From patchwork Thu Jan 3 18:45:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10747707 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 0AD676C5 for ; Thu, 3 Jan 2019 18:45:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F333828D06 for ; Thu, 3 Jan 2019 18:45:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E5DDF28D18; Thu, 3 Jan 2019 18:45:30 +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 674D028D06 for ; Thu, 3 Jan 2019 18:45:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726239AbfACSp3 (ORCPT ); Thu, 3 Jan 2019 13:45:29 -0500 Received: from mail-wr1-f67.google.com ([209.85.221.67]:32868 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726206AbfACSp2 (ORCPT ); Thu, 3 Jan 2019 13:45:28 -0500 Received: by mail-wr1-f67.google.com with SMTP id c14so34555821wrr.0 for ; Thu, 03 Jan 2019 10:45:27 -0800 (PST) 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=LcZuxDuPGnY34gBBOzPjzW9RC6MdmGqedzN7uzgRX8A=; b=JzRV4OzU47GC2npsOEq89Allc1qgPv+Y5jsoLkXuyflZ9xTmZcqNEWdvopVB2mLN9u 8dO+4sD19DkkXcPnobH6i4C8sPCDcTKX0Zb5bMIzj7AAWZze9z4tJvCau1rxfVHhRRRb jSjusOJhz6SUeB4bWg1pRK3Ec1iK+PCIbicMVihCOHNB3eu8wG57R5YW7mn3YHEbjXfG GoNIzVch9Hl/MBebbU2cyVjj/+ZtkiaLrajzmanxTB4cyMH9xs/7d39MOEsVTcaLg585 xYTZJkUhlbbMrBQ3Hrw6gURwz+PJUt3SD5vFdNZwyzVNZuM8xmb9QtROaHCZOT2IPHuL VF0w== 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=LcZuxDuPGnY34gBBOzPjzW9RC6MdmGqedzN7uzgRX8A=; b=VXZu7yV9oGLs6XcKwj3p6HObDl4ykBbuwxcXISEOH7p5oNSzx3alR3rAE3E6ZduY2a YzUJo/oDc3BAwH1FElHpV++qDWtU2tZdkFFQt8DCMJ6D0BJGHuDdEodK5r2RkP5359Id mlnwjRjkjSZm93C3MxZ4yTBRb6ryex+IrfLRDfKq1E/3tbahtKbYG91aGGTqQRrNkSOc XRlvW9hBrchWpkXB7x+6q0a7HLfS/Bx1/uImfQq+4833ovAYS5Q4CxzLztJ9B4GKBltG fuS4L8bY2LlD240lSm4rbP5itoPta8FWKP7HjcN7kI4njg8eejC3L3t+DAZFz3QRs6Sk sohA== X-Gm-Message-State: AJcUukd9mLPMqwZfRqw/BDn7JGrshjZe7wruW0TlyAL1oAdXN7f/M57+ mNpkyDqgiI6bImMn5WBLqqHg+A== X-Google-Smtp-Source: ALg8bN5f1SEsd4ITLAOkW46zsAXPnkQ0Kw16Q2Kzdp8Q2K31EY+gUdUwN0+RWy+mZNfdm32Jcr+xpQ== X-Received: by 2002:adf:fa05:: with SMTP id m5mr29524927wrr.155.1546541126907; Thu, 03 Jan 2019 10:45:26 -0800 (PST) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:13:8ce:d7fa:9f4c:492]) by smtp.gmail.com with ESMTPSA id t12sm52236944wrr.65.2019.01.03.10.45.25 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Jan 2019 10:45:25 -0800 (PST) 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 , Vincenzo Frascino , 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 v3 1/3] kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning Date: Thu, 3 Jan 2019 19:45:19 +0100 Message-Id: <52ddd881916bcc153a9924c154daacde78522227.1546540962.git.andreyknvl@google.com> X-Mailer: git-send-email 2.20.1.415.g653613c723-goog In-Reply-To: References: MIME-Version: 1.0 Sender: linux-sparse-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Instead of changing cache->align to be aligned to KASAN_SHADOW_SCALE_SIZE in kasan_cache_create() we can reuse the ARCH_SLAB_MINALIGN macro. Suggested-by: Vincenzo Frascino Signed-off-by: Andrey Konovalov --- arch/arm64/include/asm/cache.h | 6 ++++++ mm/kasan/common.c | 2 -- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h index 13dd42c3ad4e..eb43e09c1980 100644 --- a/arch/arm64/include/asm/cache.h +++ b/arch/arm64/include/asm/cache.h @@ -58,6 +58,12 @@ */ #define ARCH_DMA_MINALIGN (128) +#ifdef CONFIG_KASAN_SW_TAGS +#define ARCH_SLAB_MINALIGN (1ULL << KASAN_SHADOW_SCALE_SHIFT) +#else +#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long) +#endif + #ifndef __ASSEMBLY__ #include diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 03d5d1374ca7..44390392d4c9 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -298,8 +298,6 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, return; } - cache->align = round_up(cache->align, KASAN_SHADOW_SCALE_SIZE); - *flags |= SLAB_KASAN; } From patchwork Thu Jan 3 18:45:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10747725 