[thirdparty/systemd.git] / src / nss-myhostname / nss-myhostname.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <errno.h>
#include <net/if.h>
#include <netdb.h>
#include <nss.h>
#include <stdlib.h>

#include "alloc-util.h"
#include "errno-util.h"
#include "hostname-util.h"
#include "local-addresses.h"
#include "macro.h"
#include "nss-util.h"
#include "resolve-util.h"
#include "signal-util.h"
#include "socket-util.h"
#include "string-util.h"

/* We use 127.0.0.2 as IPv4 address. This has the advantage over
 * 127.0.0.1 that it can be translated back to the local hostname. For
 * IPv6 we use ::1 which unfortunately will not translate back to the
 * hostname but instead something like "localhost" or so. */

#define LOCALADDRESS_IPV4 (htobe32(INADDR_LOCALADDRESS))
#define LOCALADDRESS_IPV6 &in6addr_loopback

NSS_GETHOSTBYNAME_PROTOTYPES(myhostname);
NSS_GETHOSTBYADDR_PROTOTYPES(myhostname);

enum nss_status _nss_myhostname_gethostbyname4_r(
                const char *name,
                struct gaih_addrtuple **pat,
                char *buffer, size_t buflen,
                int *errnop, int *h_errnop,
                int32_t *ttlp) {

        struct gaih_addrtuple *r_tuple, *r_tuple_prev = NULL;
        _cleanup_free_ struct local_address *addresses = NULL;
        _cleanup_free_ char *hn = NULL;
        const char *canonical = NULL;
        int n_addresses = 0;
        uint32_t local_address_ipv4;
        size_t l, idx, ms;
        char *r_name;

        PROTECT_ERRNO;
        BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);

        assert(name);
        assert(pat);
        assert(buffer);
        assert(errnop);
        assert(h_errnop);

        if (is_localhost(name)) {
                /* We respond to 'localhost', so that /etc/hosts is optional */

                canonical = "localhost";
                local_address_ipv4 = htobe32(INADDR_LOOPBACK);

        } else if (is_gateway_hostname(name)) {

                n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
                if (n_addresses <= 0)
                        goto not_found;

                canonical = "_gateway";

        } else if (is_outbound_hostname(name)) {

                n_addresses = local_outbounds(NULL, 0, AF_UNSPEC, &addresses);
                if (n_addresses <= 0)
                        goto not_found;

                canonical = "_outbound";

        } else {
                hn = gethostname_malloc();
                if (!hn) {
                        UNPROTECT_ERRNO;
                        *errnop = ENOMEM;
                        *h_errnop = NO_RECOVERY;
                        return NSS_STATUS_TRYAGAIN;
                }

                /* We respond to our local hostname, our hostname suffixed with a single dot. */
                if (!streq(name, hn) && !streq_ptr(startswith(name, hn), "."))
                        goto not_found;

                n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses);
                if (n_addresses < 0)
                        n_addresses = 0;

                canonical = hn;
                local_address_ipv4 = LOCALADDRESS_IPV4;
        }

        l = strlen(canonical);
        ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * (n_addresses > 0 ? n_addresses : 1 + socket_ipv6_is_enabled());
        if (buflen < ms) {
                UNPROTECT_ERRNO;
                *errnop = ERANGE;
                *h_errnop = NETDB_INTERNAL;
                return NSS_STATUS_TRYAGAIN;
        }

        /* First, fill in hostname */
        r_name = buffer;
        memcpy(r_name, canonical, l+1);
        idx = ALIGN(l+1);

        assert(n_addresses >= 0);
        if (n_addresses == 0) {
                /* Second, fill in IPv6 tuple */
                if (socket_ipv6_is_enabled()) {
                        r_tuple = (struct gaih_addrtuple*) (buffer + idx);
                        r_tuple->next = r_tuple_prev;
                        r_tuple->name = r_name;
                        r_tuple->family = AF_INET6;
                        memcpy(r_tuple->addr, LOCALADDRESS_IPV6, 16);
                        r_tuple->scopeid = 0;

                        idx += ALIGN(sizeof(struct gaih_addrtuple));
                        r_tuple_prev = r_tuple;
                }

                /* Third, fill in IPv4 tuple */
                r_tuple = (struct gaih_addrtuple*) (buffer + idx);
                r_tuple->next = r_tuple_prev;
                r_tuple->name = r_name;
                r_tuple->family = AF_INET;
                *(uint32_t*) r_tuple->addr = local_address_ipv4;
                r_tuple->scopeid = 0;

                idx += ALIGN(sizeof(struct gaih_addrtuple));
                r_tuple_prev = r_tuple;
        }

        /* Fourth, fill actual addresses in, but in backwards order */
        for (int i = n_addresses; i > 0; i--) {
                struct local_address *a = addresses + i - 1;

                r_tuple = (struct gaih_addrtuple*) (buffer + idx);
                r_tuple->next = r_tuple_prev;
                r_tuple->name = r_name;
                r_tuple->family = a->family;
                r_tuple->scopeid = a->family == AF_INET6 && in6_addr_is_link_local(&a->address.in6) ? a->ifindex : 0;
                memcpy(r_tuple->addr, &a->address, 16);

                idx += ALIGN(sizeof(struct gaih_addrtuple));
                r_tuple_prev = r_tuple;
        }

