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head/lib/libcasper/services/cap_dns/cap_dns.c

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/*-
* 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 <sys/dnv.h>
#include <sys/nv.h>
#include <netinet/in.h>
#include <assert.h>
#include <errno.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libcasper.h>
#include <libcasper_service.h>
#include "cap_dns.h"
static struct hostent hent;
static void
hostent_free(struct hostent *hp)
{
unsigned int ii;
free(hp->h_name);
hp->h_name = NULL;
if (hp->h_aliases != NULL) {
for (ii = 0; hp->h_aliases[ii] != NULL; ii++)
free(hp->h_aliases[ii]);
free(hp->h_aliases);
hp->h_aliases = NULL;
}
if (hp->h_addr_list != NULL) {
for (ii = 0; hp->h_addr_list[ii] != NULL; ii++)
free(hp->h_addr_list[ii]);
free(hp->h_addr_list);
hp->h_addr_list = NULL;
}
}
static struct hostent *
hostent_unpack(const nvlist_t *nvl, struct hostent *hp)
{
unsigned int ii, nitems;
char nvlname[64];
int n;
hostent_free(hp);
hp->h_name = strdup(nvlist_get_string(nvl, "name"));
if (hp->h_name == NULL)
goto fail;
hp->h_addrtype = (int)nvlist_get_number(nvl, "addrtype");
hp->h_length = (int)nvlist_get_number(nvl, "length");
nitems = (unsigned int)nvlist_get_number(nvl, "naliases");
hp->h_aliases = calloc(sizeof(hp->h_aliases[0]), nitems + 1);
if (hp->h_aliases == NULL)
goto fail;
for (ii = 0; ii < nitems; ii++) {
n = snprintf(nvlname, sizeof(nvlname), "alias%u", ii);
assert(n > 0 && n < (int)sizeof(nvlname));
hp->h_aliases[ii] =
strdup(nvlist_get_string(nvl, nvlname));
if (hp->h_aliases[ii] == NULL)
goto fail;
}
hp->h_aliases[ii] = NULL;
nitems = (unsigned int)nvlist_get_number(nvl, "naddrs");
hp->h_addr_list = calloc(sizeof(hp->h_addr_list[0]), nitems + 1);
if (hp->h_addr_list == NULL)
goto fail;
for (ii = 0; ii < nitems; ii++) {
hp->h_addr_list[ii] = malloc(hp->h_length);
if (hp->h_addr_list[ii] == NULL)
goto fail;
n = snprintf(nvlname, sizeof(nvlname), "addr%u", ii);
assert(n > 0 && n < (int)sizeof(nvlname));
bcopy(nvlist_get_binary(nvl, nvlname, NULL),
hp->h_addr_list[ii], hp->h_length);
}
hp->h_addr_list[ii] = NULL;
return (hp);
fail:
hostent_free(hp);
h_errno = NO_RECOVERY;
return (NULL);
}
struct hostent *
cap_gethostbyname(cap_channel_t *chan, const char *name)
{
return (cap_gethostbyname2(chan, name, AF_INET));
}
struct hostent *
cap_gethostbyname2(cap_channel_t *chan, const char *name, int type)
{
struct hostent *hp;
nvlist_t *nvl;
nvl = nvlist_create(0);
nvlist_add_string(nvl, "cmd", "gethostbyname");
nvlist_add_number(nvl, "family", (uint64_t)type);
nvlist_add_string(nvl, "name", name);
nvl = cap_xfer_nvlist(chan, nvl, 0);
if (nvl == NULL) {
h_errno = NO_RECOVERY;
return (NULL);
}
if (nvlist_get_number(nvl, "error") != 0) {
h_errno = (int)nvlist_get_number(nvl, "error");
nvlist_destroy(nvl);
return (NULL);
}
hp = hostent_unpack(nvl, &hent);
nvlist_destroy(nvl);
return (hp);
}
struct hostent *
cap_gethostbyaddr(cap_channel_t *chan, const void *addr, socklen_t len,
int type)
{
struct hostent *hp;
nvlist_t *nvl;
nvl = nvlist_create(0);
nvlist_add_string(nvl, "cmd", "gethostbyaddr");
nvlist_add_binary(nvl, "addr", addr, (size_t)len);
nvlist_add_number(nvl, "family", (uint64_t)type);
nvl = cap_xfer_nvlist(chan, nvl, 0);
if (nvl == NULL) {
