Systemd/src/nss-resolve/nss-resolve.c

705 lines
21 KiB
C

/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <dlfcn.h>
#include <errno.h>
#include <netdb.h>
#include <nss.h>
#include <stdlib.h>
#include <string.h>
#include "sd-bus.h"
#include "bus-common-errors.h"
#include "in-addr-util.h"
#include "macro.h"
#include "nss-util.h"
#include "string-util.h"
#include "util.h"
#include "signal-util.h"
NSS_GETHOSTBYNAME_PROTOTYPES(resolve);
NSS_GETHOSTBYADDR_PROTOTYPES(resolve);
#define DNS_CALL_TIMEOUT_USEC (45*USEC_PER_SEC)
typedef void (*voidfunc_t)(void);
static voidfunc_t find_fallback(const char *module, const char *symbol) {
void *dl;
/* Try to find a fallback NSS module symbol */
dl = dlopen(module, RTLD_LAZY|RTLD_NODELETE);
if (!dl)
return NULL;
return dlsym(dl, symbol);
}
static bool bus_error_shall_fallback(sd_bus_error *e) {
return sd_bus_error_has_name(e, SD_BUS_ERROR_SERVICE_UNKNOWN) ||
sd_bus_error_has_name(e, SD_BUS_ERROR_NAME_HAS_NO_OWNER) ||
sd_bus_error_has_name(e, SD_BUS_ERROR_NO_REPLY) ||
sd_bus_error_has_name(e, SD_BUS_ERROR_ACCESS_DENIED);
}
static int count_addresses(sd_bus_message *m, int af, const char **canonical) {
int c = 0, r;
assert(m);
assert(canonical);
r = sd_bus_message_enter_container(m, 'a', "(iiay)");
if (r < 0)
return r;
while ((r = sd_bus_message_enter_container(m, 'r', "iiay")) > 0) {
int family, ifindex;
assert_cc(sizeof(int32_t) == sizeof(int));
r = sd_bus_message_read(m, "ii", &ifindex, &family);
if (r < 0)
return r;
r = sd_bus_message_skip(m, "ay");
if (r < 0)
return r;
r = sd_bus_message_exit_container(m);
if (r < 0)
return r;
if (af != AF_UNSPEC && family != af)
continue;
c++;
}
if (r < 0)
return r;
r = sd_bus_message_exit_container(m);
if (r < 0)
return r;
r = sd_bus_message_read(m, "s", canonical);
if (r < 0)
return r;
r = sd_bus_message_rewind(m, true);
if (r < 0)
return r;
return c;
}
enum nss_status _nss_resolve_gethostbyname4_r(
const char *name,
struct gaih_addrtuple **pat,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp) {
enum nss_status (*fallback)(
const char *name,
struct gaih_addrtuple **pat,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp);
_cleanup_(sd_bus_message_unrefp) sd_bus_message *req = NULL, *reply = NULL;
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
struct gaih_addrtuple *r_tuple, *r_tuple_first = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
const char *canonical = NULL;
size_t l, ms, idx;
char *r_name;
int c, r, i = 0;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
assert(name);
assert(pat);
assert(buffer);
assert(errnop);
assert(h_errnop);
r = sd_bus_open_system(&bus);
if (r < 0)
goto fallback;
r = sd_bus_message_new_method_call(
bus,
&req,
"org.freedesktop.resolve1",
"/org/freedesktop/resolve1",
"org.freedesktop.resolve1.Manager",
"ResolveHostname");
if (r < 0)
goto fail;
r = sd_bus_message_set_auto_start(req, false);
if (r < 0)
goto fail;
r = sd_bus_message_append(req, "isit", 0, name, AF_UNSPEC, (uint64_t) 0);
if (r < 0)
goto fail;
r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply);
if (r < 0) {
if (sd_bus_error_has_name(&error, _BUS_ERROR_DNS "NXDOMAIN")) {
*errnop = ESRCH;
*h_errnop = HOST_NOT_FOUND;
return NSS_STATUS_NOTFOUND;
}
if (bus_error_shall_fallback(&error))
goto fallback;
goto fail;
}