        /* Verify the size matches */
        assert(idx == ms);

        /* Nscd expects us to store the first record in **pat. */
        if (*pat)
                **pat = *r_tuple_prev;
        else
                *pat = r_tuple_prev;

        if (ttlp)
                *ttlp = 0;

        /* Explicitly reset both *h_errnop and h_errno to work around
         * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
        *h_errnop = NETDB_SUCCESS;
        h_errno = 0;

        return NSS_STATUS_SUCCESS;

not_found:
        *h_errnop = HOST_NOT_FOUND;
        return NSS_STATUS_NOTFOUND;
}

static enum nss_status fill_in_hostent(
                const char *canonical, const char *additional,
                int af,
                struct local_address *addresses, unsigned n_addresses,
                uint32_t local_address_ipv4,
                struct hostent *result,
                char *buffer, size_t buflen,
                int *errnop, int *h_errnop,
                int32_t *ttlp,
                char **canonp) {

        size_t l_canonical, l_additional, idx, ms, alen;
        char *r_addr, *r_name, *r_aliases, *r_alias = NULL, *r_addr_list;
        struct local_address *a;
        unsigned n, c;

        assert(canonical);
        assert(IN_SET(af, AF_INET, AF_INET6));
        assert(result);
        assert(buffer);
        assert(errnop);
        assert(h_errnop);

        PROTECT_ERRNO;

        alen = FAMILY_ADDRESS_SIZE(af);

        for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++)
                if (af == a->family)
                        c++;

        l_canonical = strlen(canonical);
        l_additional = strlen_ptr(additional);
        ms = ALIGN(l_canonical+1)+
                (additional ? ALIGN(l_additional+1) : 0) +
                sizeof(char*) +
                (additional ? sizeof(char*) : 0) +
                (c > 0 ? c : af == AF_INET ? 1 : socket_ipv6_is_enabled()) * ALIGN(alen) +
                (c > 0 ? c+1 : af == AF_INET ? 2 : (unsigned) socket_ipv6_is_enabled() + 1) * sizeof(char*);

        if (buflen < ms) {
                UNPROTECT_ERRNO;
                *errnop = ERANGE;
                *h_errnop = NETDB_INTERNAL;
                return NSS_STATUS_TRYAGAIN;
        }

        /* First, fill in hostnames */
        r_name = buffer;
        memcpy(r_name, canonical, l_canonical+1);
        idx = ALIGN(l_canonical+1);

        if (additional) {
                r_alias = buffer + idx;
                memcpy(r_alias, additional, l_additional+1);
                idx += ALIGN(l_additional+1);
        }

        /* Second, create aliases array */
        r_aliases = buffer + idx;
        if (additional) {
                ((char**) r_aliases)[0] = r_alias;
                ((char**) r_aliases)[1] = NULL;
                idx += 2*sizeof(char*);
        } else {
                ((char**) r_aliases)[0] = NULL;
                idx += sizeof(char*);
        }

        /* Third, add addresses */
        r_addr = buffer + idx;
        if (c > 0) {
                unsigned i = 0;

                for (a = addresses, n = 0; n < n_addresses; a++, n++) {
                        if (af != a->family)
                                continue;

                        memcpy(r_addr + i*ALIGN(alen), &a->address, alen);
                        i++;
                }

                assert(i == c);
                idx += c*ALIGN(alen);

        } else if (af == AF_INET) {
                *(uint32_t*) r_addr = local_address_ipv4;
                idx += ALIGN(alen);
        } else if (socket_ipv6_is_enabled()) {
                memcpy(r_addr, LOCALADDRESS_IPV6, 16);
                idx += ALIGN(alen);
        }

        /* Fourth, add address pointer array */
        r_addr_list = buffer + idx;
        if (c > 0) {
                unsigned i;

                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*);

        } else if (af == AF_INET || socket_ipv6_is_enabled()) {
                ((char**) r_addr_list)[0] = r_addr;
                ((char**) r_addr_list)[1] = NULL;
                idx += 2 * sizeof(char*);
        } else {
                ((char**) r_addr_list)[0] = NULL;
                idx += sizeof(char*);
        }

        /* Verify the size matches */
        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;

        if (ttlp)
                *ttlp = 0;

        if (canonp)
                *canonp = r_name;

        /* Explicitly reset both *h_errnop and h_errno to work around
         * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
        *h_errnop = NETDB_SUCCESS;
        h_errno = 0;

        return NSS_STATUS_SUCCESS;
}

enum nss_status _nss_myhostname_gethostbyname3_r(
                const char *name,
                int af,
                struct hostent *host,
                char *buffer, size_t buflen,
                int *errnop, int *h_errnop,
                int32_t *ttlp,
                char **canonp) {