h_errno = NO_RECOVERY;
return (NULL);
}
if (nvlist_get_number(nvl, "error") != 0) {
h_errno = (int)nvlist_get_number(nvl, "error");
nvlist_destroy(nvl);
return (NULL);
}
hp = hostent_unpack(nvl, &hent);
nvlist_destroy(nvl);
return (hp);
}
static struct addrinfo *
addrinfo_unpack(const nvlist_t *nvl)
{
struct addrinfo *ai;
const void *addr;
size_t addrlen;
const char *canonname;
addr = nvlist_get_binary(nvl, "ai_addr", &addrlen);
ai = malloc(sizeof(*ai) + addrlen);
if (ai == NULL)
return (NULL);
ai->ai_flags = (int)nvlist_get_number(nvl, "ai_flags");
ai->ai_family = (int)nvlist_get_number(nvl, "ai_family");
ai->ai_socktype = (int)nvlist_get_number(nvl, "ai_socktype");
ai->ai_protocol = (int)nvlist_get_number(nvl, "ai_protocol");
ai->ai_addrlen = (socklen_t)addrlen;
canonname = dnvlist_get_string(nvl, "ai_canonname", NULL);
if (canonname != NULL) {
ai->ai_canonname = strdup(canonname);
if (ai->ai_canonname == NULL) {
free(ai);
return (NULL);
}
} else {
ai->ai_canonname = NULL;
}
ai->ai_addr = (void *)(ai + 1);
bcopy(addr, ai->ai_addr, addrlen);
ai->ai_next = NULL;
return (ai);
}
int
cap_getaddrinfo(cap_channel_t *chan, const char *hostname, const char *servname,
const struct addrinfo *hints, struct addrinfo **res)
{
struct addrinfo *firstai, *prevai, *curai;
unsigned int ii;
const nvlist_t *nvlai;
char nvlname[64];
nvlist_t *nvl;
int error, n;
nvl = nvlist_create(0);
nvlist_add_string(nvl, "cmd", "getaddrinfo");
if (hostname != NULL)
nvlist_add_string(nvl, "hostname", hostname);
if (servname != NULL)
nvlist_add_string(nvl, "servname", servname);
if (hints != NULL) {
nvlist_add_number(nvl, "hints.ai_flags",
(uint64_t)hints->ai_flags);
nvlist_add_number(nvl, "hints.ai_family",
(uint64_t)hints->ai_family);
nvlist_add_number(nvl, "hints.ai_socktype",
(uint64_t)hints->ai_socktype);
nvlist_add_number(nvl, "hints.ai_protocol",
(uint64_t)hints->ai_protocol);
}
nvl = cap_xfer_nvlist(chan, nvl, 0);
if (nvl == NULL)
return (EAI_MEMORY);
if (nvlist_get_number(nvl, "error") != 0) {
error = (int)nvlist_get_number(nvl, "error");
nvlist_destroy(nvl);
return (error);
}
nvlai = NULL;
firstai = prevai = curai = NULL;
for (ii = 0; ; ii++) {
n = snprintf(nvlname, sizeof(nvlname), "res%u", ii);
assert(n > 0 && n < (int)sizeof(nvlname));
if (!nvlist_exists_nvlist(nvl, nvlname))
break;
nvlai = nvlist_get_nvlist(nvl, nvlname);
curai = addrinfo_unpack(nvlai);
if (curai == NULL)
break;
if (prevai != NULL)
prevai->ai_next = curai;
else if (firstai == NULL)
firstai = curai;
prevai = curai;
}
nvlist_destroy(nvl);
if (curai == NULL && nvlai != NULL) {
if (firstai == NULL)
freeaddrinfo(firstai);
return (EAI_MEMORY);
}
*res = firstai;
return (0);
}
int
cap_getnameinfo(cap_channel_t *chan, const struct sockaddr *sa, socklen_t salen,
char *host, size_t hostlen, char *serv, size_t servlen, int flags)
{
nvlist_t *nvl;
int error;
nvl = nvlist_create(0);
nvlist_add_string(nvl, "cmd", "getnameinfo");
nvlist_add_number(nvl, "hostlen", (uint64_t)hostlen);
nvlist_add_number(nvl, "servlen", (uint64_t)servlen);
nvlist_add_binary(nvl, "sa", sa, (size_t)salen);
nvlist_add_number(nvl, "flags", (uint64_t)flags);
nvl = cap_xfer_nvlist(chan, nvl, 0);
if (nvl == NULL)
return (EAI_MEMORY);
if (nvlist_get_number(nvl, "error") != 0) {
error = (int)nvlist_get_number(nvl, "error");