c = count_addresses(reply, AF_UNSPEC, &canonical);
if (c < 0) {
r = c;
goto fail;
}
if (c == 0) {
*errnop = ESRCH;
*h_errnop = HOST_NOT_FOUND;
return NSS_STATUS_NOTFOUND;
}
if (isempty(canonical))
canonical = name;
l = strlen(canonical);
ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * c;
if (buflen < ms) {
*errnop = ENOMEM;
*h_errnop = TRY_AGAIN;
return NSS_STATUS_TRYAGAIN;
}
/* First, append name */
r_name = buffer;
memcpy(r_name, canonical, l+1);
idx = ALIGN(l+1);
/* Second, append addresses */
r_tuple_first = (struct gaih_addrtuple*) (buffer + idx);
r = sd_bus_message_enter_container(reply, 'a', "(iiay)");
if (r < 0)
goto fail;
while ((r = sd_bus_message_enter_container(reply, 'r', "iiay")) > 0) {
int family, ifindex;
const void *a;
size_t sz;
assert_cc(sizeof(int32_t) == sizeof(int));
r = sd_bus_message_read(reply, "ii", &ifindex, &family);
if (r < 0)
goto fail;
if (ifindex < 0) {
r = -EINVAL;
goto fail;
}
r = sd_bus_message_read_array(reply, 'y', &a, &sz);
if (r < 0)
goto fail;
r = sd_bus_message_exit_container(reply);
if (r < 0)
goto fail;
if (!IN_SET(family, AF_INET, AF_INET6))
continue;
if (sz != FAMILY_ADDRESS_SIZE(family)) {
r = -EINVAL;
goto fail;
}
r_tuple = (struct gaih_addrtuple*) (buffer + idx);
r_tuple->next = i == c-1 ? NULL : (struct gaih_addrtuple*) ((char*) r_tuple + ALIGN(sizeof(struct gaih_addrtuple)));
r_tuple->name = r_name;
r_tuple->family = family;
r_tuple->scopeid = ifindex;
memcpy(r_tuple->addr, a, sz);
idx += ALIGN(sizeof(struct gaih_addrtuple));
i++;
}
if (r < 0)
goto fail;
assert(i == c);
assert(idx == ms);
if (*pat)
**pat = *r_tuple_first;
else
*pat = r_tuple_first;
if (ttlp)
*ttlp = 0;
/* Explicitly reset all error variables */
*errnop = 0;
*h_errnop = NETDB_SUCCESS;
h_errno = 0;
return NSS_STATUS_SUCCESS;
fallback:
fallback = (enum nss_status (*)(const char *name,
struct gaih_addrtuple **pat,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp))
find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyname4_r");
if (fallback)
return fallback(name, pat, buffer, buflen, errnop, h_errnop, ttlp);
fail:
*errnop = -r;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
enum nss_status _nss_resolve_gethostbyname3_r(
const char *name,
int af,
struct hostent *result,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp,
char **canonp) {
enum nss_status (*fallback)(
const char *name,
int af,
struct hostent *result,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp,
char **canonp);
_cleanup_(sd_bus_message_unrefp) sd_bus_message *req = NULL, *reply = NULL;
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
char *r_name, *r_aliases, *r_addr, *r_addr_list;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
size_t l, idx, ms, alen;
const char *canonical;
int c, r, i = 0;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
assert(name);
assert(result);
assert(buffer);
assert(errnop);
assert(h_errnop);
if (af == AF_UNSPEC)
af = AF_INET;
if (af != AF_INET && af != AF_INET6) {
r = -EAFNOSUPPORT;
goto fail;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fallback;
r = sd_bus_message_new_method_call(
bus,
&req,
"org.freedesktop.resolve1",
"/org/freedesktop/resolve1",
"org.freedesktop.resolve1.Manager",
"ResolveHostname");
if (r < 0)
goto fail;
r = sd_bus_message_set_auto_start(req, false);
if (r < 0)
