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=-16.6 required=3.0 tests=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,USER_AGENT_GIT, 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 5C62EC18E7D for ; Wed, 22 May 2019 10:02:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 045502070D for ; Wed, 22 May 2019 10:02:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="mwa0/Ji2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 045502070D Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8FAFE6B0003; Wed, 22 May 2019 06:02:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8AC476B0006; Wed, 22 May 2019 06:02:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 799816B0007; Wed, 22 May 2019 06:02:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) by kanga.kvack.org (Postfix) with ESMTP id 4DB556B0003 for ; Wed, 22 May 2019 06:02:01 -0400 (EDT) Received: by mail-qk1-f197.google.com with SMTP id n65so1759249qke.12 for ; Wed, 22 May 2019 03:02:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:date:message-id:mime-version :subject:from:to:cc; bh=YHDO2phcBlcC8egLCS1LoSqogxMYR/g87S2UaCiOpn4=; b=sNyo3JCDkEdioYEOUM3+T4RoClGjASSpWxwbkTI3MnQ9ckVnu4c1UwzOMFtsKoaBNr vnys2xSbJ0Tf5W3GBJibp6DPAyeoZcpnKyBcMUIyWwyIHOWFMbjksmrR28MeA7xSVMtg HqSqNalJwaghwNlSDAFUGYZ/4koL8nZv9EDT745F277001tElVApacFEgqF42CjP6r+n aprQORwK8K3ABcQoQKDMqSDvJDGK5LOhrJAqmduNXHmXDbV+Rkd0YVVWyEIq+i5VfRQZ wOajU4QsBE38qJhbhQWyAklPqKRf6D8ypViBj3UNV70EYCc8mvSd4xRqgT0/BmFkjhi5 vCOA== X-Gm-Message-State: APjAAAVeboQM0iAieJyc89OJyyfr0cCWEiVXMtCH+O4CmxtQ3LthdWkr JTxv1eaDuQQlSLa2YNTu4CTEc8H1cvqJ0CzA953hGmc5Z86ORqfBPSNIXZ6SnuB0bNwvvzfAoRR h97WBBJCJr4F3z7FY6S+klUCQmmJFhTBqXa1QzrE2qE4vQiHYU8XN6zXPU+zhdrvBGA== X-Received: by 2002:a0c:d0fc:: with SMTP id b57mr48398918qvh.70.1558519320957; Wed, 22 May 2019 03:02:00 -0700 (PDT) X-Received: by 2002:a0c:d0fc:: with SMTP id b57mr48398826qvh.70.1558519319889; Wed, 22 May 2019 03:01:59 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1558519319; cv=none; d=google.com; s=arc-20160816; b=OCE5QO0LzKroIG6Trq9qI3uT0l+csg0eg1/FSz+4Zk2G9Irk7pwbUp0Q43rDQdPOTY KSYVMMr/sbNn0VPSpyKs7WER9Kudyr/SO47pMDv2tgC60L4c/djHD6fnLGnWqGMoTXag ju/ZSadUwAlV/jy0/CcPEBQwR0GuXTTdOFLfTP2hUVyScNz1D0VF+siOjPVYqnXrYU3s tj45ER8Kh5C7hFwDXusApRChbNArstI4V1L37oCbqrdsmuKBXjHcvNKg4/Ug0nWMTgaA E7LAT9G8SjPgHRFJRV9HVJKCp42HGwCYIN4IVRu8H5bPiSd4mZ+d+36oUG4wBOGIcspE e3KA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:from:subject:mime-version:message-id:date:dkim-signature; bh=YHDO2phcBlcC8egLCS1LoSqogxMYR/g87S2UaCiOpn4=; b=CY1FlBghOeSvxCzrKKPZBNHhwpJ8YknOpdaZye4Op5ZUAhkzOejaa+K0DdRQXrWXA0 fFfvcRRbMLneIGZ9S7DZRfeKbyX5cWK9siTPb9ojTE/oKgVlbfdhBtIHEHK1YA0zvF8V yvs/1TvG8bWcWwNkJqvWwY8GB+ugJ0FxFbLB5fmFvFBtHWwg7TnkOGY+CkqHODxSScUM aPJyRTtRNxOMPglM6NyObbH95tZN0y5jprqfJBdjYyq8OVGCrz/NoFNXNMPRA3jr9ary ggBIda9EUGWGoRG8r8BoytLtXaM1ccFegyPvC9NFoujancxQAGuljDIG2sGI9orJeBKH ECWQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b="mwa0/Ji2"; spf=pass (google.com: domain of 3fx7lxaukcnq4bl4h6ee6b4.2ecb8dkn-ccal02a.eh6@flex--elver.bounces.google.com designates 209.85.220.73 as permitted sender) smtp.mailfrom=3Fx7lXAUKCNQ4BL4H6EE6B4.2ECB8DKN-CCAL02A.EH6@flex--elver.bounces.google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from mail-sor-f73.google.com (mail-sor-f73.google.com. [209.85.220.73]) by mx.google.com with SMTPS id o72sor1201854qke.61.2019.05.22.03.01.59 for (Google Transport Security); Wed, 22 May 2019 03:01:59 -0700 (PDT) Received-SPF: pass (google.com: domain of 3fx7lxaukcnq4bl4h6ee6b4.2ecb8dkn-ccal02a.eh6@flex--elver.bounces.google.com designates 209.85.220.73 as permitted sender) client-ip=209.85.220.73; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b="mwa0/Ji2"; spf=pass (google.com: domain of 3fx7lxaukcnq4bl4h6ee6b4.2ecb8dkn-ccal02a.eh6@flex--elver.bounces.google.com designates 209.85.220.73 