just change it to say "This is to prepare for the upcoming ..." > after the below paragraph? > > > Rework print_memory_metadata() to make it agnostic with regard to the > > way metadata is stored. Allow providing a separate metadata_fetch_row() > > implementation for each KASAN mode. Hardware tag-based KASAN will provide > > its own implementation that doesn't use shadow memory. > > (i.e. move it here) > > > No functional changes for software modes. > > > > Signed-off-by: Andrey Konovalov > > Signed-off-by: Vincenzo Frascino > > Other than that, > > Reviewed-by: Marco Elver Thanks! > > > --- > > Change-Id: I5b0ed1d079ea776e620beca6a529a861e7dced95 > > --- > > mm/kasan/kasan.h | 8 ++++++ > > mm/kasan/report.c | 56 +++++++++++++++++++-------------------- > > mm/kasan/report_generic.c | 5 ++++ > > mm/kasan/report_sw_tags.c | 5 ++++ > > 4 files changed, 45 insertions(+), 29 deletions(-) > > > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > > index 0bf669fad345..50b59c8f8be2 100644 > > --- a/mm/kasan/kasan.h > > +++ b/mm/kasan/kasan.h > > @@ -57,6 +57,13 @@ > > #define KASAN_ABI_VERSION 1 > > #endif > > > > +/* Metadata layout customization. */ > > +#define META_BYTES_PER_BLOCK 1 > > +#define META_BLOCKS_PER_ROW 16 > > +#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK) > > +#define META_MEM_BYTES_PER_ROW (META_BYTES_PER_ROW * KASAN_GRANULE_SIZE) > > +#define META_ROWS_AROUND_ADDR 2 > > + > > struct kasan_access_info { > > const void *access_addr; > > const void *first_bad_addr; > > @@ -168,6 +175,7 @@ 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); > > +void metadata_fetch_row(char *buffer, void *row); > > > > #ifdef CONFIG_KASAN_STACK_ENABLE > > void print_address_stack_frame(const void *addr); > > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > > index 13b27675a696..3924127b4786 100644 > > --- a/mm/kasan/report.c > > +++ b/mm/kasan/report.c > > @@ -31,12 +31,6 @@ > > #include "kasan.h" > > #include "../slab.h" > > > > -/* Metadata layout customization. */ > > -#define META_BYTES_PER_BLOCK 1 > > -#define META_BLOCKS_PER_ROW 16 > > -#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK) > > -#define META_ROWS_AROUND_ADDR 2 > > - > > static unsigned long kasan_flags; > > > > #define KASAN_BIT_REPORTED 0 > > @@ -236,55 +230,59 @@ static void print_address_description(void *addr, u8 tag) > > print_address_stack_frame(addr); > > } > > > > -static bool row_is_guilty(const void *row, const void *guilty) > > +static bool meta_row_is_guilty(const void *row, const void *addr) > > { > > - return (row <= guilty) && (guilty < row + META_BYTES_PER_ROW); > > + return (row <= addr) && (addr < row + META_MEM_BYTES_PER_ROW); > > } > > > > -static int shadow_pointer_offset(const void *row, const void *shadow) > > +static int meta_pointer_offset(const void *row, const void *addr) > > { > > - /* The length of ">ff00ff00ff00ff00: " is > > - * 3 + (BITS_PER_LONG/8)*2 chars. > > + /* > > + * Memory state around the buggy address: > > + * ff00ff00ff00ff00: 00 00 00 05 fe fe fe fe fe fe fe fe fe fe fe fe > > + * ... > > + * > > + * The length of ">ff00ff00ff00ff00: " is > > + * 3 + (BITS_PER_LONG / 8) * 2 chars. > > + * The length of each granule metadata is 2 bytes > > + * plus 1 byte for space. > > */ > > - return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 + > > - (shadow - row) / META_BYTES_PER_BLOCK + 1; > > + return 3 + (BITS_PER_LONG / 8) * 2 + > > + (addr - row) / KASAN_GRANULE_SIZE * 3 + 1; > > } > > > > static void print_memory_metadata(const void *addr) > > { > > int i; > > - const void *shadow = kasan_mem_to_shadow(addr); > > - const void *shadow_row; > > + void *row; > > > > - shadow_row = (void *)round_down((unsigned long)shadow, > > - META_BYTES_PER_ROW) > > - - META_ROWS_AROUND_ADDR * META_BYTES_PER_ROW; > > + row = (void *)round_down((unsigned long)addr, META_MEM_BYTES_PER_ROW) > > + - META_ROWS_AROUND_ADDR * META_MEM_BYTES_PER_ROW; > > > > pr_err("Memory state around the buggy address:\n"); > > > > for (i = -META_ROWS_AROUND_ADDR; i <= META_ROWS_AROUND_ADDR; i++) { > > - const void *kaddr = kasan_shadow_to_mem(shadow_row); > > - char buffer[4 + (BITS_PER_LONG/8)*2]; > > - char shadow_buf[META_BYTES_PER_ROW]; > > + char buffer[4 + (BITS_PER_LONG / 8) * 2]; > > + char metadata[META_BYTES_PER_ROW]; > > > > snprintf(buffer, sizeof(buffer), > > - (i == 0) ? ">%px: " : " %px: ", kaddr); > > + (i == 0) ? ">%px: " : " %px: ", row); > > + > > /* > > * We should not pass a shadow pointer to generic > > * function, because generic functions may try to > > * access kasan mapping for the passed address. > > */ > > - memcpy(shadow_buf, shadow_row, META_BYTES_PER_ROW); > > + metadata_fetch_row(&metadata[0], row); > > + > > print_hex_dump(KERN_ERR, buffer, > > DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1, > > - shadow_buf, META_BYTES_PER_ROW, 0); > > + metadata, META_BYTES_PER_ROW, 0); > > > > - if (row_is_guilty(shadow_row, shadow)) > > - pr_err("%*c\n", > > - shadow_pointer_offset(shadow_row, shadow), > > - '^'); > > + if (meta_row_is_guilty(row, addr)) > > + pr_err("%*c\n", meta_pointer_offset(row, addr), '^'); > > > > - shadow_row += META_BYTES_PER_ROW; > > + row += META_MEM_BYTES_PER_ROW; > > } > > } > > > > diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c > > index ff067071cd28..de7a85c83106 100644 > > --- a/mm/kasan/report_generic.c > > +++ b/mm/kasan/report_generic.c > > @@ -122,6 +122,11 @@ const char *get_bug_type(struct kasan_access_info *info) > > return get_wild_bug_type(info); > > } > > > > +void metadata_fetch_row(char *buffer, void *row) > > +{ > > + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); > > +} > > + > > #ifdef CONFIG_KASAN_STACK_ENABLE > > static bool __must_check tokenize_frame_descr(const char **frame_descr, > > char *token, size_t max_tok_len, > > diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c > > index c87d5a343b4e..add2dfe6169c 100644 > > --- a/mm/kasan/report_sw_tags.c > > +++ b/mm/kasan/report_sw_tags.c > > @@ -80,6 +80,11 @@ void *find_first_bad_addr(void *addr, size_t size) > > return p; > > } > > > > +void metadata_fetch_row(char *buffer, void *row) > > +{ > > + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); > > +} > > + > > void print_tags(u8 addr_tag, const void *addr) > > { > > u8 *shadow = (u8 *)kasan_mem_to_shadow(addr); > > -- > > 2.28.0.681.g6f77f65b4e-goog > > 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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 15769C4727E for ; 