        _cleanup_free_ struct local_address *addresses = NULL;
        const char *canonical, *additional = NULL;
        _cleanup_free_ char *hn = NULL;
        uint32_t local_address_ipv4 = 0;
        int n_addresses = 0;

        PROTECT_ERRNO;
        BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);

        assert(name);
        assert(host);
        assert(buffer);
        assert(errnop);
        assert(h_errnop);

        if (af == AF_UNSPEC)
                af = AF_INET;

        if (!IN_SET(af, AF_INET, AF_INET6)) {
                UNPROTECT_ERRNO;
                *errnop = EAFNOSUPPORT;
                *h_errnop = NO_DATA;
                return NSS_STATUS_UNAVAIL;
        }

        if (is_localhost(name)) {
                if (af == AF_INET6 && !socket_ipv6_is_enabled())
                        goto not_found;

                canonical = "localhost";
                local_address_ipv4 = htobe32(INADDR_LOOPBACK);

        } else if (is_gateway_hostname(name)) {

                n_addresses = local_gateways(NULL, 0, af, &addresses);
                if (n_addresses <= 0)
                        goto not_found;

                canonical = "_gateway";

        } else if (is_outbound_hostname(name)) {

                n_addresses = local_outbounds(NULL, 0, af, &addresses);
                if (n_addresses <= 0)
                        goto not_found;

                canonical = "_outbound";

        } else {
                hn = gethostname_malloc();
                if (!hn) {
                        UNPROTECT_ERRNO;
                        *errnop = ENOMEM;
                        *h_errnop = NO_RECOVERY;
                        return NSS_STATUS_TRYAGAIN;
                }

                if (!streq(name, hn) && !streq_ptr(startswith(name, hn), "."))
                        goto not_found;

                n_addresses = local_addresses(NULL, 0, af, &addresses);
                if (n_addresses < 0)
                        n_addresses = 0;

                canonical = hn;
                additional = n_addresses <= 0 && af == AF_INET6 ? "localhost" : NULL;
                local_address_ipv4 = LOCALADDRESS_IPV4;
        }

        UNPROTECT_ERRNO;

        return fill_in_hostent(
                        canonical, additional,
                        af,
                        addresses, n_addresses,
                        local_address_ipv4,
                        host,
                        buffer, buflen,
                        errnop, h_errnop,
                        ttlp,
                        canonp);

not_found:
        *h_errnop = HOST_NOT_FOUND;
        return NSS_STATUS_NOTFOUND;
}

enum nss_status _nss_myhostname_gethostbyaddr2_r(
                const void* addr, socklen_t len,
                int af,
                struct hostent *host,
                char *buffer, size_t buflen,
                int *errnop, int *h_errnop,
                int32_t *ttlp) {

        const char *canonical = NULL, *additional = NULL;
        uint32_t local_address_ipv4 = LOCALADDRESS_IPV4;
        _cleanup_free_ struct local_address *addresses = NULL;
        _cleanup_free_ char *hn = NULL;
        int n_addresses = 0;
        struct local_address *a;
        bool additional_from_hostname = false;
        unsigned n;

        PROTECT_ERRNO;
        BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);

        assert(addr);
        assert(host);
        assert(buffer);
        assert(errnop);
        assert(h_errnop);

        if (!IN_SET(af, AF_INET, AF_INET6)) {
                UNPROTECT_ERRNO;
                *errnop = EAFNOSUPPORT;
                *h_errnop = NO_DATA;
                return NSS_STATUS_UNAVAIL;
        }

        if (len != FAMILY_ADDRESS_SIZE(af)) {
                UNPROTECT_ERRNO;
                *errnop = EINVAL;
                *h_errnop = NO_RECOVERY;
                return NSS_STATUS_UNAVAIL;
        }

        if (af == AF_INET) {
                if ((*(uint32_t*) addr) == LOCALADDRESS_IPV4)
                        goto found;

                if ((*(uint32_t*) addr) == htobe32(INADDR_LOOPBACK)) {
                        canonical = "localhost";
                        local_address_ipv4 = htobe32(INADDR_LOOPBACK);
                        goto found;
                }

        } else {
                assert(af == AF_INET6);

                if (socket_ipv6_is_enabled())
                        goto not_found;

                if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) {
                        canonical = "localhost";
                        additional_from_hostname = true;
                        goto found;
                }
        }

        n_addresses = local_addresses(NULL, 0, af, &addresses);
        for (a = addresses, n = 0; (int) n < n_addresses; n++, a++)
                if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0)
                        goto found;

        addresses = mfree(addresses);

        n_addresses = local_gateways(NULL, 0, af, &addresses);
        for (a = addresses, n = 0; (int) n < n_addresses; n++, a++)
                if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) {
                        canonical = "_gateway";
                        goto found;
                }

not_found:
        *h_errnop = HOST_NOT_FOUND;
        return NSS_STATUS_NOTFOUND;

found:
        if (!canonical || additional_from_hostname) {
                hn = gethostname_malloc();
                if (!hn) {
                        UNPROTECT_ERRNO;
                        *errnop = ENOMEM;
                        *h_errnop = NO_RECOVERY;
                        return NSS_STATUS_TRYAGAIN;
                }

                if (!canonical)
                        canonical = hn;
                else
                        additional = hn;
        }