as permitted sender) smtp.mailfrom=3Fx7lXAUKCNQ4BL4H6EE6B4.2ECB8DKN-CCAL02A.EH6@flex--elver.bounces.google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=YHDO2phcBlcC8egLCS1LoSqogxMYR/g87S2UaCiOpn4=; b=mwa0/Ji2fwq1sL7J2eSSr4vCq9PNV3hbM11Qg1tdKLGQ5d7+nG9aVi4Fat+xUhdPTe KY7ytt6yyj8b6NQOtQNVNpbL7t5GFXr43RK9T4LDARNewa5CgXHUcwdRsMEapBDkilU2 nCDcjWwPutBaBP9ZW1Ucu7OHU2UTN6f4oDjElZLJwyQs2zdDMlLzgt+bbl93IfPWTK3H DvmpPrgIm2KGNJeacgV2alsgCg2w8lFOfOycBx3okBz31SbMZNbebe5tVcSvOpAXgfD0 x9/g/QZHgoQxxB3LOcFKBwgp78ELoWNPKqD3MdxdLEKAcQMix6hXScjcJlCc8tekGVBn 6RaA== X-Google-Smtp-Source: APXvYqx/VaQ5jlC/Ooy3ieBuu8+ppktY0rK3DL633eMh4j8i6rRO3/+v8ktj4Xm073TLE+hG9+z/3PdezQ== X-Received: by 2002:a37:4cc9:: with SMTP id z192mr59997831qka.198.1558519319575; Wed, 22 May 2019 03:01:59 -0700 (PDT) Date: Wed, 22 May 2019 12:00:50 +0200 Message-Id: <20190522100048.146841-1-elver@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a-goog Subject: [PATCH v3] mm/kasan: Print frame description for stack bugs From: Marco Elver To: aryabinin@virtuozzo.com, dvyukov@google.com, glider@google.com, andreyknvl@google.com, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kasan-dev@googlegroups.com, Marco Elver 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: This adds support for printing stack frame description on invalid stack accesses. The frame description is embedded by the compiler, which is parsed and then pretty-printed. Currently, we can only print the stack frame info for accesses to the task's own stack, but not accesses to other tasks' stacks. Example of what it looks like: [ 17.924050] page dumped because: kasan: bad access detected [ 17.924908] [ 17.925153] addr ffff8880673ef98a is located in stack of task insmod/2008 at offset 106 in frame: [ 17.926542] kasan_stack_oob+0x0/0xf5 [test_kasan] [ 17.927932] [ 17.928206] this frame has 2 objects: [ 17.928783] [32, 36) 'i' [ 17.928784] [96, 106) 'stack_array' [ 17.929216] [ 17.930031] Memory state around the buggy address: Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=198435 Signed-off-by: Marco Elver --- Changes since v2: - Comment about why line number is stripped. - Add BUILD_BUG_ON(CONFIG_STACK_GROWSUP). Changes since v1: - Fix types in printf (%zu -> %lu). - Prefer 'unsigned long', to ensure offset/points are pointer sized, as emitted by ASAN instrumentation. Change-Id: I4836cde103052991ac8871796a45b4c977c9e2e7 --- mm/kasan/kasan.h | 5 ++ mm/kasan/report.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 170 insertions(+) diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 3ce956efa0cb..1979db4763e2 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -43,6 +43,11 @@ #define KASAN_ALLOCA_REDZONE_SIZE 32 +/* + * Stack frame marker (compiler ABI). + */ +#define KASAN_CURRENT_STACK_FRAME_MAGIC 0x41B58AB3 + /* Don't break randconfig/all*config builds */ #ifndef KASAN_ABI_VERSION #define KASAN_ABI_VERSION 1 diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 03a443579386..0e5f965f1882 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -28,6 +28,7 @@ #include #include #include +#include #include @@ -181,6 +182,168 @@ static inline bool init_task_stack_addr(const void *addr) sizeof(init_thread_union.stack)); } +static bool __must_check tokenize_frame_descr(const char **frame_descr, + char *token, size_t max_tok_len, + unsigned long *value) +{ + const char *sep = strchr(*frame_descr, ' '); + + if (sep == NULL) + sep = *frame_descr + strlen(*frame_descr); + + if (token != NULL) { + const size_t tok_len = sep - *frame_descr; + + if (tok_len + 1 > max_tok_len) { + pr_err("KASAN internal error: frame description too long: %s\n", + *frame_descr); + return false; + } + + /* Copy token (+ 1 byte for '\0'). */ + strlcpy(token, *frame_descr, tok_len + 1); + } + + /* Advance frame_descr past separator. */ + *frame_descr = sep + 1; + + if (value != NULL && kstrtoul(token, 10, value)) { + pr_err("KASAN internal error: not a valid number: %s\n", token); + return false; + } + + return true; +} + +static void print_decoded_frame_descr(const char *frame_descr) +{ + /* + * We need to parse the following string: + * "n alloc_1 alloc_2 ... alloc_n" + * where alloc_i looks like + * "offset size len name" + * or "offset size len name:line". + */ + + char token[64]; + unsigned long num_objects; + + if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), + &num_objects)) + return; + + pr_err("\n"); + pr_err("this frame has %lu %s:\n", num_objects, + num_objects == 1 ? "object" : "objects"); + + while (num_objects--) { + unsigned long offset; + unsigned long size; + + /* access offset */ + if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), + &offset)) + return; + /* access size */ + if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), + &size)) + return; + /* name length (unused) */ + if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL)) + return; + /* object name */ + if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), + NULL)) + return; + + /* Strip line number; without filename it's not very helpful. */ + strreplace(token, ':', '\0'); + + /* Finally, print object information. */ + pr_err(" [%lu, %lu) '%s'", offset, offset + size, token); + } +} + +static bool __must_check get_address_stack_frame_info(const void *addr, + unsigned long *offset, + const char **frame_descr, + const void **frame_pc) +{ + unsigned long aligned_addr; + unsigned long mem_ptr; + const u8 *shadow_bottom; + const u8 *shadow_ptr; + const unsigned long *frame; + + BUILD_BUG_ON(IS_ENABLED(CONFIG_STACK_GROWSUP)); + + /* + * NOTE: We currently only support printing frame information for + * accesses to the task's own stack. + */ + if (!object_is_on_stack(addr)) + return false; + + aligned_addr = round_down((unsigned long)addr, sizeof(long)); + mem_ptr = round_down(aligned_addr, KASAN_SHADOW_SCALE_SIZE); + shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr); + shadow_bottom = kasan_mem_to_shadow(end_of_stack(current)); + + while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) { + shadow_ptr--; + mem_ptr -= KASAN_SHADOW_SCALE_SIZE; + } + + while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) { + shadow_ptr--; + mem_ptr -= KASAN_SHADOW_SCALE_SIZE; + } + + if (shadow_ptr < shadow_bottom) + return false; + + frame = (const unsigned long *)(mem_ptr + KASAN_SHADOW_SCALE_SIZE); + if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) { + pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n", + frame[0]); + return false; + } + + *offset = (unsigned long)addr - (unsigned long)frame; + *frame_descr = (const char *)frame[1]; + *frame_pc = (void *)frame[2]; + + return true; +} + +static void print_address_stack_frame(const void *addr) +{ + unsigned long offset; + const char *frame_descr; + const void *frame_pc; + + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) + return; + + if (!get_address_stack_frame_info(addr, &offset, &frame_descr, + &frame_pc)) + return; + + /* + * get_address_stack_frame_info only returns true if the given addr is + * on the current task's stack. + */ + pr_err("\n"); + pr_err("addr %px is located in stack of task %s/%d at offset %lu in frame:\n", + addr, current->comm, task_pid_nr(current), offset); + pr_err(" %pS\n", frame_pc); + + if (!frame_descr) + return; + + print_decoded_frame_descr(frame_descr); +} + static void print_address_description(void *addr) { struct page *page = addr_to_page(addr); @@ -204,6 +367,8 @@ static void print_address_description(void *addr) pr_err("The buggy address belongs to the page:\n"); dump_page(page, "kasan: bad access detected"); } + + print_address_stack_frame(addr); } static bool row_is_guilty(const void *row, const void *guilty) -- 2.21.0.1020.gf2820cf01a-goog