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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=lYN4Jo8znVBvexmXtOTq7Vyw02r7hMLAu1E79NO6g4Y=; b=f+DyuNrfggIBkLJq8VtrShh3Ycvfpa3SGhQf4aX3B0mjhlg6LLLBLmLuePy6CZZkvA djYrTx39yVR0uUYBrKmpKbKLGNy/QyZiC8zmQYlY1M84ynfFRFidLCf0SBYkUVl3bo9T rZ0ESbbCJTSchdEcuMbBaczZGIlyWtl1cSMvoG+UJ9u6snm6KYDQ+sp1mZee8XOySwEL sm5E7I1m5dAxiVP7tIbRE+qyYGTq2ELDzyhoiZIxBGWHajTA5sKnK+27R+fpNx9b9AGs k/FcSAcJLJwo5+o2xuKmJbddWx71qF7z49UxnGQcSP9DSpqVpWIEwY3D1DWEYQwPmzI0 FNEA== X-Gm-Message-State: AOAM53368YG4iWOG37rJgCUMdgHXV/dN7RrOrCh9+lfKDABS743Mo2eV l+fhF4qo5bk1kENZccOXFLnnh2dvF7Rmzx5u/2ykjA== X-Google-Smtp-Source: ABdhPJxYUpKcj6UaxygvMWUbW4f2EntDeZNwix3KAhCgYDPQEpkY6t+bQ0VA6jtlFLf5ATMLr/wDCD2h89mtjTs7RaY= X-Received: by 2002:a63:2209:: with SMTP id i9mr7781306pgi.130.1601589395167; Thu, 01 Oct 2020 14:56:35 -0700 (PDT) MIME-Version: 1.0 References: <494045645c31b7f9298851118cb0b7f8964ac0f4.1600987622.git.andreyknvl@google.com> <20201001175402.GP4162920@elver.google.com> In-Reply-To: <20201001175402.GP4162920@elver.google.com> From: Andrey Konovalov Date: Thu, 1 Oct 2020 23:56:24 +0200 Message-ID: Subject: Re: [PATCH v3 20/39] kasan: separate metadata_fetch_row for each mode To: Marco Elver Cc: Dmitry Vyukov , Vincenzo Frascino , Catalin Marinas , kasan-dev , Andrey Ryabinin , Alexander Potapenko , Evgenii Stepanov , Elena Petrova , Branislav Rankov , Kevin Brodsky , Will Deacon , Andrew Morton , Linux ARM , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Oct 1, 2020 at 7:54 PM wrote: > > On Fri, Sep 25, 2020 at 12:50AM +0200, Andrey Konovalov wrote: > > This is a preparatory commit for the upcoming addition of a new hardware > > tag-based (MTE-based) KASAN mode. > > Not sure why I've only noticed this now, but all these patches seem to > say "This is a preparatory commit" -- I don't think "commit" is > applicable, and "This .. patch" is discouraged. "This commit" is used all over the place if you do git log, so it should be fine. > > Maybe just change it to say "This is to prepare for the upcoming ..." > after the below paragraph? > > > Rework print_memory_metadata() to make it agnostic with regard to the > > way metadata is stored. Allow providing a separate metadata_fetch_row() > > implementation for each KASAN mode. Hardware tag-based KASAN will provide > > its own implementation that doesn't use shadow memory. > > (i.e. move it here) > > > No functional changes for software modes. > > > > Signed-off-by: Andrey Konovalov > > Signed-off-by: Vincenzo Frascino > > Other than that, > > Reviewed-by: Marco Elver Thanks! > > > --- > > Change-Id: I5b0ed1d079ea776e620beca6a529a861e7dced95 > > --- > > mm/kasan/kasan.h | 8 ++++++ > > mm/kasan/report.c | 56 +++++++++++++++++++-------------------- > > mm/kasan/report_generic.c | 5 ++++ > > mm/kasan/report_sw_tags.c | 5 ++++ > > 4 files changed, 45 insertions(+), 29 deletions(-) > > > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > > index 0bf669fad345..50b59c8f8be2 100644 > > --- a/mm/kasan/kasan.h > > +++ b/mm/kasan/kasan.h > > @@ -57,6 +57,13 @@ > > #define KASAN_ABI_VERSION 1 > > #endif > > > > +/* Metadata layout customization. */ > > +#define META_BYTES_PER_BLOCK 1 > > +#define META_BLOCKS_PER_ROW 16 > > +#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK) > > +#define