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 5D69914E5 for ; Thu, 3 Jan 2019 18:45:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 50D4728D04 for ; Thu, 3 Jan 2019 18:45:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 40A6028D06; Thu, 3 Jan 2019 18:45:48 +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=unavailable 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 EF5F228D04 for ; Thu, 3 Jan 2019 18:45:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726254AbfACSpm (ORCPT ); Thu, 3 Jan 2019 13:45:42 -0500 Received: from mail-wr1-f66.google.com ([209.85.221.66]:39532 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726242AbfACSpa (ORCPT ); Thu, 3 Jan 2019 13:45:30 -0500 Received: by mail-wr1-f66.google.com with SMTP id t27so34500190wra.6 for ; Thu, 03 Jan 2019 10:45:29 -0800 (PST) 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=wqfuZcAjUCBtOLKWkS6SRZq/hte3EYpV7rEPQw3hkz8=; b=Ba8p1LN6oK3Pi0Fl7zZMXYDUR1uRcqSUKMdpT1Q7mAQ6syoy5qLvkHGMUj6j/vGuB2 mPO5FuGEoA96YcXVqzSpSwHEKELmv7R+EvR+inn+PIduuMt4TwXWHgaGeZc0ky7vvm86 yH9L4u9oYTTxmMJbx5HQX1aqZm017enJlCtGAbNGdHs15wOBu7Y61tXbAM6zeVySF49T mmuEIvLHrEZb5taS7g9ooF90sN5EBjH7gGfduXn1VTHmhUOpSR2P22jZqk1x1eBZqFiP sH2YY6VeZEfqquy8gfHxRd99KsANe2ythZVkjVH7ZxaZekAiskkZhF+Vg3IKqAONrIV4 HEZg== 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=wqfuZcAjUCBtOLKWkS6SRZq/hte3EYpV7rEPQw3hkz8=; b=MrvPTtn3L5U4es/AZnSuEzzNngN1N2NQ1g0s3Wz4GFP2ar5MGEto0hYKts5TgpYAzL a8rqkP1hYtOxR0Jo1zGI8mjXlQbjIz6iQCR+u6Dbjlt73f6N22fshUo1apSERG0S/aaD k6dmxj4I6zB6tC54AlvIaV5OmDPaIIt/doTjJYjt/J47mo9Y3LJSFjpJOCOpWGmOuNHU Bb3r8o/ZXV+xyPvx4riKl8lVu4J3jzDupVhcijbBVFQ+gh1Lyj2JrPTK/GcrMRsZGPX7 eaQMWRAeOmjT4BMHDOmGwXPTmuDsWMT6gxz9IIz1+GwOOIw907x9Mws+vpbsRY+KIhRB mPLg== X-Gm-Message-State: AJcUukdTe71LJnbzbovLT202GrdYlAm1/9XtsQ8klDu/AioWEbDDzw70 ZuIC+FY+gCtV3xuHEe97gKHajA== X-Google-Smtp-Source: ALg8bN4LFcO01Vv4WTRKcuv5YTd1wsOefh/eH/jXvbvXe+jy9rGwknH3ImOWsoQ1UvdKBEe2ffL9iQ== X-Received: by 2002:a05:6000:f:: with SMTP id h15mr40972842wrx.248.1546541128878; Thu, 03 Jan 2019 10:45:28 -0800 (PST) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:13:8ce:d7fa:9f4c:492]) by smtp.gmail.com with ESMTPSA id t12sm52236944wrr.65.2019.01.03.10.45.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Jan 2019 10:45:27 -0800 (PST) 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 , Vincenzo Frascino , 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 v3 2/3] kasan: make tag based mode work with CONFIG_HARDENED_USERCOPY Date: Thu, 3 Jan 2019 19:45:20 +0100 Message-Id: <7e756a298d514c4482f52aea6151db34818d395d.1546540962.git.andreyknvl@google.com> X-Mailer: git-send-email 2.20.1.415.g653613c723-goog In-Reply-To: References: MIME-Version: 1.0 Sender: linux-sparse-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP With CONFIG_HARDENED_USERCOPY enabled __check_heap_object() compares and then subtracts a potentially tagged pointer with a non-tagged address of the page that this pointer belongs to, which leads to unexpected behavior. Untag the pointer in __check_heap_object() before doing any of these operations. Signed-off-by: Andrey Konovalov --- mm/slub.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index 36c0befeebd8..1e3d0ec4e200 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3846,6 +3846,8 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, unsigned int offset; size_t object_size; + ptr = kasan_reset_tag(ptr); + /* Find object and usable object size. */ s = page->slab_cache; From patchwork Thu Jan 3 18:45:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10747721 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 969266C5 for ; Thu, 3 Jan 2019 18:45:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 87B7228D09 for ; Thu, 3 Jan 2019 18:45:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7B63428D06; Thu, 3 Jan 2019 18:45:42 +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=unavailable 