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-rw-r--r--src/nss-resolve/nss-resolve.c657
1 files changed, 657 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..8370fed
--- /dev/null
+++ b/src/nss-resolve/nss-resolve.c
@@ -0,0 +1,657 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#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;
+}
+
+static bool avoid_deadlock(void) {
+
+ /* Check whether this lookup might have a chance of deadlocking because we are called from the service manager
+ * code activating systemd-resolved.service. After all, we shouldn't synchronously do lookups to
+ * systemd-resolved if we are required to finish before it can be started. This of course won't detect all
+ * possible dead locks of this kind, but it should work for the most obvious cases. */
+
+ if (geteuid() != 0) /* Ignore the env vars unless we are privileged. */
+ return false;
+
+ return streq_ptr(getenv("SYSTEMD_ACTIVATION_UNIT"), "systemd-resolved.service") &&
+ streq_ptr(getenv("SYSTEMD_ACTIVATION_SCOPE"), "system");
+}
+
+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;
+
+ PROTECT_ERRNO;
+ BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
+
+ assert(name);
+ assert(pat);
+ assert(buffer);
+ assert(errnop);
+ assert(h_errnop);
+
+ if (avoid_deadlock()) {
+ r = -EDEADLK;
+ 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_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") ||
+ !bus_error_shall_fallback(&error))
+ goto not_found;
+
+ /* 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). */
+ goto fail;
+ }
+
+ c = count_addresses(reply, AF_UNSPEC, &canonical);
+ if (c < 0) {
+ r = c;
+ goto fail;
+ }
+ if (c == 0)
+ goto not_found;
+
+ if (isempty(canonical))
+ canonical = 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);
+
+ 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 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 ret;
+
+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_(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;
+
+ 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;
+ }
+
+ if (avoid_deadlock()) {
+ r = -EDEADLK;
+ 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") ||
+ !bus_error_shall_fallback(&error))
+ goto not_found;
+
+ goto fail;
+ }
+
+ c = count_addresses(reply, af, &canonical);
+ if (c < 0) {
+ r = c;
+ goto fail;
+ }
+ if (c == 0)
+ goto not_found;
+
+ 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) {
+ 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;
+
+ 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;
+
+ 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 ret;
+
+not_found:
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+}
+
+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;
+
+ 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)) {
+ UNPROTECT_ERRNO;
+ *errnop = EINVAL;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ if (avoid_deadlock()) {
+ r = -EDEADLK;
+ 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",
+ "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") ||
+ !bus_error_shall_fallback(&error))
+ goto not_found;
+
+ 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)
+ goto not_found;
+
+ 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) {
+ 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;
+ 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 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 ret;
+
+not_found:
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+}
+
+NSS_GETHOSTBYNAME_FALLBACKS(resolve);
+NSS_GETHOSTBYADDR_FALLBACKS(resolve);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 12:42:40 +0000