        UNPROTECT_ERRNO;
        return fill_in_hostent(
                        canonical, additional,
                        af,
                        addresses, n_addresses,
                        local_address_ipv4,
                        host,
                        buffer, buflen,
                        errnop, h_errnop,
                        ttlp,
                        NULL);
}

NSS_GETHOSTBYNAME_FALLBACKS(myhostname);
NSS_GETHOSTBYADDR_FALLBACKS(myhostname);
Commit	Line	Data
db9ecf05	1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
6b21f0cf	2
6b21f0cf	3	#include <errno.h>
4e8c8252	4	#include <net/if.h>
07630cea LP	5	#include <netdb.h>
07630cea LP	6	#include <nss.h>
8041b5ba	7	#include <stdlib.h>
8041b5ba	8
b5efdb8a	9	#include "alloc-util.h"
2b2fec7d	10	#include "errno-util.h"
07630cea	11	#include "hostname-util.h"
e80af1bd	12	#include "local-addresses.h"
1c633045	13	#include "macro.h"
c9fdc26e	14	#include "nss-util.h"
056c398b	15	#include "resolve-util.h"
0c5eb056	16	#include "signal-util.h"
db50d326	17	#include "socket-util.h"
07630cea	18	#include "string-util.h"
4e8c8252 LP	19
	20	/* We use 127.0.0.2 as IPv4 address. This has the advantage over
	21	* 127.0.0.1 that it can be translated back to the local hostname. For
	22	* IPv6 we use ::1 which unfortunately will not translate back to the
3fdcecc8	23	* hostname but instead something like "localhost" or so. */
4e8c8252	24
056c398b	25	#define LOCALADDRESS_IPV4 (htobe32(INADDR_LOCALADDRESS))
4e8c8252	26	#define LOCALADDRESS_IPV6 &in6addr_loopback
4e8c8252	27
c9fdc26e LP	28	NSS_GETHOSTBYNAME_PROTOTYPES(myhostname);
c9fdc26e LP	29	NSS_GETHOSTBYADDR_PROTOTYPES(myhostname);
8041b5ba	30
4e8c8252 LP	31	enum nss_status _nss_myhostname_gethostbyname4_r(
	32	const char *name,
	33	struct gaih_addrtuple **pat,
	34	char *buffer, size_t buflen,
	35	int errnop, int h_errnop,
	36	int32_t *ttlp) {
	37
8041b5ba	38	struct gaih_addrtuple r_tuple, r_tuple_prev = NULL;
e80af1bd	39	_cleanup_free_ struct local_address *addresses = NULL;
5502f0d9 LP	40	_cleanup_free_ char *hn = NULL;
5502f0d9 LP	41	const char *canonical = NULL;
a1077c84	42	int n_addresses = 0;
e8a7a315	43	uint32_t local_address_ipv4;
5502f0d9 LP	44	size_t l, idx, ms;
5502f0d9 LP	45	char *r_name;
4e8c8252	46
06202b9e	47	PROTECT_ERRNO;
0c5eb056 LP	48	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	49
5502f0d9 LP	50	assert(name);
	51	assert(pat);
	52	assert(buffer);
	53	assert(errnop);
	54	assert(h_errnop);
	55
	56	if (is_localhost(name)) {
a1fdbcbe	57	/* We respond to 'localhost', so that /etc/hosts is optional */
4e8c8252	58
e8a7a315	59	canonical = "localhost";
8e38570e	60	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e9140aff	61
46a5e0e7	62	} else if (is_gateway_hostname(name)) {
e9140aff	63
1d050e1e	64	n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
e09e7ac3 LP	65	if (n_addresses <= 0)
e09e7ac3 LP	66	goto not_found;
e9140aff	67
5248e7e1	68	canonical = "_gateway";
e9140aff	69
a1fdbcbe LP	70	} else if (is_outbound_hostname(name)) {
	71
	72	n_addresses = local_outbounds(NULL, 0, AF_UNSPEC, &addresses);
	73	if (n_addresses <= 0)
	74	goto not_found;
	75
	76	canonical = "_outbound";
	77
e8a7a315	78	} else {
5502f0d9 LP	79	hn = gethostname_malloc();
5502f0d9 LP	80	if (!hn) {
cdccd29f	81	UNPROTECT_ERRNO;
0192cbdb	82	*errnop = ENOMEM;
e8a7a315	83	*h_errnop = NO_RECOVERY;
5502f0d9	84	return NSS_STATUS_TRYAGAIN;
e8a7a315 LP	85	}
e8a7a315 LP	86
38b38500	87	/* We respond to our local hostname, our hostname suffixed with a single dot. */