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 E46B028D04 for ; Thu, 3 Jan 2019 18:45:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726127AbfACSpl (ORCPT ); Thu, 3 Jan 2019 13:45:41 -0500 Received: from mail-wr1-f66.google.com ([209.85.221.66]:39543 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726264AbfACSpe (ORCPT ); Thu, 3 Jan 2019 13:45:34 -0500 Received: by mail-wr1-f66.google.com with SMTP id t27so34500306wra.6 for ; Thu, 03 Jan 2019 10:45:31 -0800 (PST) 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=loqk+YaJssCyhGzAFNinnRGb50LrNU13L8MGywEfc18=; b=hTmg+DGuRIQF2vlqz/Vhl1D+/+mvgPMsjqLDHi0P1rk+WOre7zmTu5qqGxv3MuZCCE UmLGhAKFZbzdsd4JMY8pdmgI4HYcHr4YnHntxG+Gt//m4C9Qndntnz8PKfjmfZeLTDpd K0fspUq1NKHV5A284NV0qPwtJ8DdvroBOj8kdD2qczrMK2lmGiPk5KVZxusGtbJdfqwR UUZxn2Qs6thHtP1o2ZG8BwsnsoATqNMckkznlYwnbdZQ8C3QDsxrTRM76uXF0vMqJHwb NV6DgqPzaJ4SZY9nrBP+8lLvzwTIs4vFYaq5Eyd/Nw+pUV8pY0KTWdZ5qFjegRMm8Ha4 w6xQ== 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=loqk+YaJssCyhGzAFNinnRGb50LrNU13L8MGywEfc18=; b=e5grnNfDI16HvGBInzWj/jHDaw345n+ZOJKw4uYBtRR3XjCE9g6kxabuE6BiWHxh3i pQCs5kD424evrgihscMrM8DC1h5AZFKb4V2FvvI4gZ99AaqZARGcQX+mA7x5iF+aiaxK HsNdaoGbfEQZkbjj3iKdV0jDdFDJrpVCFy2/dBeyqjyNoZRdRCCnVq7kY/NWOu/C+Lch tUQFpKatWsGG7dcCfneUyEP/BH3ODSnvKGkZZei7NBSicGM3BLbD5T84Z7CFmq5wD5e3 97DEb/U8ZNal4DN8rnX6J2Ibw2j2l+4BLyjvw+1UDyhGDLo6Qr0Iicik+cl6U16NITr/ 9shA== X-Gm-Message-State: AJcUukcCFfc661E07Xah62Fy7zUZxV+M8eVBynitoiSZw5FDyfQ4ybPB iGXAeknjh8lO/XD6mnhUIN3bNg== X-Google-Smtp-Source: ALg8bN4jM3MVHQyzwSzizLWeommEZcTAUOfqxGGPUDgiXkfn7dghhnI866UT0Yj3Z9dcwdbzSDIU7w== X-Received: by 2002:adf:e34b:: with SMTP id n11mr39771740wrj.91.1546541130566; Thu, 03 Jan 2019 10:45:30 -0800 (PST) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:13:8ce:d7fa:9f4c:492]) by smtp.gmail.com with ESMTPSA id t12sm52236944wrr.65.2019.01.03.10.45.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Jan 2019 10:45:29 -0800 (PST) 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 , Vincenzo Frascino , 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 v3 3/3] kasan: fix krealloc handling for tag-based mode Date: Thu, 3 Jan 2019 19:45:21 +0100 Message-Id: X-Mailer: git-send-email 2.20.1.415.g653613c723-goog In-Reply-To: References: MIME-Version: 1.0 Sender: linux-sparse-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Right now tag-based KASAN can retag the memory that is reallocated via krealloc and return a differently tagged pointer even if the same slab object gets used and no reallocated technically happens. There are a few issues with this approach. One is that krealloc callers can't rely on comparing the return value with the passed argument to check whether reallocation happened. Another is that if a caller knows that no reallocation happened, that it can access object memory through the old pointer, which leads to false positives. Look at nf_ct_ext_add() to see an example. Fix this by keeping the same tag if the memory don't actually gets reallocated during krealloc. Signed-off-by: Andrey Konovalov --- mm/kasan/common.c | 63 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 43 insertions(+), 20 deletions(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 44390392d4c9..73c9cbfdedf4 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -347,28 +347,43 @@ void kasan_poison_object_data(struct kmem_cache *cache, void *object) } /* - * Since it's desirable to only call object contructors once during slab - * allocation, we preassign tags to all such objects. Also preassign tags for - * SLAB_TYPESAFE_BY_RCU slabs to avoid use-after-free reports. - * For SLAB allocator we can't preassign tags randomly since the freelist is - * stored as an array of indexes instead of a linked list. Assign tags based - * on objects indexes, so that objects that are next to each other get - * different tags. - * After a tag is assigned, the object always gets allocated with the same tag. - * The reason