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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 657E2C432BE for ; Sat, 31 Jul 2021 18:22:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4923A60F3A for ; Sat, 31 Jul 2021 18:22:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229645AbhGaSWZ (ORCPT ); Sat, 31 Jul 2021 14:22:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229505AbhGaSWX (ORCPT ); Sat, 31 Jul 2021 14:22:23 -0400 Received: from mail-yb1-xb34.google.com (mail-yb1-xb34.google.com [IPv6:2607:f8b0:4864:20::b34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66CD6C06175F; Sat, 31 Jul 2021 11:22:17 -0700 (PDT) Received: by mail-yb1-xb34.google.com with SMTP id x192so21774244ybe.0; Sat, 31 Jul 2021 11:22:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to:cc; bh=B2wyjC7Ur8M6OKOZpCw0kgf58az5KHkX+mP2rwt1ZRE=; b=mixLP0SLeFkQtWsAk2J4lgpkl+YJdChpJ1SrVFalxOB8GvfNRDRfA3QHu9Z3IS9Amm r7nuRG31yEh3kq/GfqueEYAm3+upszhMKm2lZuWouHIWmtAUoFL8zk2SeiyLMtEv2Erk R870OkCpzJIeF4F/9esYmuunM2u0seiC0N3cW121LDdMWMncUN5WYh4rX3HXiqd5yb3z 8GDOZqP8w0ilAPpLYWLS738q7C1S/cjS8uVB/So0EeASn94Ii0AG7fpn4OYvaNlRZEce //ROKmc1uw2/UzkEYiHzruNRE9whFmI1XaRGEazMlogbDKKCv8W33nSfXYF4bTjfJL5y BVzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to:cc; bh=B2wyjC7Ur8M6OKOZpCw0kgf58az5KHkX+mP2rwt1ZRE=; b=YetLGsfEer80FDSlnQayl5hfNpqLFvDn9J3fCxlY19lnjFc7touCP0NKTgleo+MI8J D2L/xPMIH183TylvWtCq80esVCb3rSPzBKLqXusen6FOLtWyD/9PHiIWJNKj87WqByJR NkMqxmAqbR5VhIXFwQ6TX8Eg35KyFeXQKiRT6OLgXXIFpB5lTDK02NLWjOLIcQXVIa8w Qasj+8VlA/CxHSyN9wIXE5IBBrsJXKjsiarwhQ+MTYEmDMwOCj4vGuxeubAjxxK1jjdT GZpOtKxOictuC0DTzqR2x7enGPFggBa6+DknUCiB6lzgUCmIMr5YNhxDmV9hkN006uHC b1Ug== X-Gm-Message-State: AOAM531EX1PUN8Gi1ofbLrUxez8NvDEEPUmKSli4wKZ/RPsW98yBeb3e DH8xRlRPpNdHPC2D7XQeiy30a2krotfbVjltp+8r6z+/dQ4b1Q== X-Google-Smtp-Source: ABdhPJzjVJvCxfkw59ibTUW0/DK5/bDfo7ySAlMaxICS3bxtLC7FuUGxj03ud6oYX9dsUQby7ulgsCgJRH8AOvzUjis= X-Received: by 2002:a05:6902:1109:: with SMTP id o9mr11021445ybu.448.1627755736477; Sat, 31 Jul 2021 11:22:16 -0700 (PDT) MIME-Version: 1.0 From: Sudip Mukherjee Date: Sat, 31 Jul 2021 19:21:40 +0100 Message-ID: Subject: KASAN: stack-out-of-bounds in iov_iter_revert To: Jens Axboe , Pavel Begunkov Cc: io-uring@vger.kernel.org, linux-kernel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jens, Pavel, We had been running syzkaller on v5.10.y and a "KASAN: stack-out-of-bounds in iov_iter_revert" was being reported on it. I got some time to check that today and have managed to get a syzkaller reproducer. I dont have a C reproducer which I can share but I can use the syz-reproducer to reproduce this with v5.14-rc3 and also with next-20210730. ================================================================== [ 74.211232] BUG: KASAN: stack-out-of-bounds in iov_iter_revert+0x809/0x900 [ 74.212778] Read of size 8 at addr ffff888025dc78b8 by task syz-executor.0/828 [ 74.214756] CPU: 0 PID: 828 Comm: syz-executor.0 Not tainted 5.14.0-rc3-next-20210730 #1 [ 74.216525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 74.219033] Call Trace: [ 74.219683] dump_stack_lvl+0x8b/0xb3 [ 74.220706] print_address_description.constprop.0+0x1f/0x140 [ 74.222272] ? iov_iter_revert+0x809/0x900 [ 74.223285] ? iov_iter_revert+0x809/0x900 [ 74.224226] kasan_report.cold+0x7f/0x11b [ 74.225147] ? iov_iter_revert+0x809/0x900 [ 74.226085] iov_iter_revert+0x809/0x900 [ 