diff options
Diffstat (limited to 'src/nss-resolve/nss-resolve.c')
| -rw-r--r-- | src/nss-resolve/nss-resolve.c | 664 |
1 files changed, 664 insertions, 0 deletions
diff --git a/src/nss-resolve/nss-resolve.c b/src/nss-resolve/nss-resolve.c new file mode 100644 index 0000000..3fee4f5 --- /dev/null +++ b/src/nss-resolve/nss-resolve.c @@ -0,0 +1,664 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <errno.h> +#include <netdb.h> +#include <nss.h> +#include <stdlib.h> +#include <sys/types.h> +#include <unistd.h> + +#include "errno-util.h" +#include "in-addr-util.h" +#include "macro.h" +#include "nss-util.h" +#include "resolved-def.h" +#include "signal-util.h" +#include "string-util.h" +#include "strv.h" +#include "varlink.h" + +NSS_GETHOSTBYNAME_PROTOTYPES(resolve); +NSS_GETHOSTBYADDR_PROTOTYPES(resolve); + +static bool error_shall_fallback(const char *error_id) { + return STR_IN_SET(error_id, + VARLINK_ERROR_DISCONNECTED, + VARLINK_ERROR_TIMEOUT, + VARLINK_ERROR_PROTOCOL, + VARLINK_ERROR_INTERFACE_NOT_FOUND, + VARLINK_ERROR_METHOD_NOT_FOUND, + VARLINK_ERROR_METHOD_NOT_IMPLEMENTED); +} + +static int connect_to_resolved(Varlink **ret) { + _cleanup_(varlink_unrefp) Varlink *link = NULL; + int r; + + r = varlink_connect_address(&link, "/run/systemd/resolve/io.systemd.Resolve"); + if (r < 0) + return r; + + r = varlink_set_relative_timeout(link, SD_RESOLVED_QUERY_TIMEOUT_USEC); + if (r < 0) + return r; + + *ret = TAKE_PTR(link); + return 0; +} + +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; +} + +static int json_dispatch_ifindex(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata) { + int *ifi = userdata; + intmax_t t; + + assert(variant); + assert(ifi); + + if (!json_variant_is_integer(variant)) + return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is not an integer.", strna(name)); + + t = json_variant_integer(variant); + if (t <= 0 || t > INT_MAX) + return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is out of bounds for an interface index.", strna(name)); + + *ifi = (int) t; + return 0; +} + +static int json_dispatch_family(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata) { + int *family = userdata; + intmax_t t; + + assert(variant); + assert(family); + + if (!json_variant_is_integer(variant)) + return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is not an integer.", strna(name)); + + t = json_variant_integer(variant); + if (t < 0 || t > INT_MAX) + return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is not a valid family.", strna(name)); + + *family = (int) t; + return 0; +} + +typedef struct ResolveHostnameReply { + JsonVariant *addresses; + char *name; + uint64_t flags; +} ResolveHostnameReply; + +static void resolve_hostname_reply_destroy(ResolveHostnameReply *p) { + assert(p); + + json_variant_unref(p->addresses); + free(p->name); +} + +static const JsonDispatch resolve_hostname_reply_dispatch_table[] = { + { "addresses", JSON_VARIANT_ARRAY, json_dispatch_variant, offsetof(ResolveHostnameReply, addresses), JSON_MANDATORY }, + { "name", JSON_VARIANT_STRING, json_dispatch_string, offsetof(ResolveHostnameReply, name), 0 }, + { "flags", JSON_VARIANT_UNSIGNED, json_dispatch_uint64, offsetof(ResolveHostnameReply, flags), 0 }, + {} +}; + +typedef struct AddressParameters { + int ifindex; + int family; + union in_addr_union address; + size_t address_size; +} AddressParameters; + +static int json_dispatch_address(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata) { + AddressParameters *p = userdata; + union in_addr_union buf = {}; + JsonVariant *i; + size_t n, k = 0; + + assert(variant); + assert(p); + + if (!json_variant_is_array(variant)) + return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is not an array.", strna(name)); + + n = json_variant_elements(variant); + if (!IN_SET(n, 4, 16)) + return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is array of unexpected size.", strna(name)); + + JSON_VARIANT_ARRAY_FOREACH(i, variant) { + intmax_t b; + + if (!json_variant_is_integer(i)) + return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "Element %zu of JSON field '%s' is not an integer.", k, strna(name)); + + b = json_variant_integer(i); + if (b < 0 || b > 0xff) + return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "Element %zu of JSON field '%s' is out of range 0…255.", k, strna(name)); + + buf.bytes[k++] = (uint8_t) b; + } + + p->address = buf; + p->address_size = k; + + return 0; +} + +static const JsonDispatch address_parameters_dispatch_table[] = { + { "ifindex", JSON_VARIANT_INTEGER, json_dispatch_ifindex, offsetof(AddressParameters, ifindex), 