e09e7ac3 LP	88	if (!streq(name, hn) && !streq_ptr(startswith(name, hn), "."))
e09e7ac3 LP	89	goto not_found;
e8a7a315	90
1d050e1e	91	n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses);
e80af1bd LP	92	if (n_addresses < 0)
e80af1bd LP	93	n_addresses = 0;
e8a7a315 LP	94
	95	canonical = hn;
	96	local_address_ipv4 = LOCALADDRESS_IPV4;
	97	}
8041b5ba	98
e8a7a315	99	l = strlen(canonical);
db50d326	100	ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * (n_addresses > 0 ? n_addresses : 1 + socket_ipv6_is_enabled());
4e8c8252	101	if (buflen < ms) {
cdccd29f	102	UNPROTECT_ERRNO;
0192cbdb	103	*errnop = ERANGE;
cda458a5	104	*h_errnop = NETDB_INTERNAL;
4e8c8252 LP	105	return NSS_STATUS_TRYAGAIN;
	106	}
	107
	108	/* First, fill in hostname */
	109	r_name = buffer;
e8a7a315	110	memcpy(r_name, canonical, l+1);
4e8c8252 LP	111	idx = ALIGN(l+1);
4e8c8252 LP	112
68a9c7c4 ZJS	113	assert(n_addresses >= 0);
68a9c7c4 ZJS	114	if (n_addresses == 0) {
8041b5ba	115	/* Second, fill in IPv6 tuple */
db50d326 YW	116	if (socket_ipv6_is_enabled()) {
	117	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	118	r_tuple->next = r_tuple_prev;
	119	r_tuple->name = r_name;
	120	r_tuple->family = AF_INET6;
	121	memcpy(r_tuple->addr, LOCALADDRESS_IPV6, 16);
	122	r_tuple->scopeid = 0;
	123
	124	idx += ALIGN(sizeof(struct gaih_addrtuple));
	125	r_tuple_prev = r_tuple;
	126	}
8041b5ba LP	127
	128	/* Third, fill in IPv4 tuple */
	129	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	130	r_tuple->next = r_tuple_prev;
	131	r_tuple->name = r_name;
	132	r_tuple->family = AF_INET;
e8a7a315	133	(uint32_t) r_tuple->addr = local_address_ipv4;
a1077c84	134	r_tuple->scopeid = 0;
8041b5ba LP	135
	136	idx += ALIGN(sizeof(struct gaih_addrtuple));
	137	r_tuple_prev = r_tuple;
	138	}
	139
	140	/* Fourth, fill actual addresses in, but in backwards order */
92e9df9c YW	141	for (int i = n_addresses; i > 0; i--) {
	142	struct local_address *a = addresses + i - 1;
	143
8041b5ba LP	144	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	145	r_tuple->next = r_tuple_prev;
	146	r_tuple->name = r_name;
	147	r_tuple->family = a->family;
94876904	148	r_tuple->scopeid = a->family == AF_INET6 && in6_addr_is_link_local(&a->address.in6) ? a->ifindex : 0;
5502f0d9	149	memcpy(r_tuple->addr, &a->address, 16);
8041b5ba LP	150
	151	idx += ALIGN(sizeof(struct gaih_addrtuple));
	152	r_tuple_prev = r_tuple;
	153	}
4e8c8252 LP	154
	155	/* Verify the size matches */
	156	assert(idx == ms);
	157
d2f1f23a ED	158	/* Nscd expects us to store the first record in *pat. /
	159	if (*pat)
	160	*pat = r_tuple_prev;
	161	else
	162	*pat = r_tuple_prev;
4e8c8252 LP	163
	164	if (ttlp)
	165	*ttlp = 0;
	166
06202b9e YW	167	/* Explicitly reset both *h_errnop and h_errno to work around
06202b9e YW	168	* https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
e70df46b LP	169	*h_errnop = NETDB_SUCCESS;
	170	h_errno = 0;
	171
4e8c8252	172	return NSS_STATUS_SUCCESS;
e09e7ac3 LP	173
	174	not_found:
	175	*h_errnop = HOST_NOT_FOUND;
	176	return NSS_STATUS_NOTFOUND;
4e8c8252	177	}
6b21f0cf LP	178
6b21f0cf LP	179	static enum nss_status fill_in_hostent(
e8a7a315	180	const char canonical, const char additional,
4e8c8252	181	int af,
e80af1bd	182	struct local_address *addresses, unsigned n_addresses,
e8a7a315	183	uint32_t local_address_ipv4,
4e8c8252 LP	184	struct hostent *result,
4e8c8252 LP	185	char *buffer, size_t buflen,
0192cbdb	186	int errnop, int h_errnop,
4e8c8252 LP	187	int32_t *ttlp,