META_MEM_BYTES_PER_ROW (META_BYTES_PER_ROW * KASAN_GRANULE_SIZE) > > +#define META_ROWS_AROUND_ADDR 2 > > + > > struct kasan_access_info { > > const void *access_addr; > > const void *first_bad_addr; > > @@ -168,6 +175,7 @@ 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); > > +void metadata_fetch_row(char *buffer, void *row); > > > > #ifdef CONFIG_KASAN_STACK_ENABLE > > void print_address_stack_frame(const void *addr); > > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > > index 13b27675a696..3924127b4786 100644 > > --- a/mm/kasan/report.c > > +++ b/mm/kasan/report.c > > @@ -31,12 +31,6 @@ > > #include "kasan.h" > > #include "../slab.h" > > > > -/* Metadata layout customization. */ > > -#define META_BYTES_PER_BLOCK 1 > > -#define META_BLOCKS_PER_ROW 16 > > -#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK) > > -#define META_ROWS_AROUND_ADDR 2 > > - > > static unsigned long kasan_flags; > > > > #define KASAN_BIT_REPORTED 0 > > @@ -236,55 +230,59 @@ static void print_address_description(void *addr, u8 tag) > > print_address_stack_frame(addr); > > } > > > > -static bool row_is_guilty(const void *row, const void *guilty) > > +static bool meta_row_is_guilty(const void *row, const void *addr) > > { > > - return (row <= guilty) && (guilty < row + META_BYTES_PER_ROW); > > + return (row <= addr) && (addr < row + META_MEM_BYTES_PER_ROW); > > } > > > > -static int shadow_pointer_offset(const void *row, const void *shadow) > > +static int meta_pointer_offset(const void *row, const void *addr) > > { > > - /* The length of ">ff00ff00ff00ff00: " is > > - * 3 + (BITS_PER_LONG/8)*2 chars. > > + /* > > + * Memory state around the buggy address: > > + * ff00ff00ff00ff00: 00 00 00 05 fe fe fe fe fe fe fe fe fe fe fe fe > > + * ... > > + * > > + * The length of ">ff00ff00ff00ff00: " is > > + * 3 + (BITS_PER_LONG / 8) * 2 chars. > > + * The length of each granule metadata is 2 bytes > > + * plus 1 byte for space. > > */ > > - return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 + > > - (shadow - row) / META_BYTES_PER_BLOCK + 1; > > + return 3 + (BITS_PER_LONG / 8) * 2 + > > + (addr - row) / KASAN_GRANULE_SIZE * 3 + 1; > > } > > > > static void print_memory_metadata(const void *addr) > > { > > int i; > > - const void *shadow = kasan_mem_to_shadow(addr); > > - const void *shadow_row; > > + void *row; > > > > - shadow_row = (void *)round_down((unsigned long)shadow, > > - META_BYTES_PER_ROW) > > - - META_ROWS_AROUND_ADDR * META_BYTES_PER_ROW; > > + row = (void *)round_down((unsigned long)addr, META_MEM_BYTES_PER_ROW) > > + - META_ROWS_AROUND_ADDR * META_MEM_BYTES_PER_ROW; > > > > pr_err("Memory state around the buggy address:\n"); > > > > for (i = -META_ROWS_AROUND_ADDR; i <= META_ROWS_AROUND_ADDR; i++) { > > - const void *kaddr = kasan_shadow_to_mem(shadow_row); > > - char buffer[4 + (BITS_PER_LONG/8)*2]; > > - char shadow_buf[META_BYTES_PER_ROW]; > > + char buffer[4 + (BITS_PER_LONG / 8) * 2]; > > + char metadata[META_BYTES_PER_ROW]; > > > > snprintf(buffer, sizeof(buffer), > > - (i == 0) ? ">%px: " : " %px: ", kaddr); > > + (i == 0) ? ">%px: " : " %px: ", row); > > + > > /* > > * We should not pass a shadow pointer to generic > > * function, because generic functions may try to > > * access