goto fail;
r = sd_bus_message_append(req, "isit", 0, name, af, (uint64_t) 0);
if (r < 0)
goto fail;
r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply);
if (r < 0) {
if (sd_bus_error_has_name(&error, _BUS_ERROR_DNS "NXDOMAIN")) {
*errnop = ESRCH;
*h_errnop = HOST_NOT_FOUND;
return NSS_STATUS_NOTFOUND;
}
if (bus_error_shall_fallback(&error))
goto fallback;
goto fail;
}
c = count_addresses(reply, af, &canonical);
if (c < 0) {
r = c;
goto fail;
}
if (c == 0) {
*errnop = ESRCH;
*h_errnop = HOST_NOT_FOUND;
return NSS_STATUS_NOTFOUND;
}
if (isempty(canonical))
canonical = name;
alen = FAMILY_ADDRESS_SIZE(af);
l = strlen(canonical);
ms = ALIGN(l+1) + c * ALIGN(alen) + (c+2) * sizeof(char*);
if (buflen < ms) {
*errnop = ENOMEM;
*h_errnop = TRY_AGAIN;
return NSS_STATUS_TRYAGAIN;
}
/* First, append name */
r_name = buffer;
memcpy(r_name, canonical, l+1);
idx = ALIGN(l+1);
/* Second, create empty aliases array */
r_aliases = buffer + idx;
((char**) r_aliases)[0] = NULL;
idx += sizeof(char*);
/* Third, append addresses */
r_addr = buffer + idx;
r = sd_bus_message_enter_container(reply, 'a', "(iiay)");
if (r < 0)
goto fail;
while ((r = sd_bus_message_enter_container(reply, 'r', "iiay")) > 0) {
int ifindex, family;
const void *a;
size_t sz;
r = sd_bus_message_read(reply, "ii", &ifindex, &family);
if (r < 0)
goto fail;
if (ifindex < 0) {
r = -EINVAL;
goto fail;
}
r = sd_bus_message_read_array(reply, 'y', &a, &sz);
if (r < 0)
goto fail;
r = sd_bus_message_exit_container(reply);
if (r < 0)
goto fail;
if (family != af)
continue;
if (sz != alen) {
r = -EINVAL;
goto fail;
}
memcpy(r_addr + i*ALIGN(alen), a, alen);
i++;
}
if (r < 0)
goto fail;
assert(i == c);
idx += c * ALIGN(alen);
/* Fourth, append address pointer array */
r_addr_list = buffer + idx;
for (i = 0; i < c; i++)
((char**) r_addr_list)[i] = r_addr + i*ALIGN(alen);
((char**) r_addr_list)[i] = NULL;
idx += (c+1) * sizeof(char*);
assert(idx == ms);
result->h_name = r_name;
result->h_aliases = (char**) r_aliases;
result->h_addrtype = af;
result->h_length = alen;
result->h_addr_list = (char**) r_addr_list;
/* Explicitly reset all error variables */
*errnop = 0;
*h_errnop = NETDB_SUCCESS;
h_errno = 0;
if (ttlp)
*ttlp = 0;
if (canonp)
*canonp = r_name;
return NSS_STATUS_SUCCESS;
fallback:
fallback = (enum nss_status (*)(const char *name,
int af,
struct hostent *result,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp,
char **canonp))
find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyname3_r");
if (fallback)
return fallback(name, af, result, buffer, buflen, errnop, h_errnop, ttlp, canonp);
fail:
*errnop = -r;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
enum nss_status _nss_resolve_gethostbyaddr2_r(
const void* addr, socklen_t len,
int af,
struct hostent *result,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp) {
enum nss_status (*fallback)(
const void* addr, socklen_t len,
int af,
struct hostent *result,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp);
_cleanup_(sd_bus_message_unrefp) sd_bus_message *req = NULL, *reply = NULL;
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
char *r_name, *r_aliases, *r_addr, *r_addr_list;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
unsigned c = 0, i = 0;
size_t ms = 0, idx;
const char *n;
