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Systemd/src/nss-resolve/nss-resolve.c
Zbigniew Jędrzejewski-Szmek 11a1589223 tree-wide: drop license boilerplate 
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.

I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
2018-04-06 18:58:55 +02:00

635 lines
18 KiB
C
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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
***/
#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 "resolved-def.h"
#include "string-util.h"
#include "util.h"
#include "signal-util.h"
NSS_GETHOSTBYNAME_PROTOTYPES(resolve);
NSS_GETHOSTBYADDR_PROTOTYPES(resolve);
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;
}
static uint32_t ifindex_to_scopeid(int family, const void *a, int ifindex) {
struct in6_addr in6;
if (family != AF_INET6)
return 0;
/* Some apps can't deal with the scope ID attached to non-link-local addresses. Hence, let's suppress that. */
assert(sizeof(in6) == FAMILY_ADDRESS_SIZE(AF_INET6));
memcpy(&in6, a, sizeof(struct in6_addr));
return IN6_IS_ADDR_LINKLOCAL(&in6) ? ifindex : 0;
}
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) {
_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;
enum nss_status ret = NSS_STATUS_UNAVAIL;
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 fail;
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, SD_RESOLVED_QUERY_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;
}
/* Return NSS_STATUS_UNAVAIL when communication with systemd-resolved fails,
allowing falling back to other nss modules. Treat all other error conditions as
NOTFOUND. This includes DNSSEC errors and suchlike. (We don't use UNAVAIL in this
case so that the nsswitch.conf configuration can distuingish such executed but
negative replies from complete failure to talk to resolved). */
if (!bus_error_shall_fallback(&error))
ret = NSS_STATUS_NOTFOUND;
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 = ERANGE;
*h_errnop = NETDB_INTERNAL;
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_to_scopeid(family, a, 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;
fail:
*errnop = -r;
*h_errnop = NO_RECOVERY;
return ret;
}
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) {
_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;
enum nss_status ret = NSS_STATUS_UNAVAIL;
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 (!IN_SET(af, AF_INET, AF_INET6)) {
r = -EAFNOSUPPORT;
goto fail;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
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, SD_RESOLVED_QUERY_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))
ret = NSS_STATUS_NOTFOUND;
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 = ERANGE;
*h_errnop = NETDB_INTERNAL;
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;
fail:
*errnop = -r;
*h_errnop = NO_RECOVERY;
return ret;
}
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) {
_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;
enum nss_status ret = NSS_STATUS_UNAVAIL;
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 fail;
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, SD_RESOLVED_QUERY_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))
ret = NSS_STATUS_NOTFOUND;
goto fail;
}
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 = ERANGE;
*h_errnop = NETDB_INTERNAL;
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;
fail:
*errnop = -r;
*h_errnop = NO_RECOVERY;
return ret;
}
NSS_GETHOSTBYNAME_FALLBACKS(resolve);
NSS_GETHOSTBYADDR_FALLBACKS(resolve);
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