is that we can't change tags for objects with constructors on - * reallocation (even for non-SLAB_TYPESAFE_BY_RCU), because the constructor - * code can save the pointer to the object somewhere (e.g. in the object - * itself). Then if we retag it, the old saved pointer will become invalid. + * This function assigns a tag to an object considering the following: + * 1. A cache might have a constructor, which might save a pointer to a slab + * object somewhere (e.g. in the object itself). We preassign a tag for + * each object in caches with constructors during slab creation and reuse + * the same tag each time a particular object is allocated. + * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be + * accessed after being freed. We preassign tags for objects in these + * caches as well. + * 3. For SLAB allocator we can't preassign tags randomly since the freelist + * is stored as an array of indexes instead of a linked list. Assign tags + * based on objects indexes, so that objects that are next to each other + * get different tags. */ -static u8 assign_tag(struct kmem_cache *cache, const void *object, bool new) +static u8 assign_tag(struct kmem_cache *cache, const void *object, + bool init, bool krealloc) { + /* Reuse the same tag for krealloc'ed objects. */ + if (krealloc) + return get_tag(object); + + /* + * If the cache neither has a constructor nor has SLAB_TYPESAFE_BY_RCU + * set, assign a tag when the object is being allocated (init == false). + */ if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU)) - return new ? KASAN_TAG_KERNEL : random_tag(); + return init ? KASAN_TAG_KERNEL : random_tag(); + /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */ #ifdef CONFIG_SLAB + /* For SLAB assign tags based on the object index in the freelist. */ return (u8)obj_to_index(cache, virt_to_page(object), (void *)object); #else - return new ? random_tag() : get_tag(object); + /* + * For SLUB assign a random tag during slab creation, otherwise reuse + * the already assigned tag. + */ + return init ? random_tag() : get_tag(object); #endif } @@ -384,7 +399,8 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, __memset(alloc_info, 0, sizeof(*alloc_info)); if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) - object = set_tag(object, assign_tag(cache, object, true)); + object = set_tag(object, + assign_tag(cache, object, true, false)); return (void *)object; } @@ -450,8 +466,8 @@ bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) return __kasan_slab_free(cache, object, ip, true); } -void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object, - size_t size, gfp_t flags) +static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, + size_t size, gfp_t flags, bool krealloc) { unsigned long redzone_start; unsigned long redzone_end; @@ -469,7 +485,7 @@ void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object, KASAN_SHADOW_SCALE_SIZE); if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) - tag = assign_tag(cache, object, false); + tag = assign_tag(cache, object, false, krealloc); /* Tag is ignored in set_tag without CONFIG_KASAN_SW_TAGS */ kasan_unpoison_shadow(set_tag(object, tag), size); @@ -481,6 +497,12 @@ void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object, return set_tag(object, tag); } + +void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object, + size_t size, gfp_t flags) +{ + return __kasan_kmalloc(cache, object, size, flags, false); +} EXPORT_SYMBOL(kasan_kmalloc); void * __must_check kasan_kmalloc_large(const void *ptr, size_t size, @@ -520,7 +542,8 @@ void * __must_check kasan_krealloc(const void *object, size_t size, gfp_t flags) if (unlikely(!PageSlab(page))) return kasan_kmalloc_large(object, size, flags); else - return kasan_kmalloc(page->slab_cache, object, size, flags); + return __kasan_kmalloc(page->slab_cache, object, size, + flags, true); } void kasan_poison_kfree(void *ptr, unsigned long ip)