int r, ifindex;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
assert(addr);
assert(result);
assert(buffer);
assert(errnop);
assert(h_errnop);
if (!IN_SET(af, AF_INET, AF_INET6)) {
*errnop = EAFNOSUPPORT;
*h_errnop = NO_DATA;
return NSS_STATUS_UNAVAIL;
}
if (len != FAMILY_ADDRESS_SIZE(af)) {
*errnop = EINVAL;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fallback;
r = sd_bus_message_new_method_call(
bus,
&req,
"org.freedesktop.resolve1",
"/org/freedesktop/resolve1",
"org.freedesktop.resolve1.Manager",
"ResolveAddress");
if (r < 0)
goto fail;
r = sd_bus_message_set_auto_start(req, false);
if (r < 0)
goto fail;
r = sd_bus_message_append(req, "ii", 0, af);
if (r < 0)
goto fail;
r = sd_bus_message_append_array(req, 'y', addr, len);
if (r < 0)
goto fail;
r = sd_bus_message_append(req, "t", (uint64_t) 0);
if (r < 0)
goto fail;
r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply);
if (r < 0) {
if (sd_bus_error_has_name(&error, _BUS_ERROR_DNS "NXDOMAIN")) {
*errnop = ESRCH;
*h_errnop = HOST_NOT_FOUND;
return NSS_STATUS_NOTFOUND;
}
if (bus_error_shall_fallback(&error))
goto fallback;
*errnop = -r;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
r = sd_bus_message_enter_container(reply, 'a', "(is)");
if (r < 0)
goto fail;
while ((r = sd_bus_message_read(reply, "(is)", &ifindex, &n)) > 0) {
if (ifindex < 0) {
r = -EINVAL;
goto fail;
}
c++;
ms += ALIGN(strlen(n) + 1);
}
if (r < 0)
goto fail;
r = sd_bus_message_rewind(reply, false);
if (r < 0)
return r;
if (c <= 0) {
*errnop = ESRCH;
*h_errnop = HOST_NOT_FOUND;
return NSS_STATUS_NOTFOUND;
}
ms += ALIGN(len) + /* the address */
2 * sizeof(char*) + /* pointers to the address, plus trailing NULL */
c * sizeof(char*); /* pointers to aliases, plus trailing NULL */
if (buflen < ms) {
*errnop = ENOMEM;
*h_errnop = TRY_AGAIN;
return NSS_STATUS_TRYAGAIN;
}
/* First, place address */
r_addr = buffer;
memcpy(r_addr, addr, len);
idx = ALIGN(len);
/* Second, place address list */
r_addr_list = buffer + idx;
((char**) r_addr_list)[0] = r_addr;
((char**) r_addr_list)[1] = NULL;
idx += sizeof(char*) * 2;
/* Third, reserve space for the aliases array */
r_aliases = buffer + idx;
idx += sizeof(char*) * c;
/* Fourth, place aliases */
i = 0;
r_name = buffer + idx;
while ((r = sd_bus_message_read(reply, "(is)", &ifindex, &n)) > 0) {
char *p;
size_t l;
l = strlen(n);
p = buffer + idx;
memcpy(p, n, l+1);
if (i > 0)
((char**) r_aliases)[i-1] = p;
i++;
idx += ALIGN(l+1);
}
if (r < 0)
goto fail;
((char**) r_aliases)[c-1] = NULL;
assert(idx == ms);
result->h_name = r_name;
result->h_aliases = (char**) r_aliases;
result->h_addrtype = af;
result->h_length = len;
result->h_addr_list = (char**) r_addr_list;
if (ttlp)
*ttlp = 0;
/* Explicitly reset all error variables */
*errnop = 0;
*h_errnop = NETDB_SUCCESS;
h_errno = 0;
return NSS_STATUS_SUCCESS;
fallback:
fallback = (enum nss_status (*)(
const void* addr, socklen_t len,
int af,
struct hostent *result,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp))
find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyaddr2_r");
if (fallback)
return fallback(addr, len, af, result, buffer, buflen, errnop, h_errnop, ttlp);
fail:
*errnop = -r;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
NSS_GETHOSTBYNAME_FALLBACKS(resolve);
NSS_GETHOSTBYADDR_FALLBACKS(resolve);