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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]:49252 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jrNeU-0002lx-Np for qemu-devel@archiver.kernel.org; Fri, 03 Jul 2020 11:30:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51078) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jrNbj-00074Z-Bn for qemu-devel@nongnu.org; Fri, 03 Jul 2020 11:28:07 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:42058) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jrNbf-0006cO-R3 for qemu-devel@nongnu.org; Fri, 03 Jul 2020 11:28:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593790080; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nGqi3SN32stCXF5/qmcRGZpat5DOF5S0r6YBTnx6GI4=; b=Gd2A8bE7wt3txVGwtywm39BuVK1ezNQ4oHZQKdvtFc61qaSdxj4V/5fdxuNyeUBFiFJOIE zGgChgmQFkNp0FHhnob2P1/5M6KgLLRqCWwdZpCd7YGEuUETGQAlRu2TPS6jnRQP6j0y3R Hc0KTKAkP+EtXlSb2TflFPJABzDQAYs= 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-2-Jq6HaIslNGejucH0sOrMQw-1; Fri, 03 Jul 2020 11:27:58 -0400 X-MC-Unique: Jq6HaIslNGejucH0sOrMQw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4446A80183C; Fri, 3 Jul 2020 15:27:57 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-114-207.ams2.redhat.com [10.36.114.207]) by smtp.corp.redhat.com (Postfix) with ESMTP id 46BB21972A; Fri, 3 Jul 2020 15:27:56 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, quintela@redhat.com, zhukeqian1@huawei.com, stefanha@redhat.com Subject: [PULL 3/5] virtiofsd: Allow addition or removal of capabilities Date: Fri, 3 Jul 2020 16:27:46 +0100 Message-Id: <20200703152748.277255-4-dgilbert@redhat.com> In-Reply-To: <20200703152748.277255-1-dgilbert@redhat.com> References: <20200703152748.277255-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=205.139.110.61; envelope-from=dgilbert@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/03 03:17:33 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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" Allow capabilities to be added or removed from the allowed set for the daemon; e.g. default: CapPrm: 00000000880000df CapEff: 00000000880000df -o modcaps=+sys_admin CapPrm: 00000000882000df CapEff: 00000000882000df -o modcaps=+sys_admin:-chown CapPrm: 00000000882000de CapEff: 00000000882000de Signed-off-by: Dr. David Alan Gilbert Message-Id: <20200629115420.98443-4-dgilbert@redhat.com> Acked-by: Vivek Goyal Reviewed-by: Stefan Hajnoczi Signed-off-by: Dr. David Alan Gilbert --- docs/tools/virtiofsd.rst | 5 +++ tools/virtiofsd/helper.c | 2 ++ tools/virtiofsd/passthrough_ll.c | 53 ++++++++++++++++++++++++++++++-- 3 files changed, 58 insertions(+), 2 deletions(-) diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst index 378594c422..824e713491 100644 --- a/docs/tools/virtiofsd.rst +++ b/docs/tools/virtiofsd.rst @@ -54,6 +54,11 @@ Options * flock|no_flock - Enable/disable flock. The default is ``no_flock``. + * modcaps=CAPLIST + Modify the list of capabilities allowed; CAPLIST is a colon separated + list of capabilities, each preceded by either + or -, e.g. + ''+sys_admin:-chown''. + * log_level=LEVEL - Print only log messages matching LEVEL or more severe. LEVEL is one of ``err``, ``warn``, ``info``, or ``debug``. The default is ``info``. diff --git a/tools/virtiofsd/helper.c b/tools/virtiofsd/helper.c index 00a1ef666a..3105b6c23a 100644 --- a/tools/virtiofsd/helper.c +++ b/tools/virtiofsd/helper.c @@ -174,6 +174,8 @@ void fuse_cmdline_help(void) " default: no_writeback\n" " -o xattr|no_xattr enable/disable xattr\n" " default: no_xattr\n" + " -o modcaps=CAPLIST Modify the list of capabilities\n" + " e.g. -o modcaps=+sys_admin:-chown\n" " --rlimit-nofile= set maximum number of file descriptors\n" " (0 leaves rlimit unchanged)\n" " default: min(1000000, fs.file-max - 16384)\n" diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 99d562046a..94e0de2d2b 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -145,6 +145,7 @@ struct lo_data { int posix_lock; int xattr; char *source; + char *modcaps; double timeout; int cache; int timeout_set; @@ -170,6 +171,7 @@ static const struct fuse_opt lo_opts[] = { { "no_posix_lock", offsetof(struct lo_data, posix_lock), 0 }, { "xattr", offsetof(struct lo_data, xattr), 1 }, { "no_xattr", offsetof(struct lo_data, xattr), 0 }, + { "modcaps=%s", offsetof(struct lo_data, modcaps), 0 }, { "timeout=%lf", offsetof(struct lo_data, timeout), 0 }, { "timeout=", offsetof(struct lo_data, timeout_set), 1 }, { "cache=none", offsetof(struct lo_data, cache), CACHE_NONE }, @@ -2570,9 +2572,11 @@ static void setup_mounts(const char *source) /* * Only keep whitelisted capabilities that are needed for file system operation + * The (possibly NULL) modcaps_in string passed in is free'd before exit. */ -static void setup_capabilities(void) +static void setup_capabilities(char *modcaps_in) { + char *modcaps = modcaps_in; pthread_mutex_lock(&cap.mutex); capng_restore_state(&cap.saved); @@ -2604,6 +2608,51 @@ static void setup_capabilities(void) exit(1); } + /* + * The modcaps option is a colon separated list of caps, + * each preceded by either + or -. + */ + while (modcaps) { + capng_act_t action; + int cap; + + char *next = strchr(modcaps, ':'); + if (next) { + *next = '\0'; + next++; + } + + switch (modcaps[0]) { + case '+': + action = CAPNG_ADD; + break; + + case '-': + action = CAPNG_DROP; + break; + + default: + fuse_log(FUSE_LOG_ERR, + "%s: Expecting '+'/'-' in modcaps but found '%c'\n", + __func__, modcaps[0]); + exit(1); + } + cap = capng_name_to_capability(modcaps + 1); + if (cap < 0) { + fuse_log(FUSE_LOG_ERR, "%s: Unknown capability '%s'\n", __func__, + modcaps); + exit(1); + } + if (capng_update(action, CAPNG_PERMITTED | CAPNG_EFFECTIVE, cap)) { + fuse_log(FUSE_LOG_ERR, "%s: capng_update failed for '%s'\n", + __func__, modcaps); + exit(1); + } + + modcaps = next; + } + g_free(modcaps_in); + if (capng_apply(CAPNG_SELECT_BOTH)) { fuse_log(FUSE_LOG_ERR, "%s: capng_apply failed\n", __func__); exit(1); @@ -2627,7 +2676,7 @@ static void setup_sandbox(struct lo_data *lo, struct fuse_session *se, setup_namespaces(lo, se); setup_mounts(lo->source); setup_seccomp(enable_syslog); - setup_capabilities(); + setup_capabilities(g_strdup(lo->modcaps)); } /* Set the maximum number of open file descriptors */ -- 2.26.2