1 files changed, 425 insertions, 0 deletions
diff --git a/libexec/casper/dns/dns.c b/libexec/casper/dns/dns.c
new file mode 100644
index 000000000000..6be022ab6566
--- /dev/null
+++ b/libexec/casper/dns/dns.c
@@ -0,0 +1,425 @@
+/*-
+ * Copyright (c) 2012-2013 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * This software was developed by Pawel Jakub Dawidek under sponsorship from
+ * the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <netinet/in.h>
+
+#include <errno.h>
+#include <netdb.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <libcapsicum.h>
+#include <libcapsicum_dns.h>
+#include <libcasper.h>
+#include <nv.h>
+#include <pjdlog.h>
+
+static bool
+dns_allowed_type(const nvlist_t *limits, const char *type)
+{
+	const char *name;
+	bool notypes;
+	void *cookie;
+
+	if (limits == NULL)
+		return (true);
+
+	notypes = true;
+	cookie = NULL;
+	while ((name = nvlist_next(limits, NULL, &cookie)) != NULL) {
+		if (strncmp(name, "type", sizeof("type") - 1) != 0)
+			continue;
+		notypes = false;
+		if (strcmp(nvlist_get_string(limits, name), type) == 0)
+			return (true);
+	}
+
+	/* If there are no types at all, allow any type. */
+	if (notypes)
+		return (true);
+
+	return (false);
+}
+
+static bool
+dns_allowed_family(const nvlist_t *limits, int family)
+{
+	const char *name;
+	bool nofamilies;
+	void *cookie;
+
+	if (limits == NULL)
+		return (true);
+
+	nofamilies = true;
+	cookie = NULL;
+	while ((name = nvlist_next(limits, NULL, &cookie)) != NULL) {
+		if (strncmp(name, "family", sizeof("family") - 1) != 0)
+			continue;
+		nofamilies = false;
+		if (family == AF_UNSPEC)
+			continue;
+		if (nvlist_get_number(limits, name) == (uint64_t)family)
+			return (true);
+	}
+
+	/* If there are no families at all, allow any family. */
+	if (nofamilies)
+		return (true);
+
+	return (false);
+}
+
+static void
+hostent_pack(const struct hostent *hp, nvlist_t *nvl)
+{
+	unsigned int ii;
+
+	nvlist_add_string(nvl, "name", hp->h_name);
+	nvlist_add_number(nvl, "addrtype", (uint64_t)hp->h_addrtype);
+	nvlist_add_number(nvl, "length", (uint64_t)hp->h_length);
+
+	if (hp->h_aliases == NULL) {
+		nvlist_add_number(nvl, "naliases", 0);
+	} else {
+		for (ii = 0; hp->h_aliases[ii] != NULL; ii++) {
+			nvlist_addf_string(nvl, hp->h_aliases[ii], "alias%u",
+			    ii);
+		}
+		nvlist_add_number(nvl, "naliases", (uint64_t)ii);
+	}
+
+	if (hp->h_addr_list == NULL) {
+		nvlist_add_number(nvl, "naddrs", 0);
+	} else {
+		for (ii = 0; hp->h_addr_list[ii] != NULL; ii++) {
+			nvlist_addf_binary(nvl, hp->h_addr_list[ii],
+			    (size_t)hp->h_length, "addr%u", ii);
+		}
+		nvlist_add_number(nvl, "naddrs", (uint64_t)ii);
+	}
+}
+
+static int
+dns_gethostbyname(const nvlist_t *limits, const nvlist_t *nvlin,
+    nvlist_t *nvlout)
+{
+	struct hostent *hp;
+	int family;
+
+	if (!dns_allowed_type(limits, "NAME"))
+		return (NO_RECOVERY);
+
+	family = (int)nvlist_get_number(nvlin, "family");
+
+	if (!dns_allowed_family(limits, family))
+		return (NO_RECOVERY);
+
+	hp = gethostbyname2(nvlist_get_string(nvlin, "name"), family);
+	if (hp == NULL)
+		return (h_errno);
+	hostent_pack(hp, nvlout);
+	return (0);
+}
+
+static int
+dns_gethostbyaddr(const nvlist_t *limits, const nvlist_t *nvlin,
+    nvlist_t *nvlout)
