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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 1547BC4363A for ; Fri, 30 Oct 2020 13:02:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A11E1206FA for ; Fri, 30 Oct 2020 13:02:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=szeredi.hu header.i=@szeredi.hu header.b="c/0np4r5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726612AbgJ3NCh (ORCPT ); Fri, 30 Oct 2020 09:02:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726566AbgJ3NCg (ORCPT ); Fri, 30 Oct 2020 09:02:36 -0400 Received: from mail-vk1-xa30.google.com (mail-vk1-xa30.google.com [IPv6:2607:f8b0:4864:20::a30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7F65C0613D6 for ; Fri, 30 Oct 2020 06:02:34 -0700 (PDT) Received: by mail-vk1-xa30.google.com with SMTP id i62so1430605vkb.7 for ; Fri, 30 Oct 2020 06:02:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szeredi.hu; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=hfUp6uvT0mNo9qOvWz4kadVZif4hwG0EcrIPidc71AU=; b=c/0np4r5fnnReVFjWkDWXo8hF0To3ovSOoxgoL/QWs9VxL86iqjKdadij03d378/T5 B7rjoCbR258EwTEX+UW+6QMPF65hDWZsco0RfSUG9stFDcsd6ZZkDH+4oFGIQiro7Wrf /VUafL5CtS83KydlI6lpgD86QMrk86JITh21I= 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=hfUp6uvT0mNo9qOvWz4kadVZif4hwG0EcrIPidc71AU=; b=jD9NwCv5AY1aVRnshiytwpzqFOC9yBMpqRGGIcyYLmwFKY3mGUqdz6W8VutHHeTZ9C TdKi5fzwDDnJMopTrPBLJXdK0v/CsmiRYD31qmVjzy6HnoSi/UBZQWL1Rc4oNJHmqIzK lO8ynduSJAUeqSj8cZa0lGO0GG4ka7l+iKxT9DYvvgnGG/CR31i3LQvVHfwX2OG5vJPc FgsxJbGMM5LrK4afQuEScl7w0Kx7EhUZeMfEQBc5H1PK7JpB/tfKBGpmJBtpV4ZRK5/z TKpvkgJNElb3aWDnNovW4r7KlaLqsfHbob/jK1x/u5LEGnReOLRiIU5/u08iJwb52pRM gnnQ== X-Gm-Message-State: AOAM530jQ7SOh6vqIoBLkc7f5lNcgsfjVUD1eQYtj/ze+y2J4MoGA39U ziMRtY689KuDKrKNlYiNeacEbK4j62orMEKOeKjilQ== X-Google-Smtp-Source: ABdhPJxPa9+zamc48OrPbKG+5+YeIbGDLouPEl6taVV7SKI2yGqJZrMzqI/DHpB0Je2VEJI3rTxbB6w6g9+fXjI8Kns= X-Received: by 2002:a1f:23d0:: with SMTP id j199mr6640364vkj.11.1604062953264; Fri, 30 Oct 2020 06:02:33 -0700 (PDT) MIME-Version: 1.0 References: <0000000000008caae305ab9a5318@google.com> <000000000000a726a405ada4b6cf@google.com> In-Reply-To: From: Miklos Szeredi Date: Fri, 30 Oct 2020 14:02:22 +0100 Message-ID: Subject: Re: general protection fault in security_inode_getattr To: Ondrej Mosnacek Cc: syzbot , andriin@fb.com, Alexei Starovoitov , bpf , Daniel Borkmann , James Morris , john.fastabend@gmail.com, kafai@fb.com, KP Singh , Linux kernel mailing list , Linux Security Module list , network dev , "Serge E. Hallyn" , Song Liu , syzkaller-bugs , yhs@fb.com, linux-fsdevel@vger.kernel.org, overlayfs Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org On Mon, Aug 24, 2020 at 11:00 PM Ondrej Mosnacek wrote: > > On Mon, Aug 24, 2020 at 9:37 PM syzbot > wrote: > > syzbot has found a reproducer for the following issue on: > > Looping in fsdevel and OverlayFS maintainers, as this seems to be > FS/OverlayFS related... Hmm, the oopsing code is always something like: All code ======== 0: 1b fe sbb %esi,%edi 2: 49 8d 5e 08 lea 0x8(%r14),%rbx 6: 48 89 d8 mov %rbx,%rax 9: 48 c1 e8 03 shr $0x3,%rax d: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) 12: 74 08 je 0x1c 14: 48 89 df mov %rbx,%rdi 17: e8 bc b4 5b fe callq 0xfffffffffe5bb4d8 1c: 48 8b 1b mov (%rbx),%rbx 1f: 48 83 c3 68 add $0x68,%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax 2a:* 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 48 89 df mov %rbx,%rdi 34: e8 9f b4 5b fe callq 0xfffffffffe5bb4d8 39: 48 8b 1b mov (%rbx),%rbx 3c: 48 83 c3 0c add $0xc,%rbx And that looks (to me) like the unrolled loop in call_int_hook(). I don't see how that could be related to overlayfs, though it's definitely interesting why it only triggers from overlay->vfs_getattr()->security_inode_getattr()... Thanks, Miklos