kasan mapping for the passed address. > > */ > > - memcpy(shadow_buf, shadow_row, META_BYTES_PER_ROW); > > + metadata_fetch_row(&metadata[0], row); > > + > > print_hex_dump(KERN_ERR, buffer, > > DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1, > > - shadow_buf, META_BYTES_PER_ROW, 0); > > + metadata, META_BYTES_PER_ROW, 0); > > > > - if (row_is_guilty(shadow_row, shadow)) > > - pr_err("%*c\n", > > - shadow_pointer_offset(shadow_row, shadow), > > - '^'); > > + if (meta_row_is_guilty(row, addr)) > > + pr_err("%*c\n", meta_pointer_offset(row, addr), '^'); > > > > - shadow_row += META_BYTES_PER_ROW; > > + row += META_MEM_BYTES_PER_ROW; > > } > > } > > > > diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c > > index ff067071cd28..de7a85c83106 100644 > > --- a/mm/kasan/report_generic.c > > +++ b/mm/kasan/report_generic.c > > @@ -122,6 +122,11 @@ const char *get_bug_type(struct kasan_access_info *info) > > return get_wild_bug_type(info); > > } > > > > +void metadata_fetch_row(char *buffer, void *row) > > +{ > > + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); > > +} > > + > > #ifdef CONFIG_KASAN_STACK_ENABLE > > static bool __must_check tokenize_frame_descr(const char **frame_descr, > > char *token, size_t max_tok_len, > > diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c > > index c87d5a343b4e..add2dfe6169c 100644 > > --- a/mm/kasan/report_sw_tags.c > > +++ b/mm/kasan/report_sw_tags.c > > @@ -80,6 +80,11 @@ void *find_first_bad_addr(void *addr, size_t size) > > return p; > > } > > > > +void metadata_fetch_row(char *buffer, void *row) > > +{ > > + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); > > +} > > + > > void print_tags(u8 addr_tag, const void *addr) > > { > > u8 *shadow = (u8 *)kasan_mem_to_shadow(addr); > > -- > > 2.28.0.681.g6f77f65b4e-goog > > 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=-9.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 3D8F2C4727E for ; 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Thu, 01 Oct 2020 14:56:35 -0700 (PDT) MIME-Version: 1.0 References: <494045645c31b7f9298851118cb0b7f8964ac0f4.1600987622.git.andreyknvl@google.com> <20201001175402.GP4162920@elver.google.com> In-Reply-To: <20201001175402.GP4162920@elver.google.com> From: Andrey Konovalov Date: Thu, 1 Oct 2020 23:56:24 +0200 Message-ID: Subject: Re: [PATCH v3 20/39] kasan: separate metadata_fetch_row for each mode To: Marco Elver X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201001_175637_939782_35CD8C1A X-CRM114-Status: GOOD ( 34.57 ) 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: Linux ARM , Branislav Rankov , Elena Petrova , Catalin Marinas , Kevin Brodsky , Will Deacon , LKML , kasan-dev , Linux Memory Management List , Alexander Potapenko , Evgenii Stepanov , Andrey Ryabinin , Andrew Morton , Vincenzo Frascino , 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 Thu, Oct 1, 2020 at 7:54 PM wrote: > > On Fri, Sep 25, 2020 at 12:50AM +0200, Andrey Konovalov wrote: > > This is a preparatory commit for the upcoming addition of a new hardware > > tag-based (MTE-based) KASAN mode. > > Not sure why I've only noticed this now, but all these patches seem to > say "This is a preparatory commit" -- I don't think "commit" is > applicable, and "This .. patch" is