+{
+	struct hostent *hp;
+	const void *addr;
+	size_t addrsize;
+	int family;
+
+	if (!dns_allowed_type(limits, "ADDR"))
+		return (NO_RECOVERY);
+
+	family = (int)nvlist_get_number(nvlin, "family");
+
+	if (!dns_allowed_family(limits, family))
+		return (NO_RECOVERY);
+
+	addr = nvlist_get_binary(nvlin, "addr", &addrsize);
+	hp = gethostbyaddr(addr, (socklen_t)addrsize, family);
+	if (hp == NULL)
+		return (h_errno);
+	hostent_pack(hp, nvlout);
+	return (0);
+}
+
+static int
+dns_getnameinfo(const nvlist_t *limits, const nvlist_t *nvlin, nvlist_t *nvlout)
+{
+	struct sockaddr_storage sast;
+	const void *sabin;
+	char *host, *serv;
+	size_t sabinsize, hostlen, servlen;
+	socklen_t salen;
+	int error, flags;
+
+	if (!dns_allowed_type(limits, "NAME"))
+		return (NO_RECOVERY);
+
+	error = 0;
+	host = serv = NULL;
+	memset(&sast, 0, sizeof(sast));
+
+	hostlen = (size_t)nvlist_get_number(nvlin, "hostlen");
+	servlen = (size_t)nvlist_get_number(nvlin, "servlen");
+
+	if (hostlen > 0) {
+		host = calloc(1, hostlen + 1);
+		if (host == NULL) {
+			error = EAI_MEMORY;
+			goto out;
+		}
+	}
+	if (servlen > 0) {
+		serv = calloc(1, servlen + 1);
+		if (serv == NULL) {
+			error = EAI_MEMORY;
+			goto out;
+		}
+	}
+
+	sabin = nvlist_get_binary(nvlin, "sa", &sabinsize);
+	if (sabinsize > sizeof(sast)) {
+		error = EAI_FAIL;
+		goto out;
+	}
+
+	memcpy(&sast, sabin, sabinsize);
+	salen = (socklen_t)sabinsize;
+
+	if ((sast.ss_family != AF_INET ||
+	     salen != sizeof(struct sockaddr_in)) &&
+	    (sast.ss_family != AF_INET6 ||
+	     salen != sizeof(struct sockaddr_in6))) {
+		error = EAI_FAIL;
+		goto out;
+	}
+
+	if (!dns_allowed_family(limits, (int)sast.ss_family))
+		return (NO_RECOVERY);
+
+	flags = (int)nvlist_get_number(nvlin, "flags");
+
+	error = getnameinfo((struct sockaddr *)&sast, salen, host, hostlen,
+	    serv, servlen, flags);
+	if (error != 0)
+		goto out;
+
+	nvlist_move_string(nvlout, "host", host);
+	nvlist_move_string(nvlout, "serv", serv);
+out:
+	if (error != 0) {
+		free(host);
+		free(serv);
+	}
+	return (error);
+}
+
+static nvlist_t *
+addrinfo_pack(const struct addrinfo *ai)
+{
+	nvlist_t *nvl;
+
+	nvl = nvlist_create(0);
+	nvlist_add_number(nvl, "ai_flags", (uint64_t)ai->ai_flags);
+	nvlist_add_number(nvl, "ai_family", (uint64_t)ai->ai_family);
+	nvlist_add_number(nvl, "ai_socktype", (uint64_t)ai->ai_socktype);
+	nvlist_add_number(nvl, "ai_protocol", (uint64_t)ai->ai_protocol);
+	nvlist_add_binary(nvl, "ai_addr", ai->ai_addr, (size_t)ai->ai_addrlen);
+	nvlist_add_string(nvl, "ai_canonname", ai->ai_canonname);
+
+	return (nvl);
+}
+
+static int
+dns_getaddrinfo(const nvlist_t *limits, const nvlist_t *nvlin, nvlist_t *nvlout)
+{
+	struct addrinfo hints, *hintsp, *res, *cur;
+	const char *hostname, *servname;
+	nvlist_t *elem;
+	unsigned int ii;
+	int error, family;
+
+	if (!dns_allowed_type(limits, "ADDR"))
+		return (NO_RECOVERY);
+
+	hostname = nvlist_get_string(nvlin, "hostname");
+	servname = nvlist_get_string(nvlin, "servname");
+	if (nvlist_exists_number(nvlin, "hints.ai_flags")) {
+		size_t addrlen;
+
+		hints.ai_flags = (int)nvlist_get_number(nvlin,
+		    "hints.ai_flags");
+		hints.ai_family = (int)nvlist_get_number(nvlin,
+		    "hints.ai_family");