	188	char **canonp) {
	189
d4c9895d	190	size_t l_canonical, l_additional, idx, ms, alen;
e8a7a315	191	char r_addr, r_name, r_aliases, r_alias = NULL, *r_addr_list;
e80af1bd	192	struct local_address *a;
e8a7a315	193	unsigned n, c;
8041b5ba	194
5502f0d9	195	assert(canonical);
db50d326	196	assert(IN_SET(af, AF_INET, AF_INET6));
5502f0d9 LP	197	assert(result);
	198	assert(buffer);
	199	assert(errnop);
	200	assert(h_errnop);
	201
cdccd29f LP	202	PROTECT_ERRNO;
cdccd29f LP	203
9d485985	204	alen = FAMILY_ADDRESS_SIZE(af);
8041b5ba	205
8041b5ba LP	206	for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++)
	207	if (af == a->family)
	208	c++;
4e8c8252	209
e8a7a315	210	l_canonical = strlen(canonical);
7bf7ce28	211	l_additional = strlen_ptr(additional);
e8a7a315 LP	212	ms = ALIGN(l_canonical+1)+
e8a7a315 LP	213	(additional ? ALIGN(l_additional+1) : 0) +
5502f0d9	214	sizeof(char*) +
e8a7a315	215	(additional ? sizeof(char*) : 0) +
db50d326 YW	216	(c > 0 ? c : af == AF_INET ? 1 : socket_ipv6_is_enabled()) * ALIGN(alen) +
db50d326 YW	217	(c > 0 ? c+1 : af == AF_INET ? 2 : (unsigned) socket_ipv6_is_enabled() + 1) * sizeof(char*);
8041b5ba	218
4e8c8252	219	if (buflen < ms) {
cdccd29f	220	UNPROTECT_ERRNO;
0192cbdb	221	*errnop = ERANGE;
cda458a5	222	*h_errnop = NETDB_INTERNAL;
4e8c8252 LP	223	return NSS_STATUS_TRYAGAIN;
	224	}
	225
e8a7a315	226	/* First, fill in hostnames */
4e8c8252	227	r_name = buffer;
e8a7a315 LP	228	memcpy(r_name, canonical, l_canonical+1);
e8a7a315 LP	229	idx = ALIGN(l_canonical+1);
4e8c8252	230
e8a7a315 LP	231	if (additional) {
	232	r_alias = buffer + idx;
	233	memcpy(r_alias, additional, l_additional+1);
	234	idx += ALIGN(l_additional+1);
	235	}
	236
	237	/* Second, create aliases array */
4e8c8252	238	r_aliases = buffer + idx;
e8a7a315 LP	239	if (additional) {
	240	((char**) r_aliases)[0] = r_alias;
	241	((char**) r_aliases)[1] = NULL;
	242	idx += 2sizeof(char);
	243	} else {
	244	((char**) r_aliases)[0] = NULL;
	245	idx += sizeof(char*);
	246	}
4e8c8252	247
8041b5ba	248	/* Third, add addresses */
4e8c8252	249	r_addr = buffer + idx;
8041b5ba LP	250	if (c > 0) {
	251	unsigned i = 0;
	252
	253	for (a = addresses, n = 0; n < n_addresses; a++, n++) {
	254	if (af != a->family)
	255	continue;
	256
5502f0d9	257	memcpy(r_addr + i*ALIGN(alen), &a->address, alen);
8041b5ba LP	258	i++;
	259	}
	260
	261	assert(i == c);
	262	idx += c*ALIGN(alen);
8041b5ba	263
db50d326 YW	264	} else if (af == AF_INET) {
	265	(uint32_t) r_addr = local_address_ipv4;
	266	idx += ALIGN(alen);
	267	} else if (socket_ipv6_is_enabled()) {
	268	memcpy(r_addr, LOCALADDRESS_IPV6, 16);
8041b5ba LP	269	idx += ALIGN(alen);
8041b5ba LP	270	}
4e8c8252 LP	271
	272	/* Fourth, add address pointer array */
	273	r_addr_list = buffer + idx;
8041b5ba	274	if (c > 0) {
d4c9895d	275	unsigned i;
8041b5ba	276
d4c9895d LP	277	for (i = 0; i < c; i++)
d4c9895d LP	278	((char*) r_addr_list)[i] = r_addr + iALIGN(alen);
8041b5ba	279
d4c9895d LP	280	((char**) r_addr_list)[i] = NULL;
d4c9895d LP	281	idx += (c+1) * sizeof(char*);
8041b5ba	282
db50d326	283	} else if (af == AF_INET \|\| socket_ipv6_is_enabled()) {
8041b5ba LP	284	((char**) r_addr_list)[0] = r_addr;
8041b5ba LP	285	((char**) r_addr_list)[1] = NULL;
d4c9895d	286	idx += 2 * sizeof(char*);
db50d326 YW	287	} else {
	288	((char**) r_addr_list)[0] = NULL;
	289	idx += sizeof(char*);
8041b5ba	290	}
4e8c8252 LP	291
	292	/* Verify the size matches */
	293	assert(idx == ms);
	294
	295	result->h_name = r_name;
