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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 4501AC2B9F4 for ; Tue, 22 Jun 2021 15:04:29 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D7F1560FEA for ; Tue, 22 Jun 2021 15:04:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D7F1560FEA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:41296 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lvhwy-0007UX-22 for qemu-devel@archiver.kernel.org; Tue, 22 Jun 2021 11:04:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47620) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lvhvY-0005My-BA for qemu-devel@nongnu.org; Tue, 22 Jun 2021 11:03:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:57966) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lvhvV-0002EU-Kd for qemu-devel@nongnu.org; Tue, 22 Jun 2021 11:03:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624374177; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=GYHw+a4jcDV8eMqrXFiyqDYUFSlINPx31y0CDnd1/DU=; b=Q+7QoYwVJgeTT7Bw/ozJ0SYxdGDbngmdS6uh460KW7GS1sPUJk5zlqBxAUuWZ+mDJhp+Ar LHdJVzDdHuVQBzqo8D7YXjPJIBX1ef+Azf1EZVOH/kAF/JuXvc5KTp8jRqfJ7QqVACwOhd 8+aAa0XeJN5ABI7yD56wHFETXVEDsPk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-221-yEhvsp-vMeCzLD_k_2BDLg-1; Tue, 22 Jun 2021 11:02:50 -0400 X-MC-Unique: yEhvsp-vMeCzLD_k_2BDLg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A8176192CC42; Tue, 22 Jun 2021 15:02:49 +0000 (UTC) Received: from redhat.com (ovpn-114-58.ams2.redhat.com [10.36.114.58]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D77956090F; Tue, 22 Jun 2021 15:02:48 +0000 (UTC) Date: Tue, 22 Jun 2021 17:02:47 +0200 From: Kevin Wolf To: Max Reitz Subject: Re: [PATCH 3/4] export/fuse: Let permissions be adjustable Message-ID: References: <20210614144407.134243-1-mreitz@redhat.com> <20210614144407.134243-4-mreitz@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210614144407.134243-4-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.223, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 14.06.2021 um 16:44 hat Max Reitz geschrieben: > Allow changing the file mode, UID, and GID through SETATTR. > > This only really makes sense with allow-other, though (because without > it, the effective access mode is fixed to be 0600 (u+rw) with qemu's > user being the file's owner), so changing these stat fields is not > allowed without allow-other. > > Signed-off-by: Max Reitz > --- > block/export/fuse.c | 48 ++++++++++++++++++++++++++++++++++----------- > 1 file changed, 37 insertions(+), 11 deletions(-) > > diff --git a/block/export/fuse.c b/block/export/fuse.c > index 1d54286d90..742e0af657 100644 > --- a/block/export/fuse.c > +++ b/block/export/fuse.c > @@ -47,6 +47,10 @@ typedef struct FuseExport { > bool writable; > bool growable; > bool allow_other; > + > + mode_t st_mode; > + uid_t st_uid; > + gid_t st_gid; > } FuseExport; > > static GHashTable *exports; > @@ -120,6 +124,13 @@ static int fuse_export_create(BlockExport *blk_exp, > exp->growable = args->growable; > exp->allow_other = args->allow_other; > > + exp->st_mode = S_IFREG | S_IRUSR; > + if (exp->writable) { > + exp->st_mode |= S_IWUSR; > + } > + exp->st_uid = getuid(); > + exp->st_gid = getgid(); > + > ret = setup_fuse_export(exp, args->mountpoint, errp); > if (ret < 0) { > goto fail; > @@ -329,7 +340,6 @@ static void fuse_getattr(fuse_req_t req, fuse_ino_t inode, > int64_t length, allocated_blocks; > time_t now = time(NULL); > FuseExport *exp = fuse_req_userdata(req); > - mode_t mode; > > length = blk_getlength(exp->common.blk); > if (length < 0) { > @@ -344,17 +354,12 @@ static void fuse_getattr(fuse_req_t req, fuse_ino_t inode, > allocated_blocks = DIV_ROUND_UP(allocated_blocks, 512); > } > > - mode = S_IFREG | S_IRUSR; > - if (exp->writable) { > - mode |= S_IWUSR; > - } > - > statbuf = (struct stat) { > .st_ino = inode, > - .st_mode = mode, > + .st_mode = exp->st_mode, > .st_nlink = 1, > - .st_uid = getuid(), > - .st_gid = getgid(), > + .st_uid = exp->st_uid, > + .st_gid = exp->st_gid, > .st_size = length, > .st_blksize = blk_bs(exp->common.blk)->bl.request_alignment, > .st_blocks = allocated_blocks, > @@ -400,15 +405,23 @@ static int fuse_do_truncate(const FuseExport *exp, int64_t size, > } > > /** > - * Let clients set file attributes. Only resizing is supported. > + * Let clients set file attributes. With allow_other, only resizing and > + * changing permissions (st_mode, st_uid, st_gid) is allowed. Without > + * allow_other, only resizing is supported. > */ > static void fuse_setattr(fuse_req_t req, fuse_ino_t inode, struct stat *statbuf, > int to_set, struct fuse_file_info *fi) > { > FuseExport *exp = fuse_req_userdata(req); > + int supported_attrs; > int ret; > > - if (to_set & ~FUSE_SET_ATTR_SIZE) { > + supported_attrs = FUSE_SET_ATTR_SIZE; > + if (exp->allow_other) { > + supported_attrs |= FUSE_SET_ATTR_MODE | FUSE_SET_ATTR_UID | > + FUSE_SET_ATTR_GID; > + } > + if (to_set & ~supported_attrs) { > fuse_reply_err(req, ENOTSUP); > return; > } > @@ -426,6 +439,19 @@ static void fuse_setattr(fuse_req_t req, fuse_ino_t inode, struct stat *statbuf, > } > } > > + if (to_set & FUSE_SET_ATTR_MODE) { > + /* Only allow changing the file mode, not the type */ > + exp->st_mode = (statbuf->st_mode & 07777) | S_IFREG; > + } Should we check that the mode actually makes sense? Not sure if making an image executable has a good use case, and making it writable in the permissions for a read-only export isn't a good idea either. > + > + if (to_set & FUSE_SET_ATTR_UID) { > + exp->st_uid = statbuf->st_uid; > + } > + > + if (to_set & FUSE_SET_ATTR_GID) { > + exp->st_gid = statbuf->st_gid; > + } > + > fuse_getattr(req, inode, fi); > } Kevin