74.227002] ? lock_is_held_type+0x98/0x110 [ 74.227960] io_write+0x57d/0xe40 [ 74.228730] ? io_read+0x10d0/0x10d0 [ 74.229550] ? lockdep_hardirqs_on_prepare+0x3e0/0x3e0 [ 74.230746] ? lock_is_held_type+0x98/0x110 [ 74.231699] ? __lock_acquire+0xbb1/0x5b00 [ 74.232647] io_issue_sqe+0x4da/0x6a80 [ 74.233507] ? mark_lock+0xfc/0x2d80 [ 74.234349] ? __is_insn_slot_addr+0x14d/0x250 [ 74.235385] ? lock_chain_count+0x20/0x20 [ 74.236312] ? io_write+0xe40/0xe40 [ 74.237119] ? lock_is_held_type+0x98/0x110 [ 74.238076] ? find_held_lock+0x2c/0x110 [ 74.238992] ? lock_release+0x1dd/0x6b0 [ 74.239874] ? __fget_files+0x21c/0x3e0 [ 74.240757] ? lock_downgrade+0x6d0/0x6d0 [ 74.241672] ? lock_release+0x1dd/0x6b0 [ 74.242578] __io_queue_sqe+0x1ac/0xe60 [ 74.243471] ? io_issue_sqe+0x6a80/0x6a80 [ 74.244402] ? lock_is_held_type+0x98/0x110 [ 74.245358] io_submit_sqes+0x3f6e/0x76a0 [ 74.246281] ? xa_load+0x158/0x290 [ 74.247113] ? __do_sys_io_uring_enter+0x90c/0x1a20 [ 74.248207] __do_sys_io_uring_enter+0x90c/0x1a20 [ 74.249277] ? vm_mmap_pgoff+0xe8/0x280 [ 74.250163] ? io_submit_sqes+0x76a0/0x76a0 [ 74.251149] ? randomize_stack_top+0x100/0x100 [ 74.252178] ? __do_sys_futex+0xf2/0x3d0 [ 74.253074] ? __do_sys_futex+0xfb/0x3d0 [ 74.253980] ? do_futex+0x18c0/0x18c0 [ 74.254852] ? lockdep_hardirqs_on_prepare+0x273/0x3e0 [ 74.256022] ? syscall_enter_from_user_mode+0x1d/0x50 [ 74.257167] do_syscall_64+0x3b/0x90 [ 74.257984] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 74.259125] RIP: 0033:0x466609 [ 74.259830] Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 [ 74.263910] RSP: 002b:00007ffdb23903f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa [ 74.265579] RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 0000000000466609 [ 74.267162] RDX: 0000000000000000 RSI: 00000000000058ab RDI: 0000000000000003 [ 74.268745] RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 [ 74.270303] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 [ 74.271899] R13: 00007ffdb2390590 R14: 000000000056bf80 R15: 000000000001215c [ 74.273856] The buggy address belongs to the page: [ 74.274948] page:00000000bd0ec836 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x25dc7 [ 74.277000] flags: 0x100000000000000(node=0|zone=1) [ 74.278119] raw: 0100000000000000 0000000000000000 ffffea00009771c8 0000000000000000 [ 74.279853] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 74.281553] page dumped because: kasan: bad access detected [ 74.283166] addr ffff888025dc78b8 is located in stack of task syz-executor.0/828 at offset 152 in frame: [ 74.285238] io_write+0x0/0xe40 [ 74.286338] this frame has 3 objects: [ 74.287170] [48, 56) 'iovec' [ 74.287185] [80, 120) '__iter' [ 74.287863] [160, 288) 'inline_vecs' [ 74.289751] Memory state around the buggy address: [ 74.290825] ffff888025dc7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 74.292421] ffff888025dc7800: 00 00 00 00 f1 f1 f1 f1 00 00 00 f2 f2 f2 00 00 [ 74.294022] >ffff888025dc7880: 00 00 00 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 00 [ 74.295639] ^ [ 74.296766] ffff888025dc7900: 00 00 00 00 00 00 00 00 f3 f3 f3 f3 00 00 00 00 [ 74.298373] ffff888025dc7980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 74.299959] ================================================================== Not sure if this has been already reported or not, but I will be happy to test if you have a fix for this. -- Regards Sudip