From nobody Sat Feb 7 08:13:57 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1613604881366445.4867692702103; Wed, 17 Feb 2021 15:34:41 -0800 (PST) Received: from localhost ([::1]:58394 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lCWLA-0005iA-Bf for importer@patchew.org; Wed, 17 Feb 2021 18:34:40 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:49100) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lCWHq-0003K3-Cv for qemu-devel@nongnu.org; Wed, 17 Feb 2021 18:31:14 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:57315) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lCWHn-0001wk-7V for qemu-devel@nongnu.org; Wed, 17 Feb 2021 18:31:14 -0500 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-595-U25HV5WgOoKALheem2RKdw-1; Wed, 17 Feb 2021 18:31:06 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DB6D880402C; Wed, 17 Feb 2021 23:31:04 +0000 (UTC) Received: from horse.redhat.com (ovpn-114-123.rdu2.redhat.com [10.10.114.123]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7D6CA6F440; Wed, 17 Feb 2021 23:30:58 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id E922C223D98; Wed, 17 Feb 2021 18:30:57 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613604669; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sYPS8Pue36yR43T8dgX+RjLt/Zf5JUp8lUWCh2alLbw=; b=AvUYdc6XmKW1D0rxW8dnAOwmhkg1hl3tPqdCJ8U5Kyn57Gn2oOBLozj5vz90QIc4SsA3QO qpBNC2x8SaV/+VbPeXu5DV9H95z89GUDHBEcFTVJn7iijC6pSmOzCN+16zuGKXZd5JapNS tKryvI/zhXn3NIXMp6UbQci6Dm5Yl+g= X-MC-Unique: U25HV5WgOoKALheem2RKdw-1 From: Vivek Goyal To: qemu-devel@nongnu.org, virtio-fs@redhat.com Subject: [PATCH v2 1/3] virtiofsd: Add an option to enable/disable posix acls Date: Wed, 17 Feb 2021 18:30:44 -0500 Message-Id: <20210217233046.81418-2-vgoyal@redhat.com> In-Reply-To: <20210217233046.81418-1-vgoyal@redhat.com> References: <20210217233046.81418-1-vgoyal@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=vgoyal@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; envelope-from=vgoyal@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H3=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: lhenriques@suse.de, stefanha@redhat.com, dgilbert@redhat.com, vgoyal@redhat.com, miklos@szeredi.hu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" fuse has an option FUSE_POSIX_ACL which needs to be opted in by fuse server to enable posix acls. Add virtiofsd option "-o posix_acl/no_posix_acl" to let users enable/disable posix acl support. By default it is disabled as of now. Currently even if file server has not opted in for FUSE_POSIX_ACL, user can still query acl and set acl, and system.posix_acl_access and system.posix_acl_default xattrs show up listxattr response. Miklos said this is confusing. So he said lets block and filter system.posix_acl_access and system.posix_acl_default xattrs in getxattr/setxattr/listxattr if user has explicitly disabled posix acls using -o no_posix_acl. As of now continuing to keeping the existing behavior if user did not specify any option to disable acl support due to concerns about backward compatibility. v2: block system.posix_acl_access and system.posix_acl_default xattrs if user explicitly disabled acls. (Miklos) Signed-off-by: Vivek Goyal --- tools/virtiofsd/passthrough_ll.c | 95 +++++++++++++++++++++++++++++++- 1 file changed, 94 insertions(+), 1 deletion(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough= _ll.c index 58d24c0010..26cdfbd1f0 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -169,6 +169,7 @@ struct lo_data { /* An O_PATH file descriptor to /proc/self/fd/ */ int proc_self_fd; int user_killpriv_v2, killpriv_v2; + int user_posix_acl; }; =20 static const struct fuse_opt lo_opts[] =3D { @@ -201,6 +202,8 @@ static const struct fuse_opt lo_opts[] =3D { { "announce_submounts", offsetof(struct lo_data, announce_submounts), = 1 }, { "killpriv_v2", offsetof(struct lo_data, user_killpriv_v2), 1 }, { "no_killpriv_v2", offsetof(struct lo_data, user_killpriv_v2), 0 }, + { "posix_acl", offsetof(struct lo_data, user_posix_acl), 1 }, + { "no_posix_acl", offsetof(struct lo_data, user_posix_acl), 0 }, FUSE_OPT_END }; static bool use_syslog =3D false; @@ -661,6 +664,23 @@ static void lo_init(void *userdata, struct fuse_conn_i= nfo *conn) conn->want &=3D ~FUSE_CAP_HANDLE_KILLPRIV_V2; lo->killpriv_v2 =3D 0; } + + if (lo->user_posix_acl =3D=3D 1) { + /* + * User explicitly asked for this option. Enable it unconditionall= y. + * If connection does not have this capability, it should fail + * in fuse_lowlevel.c + */ + fuse_log(FUSE_LOG_DEBUG, "lo_init: enabling posix acl\n"); + conn->want |=3D FUSE_CAP_POSIX_ACL; + } else { + /* + * Either user specified to disable posix_acl, or did not specify + * anything. In both the cases do not enable posix acl. + */ + fuse_log(FUSE_LOG_DEBUG, "lo_init: disabling posix_acl\n"); + conn->want &=3D ~FUSE_CAP_POSIX_ACL; + } } =20 static void lo_getattr(fuse_req_t req, fuse_ino_t ino, @@ -2612,6 +2632,63 @@ static int xattr_map_server(const struct lo_data *lo= , const char *server_name, return -ENODATA; } =20 +static bool block_xattr(struct lo_data *lo, const char *name) +{ + /* + * If user explicitly enabled posix_acl or did not provide any option, + * do not block acl. Otherwise block system.posix_acl_access and + * system.posix_acl_default xattrs. + */ + if (lo->user_posix_acl) { + return false; + } + if (!strcmp(name, "system.posix_acl_access") || + !strcmp(name, "system.posix_acl_default")) + return true; + + return false; +} + +/* + * Returns number of bytes in xattr_list after filtering on success. This + * could be zero as well if nothing is left after filtering. + * + * Returns negative error code on failure. + * xattr_list is modified in place. + */ +static int remove_blocked_xattrs(struct lo_data *lo, char *xattr_list, + unsigned in_size) +{ + size_t out_index, in_index; + + /* + * As of now we only filter out acl xattrs. If acls are enabled or + * they have not been explicitly disabled, there is nothing to + * filter. + */ + if (lo->user_posix_acl) { + return in_size; + } + + out_index =3D 0; + in_index =3D 0; + while (in_index < in_size) { + char *in_ptr =3D xattr_list + in_index; + + /* Length of current attribute name */ + size_t in_len =3D strlen(xattr_list + in_index) + 1; + + if (!block_xattr(lo, in_ptr)) { + if (in_index !=3D out_index) { + memmove(xattr_list + out_index, xattr_list + in_index, in_= len); + } + out_index +=3D in_len; + } + in_index +=3D in_len; + } + return out_index; +} + static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_nam= e, size_t size) { @@ -2625,6 +2702,11 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t i= no, const char *in_name, int saverr; int fd =3D -1; =20 + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name =3D NULL; name =3D in_name; if (lo->xattrmap) { @@ -2766,7 +2848,6 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t i= no, size_t size) if (ret =3D=3D 0) { goto out; } - if (lo->xattr_map_list) { /* * Map the names back, some attributes might be dropped, @@ -2813,6 +2894,12 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t = ino, size_t size) goto out; } } + + ret =3D remove_blocked_xattrs(lo, value, ret); + if (ret <=3D 0) { + saverr =3D -ret; + goto out; + } fuse_reply_buf(req, value, ret); } else { /* @@ -2851,6 +2938,11 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t i= no, const char *in_name, int saverr; int fd =3D -1; =20 + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name =3D NULL; name =3D in_name; if (lo->xattrmap) { @@ -3604,6 +3696,7 @@ int main(int argc, char *argv[]) .allow_direct_io =3D 0, .proc_self_fd =3D -1, .user_killpriv_v2 =3D -1, + .user_posix_acl =3D -1, }; struct lo_map_elem *root_elem; struct lo_map_elem *reserve_elem; --=20 2.25.4