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[156.151.31.86]) by mx.google.com with ESMTPS id 185si232170ybk.240.2019.06.20.14.38.49 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 20 Jun 2019 14:38:49 -0700 (PDT) Received-SPF: pass (google.com: domain of darrick.wong@oracle.com designates 156.151.31.86 as permitted sender) client-ip=156.151.31.86; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=HKn791tb; spf=pass (google.com: domain of darrick.wong@oracle.com designates 156.151.31.86 as permitted sender) smtp.mailfrom=darrick.wong@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5KLYHVn088700; Thu, 20 Jun 2019 21:38:38 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=D3CnJNHOIgWdUG1TcE81fq/bsWj72ILMBiE1tAPqQwo=; b=HKn791tbDcSyV5tTwA4L7n0iz31Dp5T+PYftD80uW1HfTEOKSjNNo8ILTMjO1/Rv8cOI hpROCjBB23fPljyiuqdvwYxNy/xpAecXOJ97+qJXUbuQysBIXp6+kq1M1NohTdSt2o5m bdEHlQfhcUcK9Q2VlmkUVsRBf7mVWZm2yOm4eXP0y5gikqkZmSL3eKCbJdvsPzjLY50k BfxiWb1VEIm42WU1tUp/bKXk3/F6YlHbkAbzrc8pKPgHNgEvkWIV2bY4z7UBJVZQfH8/ ZSoTLiWzgKluhc0l9SvuD6uztH108WS7lGdHTqumoJ0SNSOf6qr9qij979gZkZoaMzEB qg== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2130.oracle.com with ESMTP id 2t7809kdj1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 Jun 2019 21:38:38 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5KLacer151050; Thu, 20 Jun 2019 21:36:38 GMT Received: from pps.reinject (localhost [127.0.0.1]) by aserp3020.oracle.com with ESMTP id 2t77ypkrr0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 20 Jun 2019 21:36:38 +0000 Received: from aserp3020.oracle.com (aserp3020.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x5KLabeL151041; Thu, 20 Jun 2019 21:36:37 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3020.oracle.com with ESMTP id 2t77ypkrqs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 Jun 2019 21:36:37 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x5KLaWqH007037; Thu, 20 Jun 2019 21:36:32 GMT Received: from localhost (/10.145.179.81) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 20 Jun 2019 14:36:31 -0700 Date: Thu, 20 Jun 2019 14:36:29 -0700 From: "Darrick J. Wong" To: Jan Kara Cc: matthew.garrett@nebula.com, yuchao0@huawei.com, tytso@mit.edu, ard.biesheuvel@linaro.org, josef@toxicpanda.com, clm@fb.com, adilger.kernel@dilger.ca, viro@zeniv.linux.org.uk, jack@suse.com, dsterba@suse.com, jaegeuk@kernel.org, jk@ozlabs.org, reiserfs-devel@vger.kernel.org, linux-efi@vger.kernel.org, devel@lists.orangefs.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-nilfs@vger.kernel.org, linux-mtd@lists.infradead.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org Subject: Re: [PATCH 4/6] vfs: don't allow most setxattr to immutable files Message-ID: <20190620213629.GB5375@magnolia> References: <156022836912.3227213.13598042497272336695.stgit@magnolia> <156022840560.3227213.4776913678782966728.stgit@magnolia> <20190620140345.GI30243@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190620140345.GI30243@quack2.suse.cz> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9294 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906200154 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: On Thu, Jun 20, 2019 at 04:03:45PM +0200, Jan Kara wrote: > On Mon 10-06-19 21:46:45, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > The chattr manpage has this to say about immutable files: > > > > "A file with the 'i' attribute cannot be modified: it cannot be deleted > > or renamed, no link can be created to this file, most of the file's > > metadata can not be modified, and the file can not be opened in write > > mode." > > > > However, we don't actually check the immutable flag in the setattr code, > > which means that we can update inode flags and project ids and extent > > size hints on supposedly immutable files. Therefore, reject setflags > > and fssetxattr calls on an immutable file if the file is immutable and > > will remain that way. > > > > Signed-off-by: Darrick J. Wong > > --- > > fs/inode.c | 31 +++++++++++++++++++++++++++++++ > > 1 file changed, 31 insertions(+) > > > > > > diff --git a/fs/inode.c b/fs/inode.c > > index a3757051fd55..adfb458bf533 100644 > > --- a/fs/inode.c > > +++ b/fs/inode.c > > @@ -2184,6 +2184,17 @@ int vfs_ioc_setflags_check(struct inode *inode, int oldflags, int flags) > > !capable(CAP_LINUX_IMMUTABLE)) > > return -EPERM; > > > > + /* > > + * We aren't allowed to change any other flags if the immutable flag is > > + * already set and is not being unset. > > + */ > > + if ((oldflags & FS_IMMUTABLE_FL) && > > + (flags & FS_IMMUTABLE_FL)) { > > + if ((oldflags & ~FS_IMMUTABLE_FL) != > > + (flags & ~FS_IMMUTABLE_FL)) > > This check looks a bit strange when you've just check FS_IMMUTABLE_FL isn't > changing... Why not just oldflags != flags? > > > + if ((old_fa->fsx_xflags & FS_XFLAG_IMMUTABLE) && > > + (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)) { > > + if ((old_fa->fsx_xflags & ~FS_XFLAG_IMMUTABLE) != > > + (fa->fsx_xflags & ~FS_XFLAG_IMMUTABLE)) > > Ditto here... Good point! I'll fix it. --D > > > + return -EPERM; > > + if (old_fa->fsx_projid != fa->fsx_projid) > > + return -EPERM; > > + if ((fa->fsx_xflags & (FS_XFLAG_EXTSIZE | > > + FS_XFLAG_EXTSZINHERIT)) && > > + old_fa->fsx_extsize != fa->fsx_extsize) > > + return -EPERM; > > + if ((old_fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) && > > + old_fa->fsx_cowextsize != fa->fsx_cowextsize) > > + return -EPERM; > > + } > > + > > /* Extent size hints of zero turn off the flags. */ > > if (fa->fsx_extsize == 0) > > fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT); > > Honza > -- > Jan Kara > SUSE Labs, CR