	296	result->h_aliases = (char**) r_aliases;
	297	result->h_addrtype = af;
	298	result->h_length = alen;
	299	result->h_addr_list = (char**) r_addr_list;
	300
	301	if (ttlp)
	302	*ttlp = 0;
	303
	304	if (canonp)
	305	*canonp = r_name;
	306
06202b9e YW	307	/* Explicitly reset both *h_errnop and h_errno to work around
06202b9e YW	308	* https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
e70df46b LP	309	*h_errnop = NETDB_SUCCESS;
	310	h_errno = 0;
	311
4e8c8252	312	return NSS_STATUS_SUCCESS;
6b21f0cf LP	313	}
6b21f0cf LP	314
4e8c8252 LP	315	enum nss_status _nss_myhostname_gethostbyname3_r(
	316	const char *name,
	317	int af,
	318	struct hostent *host,
	319	char *buffer, size_t buflen,
	320	int errnop, int h_errnop,
	321	int32_t *ttlp,
	322	char **canonp) {
6b21f0cf	323
e80af1bd	324	_cleanup_free_ struct local_address *addresses = NULL;
e8a7a315	325	const char canonical, additional = NULL;
5502f0d9	326	_cleanup_free_ char *hn = NULL;
e9140aff	327	uint32_t local_address_ipv4 = 0;
e80af1bd	328	int n_addresses = 0;
5502f0d9	329
06202b9e	330	PROTECT_ERRNO;
0c5eb056 LP	331	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	332
5502f0d9 LP	333	assert(name);
	334	assert(host);
	335	assert(buffer);
	336	assert(errnop);
	337	assert(h_errnop);
6b21f0cf	338
4e8c8252 LP	339	if (af == AF_UNSPEC)
4e8c8252 LP	340	af = AF_INET;
6b21f0cf	341
ec2ce0c5	342	if (!IN_SET(af, AF_INET, AF_INET6)) {
cdccd29f	343	UNPROTECT_ERRNO;
0192cbdb	344	*errnop = EAFNOSUPPORT;
4e8c8252 LP	345	*h_errnop = NO_DATA;
	346	return NSS_STATUS_UNAVAIL;
	347	}
6b21f0cf	348
5502f0d9	349	if (is_localhost(name)) {
db50d326 YW	350	if (af == AF_INET6 && !socket_ipv6_is_enabled())
	351	goto not_found;
	352
e8a7a315	353	canonical = "localhost";
8e38570e	354	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e9140aff	355
46a5e0e7	356	} else if (is_gateway_hostname(name)) {
e9140aff	357
1d050e1e	358	n_addresses = local_gateways(NULL, 0, af, &addresses);
e09e7ac3 LP	359	if (n_addresses <= 0)
e09e7ac3 LP	360	goto not_found;
e9140aff	361
5248e7e1	362	canonical = "_gateway";
e9140aff	363
a1fdbcbe LP	364	} else if (is_outbound_hostname(name)) {
	365
	366	n_addresses = local_outbounds(NULL, 0, af, &addresses);
	367	if (n_addresses <= 0)
	368	goto not_found;
	369
	370	canonical = "_outbound";
	371
e8a7a315	372	} else {
5502f0d9 LP	373	hn = gethostname_malloc();
5502f0d9 LP	374	if (!hn) {
cdccd29f	375	UNPROTECT_ERRNO;
0192cbdb	376	*errnop = ENOMEM;
e8a7a315	377	*h_errnop = NO_RECOVERY;
5502f0d9	378	return NSS_STATUS_TRYAGAIN;
e8a7a315	379	}
6b21f0cf	380
e09e7ac3 LP	381	if (!streq(name, hn) && !streq_ptr(startswith(name, hn), "."))
e09e7ac3 LP	382	goto not_found;
e8a7a315	383
1d050e1e	384	n_addresses = local_addresses(NULL, 0, af, &addresses);
e80af1bd LP	385	if (n_addresses < 0)
e80af1bd LP	386	n_addresses = 0;
e8a7a315 LP	387
	388	canonical = hn;
	389	additional = n_addresses <= 0 && af == AF_INET6 ? "localhost" : NULL;
	390	local_address_ipv4 = LOCALADDRESS_IPV4;
4e8c8252	391	}
6b21f0cf	392
cdccd29f LP	393	UNPROTECT_ERRNO;
cdccd29f LP	394
e8a7a315 LP	395	return fill_in_hostent(
	396	canonical, additional,
	397	af,
	398	addresses, n_addresses,
	399	local_address_ipv4,
	400	host,
	401	buffer, buflen,
0192cbdb	402	errnop, h_errnop,
e8a7a315 LP	403	ttlp,
e8a7a315 LP	404	canonp);
e09e7ac3 LP	405
	406	not_found:
	407	*h_errnop = HOST_NOT_FOUND;
	408	return NSS_STATUS_NOTFOUND;
4e8c8252	409	}
6b21f0cf	410
4e8c8252 LP	411	enum nss_status _nss_myhostname_gethostbyaddr2_r(
	412	const void* addr, socklen_t len,