0 }, + { "family", JSON_VARIANT_INTEGER, json_dispatch_family, offsetof(AddressParameters, family), JSON_MANDATORY }, + { "address", JSON_VARIANT_ARRAY, json_dispatch_address, 0, JSON_MANDATORY }, + {} +}; + +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_(resolve_hostname_reply_destroy) ResolveHostnameReply p = {}; + _cleanup_(json_variant_unrefp) JsonVariant *cparams = NULL; + struct gaih_addrtuple *r_tuple = NULL, *r_tuple_first = NULL; + _cleanup_(varlink_unrefp) Varlink *link = NULL; + const char *canonical = NULL, *error_id = NULL; + JsonVariant *entry, *rparams; + size_t l, ms, idx, c = 0; + char *r_name; + int r; + + PROTECT_ERRNO; + BLOCK_SIGNALS(NSS_SIGNALS_BLOCK); + + assert(name); + assert(pat); + assert(buffer); + assert(errnop); + assert(h_errnop); + + r = connect_to_resolved(&link); + if (r < 0) + goto fail; + + r = json_build(&cparams, JSON_BUILD_OBJECT( + JSON_BUILD_PAIR("name", JSON_BUILD_STRING(name)))); + if (r < 0) + goto fail; + + /* 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 distinguish such executed but negative replies from complete failure to + * talk to resolved). */ + r = varlink_call(link, "io.systemd.Resolve.ResolveHostname", cparams, &rparams, &error_id, NULL); + if (r < 0) + goto fail; + if (!isempty(error_id)) { + if (!error_shall_fallback(error_id)) + goto not_found; + goto fail; + } + + r = json_dispatch(rparams, resolve_hostname_reply_dispatch_table, NULL, 0, &p); + if (r < 0) + goto fail; + if (json_variant_is_blank_object(p.addresses)) + goto not_found; + + JSON_VARIANT_ARRAY_FOREACH(entry, p.addresses) { + AddressParameters q = {}; + + r = json_dispatch(entry, address_parameters_dispatch_table, NULL, 0, &q); + if (r < 0) + goto fail; + + if (!IN_SET(q.family, AF_INET, AF_INET6)) + continue; + + if (q.address_size != FAMILY_ADDRESS_SIZE(q.family)) { + r = -EINVAL; + goto fail; + } + + c++; + } + + canonical = p.name ?: name; + + l = strlen(canonical); + ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * c; + if (buflen < ms) { + UNPROTECT_ERRNO; + *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); + + JSON_VARIANT_ARRAY_FOREACH(entry, p.addresses) { + AddressParameters q = {}; + + r = json_dispatch(entry, address_parameters_dispatch_table, NULL, 0, &q); + if (r < 0) + goto fail; + + if (!IN_SET(q.family, AF_INET, AF_INET6)) + continue; + + r_tuple = (struct gaih_addrtuple*) (buffer + idx); + r_tuple->next = (struct gaih_addrtuple*) ((char*) r_tuple + ALIGN(sizeof(struct gaih_addrtuple))); + r_tuple->name = r_name; + r_tuple->family = q.family; + r_tuple->scopeid = ifindex_to_scopeid(q.family, &q.address, q.ifindex); + memcpy(r_tuple->addr, &q.address, q.address_size); + + idx += ALIGN(sizeof(struct gaih_addrtuple)); + } + + assert(r_tuple); + r_tuple->next = NULL; /* Override last next pointer */ + + assert(idx == ms); + + if (*pat) + **pat = *r_tuple_first; + else + *pat = r_tuple_first; + + 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; + +fail: + UNPROTECT_ERRNO; + *errnop = -r; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + +not_found: + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; +} + +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_(resolve_hostname_reply_destroy) ResolveHostnameReply p = {}; + _cleanup_(json_variant_unrefp) JsonVariant *cparams = NULL; + char *r_name, *r_aliases, *r_addr, *r_addr_list; + _cleanup_(varlink_unrefp) Varlink *link = NULL; + const char *canonical, *error_id = NULL; + size_t l, idx, ms, alen, i = 0, c = 0; + JsonVariant *entry, *rparams; + int r; + + PROTECT_ERRNO; + 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 = connect_to_resolved(&link); + if (r < 0) + goto fail; + + r = json_build(&cparams, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("name", JSON_BUILD_STRING(name)), + JSON_BUILD_PAIR("family", JSON_BUILD_INTEGER(af)))); + if (r < 0) + goto fail; + + r = varlink_call(link, "io.systemd.Resolve.ResolveHostname", cparams, &rparams, &error_id, NULL); + if (r < 0) + goto fail; + if (!isempty(error_id)) { + if (!error_shall_fallback(error_id)) + goto not_found; + goto fail; + } + + r = json_dispatch(rparams, resolve_hostname_reply_dispatch_table, NULL, 0, &p); + if (r < 0) + goto fail; + if (json_variant_is_blank_object(p.addresses)) + goto not_found; + + JSON_VARIANT_ARRAY_FOREACH(entry, p.addresses) { + AddressParameters q = {}; + + r = json_dispatch(entry, address_parameters_dispatch_table, NULL, 0, &q); + if (r < 0) + goto fail; + + if (!IN_SET(q.family, AF_INET, AF_INET6)) + continue; + + if (q.address_size != FAMILY_ADDRESS_SIZE(q.family)) { + r = -EINVAL; + goto fail; + } + + c++; + } + + canonical = p.name ?: name; + + alen = FAMILY_ADDRESS_SIZE(af); + l = strlen(canonical); + + ms = ALIGN(l+1) + c*ALIGN(alen) + (c+2) * sizeof(char*); + + if (buflen < ms) { + UNPROTECT_ERRNO; + *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; + + JSON_VARIANT_ARRAY_FOREACH(entry, p.addresses) { + AddressParameters q = {}; + + r = json_dispatch(entry, address_parameters_dispatch_table, NULL, 0, &q); + if (r < 0) + goto fail; + + if (q.family != af) + continue; + + if (q.address_size != alen) { + r = -EINVAL; + goto fail; + } + + memcpy(r_addr + i*ALIGN(alen), &q.address, alen); + i++; + } + + 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; + + 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; + +fail: + UNPROTECT_ERRNO; + *errnop = -r; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + +not_found: + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; +} + +typedef struct ResolveAddressReply { + JsonVariant *names; + uint64_t flags; +} ResolveAddressReply; + +static void resolve_address_reply_destroy(ResolveAddressReply *p) { + assert(p); + + json_variant_unref(p->names); +} + +static const JsonDispatch resolve_address_reply_dispatch_table[] = { + { "names", JSON_VARIANT_ARRAY, json_dispatch_variant, offsetof(ResolveAddressReply, names), JSON_MANDATORY }, + { "flags", JSON_VARIANT_UNSIGNED, json_dispatch_uint64, offsetof(ResolveAddressReply, flags), 0 }, + {} +}; + +typedef struct NameParameters { + int ifindex; + char *name; +} NameParameters; + +static void name_parameters_destroy(NameParameters *p) { + assert(p); + + free(p->name); +} + +static const JsonDispatch name_parameters_dispatch_table[] = { + { "ifindex", JSON_VARIANT_INTEGER, json_dispatch_ifindex, offsetof(NameParameters, ifindex), 0 }, + { "name", JSON_VARIANT_UNSIGNED, json_dispatch_string, offsetof(NameParameters, name), JSON_MANDATORY }, + {} +}; + +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_(resolve_address_reply_destroy) ResolveAddressReply p = {}; + _cleanup_(json_variant_unrefp) JsonVariant *cparams = NULL; + char *r_name, *r_aliases, *r_addr, *r_addr_list; + _cleanup_(varlink_unrefp) Varlink *link = NULL; + JsonVariant *entry, *rparams; + const char *n, *error_id; + unsigned c = 0, i = 0; + size_t ms = 0, idx; + int r; + + PROTECT_ERRNO; + BLOCK_SIGNALS(NSS_SIGNALS_BLOCK); + + assert(addr); + assert(result); + 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)) { + r = -EINVAL; + goto fail; + } + + r = connect_to_resolved(&link); + if (r < 0) + goto fail; + + r = json_build(&cparams, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("address", JSON_BUILD_BYTE_ARRAY(addr, len)), + JSON_BUILD_PAIR("family", JSON_BUILD_INTEGER(af)))); + if (r < 0) + goto fail; + + r = varlink_call(link, "io.systemd.Resolve.ResolveAddress", cparams, &rparams, &error_id, NULL); + if (r < 0) + goto fail; + if (!isempty(error_id)) { + if (!error_shall_fallback(error_id)) + goto not_found; + goto fail; + } + + r = json_dispatch(rparams, resolve_address_reply_dispatch_table, NULL, 0, &p); + if (r < 0) + goto fail; + if (json_variant_is_blank_object(p.names)) + goto not_found; + + JSON_VARIANT_ARRAY_FOREACH(entry, p.names) { + _cleanup_(name_parameters_destroy) NameParameters q = {}; + + r = json_dispatch(entry, name_parameters_dispatch_table, NULL, 0, &q); + if (r < 0) + goto fail; + + ms += ALIGN(strlen(q.name) + 1); + } + + ms += ALIGN(len) + /* the address */ + 2 * sizeof(char*) + /* pointers to the address, plus trailing NULL */ + json_variant_elements(p.names) * sizeof(char*); /* pointers to aliases, plus trailing NULL */ + + if (buflen < ms) { + UNPROTECT_ERRNO; + *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; + JSON_VARIANT_ARRAY_FOREACH(entry, p.names) { + _cleanup_(name_parameters_destroy) NameParameters q = {}; + size_t l; + char *z; + + r = json_dispatch(entry, name_parameters_dispatch_table, NULL, 0, &q); + if (r < 0) + goto fail; + + l = strlen(q.name); + z = buffer + idx; + memcpy(z, n, l+1); + + if (i > 0) + ((char**) r_aliases)[i-1] = z; + i++; + + idx += ALIGN(l+1); + } + + ((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 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; + +fail: + UNPROTECT_ERRNO; + *errnop = -r; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + +not_found: + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; +} + +NSS_GETHOSTBYNAME_FALLBACKS(resolve); +NSS_GETHOSTBYADDR_FALLBACKS(resolve); |