+		hints.ai_socktype = (int)nvlist_get_number(nvlin,
+		    "hints.ai_socktype");
+		hints.ai_protocol = (int)nvlist_get_number(nvlin,
+		    "hints.ai_protocol");
+		hints.ai_addrlen = 0;
+		hints.ai_addr = NULL;
+		hints.ai_canonname = NULL;
+		hintsp = &hints;
+		family = hints.ai_family;
+	} else {
+		hintsp = NULL;
+		family = AF_UNSPEC;
+	}
+
+	if (!dns_allowed_family(limits, family))
+		return (NO_RECOVERY);
+
+	error = getaddrinfo(hostname, servname, hintsp, &res);
+	if (error != 0)
+		goto out;
+
+	for (cur = res, ii = 0; cur != NULL; cur = cur->ai_next, ii++) {
+		elem = addrinfo_pack(cur);
+		nvlist_movef_nvlist(nvlout, elem, "res%u", ii);
+	}
+
+	freeaddrinfo(res);
+	error = 0;
+out:
+	return (error);
+}
+
+static bool
+limit_has_entry(const nvlist_t *limits, const char *prefix)
+{
+	const char *name;
+	size_t prefixlen;
+	void *cookie;
+
+	if (limits == NULL)
+		return (false);
+
+	prefixlen = strlen(prefix);
+
+	cookie = NULL;
+	while ((name = nvlist_next(limits, NULL, &cookie)) != NULL) {
+		if (strncmp(name, prefix, prefixlen) == 0)
+			return (true);
+	}
+
+	return (false);
+}
+
+static int
+dns_limit(const nvlist_t *oldlimits, const nvlist_t *newlimits)
+{
+	const char *name;
+	void *cookie;
+	int nvtype;
+	bool hastype, hasfamily;
+
+	hastype = false;
+	hasfamily = false;
+
+	cookie = NULL;
+	while ((name = nvlist_next(newlimits, &nvtype, &cookie)) != NULL) {
+		if (nvtype == NV_TYPE_STRING) {
+			const char *type;
+
+			if (strncmp(name, "type", sizeof("type") - 1) != 0)
+				return (EINVAL);
+			type = nvlist_get_string(newlimits, name);
+			if (strcmp(type, "ADDR") != 0 &&
+			    strcmp(type, "NAME") != 0) {
+				return (EINVAL);
+			}
+			if (!dns_allowed_type(oldlimits, type))
+				return (ENOTCAPABLE);
+			hastype = true;
+		} else if (nvtype == NV_TYPE_NUMBER) {
+			int family;
+
+			if (strncmp(name, "family", sizeof("family") - 1) != 0)
+				return (EINVAL);
+			family = (int)nvlist_get_number(newlimits, name);
+			if (!dns_allowed_family(oldlimits, family))
+				return (ENOTCAPABLE);
+			hasfamily = true;
+		} else {
+			return (EINVAL);
+		}
+	}
+
+	/*
+	 * If the new limit doesn't mention type or family we have to
+	 * check if the current limit does have those. Missing type or
+	 * family in the limit means that all types or families are
+	 * allowed.
+	 */
+	if (!hastype) {
+		if (limit_has_entry(oldlimits, "type"))
+			return (ENOTCAPABLE);
+	}
+	if (!hasfamily) {
+		if (limit_has_entry(oldlimits, "family"))
+			return (ENOTCAPABLE);
+	}
+
+	return (0);
+}
+
+static int
+dns_command(const char *cmd, const nvlist_t *limits, nvlist_t *nvlin,
+    nvlist_t *nvlout)
+{
+	int error;
+
+	if (strcmp(cmd, "gethostbyname") == 0)
+		error = dns_gethostbyname(limits, nvlin, nvlout);
+	else if (strcmp(cmd, "gethostbyaddr") == 0)
+		error = dns_gethostbyaddr(limits, nvlin, nvlout);
+	else if (strcmp(cmd, "getnameinfo") == 0)
+		error = dns_getnameinfo(limits, nvlin, nvlout);
+	else if (strcmp(cmd, "getaddrinfo") == 0)
+		error = dns_getaddrinfo(limits, nvlin, nvlout);
+	else
+		error = NO_RECOVERY;
+
+	return (error);
+}
+
+int
+main(int argc, char *argv[])
+{
+
+	return (service_start("system.dns", PARENT_FILENO, dns_limit,
+	    dns_command, argc, argv));
+}