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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, 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 AEDFCC433DB for ; Mon, 15 Mar 2021 13:08:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BE8B64E31 for ; Mon, 15 Mar 2021 13:08:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229821AbhCONHx (ORCPT ); Mon, 15 Mar 2021 09:07:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229889AbhCONHh (ORCPT ); Mon, 15 Mar 2021 09:07:37 -0400 Received: from mail-qv1-xf2a.google.com (mail-qv1-xf2a.google.com [IPv6:2607:f8b0:4864:20::f2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E75BC06174A for ; Mon, 15 Mar 2021 06:07:37 -0700 (PDT) Received: by mail-qv1-xf2a.google.com with SMTP id j17so7677327qvo.13 for ; Mon, 15 Mar 2021 06:07:37 -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=IM3zY04AmOlCtvAVnSd9iG5x1ewD+6ByijIwRWgL5V8=; b=BnYqxhM866S7OSAVje66mLcPnSbKq7XImiRkeGfZno3pjvUPnBR1MrMA6PinWYBy8M sQFlHjlzpygxq21VMvPDvfuEwdyEwNqhlhFPJS7qUSJQzOEzQ7Ci0xafNzFFmVmWzc9f fftSeKpcP7DJ4/SPdSpB5X1H/wCZwAFYJHD0cHhdBs6GMEVCw5XdluJhJ2twOeRlKsWo 6oLJXmXOnA/CyGjDKmRHpb0KjxJzb3wwMk0cDl/pv0Bq6Sgsr4MNNsxaffg3TxdXza01 OTCum00SOZT2gC+PZfH5cihdqejRaIbFRS9wFRZMIA5wN8uZo4a3s2EFyZysRWK/m8ew c1hA== 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=IM3zY04AmOlCtvAVnSd9iG5x1ewD+6ByijIwRWgL5V8=; b=BM3P8VEMknclDhmFam9yt6tAa6kriuZQ+hb8v4S83xu750Ev30k2dlAbjeUlJj0yMj qbNyt/xm5c6lzFNW009k8SGJ8Y5UQLRX4wmPZMaxXO7u5tkph0NG5Op8vx1vu1PRFEm8 EINeUcX/qLbwUzWuuEojmZpYCuWMB8BV7oz1FToiCRRjFz/VNW7AsyRC5IBdeWxf5na2 LCRyLkWTK3oinv+ZlMGZ0O4AEBhbEwgHBBAenYGxfX452eMnSeoa1pwoqmcC1/oPItQY /0PsuqLF+BXHUhHbRwqcSfHf0as6+9/aGjWNw1v9Njb5LdalYScVf4Vg/XGU7UPQesD6 7PWg== X-Gm-Message-State: AOAM531Gui4LqYxNVAiwcSKpqZYUz8sbsS4ZcoB63WOgQ/UVuzF7T9ym pGoMrvTewPbRWIa9f9MlxBtSCxiNwI4NduJohkkeGr+66qA= X-Google-Smtp-Source: ABdhPJwJbYDM4vf8RRkgFjAw/ezp5E66jTEphKKfCiWUo2N3D3fQbX/zuAV4uxWssANVFHhV8Z2wCW6vutN8X3C2YCU= X-Received: by 2002:a05:6214:326:: with SMTP id j6mr10679488qvu.13.1615813656317; Mon, 15 Mar 2021 06:07:36 -0700 (PDT) MIME-Version: 1.0 References: <31c4e1863a561c47d38b8e547ec38a0a713bdadc.camel@linux.ibm.com> In-Reply-To: <31c4e1863a561c47d38b8e547ec38a0a713bdadc.camel@linux.ibm.com> From: Dmitry Vyukov Date: Mon, 15 Mar 2021 14:07:23 +0100 Message-ID: Subject: Re: NULL deref in integrity_inode_get To: Mimi Zohar Cc: James Morris , "Serge E. Hallyn" , linux-security-module , LKML , d.kasatkin@samsung.com, Mimi Zohar , Eric Biggers Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: On Mon, Mar 15, 2021 at 1:41 PM Mimi Zohar wrote: > > Hi Dmitry, > > On Mon, 2021-03-15 at 11:58 +0100, Dmitry Vyukov wrote: > > Hi, > > > > I am trying to boot 5.12-rc3 with this config: > > https://github.com/google/syzkaller/blob/cc1cff8f1e1a585894796d6eae8c51eef98037e6/dashboard/config/linux/upstream-smack-kasan.config > > > > in qemu: > > qemu-system-x86_64 -enable-kvm -machine q35,nvdimm -cpu > > max,migratable=off -smp 4 -m 