| /* 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 "signal-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(0x7F000002)) |
| #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 : 2); |
| 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 */ |
| 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(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 : 1) * ALIGN(alen) + |
| (c > 0 ? c+1 : 2) * 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; |
| else |
| 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 { |
| ((char**) r_addr_list)[0] = r_addr; |
| ((char**) r_addr_list)[1] = NULL; |
| idx += 2 * 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)) { |
| 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 (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) { |
| canonical = "localhost"; |
| additional_from_hostname = true; |
| goto found; |
| } |
| } |
| |
| n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses); |
| for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) { |
| if (af != a->family) |
| continue; |
| |
| if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) |
| goto found; |
| } |
| |
| addresses = mfree(addresses); |
| |
| n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses); |
| for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) { |
| if (af != a->family) |
| continue; |
| |
| if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) { |
| canonical = "_gateway"; |
| goto 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); |