discouraged. "This commit" is used all over the place if you do git log, so it should be fine. > > Maybe just change it to say "This is to prepare for the upcoming ..." > after the below paragraph? > > > Rework print_memory_metadata() to make it agnostic with regard to the > > way metadata is stored. Allow providing a separate metadata_fetch_row() > > implementation for each KASAN mode. Hardware tag-based KASAN will provide > > its own implementation that doesn't use shadow memory. > > (i.e. move it here) > > > No functional changes for software modes. > > > > Signed-off-by: Andrey Konovalov > > Signed-off-by: Vincenzo Frascino > > Other than that, > > Reviewed-by: Marco Elver Thanks! > > > --- > > Change-Id: I5b0ed1d079ea776e620beca6a529a861e7dced95 > > --- > > mm/kasan/kasan.h | 8 ++++++ > > mm/kasan/report.c | 56 +++++++++++++++++++-------------------- > > mm/kasan/report_generic.c | 5 ++++ > > mm/kasan/report_sw_tags.c | 5 ++++ > > 4 files changed, 45 insertions(+), 29 deletions(-) > > > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > > index 0bf669fad345..50b59c8f8be2 100644 > > --- a/mm/kasan/kasan.h > > +++ b/mm/kasan/kasan.h > > @@ -57,6 +57,13 @@ > > #define KASAN_ABI_VERSION 1 > > #endif > > > > +/* Metadata layout customization. */ > > +#define META_BYTES_PER_BLOCK 1 > > +#define META_BLOCKS_PER_ROW 16 > > +#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK) > > +#define META_MEM_BYTES_PER_ROW (META_BYTES_PER_ROW * KASAN_GRANULE_SIZE) > > +#define META_ROWS_AROUND_ADDR 2 > > + > > struct kasan_access_info { > > const void *access_addr; > > const void *first_bad_addr; > > @@ -168,6 +175,7 @@ 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); > > +void metadata_fetch_row(char *buffer, void *row); > > > > #ifdef CONFIG_KASAN_STACK_ENABLE > > void print_address_stack_frame(const void *addr); > > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > > index 13b27675a696..3924127b4786 100644 > > --- a/mm/kasan/report.c > > +++ b/mm/kasan/report.c > > @@ -31,12 +31,6 @@ > > #include "kasan.h" > > #include "../slab.h" > > > > -/* Metadata layout customization. */ > > -#define META_BYTES_PER_BLOCK 1 > > -#define META_BLOCKS_PER_ROW 16 > > -#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK) > > -#define META_ROWS_AROUND_ADDR 2 > > - > > static unsigned long kasan_flags; > > > > #define KASAN_BIT_REPORTED 0 > > @@ -236,55 +230,59 @@ static void print_address_description(void *addr, u8 tag) > > print_address_stack_frame(addr); > > } > > > > -static bool row_is_guilty(const void *row, const void *guilty) > > +static bool meta_row_is_guilty(const void *row, const void *addr) > > { > > - return (row <= guilty) && (guilty < row + META_BYTES_PER_ROW); > > + return (row <= addr) && (addr < row + META_MEM_BYTES_PER_ROW); > > } > > > > -static int shadow_pointer_offset(const void *row, const void *shadow) > > +static int meta_pointer_offset(const void *row, const void *addr) > > { > > - /* The length of ">ff00ff00ff00ff00: " is > > - * 3 + (BITS_PER_LONG/8)*2 chars. > > + /* > > + * Memory state around the buggy address: > > + * ff00ff00ff00ff00: 00 00 00 05 fe fe fe fe fe fe fe fe fe fe fe fe > > + * ... > > + * > > + * The length of ">ff00ff00ff00ff00: " is > > + * 3 + (BITS_PER_LONG / 8) * 2 