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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 606B1C00528 for ; Wed, 2 Aug 2023 23:35:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229884AbjHBXfZ (ORCPT ); Wed, 2 Aug 2023 19:35:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229580AbjHBXfY (ORCPT ); Wed, 2 Aug 2023 19:35:24 -0400 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 671E7FB for ; Wed, 2 Aug 2023 16:35:23 -0700 (PDT) Received: by mail-wr1-x430.google.com with SMTP id ffacd0b85a97d-31757edd9edso281533f8f.2 for ; Wed, 02 Aug 2023 16:35:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1691019322; x=1691624122; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=GO+90fzclJczyKE+cUhJClZTVU5eDVclNQ4EsCMB8CQ=; b=Vaz//sCJd54w/NuYmNBgj+SbwssqnJf+7vr2zjK5k2rbCM9KLpugWOapGhvyC725Du HNyMLoFdBp+jWgLUIQv/LZuRqZJIMDLoiJz3vfNvg/M5U5JZ1MX7lxasc1bQ4lpBaPP1 YIhYwqY24nmuwiuJNrDDvQbqQJyc65wrSNRNf4/Q5R21sp79xSXKKd+Phy+PE5sTdvc2 3faUa5Y5Eg7M5/HpsK1K8QwwSbkH7v7tsQIMPIi8cGDUQ5TPgKrgLNfSMxgcrQql/fdS mv/fcbYf81RfKRRC7jCqasIx4oXC6rJpqDijT66GGUFIUAyv8mRoXVFQpEPhUrT+7w4f Yfqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691019322; x=1691624122; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=GO+90fzclJczyKE+cUhJClZTVU5eDVclNQ4EsCMB8CQ=; b=iG54sQL/WQBNa/rfSn58w/zNJWcDtDFiIRZT/9LT8rIDu9Z1U520N4fNfwO1WEPsak 6Hgxyx6uYGltZt+fIKHbCctjVain+3WKSCViUjdHBUcSz1DOi7bBwvfxkJZx+e8R4/ZM ABxHZB9rbsfbYOTyRXkhvQ68pDHUYLbVNLzDYv4Dyb6LFeqMFvH+rcJjwKeIIyH4de/e iWs5CIyQj3e484Gv2Faph4Ln4cEjL9zIsjam4KR7r8enyECwQG1FHsZV1JVpvsbLFhTs 3W4n/4Gj/V5l722Z4Z4+S6wZAlqPAiHcKMoqhPauyZ8SwQaSSr9peiEqiCiJOPxtJm3f ClhA== X-Gm-Message-State: ABy/qLY2flO7nQiqps40aF78WA8LsRBCoqSHFmsGMHwRqd73EgIPwWFH qbSgti/XVbvfrUMjpAjpCLw= X-Google-Smtp-Source: APBJJlHa1N/JMqjlr+codCx49T5SaCCAmgvLo8kgt1l+ytMw/4vHH6WppSWEs6uK7hhqDmbb51Vitw== X-Received: by 2002:adf:e88f:0:b0:314:35e2:e28d with SMTP id d15-20020adfe88f000000b0031435e2e28dmr5494089wrm.13.1691019321600; Wed, 02 Aug 2023 16:35:21 -0700 (PDT) Received: from [192.168.8.100] ([85.255.233.139]) by smtp.gmail.com with ESMTPSA id m12-20020adff38c000000b00313f031876esm20288800wro.43.2023.08.02.16.35.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Aug 2023 16:35:21 -0700 (PDT) Message-ID: <31e581d0-2038-684c-0941-2c06d713cbeb@gmail.com> Date: Thu, 3 Aug 2023 00:30:46 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] io_uring: annotate the struct io_kiocb slab for appropriate user copy To: Jens Axboe , io-uring Cc: Breno Leitao References: Content-Language: en-US From: Pavel Begunkov In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 8/2/23 21:42, Jens Axboe wrote: > When compiling the kernel with clang and having HARDENED_USERCOPY > enabled, the liburing openat2.t test case fails during request setup: > > usercopy: Kernel memory overwrite attempt detected to SLUB object 'io_kiocb' (offset 24, size 24)! > ------------[ cut here ]------------ > kernel BUG at mm/usercopy.c:102! > invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > CPU: 3 PID: 413 Comm: openat2.t Tainted: G N 6.4.3-g6995e2de6891-dirty #19 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org 04/01/2014 > RIP: 0010:usercopy_abort+0x84/0x90 > Code: ce 49 89 ce 48 c7 c3 68 48 98 82 48 0f 44 de 48 c7 c7 56 c6 94 82 4c 89 de 48 89 c1 41 52 41 56 53 e8 e0 51 c5 00 48 83 c4 18 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 41 57 41 56 > RSP: 0018:ffffc900016b3da0 EFLAGS: 00010296 > RAX: 0000000000000062 RBX: ffffffff82984868 RCX: 4e9b661ac6275b00 > RDX: ffff8881b90ec580 RSI: ffffffff82949a64 RDI: 00000000ffffffff > RBP: 0000000000000018 R08: 0000000000000000 R09: 0000000000000000 > R10: ffffc900016b3c88 R11: ffffc900016b3c30 R12: 00007ffe549659e0 > R13: ffff888119014000 R14: 0000000000000018 R15: 0000000000000018 > FS: 00007f862e3ca680(0000) GS:ffff8881b90c0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00005571483542a8 CR3: 