4G,slots=4,maxmem=16G -hda > > wheezy.img -kernel arch/x86/boot/bzImage -nographic -vga std > > -soundhw all -usb -usbdevice tablet -bt hci -bt device:keyboard > > -net user,host=10.0.2.10,hostfwd=tcp::10022-:22 -net > > nic,model=virtio-net-pci -object > > memory-backend-file,id=pmem1,share=off,mem-path=/dev/zero,size=64M > > -device nvdimm,id=nvdimm1,memdev=pmem1 -append "console=ttyS0 > > root=/dev/sda earlyprintk=serial rodata=n oops=panic panic_on_warn=1 > > panic=86400 lsm=smack numa=fake=2 nopcid dummy_hcd.num=8" -pidfile > > vm_pid -m 2G -cpu host > > > > But it crashes on NULL deref in integrity_inode_get during boot: > > > > Run /sbin/init as init process > > BUG: kernel NULL pointer dereference, address: 000000000000001c > > #PF: supervisor read access in kernel mode > > #PF: error_code(0x0000) - not-present page > > PGD 0 P4D 0 > > Oops: 0000 [#1] PREEMPT SMP KASAN > > CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc2+ #97 > > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS > > rel-1.13.0-44-g88ab0c15525c-prebuilt.qemu.org 04/01/2014 > > RIP: 0010:kmem_cache_alloc+0x2b/0x370 mm/slub.c:2920 > > Code: 57 41 56 41 55 41 54 41 89 f4 55 48 89 fd 53 48 83 ec 10 44 8b > > 3d d9 1f 90 0b 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 31 c0 <8b> 5f > > 1c 4cf > > RSP: 0000:ffffc9000032f9d8 EFLAGS: 00010246 > > RAX: 0000000000000000 RBX: ffff888017fc4f00 RCX: 0000000000000000 > > RDX: ffff888040220000 RSI: 0000000000000c40 RDI: 0000000000000000 > > RBP: 0000000000000000 R08: 0000000000000000 R09: ffff888019263627 > > R10: ffffffff83937cd1 R11: 0000000000000000 R12: 0000000000000c40 > > R13: ffff888019263538 R14: 0000000000000000 R15: 0000000000ffffff > > FS: 0000000000000000(0000) GS:ffff88802d180000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 000000000000001c CR3: 000000000b48e000 CR4: 0000000000750ee0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > PKRU: 55555554 > > Call Trace: > > integrity_inode_get+0x47/0x260 security/integrity/iint.c:105 > > process_measurement+0x33d/0x17e0 security/integrity/ima/ima_main.c:237 > > ima_bprm_check+0xde/0x210 security/integrity/ima/ima_main.c:474 > > security_bprm_check+0x7d/0xa0 security/security.c:845 > > search_binary_handler fs/exec.c:1708 [inline] > > exec_binprm fs/exec.c:1761 [inline] > > bprm_execve fs/exec.c:1830 [inline] > > bprm_execve+0x764/0x19a0 fs/exec.c:1792 > > kernel_execve+0x370/0x460 fs/exec.c:1973 > > try_to_run_init_process+0x14/0x4e init/main.c:1366 > > kernel_init+0x11d/0x1b8 init/main.c:1477 > > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > > Modules linked in: > > CR2: 000000000000001c > > ---[ end trace 22d601a500de7d79 ]--- > > It looks like integrity_inode_get() fails to alloc memory. Only on > failure to verify the integrity of a file would an error be returned. > I think that is what you would want to happen. Without an "appraise" > policy, this shouldn't happen. It happens at the very boot. I think the cache is NULL.