nvlist_destroy(nvl);
return (error);
}
if (host != NULL && nvlist_exists_string(nvl, "host"))
strlcpy(host, nvlist_get_string(nvl, "host"), hostlen + 1);
if (serv != NULL && nvlist_exists_string(nvl, "serv"))
strlcpy(serv, nvlist_get_string(nvl, "serv"), servlen + 1);
nvlist_destroy(nvl);
return (0);
}
static void
limit_remove(nvlist_t *limits, const char *prefix)
{
const char *name;
size_t prefixlen;
void *cookie;
prefixlen = strlen(prefix);
again:
cookie = NULL;
while ((name = nvlist_next(limits, NULL, &cookie)) != NULL) {
if (strncmp(name, prefix, prefixlen) == 0) {
nvlist_free(limits, name);
goto again;
}
}
}
int
cap_dns_type_limit(cap_channel_t *chan, const char * const *types,
size_t ntypes)
{
nvlist_t *limits;
unsigned int i;
char nvlname[64];
int n;
if (cap_limit_get(chan, &limits) < 0)
return (-1);
if (limits == NULL)
limits = nvlist_create(0);
else
limit_remove(limits, "type");
for (i = 0; i < ntypes; i++) {
n = snprintf(nvlname, sizeof(nvlname), "type%u", i);
assert(n > 0 && n < (int)sizeof(nvlname));
nvlist_add_string(limits, nvlname, types[i]);
}
return (cap_limit_set(chan, limits));
}
int
cap_dns_family_limit(cap_channel_t *chan, const int *families,
size_t nfamilies)
{
nvlist_t *limits;
unsigned int i;
char nvlname[64];
int n;
if (cap_limit_get(chan, &limits) < 0)
return (-1);
if (limits == NULL)
limits = nvlist_create(0);
else
limit_remove(limits, "family");
for (i = 0; i < nfamilies; i++) {
n = snprintf(nvlname, sizeof(nvlname), "family%u", i);
assert(n > 0 && n < (int)sizeof(nvlname));
nvlist_add_number(limits, nvlname, (uint64_t)families[i]);
}
return (cap_limit_set(chan, limits));
}
/*
* Service functions.
*/
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;
char nvlname[64];
int n;
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++) {
n = snprintf(nvlname, sizeof(nvlname), "alias%u", ii);
assert(n > 0 && n < (int)sizeof(nvlname));
nvlist_add_string(nvl, nvlname, hp->h_aliases[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++) {
n = snprintf(nvlname, sizeof(nvlname), "addr%u", ii);
assert(n > 0 && n < (int)sizeof(nvlname));
nvlist_add_binary(nvl, nvlname, hp->h_addr_list[ii],
(size_t)hp->h_length);
}
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)) {
error = NO_RECOVERY;
goto out;
}
flags = (int)nvlist_get_number(nvlin, "flags");
error = getnameinfo((struct sockaddr *)&sast, salen, host, hostlen,
serv, servlen, flags);
if (error != 0)
goto out;
if (host != NULL)
nvlist_move_string(nvlout, "host", host);
if (serv != NULL)
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);
if (ai->ai_canonname != NULL)
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;
char nvlname[64];
nvlist_t *elem;
unsigned int ii;
int error, family, n;
if (!dns_allowed_type(limits, "ADDR"))
return (NO_RECOVERY);
hostname = dnvlist_get_string(nvlin, "hostname", NULL);
servname = dnvlist_get_string(nvlin, "servname", NULL);
if (nvlist_exists_number(nvlin, "hints.ai_flags")) {
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);
n = snprintf(nvlname, sizeof(nvlname), "res%u", ii);
assert(n > 0 && n < (int)sizeof(nvlname));
nvlist_move_nvlist(nvlout, nvlname, elem);
}
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);
}
CREATE_SERVICE("system.dns", dns_limit, dns_command);