	413	int af,
	414	struct hostent *host,
	415	char *buffer, size_t buflen,
	416	int errnop, int h_errnop,
	417	int32_t *ttlp) {
6b21f0cf	418
e8a7a315	419	const char canonical = NULL, additional = NULL;
5502f0d9	420	uint32_t local_address_ipv4 = LOCALADDRESS_IPV4;
e80af1bd	421	_cleanup_free_ struct local_address *addresses = NULL;
5502f0d9	422	_cleanup_free_ char *hn = NULL;
e80af1bd LP	423	int n_addresses = 0;
e80af1bd LP	424	struct local_address *a;
3fdcecc8	425	bool additional_from_hostname = false;
e80af1bd	426	unsigned n;
5502f0d9	427
06202b9e	428	PROTECT_ERRNO;
0c5eb056 LP	429	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	430
5502f0d9 LP	431	assert(addr);
	432	assert(host);
	433	assert(buffer);
	434	assert(errnop);
	435	assert(h_errnop);
8041b5ba	436
555bd6e9	437	if (!IN_SET(af, AF_INET, AF_INET6)) {
cdccd29f	438	UNPROTECT_ERRNO;
0192cbdb	439	*errnop = EAFNOSUPPORT;
555bd6e9 LP	440	*h_errnop = NO_DATA;
	441	return NSS_STATUS_UNAVAIL;
	442	}
	443
9d485985	444	if (len != FAMILY_ADDRESS_SIZE(af)) {
cdccd29f	445	UNPROTECT_ERRNO;
0192cbdb	446	*errnop = EINVAL;
8041b5ba LP	447	*h_errnop = NO_RECOVERY;
	448	return NSS_STATUS_UNAVAIL;
	449	}
6b21f0cf	450
4e8c8252	451	if (af == AF_INET) {
8041b5ba LP	452	if (((uint32_t) addr) == LOCALADDRESS_IPV4)
8041b5ba LP	453	goto found;
6b21f0cf	454
8e38570e	455	if (((uint32_t) addr) == htobe32(INADDR_LOOPBACK)) {
e8a7a315	456	canonical = "localhost";
8e38570e	457	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e8a7a315 LP	458	goto found;
	459	}
	460
555bd6e9 LP	461	} else {
555bd6e9 LP	462	assert(af == AF_INET6);
8041b5ba	463
db50d326 YW	464	if (socket_ipv6_is_enabled())
	465	goto not_found;
	466
e8a7a315	467	if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) {
3fdcecc8 LP	468	canonical = "localhost";
3fdcecc8 LP	469	additional_from_hostname = true;
8041b5ba	470	goto found;
e8a7a315	471	}
4e8c8252 LP	472	}
4e8c8252 LP	473
db50d326 YW	474	n_addresses = local_addresses(NULL, 0, af, &addresses);
db50d326 YW	475	for (a = addresses, n = 0; (int) n < n_addresses; n++, a++)
68a9c7c4 ZJS	476	if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0)
68a9c7c4 ZJS	477	goto found;
e9140aff	478
97b11eed	479	addresses = mfree(addresses);
e9140aff	480
db50d326 YW	481	n_addresses = local_gateways(NULL, 0, af, &addresses);
db50d326 YW	482	for (a = addresses, n = 0; (int) n < n_addresses; n++, a++)
68a9c7c4	483	if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) {
5248e7e1	484	canonical = "_gateway";
68a9c7c4	485	goto found;
e9140aff	486	}
8041b5ba	487
db50d326	488	not_found:
8041b5ba	489	*h_errnop = HOST_NOT_FOUND;
8041b5ba LP	490	return NSS_STATUS_NOTFOUND;
	491
	492	found:
82e4c2d6	493	if (!canonical \|\| additional_from_hostname) {
3fdcecc8 LP	494	hn = gethostname_malloc();
3fdcecc8 LP	495	if (!hn) {
cdccd29f	496	UNPROTECT_ERRNO;
0192cbdb	497	*errnop = ENOMEM;
3fdcecc8 LP	498	*h_errnop = NO_RECOVERY;
	499	return NSS_STATUS_TRYAGAIN;
	500	}
	501
	502	if (!canonical)
	503	canonical = hn;
82e4c2d6	504	else
3fdcecc8 LP	505	additional = hn;
3fdcecc8 LP	506	}
4e8c8252	507
cdccd29f	508	UNPROTECT_ERRNO;
e8a7a315 LP	509	return fill_in_hostent(
	510	canonical, additional,
	511	af,
	512	addresses, n_addresses,
	513	local_address_ipv4,
	514	host,
	515	buffer, buflen,
0192cbdb	516	errnop, h_errnop,
e8a7a315 LP	517	ttlp,
e8a7a315 LP	518	NULL);
4e8c8252	519	}
6b21f0cf	520
c9fdc26e LP	521	NSS_GETHOSTBYNAME_FALLBACKS(myhostname);
c9fdc26e LP	522	NSS_GETHOSTBYADDR_FALLBACKS(myhostname);