0000000118c11000 CR4: 00000000003506e0 > Call Trace: > > ? __die_body+0x63/0xb0 > ? die+0x9d/0xc0 > ? do_trap+0xa7/0x180 > ? usercopy_abort+0x84/0x90 > ? do_error_trap+0xc6/0x110 > ? usercopy_abort+0x84/0x90 > ? handle_invalid_op+0x2c/0x40 > ? usercopy_abort+0x84/0x90 > ? exc_invalid_op+0x2f/0x40 > ? asm_exc_invalid_op+0x16/0x20 > ? usercopy_abort+0x84/0x90 > __check_heap_object+0xe2/0x110 > __check_object_size+0x142/0x3d0 > io_openat2_prep+0x68/0x140 > io_submit_sqes+0x28a/0x680 > __se_sys_io_uring_enter+0x120/0x580 > do_syscall_64+0x3d/0x80 > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > RIP: 0033:0x55714834de26 > Code: ca 01 0f b6 82 d0 00 00 00 8b ba cc 00 00 00 45 31 c0 31 d2 41 b9 08 00 00 00 83 e0 01 c1 e0 04 41 09 c2 b8 aa 01 00 00 0f 05 66 0f 1f 84 00 00 00 00 00 89 30 eb 89 0f 1f 40 00 8b 00 a8 06 > RSP: 002b:00007ffe549659c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa > RAX: ffffffffffffffda RBX: 00007ffe54965a50 RCX: 000055714834de26 > RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000003 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000008 > R10: 0000000000000000 R11: 0000000000000246 R12: 000055714834f057 > R13: 00007ffe54965a50 R14: 0000000000000001 R15: 0000557148351dd8 > > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:usercopy_abort+0x84/0x90 > Code: ce 49 89 ce 48 c7 c3 68 48 98 82 48 0f 44 de 48 c7 c7 56 c6 94 82 4c 89 de 48 89 c1 41 52 41 56 53 e8 e0 51 c5 00 48 83 c4 18 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 41 57 41 56 > RSP: 0018:ffffc900016b3da0 EFLAGS: 00010296 > RAX: 0000000000000062 RBX: ffffffff82984868 RCX: 4e9b661ac6275b00 > RDX: ffff8881b90ec580 RSI: ffffffff82949a64 RDI: 00000000ffffffff > RBP: 0000000000000018 R08: 0000000000000000 R09: 0000000000000000 > R10: ffffc900016b3c88 R11: ffffc900016b3c30 R12: 00007ffe549659e0 > R13: ffff888119014000 R14: 0000000000000018 R15: 0000000000000018 > FS: 00007f862e3ca680(0000) GS:ffff8881b90c0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00005571483542a8 CR3: 0000000118c11000 CR4: 00000000003506e0 > Kernel panic - not syncing: Fatal exception > Kernel Offset: disabled > ---[ end Kernel panic - not syncing: Fatal exception ]--- > > when it tries to copy struct open_how from userspace into the per-command > space in the io_kiocb. There's nothing wrong with the copy, but we're > missing the appropriate annotations for allowing user copies to/from the > io_kiocb slab. > > Allow copies in the per-command area, which is from the 'file' pointer to > when 'opcode' starts. We do have existing user copies there, but they are > not all annotated like the one that openat2_prep() uses, > copy_struct_from_user(). But in practice opcodes should be allowed to > copy data into their per-command area in the io_kiocb. > > Reported-by: Breno Leitao > Signed-off-by: Jens Axboe > > --- > > diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c > index 135da2fd0eda..d8e69461786d 100644 > --- a/io_uring/io_uring.c > +++ b/io_uring/io_uring.c > @@ -4627,8 +4627,20 @@ static int __init io_uring_init(void) > > io_uring_optable_init(); > > - req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC | > - SLAB_ACCOUNT | SLAB_TYPESAFE_BY_RCU); > + /* > + * Allow user copy in the per-command field, which starts after the > + * file in io_kiocb and until the opcode field. The openat2 handling > + * requires copying in user memory into the io_kiocb object in that > + * range, and HARDENED_USERCOPY will complain if we haven't > + * correctly annotated this range. > + */ > + req_cachep = kmem_cache_create_usercopy("io_kiocb", > + sizeof(struct io_kiocb), 0, > + SLAB_HWCACHE_ALIGN | SLAB_PANIC | > + SLAB_ACCOUNT | SLAB_TYPESAFE_BY_RCU, > + offsetof(struct io_kiocb, cmd.data), > + offsetof(struct io_kiocb, opcode) - > + offsetof(struct io_kiocb, cmd.data), NULL); sizeof_field(struct io_kiocb, cmd.data) should be less awkward -- Pavel Begunkov