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 20215C433DB for ; Thu, 18 Feb 2021 19:06:42 +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 68D4F64EBB for ; Thu, 18 Feb 2021 19:06:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68D4F64EBB 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]:38938 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lCodM-0001ZT-B9 for qemu-devel@archiver.kernel.org; Thu, 18 Feb 2021 14:06:40 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:57186) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lCobn-0000z0-1j for qemu-devel@nongnu.org; Thu, 18 Feb 2021 14:05:03 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:22752) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lCobj-0001OE-SV for qemu-devel@nongnu.org; Thu, 18 Feb 2021 14:05:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613675099; 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=kl4l5N4ensWe/8pmMW15r4zF4cSA7K60X2krykUNSWs=; b=JBfdxtXU0qwgkuvhqBHS9G60N/6ORkNOu+zgfmEI/uDVpiH6LB2wgpiT8Gb/2CA7pdiR3W LgGfgKo4V1sBVFhl+gCI/1EDzjOKdIeRS5quij2boDZAx2o7n4MOTGPpJ8kVP7gACxWha+ s7tAcEiUEua/sdyc1Gl7XZBsqkkB3RU= 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-560-Mke5rI0AOTKLokqd54QIxQ-1; Thu, 18 Feb 2021 14:04:53 -0500 X-MC-Unique: Mke5rI0AOTKLokqd54QIxQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B1735804023; Thu, 18 Feb 2021 19:04:52 +0000 (UTC) Received: from horse.redhat.com (ovpn-117-5.rdu2.redhat.com [10.10.117.5]) by smtp.corp.redhat.com (Postfix) with ESMTP id D39895C1C4; Thu, 18 Feb 2021 19:04:46 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 7455922054F; Thu, 18 Feb 2021 14:04:46 -0500 (EST) Date: Thu, 18 Feb 2021 14:04:46 -0500 From: Vivek Goyal To: qemu-devel@nongnu.org, virtio-fs@redhat.com Subject: Re: [PATCH v2.1 1/3] virtiofsd: Add an option to enable/disable posix acls Message-ID: <20210218190446.GC92815@redhat.com> References: <20210217233046.81418-1-vgoyal@redhat.com> <20210217233046.81418-2-vgoyal@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210217233046.81418-2-vgoyal@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=63.128.21.124; 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_FILL_THIS_FORM_SHORT=0.01 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, dgilbert@redhat.com, stefanha@redhat.com, miklos@szeredi.hu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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. v2.1: Fixed lo_removexattr() 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 | 100 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 99 insertions(+), 1 deletion(-) Index: rhvgoyal-qemu/tools/virtiofsd/passthrough_ll.c =================================================================== --- rhvgoyal-qemu.orig/tools/virtiofsd/passthrough_ll.c 2021-02-18 13:12:26.839770339 -0500 +++ rhvgoyal-qemu/tools/virtiofsd/passthrough_ll.c 2021-02-18 13:38:22.344930118 -0500 @@ -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; }; static const struct fuse_opt lo_opts[] = { @@ -201,6 +202,8 @@ static const struct fuse_opt lo_opts[] = { "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 = false; @@ -661,6 +664,23 @@ static void lo_init(void *userdata, stru conn->want &= ~FUSE_CAP_HANDLE_KILLPRIV_V2; lo->killpriv_v2 = 0; } + + if (lo->user_posix_acl == 1) { + /* + * User explicitly asked for this option. Enable it unconditionally. + * 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 |= 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 &= ~FUSE_CAP_POSIX_ACL; + } } static void lo_getattr(fuse_req_t req, fuse_ino_t ino, @@ -2612,6 +2632,63 @@ static int xattr_map_server(const struct return -ENODATA; } +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 = 0; + in_index = 0; + while (in_index < in_size) { + char *in_ptr = xattr_list + in_index; + + /* Length of current attribute name */ + size_t in_len = strlen(xattr_list + in_index) + 1; + + if (!block_xattr(lo, in_ptr)) { + if (in_index != out_index) { + memmove(xattr_list + out_index, xattr_list + in_index, in_len); + } + out_index += in_len; + } + in_index += in_len; + } + return out_index; +} + static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, size_t size) { @@ -2625,6 +2702,11 @@ static void lo_getxattr(fuse_req_t req, int saverr; int fd = -1; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -2766,7 +2848,6 @@ static void lo_listxattr(fuse_req_t req, if (ret == 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, goto out; } } + + ret = remove_blocked_xattrs(lo, value, ret); + if (ret <= 0) { + saverr = -ret; + goto out; + } fuse_reply_buf(req, value, ret); } else { /* @@ -2851,6 +2938,11 @@ static void lo_setxattr(fuse_req_t req, int saverr; int fd = -1; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -2917,6 +3009,11 @@ static void lo_removexattr(fuse_req_t re int saverr; int fd = -1; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -3604,6 +3701,7 @@ int main(int argc, char *argv[]) .allow_direct_io = 0, .proc_self_fd = -1, .user_killpriv_v2 = -1, + .user_posix_acl = -1, }; struct lo_map_elem *root_elem; struct lo_map_elem *reserve_elem; From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 18 Feb 2021 14:04:46 -0500 From: Vivek Goyal Message-ID: <20210218190446.GC92815@redhat.com> References: <20210217233046.81418-1-vgoyal@redhat.com> <20210217233046.81418-2-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210217233046.81418-2-vgoyal@redhat.com> Subject: Re: [Virtio-fs] [PATCH v2.1 1/3] virtiofsd: Add an option to enable/disable posix acls List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, virtio-fs@redhat.com Cc: miklos@szeredi.hu 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. v2.1: Fixed lo_removexattr() 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 | 100 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 99 insertions(+), 1 deletion(-) Index: rhvgoyal-qemu/tools/virtiofsd/passthrough_ll.c =================================================================== --- rhvgoyal-qemu.orig/tools/virtiofsd/passthrough_ll.c 2021-02-18 13:12:26.839770339 -0500 +++ rhvgoyal-qemu/tools/virtiofsd/passthrough_ll.c 2021-02-18 13:38:22.344930118 -0500 @@ -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; }; static const struct fuse_opt lo_opts[] = { @@ -201,6 +202,8 @@ static const struct fuse_opt lo_opts[] = { "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 = false; @@ -661,6 +664,23 @@ static void lo_init(void *userdata, stru conn->want &= ~FUSE_CAP_HANDLE_KILLPRIV_V2; lo->killpriv_v2 = 0; } + + if (lo->user_posix_acl == 1) { + /* + * User explicitly asked for this option. Enable it unconditionally. + * 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 |= 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 &= ~FUSE_CAP_POSIX_ACL; + } } static void lo_getattr(fuse_req_t req, fuse_ino_t ino, @@ -2612,6 +2632,63 @@ static int xattr_map_server(const struct return -ENODATA; } +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 = 0; + in_index = 0; + while (in_index < in_size) { + char *in_ptr = xattr_list + in_index; + + /* Length of current attribute name */ + size_t in_len = strlen(xattr_list + in_index) + 1; + + if (!block_xattr(lo, in_ptr)) { + if (in_index != out_index) { + memmove(xattr_list + out_index, xattr_list + in_index, in_len); + } + out_index += in_len; + } + in_index += in_len; + } + return out_index; +} + static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, size_t size) { @@ -2625,6 +2702,11 @@ static void lo_getxattr(fuse_req_t req, int saverr; int fd = -1; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -2766,7 +2848,6 @@ static void lo_listxattr(fuse_req_t req, if (ret == 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, goto out; } } + + ret = remove_blocked_xattrs(lo, value, ret); + if (ret <= 0) { + saverr = -ret; + goto out; + } fuse_reply_buf(req, value, ret); } else { /* @@ -2851,6 +2938,11 @@ static void lo_setxattr(fuse_req_t req, int saverr; int fd = -1; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -2917,6 +3009,11 @@ static void lo_removexattr(fuse_req_t re int saverr; int fd = -1; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -3604,6 +3701,7 @@ int main(int argc, char *argv[]) .allow_direct_io = 0, .proc_self_fd = -1, .user_killpriv_v2 = -1, + .user_posix_acl = -1, }; struct lo_map_elem *root_elem; struct lo_map_elem *reserve_elem;