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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 174A3C3A59C for ; Fri, 16 Aug 2019 15:30:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BB297206C1 for ; Fri, 16 Aug 2019 15:30:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=android.com header.i=@android.com header.b="n1rDvKmV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB297206C1 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=android.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 688CF6B0007; Fri, 16 Aug 2019 11:30:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 612206B0008; Fri, 16 Aug 2019 11:30:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 48B576B000A; Fri, 16 Aug 2019 11:30:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0211.hostedemail.com [216.40.44.211]) by kanga.kvack.org (Postfix) with ESMTP id 2139A6B0007 for ; Fri, 16 Aug 2019 11:30:36 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id C7C0212F57 for ; Fri, 16 Aug 2019 15:30:35 +0000 (UTC) X-FDA: 75828678030.09.key15_3f51bbea4d816 X-HE-Tag: key15_3f51bbea4d816 X-Filterd-Recvd-Size: 7139 Received: from mail-pf1-f193.google.com (mail-pf1-f193.google.com [209.85.210.193]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Fri, 16 Aug 2019 15:30:34 +0000 (UTC) Received: by mail-pf1-f193.google.com with SMTP id b24so3318389pfp.1 for ; Fri, 16 Aug 2019 08:30:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=android.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=mfAPdWffqPCiWWdG0+diH1s9rsdeIRT69OHzvRcyJZE=; b=n1rDvKmVIIzl5LQ8693geFLmZfVk3SNTRXjV+iWc+8TCGMLKeW1iTeiBjvRiueqoqF D9q8mlFSvHVsZFYo8y0kE96uO6kmQFQLzsCMbZOk0QJBcZZXpIGyVUfhKCZdaUtIfVCv i/NoHfVU/jNOhInU0nZF00JzrYo84Kc4poGmJ+0xtP3BbotZEuJh4vLNcJnKiqpzbKqX VAVojoCQ9+7vUVRbeqlgJ3x1mKtd9gYqddIhEV1djd0QWV+eU6MOHKC8ZzBAyRJxBa4j h2AWL75nzhxsVUvXnKj119sMtgytuLB07uRnQLjRyRsPInJpSQZBT6UeAUBurB9zqibi wIrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=mfAPdWffqPCiWWdG0+diH1s9rsdeIRT69OHzvRcyJZE=; b=kMiz3IKArAMx2SEeqVpvicOOwapgVfyXdO7D4MPw8Oxpsr3dYkeZxtNLOVzv4/6WeB eThx2gjSmi647z1quOMxJKOvlWUoNZFYEnR9+JW7YyK0iEfD3YojYvbyJPdoZ/EZNMpw KmF4TMlp0we96oE34hod/jLGfk3oIR+aqLzOaJbM7+4m/4f1T8hmhOestp4RiB7c65a6 8WVJt4147OdkNvU4O8c2hcV0UjwqWordXEKGb79mOzV0sepRiyCeZeCjSLt/ICemSzui Dh711ZGsrqm5EBjoRN2lQSayJdeOdvo6nKCNdVfJKwpfUNg6MLP5rKdzMKt+zbQtnIwk vuSw== X-Gm-Message-State: APjAAAX+8elGGfAVeDHI9j4TrOMs+QLZnmmOFVsRwe99DfFidcY8BXWR NvHQxpFuln5GULiBnWxXJtuCJw== X-Google-Smtp-Source: APXvYqydx2RtAVHirZjlmSa0Unc3LrMXkJsKHb448nh37ky9aF7sEwD8P8sx+d4AByX8L7k2WfP+gw== X-Received: by 2002:a17:90a:77c9:: with SMTP id e9mr7407215pjs.141.1565969433680; Fri, 16 Aug 2019 08:30:33 -0700 (PDT) Received: from nebulus.mtv.corp.google.com ([2620:15c:211:200:5404:91ba:59dc:9400]) by smtp.googlemail.com with ESMTPSA id l4sm4355544pjq.9.2019.08.16.08.30.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 16 Aug 2019 08:30:32 -0700 (PDT) Subject: Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr To: James Morris Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, kernel-team@android.com, Stephen Smalley , linux-security-module@vger.kernel.org, stable@vger.kernel.org, Eric Van Hensbergen , Latchesar Ionkov , Dominique Martinet , David Howells , Chris Mason , Josef Bacik , David Sterba , Jeff Layton , Sage Weil , Ilya Dryomov , Steve French , Tyler Hicks , Jan Kara , Theodore Ts'o , Andreas Dilger , Jaegeuk Kim , Chao Yu , Miklos Szeredi , Bob Peterson , Andreas Gruenbacher , David Woodhouse , Richard Weinberger , Dave Kleikamp , Tejun Heo , Trond Myklebust , Anna Schumaker , Mark Fasheh , Joel Becker , Joseph Qi , Mike Marshall , Martin Brandenburg , Alexander Viro , Phillip Lougher , "Darrick J. Wong" , linux-xfs@vger.kernel.org, Hugh Dickins , "David S. Miller" , Serge Hallyn , Mimi Zohar , Paul Moore , Eric Paris , Casey Schaufler , Andrew Morton , Vyacheslav Dubeyko , =?UTF-8?Q?Ernesto_A=2e_Fern=c3=a1ndez?= , Mathieu Malaterre , v9fs-developer@lists.sourceforge.net, linux-afs@lists.infradead.org, linux-btrfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, ecryptfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, cluster-devel@redhat.com, linux-mtd@lists.infradead.org, jfs-discussion@lists.sourceforge.net, linux-nfs@vger.kernel.org, ocfs2-devel@oss.oracle.com, devel@lists.orangefs.org, linux-unionfs@vger.kernel.org, reiserfs-devel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-integrity@vger.kernel.org, selinux@vger.kernel.org References: <20190812193320.200472-1-salyzyn@android.com> <20190813084801.GA972@kroah.com> <69889dec-5440-1472-ed57-380f45547581@android.com> From: Mark Salyzyn Message-ID: <92b1df4b-6433-7d01-9c08-23de10e8d527@android.com> Date: Fri, 16 Aug 2019 08:30:30 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-GB 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 8/15/19 3:27 PM, James Morris wrote: > On Thu, 15 Aug 2019, Mark Salyzyn wrote: > >> Good Idea, but using the same argument structure for set and get I would be >> concerned about the loss of compiler protection for the buffer argument; > Agreed, I missed that. Sadly, the pattern of struct getxattr_args args; memset(&args, 0, sizeof(args)); args.xxxx = ... __vfs_getxattr(&args}; ... __vfs_setxattr(&args); would be nice, so maybe we need to cool our jets and instead: struct xattr_gs_args { struct dentry *dentry; struct inode *inode; const char *name; union { void *buffer; const void *value; }; size_t size; int flags; }; value _must_ be referenced for all setxattr operations, buffer for getxattr operations (how can we enforce that?). >> struct getxattr_args { >> struct dentry *dentry; >> struct inode *inode; >> const char *name; >> void *buffer; >> size_t size; >> int flags; > Does 'get' need flags? > :-) That was the _whole_ point of the patch, flags is how we pass in the recursion so that a security/internal getxattr call has the rights to acquire the data in the lower layer(s). -- Mark