chars. > > + * The length of each granule metadata is 2 bytes > > + * plus 1 byte for space. > > */ > > - return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 + > > - (shadow - row) / META_BYTES_PER_BLOCK + 1; > > + return 3 + (BITS_PER_LONG / 8) * 2 + > > + (addr - row) / KASAN_GRANULE_SIZE * 3 + 1; > > } > > > > static void print_memory_metadata(const void *addr) > > { > > int i; > > - const void *shadow = kasan_mem_to_shadow(addr); > > - const void *shadow_row; > > + void *row; > > > > - shadow_row = (void *)round_down((unsigned long)shadow, > > - META_BYTES_PER_ROW) > > - - META_ROWS_AROUND_ADDR * META_BYTES_PER_ROW; > > + row = (void *)round_down((unsigned long)addr, META_MEM_BYTES_PER_ROW) > > + - META_ROWS_AROUND_ADDR * META_MEM_BYTES_PER_ROW; > > > > pr_err("Memory state around the buggy address:\n"); > > > > for (i = -META_ROWS_AROUND_ADDR; i <= META_ROWS_AROUND_ADDR; i++) { > > - const void *kaddr = kasan_shadow_to_mem(shadow_row); > > - char buffer[4 + (BITS_PER_LONG/8)*2]; > > - char shadow_buf[META_BYTES_PER_ROW]; > > + char buffer[4 + (BITS_PER_LONG / 8) * 2]; > > + char metadata[META_BYTES_PER_ROW]; > > > > snprintf(buffer, sizeof(buffer), > > - (i == 0) ? ">%px: " : " %px: ", kaddr); > > + (i == 0) ? ">%px: " : " %px: ", row); > > + > > /* > > * We should not pass a shadow pointer to generic > > * function, because generic functions may try to > > * access kasan mapping for the passed address. > > */ > > - memcpy(shadow_buf, shadow_row, META_BYTES_PER_ROW); > > + metadata_fetch_row(&metadata[0], row); > > + > > print_hex_dump(KERN_ERR, buffer, > > DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1, > > - shadow_buf, META_BYTES_PER_ROW, 0); > > + metadata, META_BYTES_PER_ROW, 0); > > > > - if (row_is_guilty(shadow_row, shadow)) > > - pr_err("%*c\n", > > - shadow_pointer_offset(shadow_row, shadow), > > - '^'); > > + if (meta_row_is_guilty(row, addr)) > > + pr_err("%*c\n", meta_pointer_offset(row, addr), '^'); > > > > - shadow_row += META_BYTES_PER_ROW; > > + row += META_MEM_BYTES_PER_ROW; > > } > > } > > > > diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c > > index ff067071cd28..de7a85c83106 100644 > > --- a/mm/kasan/report_generic.c > > +++ b/mm/kasan/report_generic.c > > @@ -122,6 +122,11 @@ const char *get_bug_type(struct kasan_access_info *info) > > return get_wild_bug_type(info); > > } > > > > +void metadata_fetch_row(char *buffer, void *row) > > +{ > > + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); > > +} > > + > > #ifdef CONFIG_KASAN_STACK_ENABLE > > static bool __must_check tokenize_frame_descr(const char **frame_descr, > > char *token, size_t max_tok_len, > > diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c > > index c87d5a343b4e..add2dfe6169c 100644 > > --- a/mm/kasan/report_sw_tags.c > > +++ b/mm/kasan/report_sw_tags.c > > @@ -80,6 +80,11 @@ void *find_first_bad_addr(void *addr, size_t size) > > return p; > > } > > > > +void metadata_fetch_row(char *buffer, void *row) > > +{ > > + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); > > +} > > + > > void print_tags(u8 addr_tag, const void *addr) > > { > > u8 *shadow = (u8 *)kasan_mem_to_shadow(addr); > > -- > > 2.28.0.681.g6f77f65b4e-goog > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel