From patchwork Fri Oct 23 16:58:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 302122 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=-9.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 D69EBC4363A for ; Fri, 23 Oct 2020 17:19:16 +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 4ECE520E65 for ; Fri, 23 Oct 2020 17:19:16 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Fri, 23 Oct 2020 16:58:33 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-113-212.ams2.redhat.com [10.36.113.212]) by smtp.corp.redhat.com (Postfix) with ESMTP id D7F241002388; Fri, 23 Oct 2020 16:58:31 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com, dinechin@redhat.com, virtio-fs@redhat.com Subject: [PATCH v4 5/5] tools/virtiofsd: xattr name mappings: Simple 'map' Date: Fri, 23 Oct 2020 17:58:12 +0100 Message-Id: <20201023165812.36028-6-dgilbert@redhat.com> In-Reply-To: <20201023165812.36028-1-dgilbert@redhat.com> References: <20201023165812.36028-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/23 01:44:00 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: "Dr. David Alan Gilbert" The mapping rule system implemented in the last few patches is extremely flexible, but not easy to use. Add a simple 'map' type as a sprinkling of sugar to make it easy. e.g. -o xattrmap=":map::user.virtiofs.:" would be sufficient to prefix all xattr's or -o xattrmap=":map:trusted.:user.virtiofs.:" would just prefix 'trusted.' xattr's and leave everything else alone. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Stefan Hajnoczi --- docs/tools/virtiofsd.rst | 19 ++++++ tools/virtiofsd/passthrough_ll.c | 112 ++++++++++++++++++++++++++++++- 2 files changed, 130 insertions(+), 1 deletion(-) diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst index 4e74690eca..24268fd67e 100644 --- a/docs/tools/virtiofsd.rst +++ b/docs/tools/virtiofsd.rst @@ -129,6 +129,7 @@ Each rule consists of a number of fields separated with a separator that is the first non-white space character in the rule. This separator must then be used for the whole rule. White space may be added before and after each rule. + Using ':' as the separator a rule is of the form: ``:type:scope:key:prepend:`` @@ -201,6 +202,14 @@ e.g.: would hide 'security.' xattr's in listxattr from the server. +A simpler 'map' type provides a shorter syntax for the common case: + +``:map:key:prepend:`` + +The 'map' type adds a number of separate rules to add **prepend** as a prefix +to the matched **key** (or all attributes if **key** is empty). +There may be at most one 'map' rule and it must be the last rule in the set. + xattr-mapping Examples ---------------------- @@ -216,6 +225,11 @@ the first rule prefixes and strips 'user.virtiofs.', the second rule hides any non-prefixed attributes that the host set. +This is equivalent to the 'map' rule: + +:: +-o xattrmap=":map::user.virtiofs.:" + 2) Prefix 'trusted.' attributes, allow others through :: @@ -238,6 +252,11 @@ the 'user.viritofs.' path directly. Finally, the fourth rule lets all remaining attributes through. +This is equivalent to the 'map' rule: + +:: +-o xattrmap="/map/trusted./user.virtiofs./" + 3) Hide 'security.' attributes, and allow everything else :: diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 57f584ee49..9f1ad9698d 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -2078,6 +2078,109 @@ static void free_xattrmap(struct lo_data *lo) lo->xattr_map_nentries = -1; } +/* + * Handle the 'map' type, which is sugar for a set of commands + * for the common case of prefixing a subset or everything, + * and allowing anything not prefixed through. + * It must be the last entry in the stream, although there + * can be other entries before it. + * The form is: + * :map:key:prefix: + * + * key maybe empty in which case all entries are prefixed. + */ +static void parse_xattrmap_map(struct lo_data *lo, + const char *rule, char sep) +{ + const char *tmp; + char *key; + char *prefix; + XattrMapEntry tmp_entry; + + if (*rule != sep) { + fuse_log(FUSE_LOG_ERR, + "%s: Expecting '%c' after 'map' keyword, found '%c'\n", + __func__, sep, *rule); + exit(1); + } + + rule++; + + /* At start of 'key' field */ + tmp = strchr(rule, sep); + if (!tmp) { + fuse_log(FUSE_LOG_ERR, + "%s: Missing '%c' at end of key field in map rule\n", + __func__, sep); + exit(1); + } + + key = g_strndup(rule, tmp - rule); + rule = tmp + 1; + + /* At start of prefix field */ + tmp = strchr(rule, sep); + if (!tmp) { + fuse_log(FUSE_LOG_ERR, + "%s: Missing '%c' at end of prefix field in map rule\n", + __func__, sep); + exit(1); + } + + prefix = g_strndup(rule, tmp - rule); + rule = tmp + 1; + + /* + * This should be the end of the string, we don't allow + * any more commands after 'map'. + */ + if (*rule) { + fuse_log(FUSE_LOG_ERR, + "%s: Expecting end of command after map, found '%c'\n", + __func__, *rule); + exit(1); + } + + /* 1st: Prefix matches/everything */ + tmp_entry.flags = XATTR_MAP_FLAG_PREFIX | XATTR_MAP_FLAG_ALL; + tmp_entry.key = g_strdup(key); + tmp_entry.prepend = g_strdup(prefix); + add_xattrmap_entry(lo, &tmp_entry); + + if (!*key) { + /* Prefix all case */ + + /* 2nd: Hide any non-prefixed entries on the host */ + tmp_entry.flags = XATTR_MAP_FLAG_BAD | XATTR_MAP_FLAG_ALL; + tmp_entry.key = g_strdup(""); + tmp_entry.prepend = g_strdup(""); + add_xattrmap_entry(lo, &tmp_entry); + } else { + /* Prefix matching case */ + + /* 2nd: Hide non-prefixed but matching entries on the host */ + tmp_entry.flags = XATTR_MAP_FLAG_BAD | XATTR_MAP_FLAG_SERVER; + tmp_entry.key = g_strdup(""); /* Not used */ + tmp_entry.prepend = g_strdup(key); + add_xattrmap_entry(lo, &tmp_entry); + + /* 3rd: Stop the client accessing prefixed attributes directly */ + tmp_entry.flags = XATTR_MAP_FLAG_BAD | XATTR_MAP_FLAG_CLIENT; + tmp_entry.key = g_strdup(prefix); + tmp_entry.prepend = g_strdup(""); /* Not used */ + add_xattrmap_entry(lo, &tmp_entry); + + /* 4th: Everything else is OK */ + tmp_entry.flags = XATTR_MAP_FLAG_OK | XATTR_MAP_FLAG_ALL; + tmp_entry.key = g_strdup(""); + tmp_entry.prepend = g_strdup(""); + add_xattrmap_entry(lo, &tmp_entry); + } + + g_free(key); + g_free(prefix); +} + static void parse_xattrmap(struct lo_data *lo) { const char *map = lo->xattrmap; @@ -2106,10 +2209,17 @@ static void parse_xattrmap(struct lo_data *lo) tmp_entry.flags |= XATTR_MAP_FLAG_OK; } else if (strstart(map, "bad", &map)) { tmp_entry.flags |= XATTR_MAP_FLAG_BAD; + } else if (strstart(map, "map", &map)) { + /* + * map is sugar that adds a number of rules, and must be + * the last entry. + */ + parse_xattrmap_map(lo, map, sep); + return; } else { fuse_log(FUSE_LOG_ERR, "%s: Unexpected type;" - "Expecting 'prefix', 'ok', or 'bad' in rule %zu\n", + "Expecting 'prefix', 'ok', 'bad' or 'map' in rule %zu\n", __func__, lo->xattr_map_nentries); exit(1); }