]> git.ipfire.org Git - thirdparty/systemd.git/blobdiff - src/nss-resolve/nss-resolve.c
Merge pull request #31524 from poettering/secure-getenv-naming-fix
[thirdparty/systemd.git] / src / nss-resolve / nss-resolve.c
index e2a29475a225536ffb0c49ce71269393de1dbe29..3cefb6394c8336419e6aa843aba3bb85dc86ce47 100644 (file)
@@ -10,6 +10,7 @@
 
 #include "env-util.h"
 #include "errno-util.h"
+#include "glyph-util.h"
 #include "in-addr-util.h"
 #include "macro.h"
 #include "nss-util.h"
 #include "strv.h"
 #include "varlink.h"
 
-static JsonDispatchFlags json_dispatch_flags = 0;
+static JsonDispatchFlags json_dispatch_flags = JSON_ALLOW_EXTENSIONS;
 
 static void setup_logging(void) {
-        log_parse_environment();
+        log_parse_environment_variables();
 
         if (DEBUG_LOGGING)
                 json_dispatch_flags = JSON_LOG;
@@ -41,6 +42,9 @@ NSS_GETHOSTBYNAME_PROTOTYPES(resolve);
 NSS_GETHOSTBYADDR_PROTOTYPES(resolve);
 
 static bool error_shall_fallback(const char *error_id) {
+        /* The Varlink errors where we shall signal "please fallback" back to the NSS stack, so that some
+         * fallback module can be loaded. (These are mostly all Varlink-internal errors, as apparently we
+         * then were unable to even do IPC with systemd-resolved.) */
         return STR_IN_SET(error_id,
                           VARLINK_ERROR_DISCONNECTED,
                           VARLINK_ERROR_TIMEOUT,
@@ -50,6 +54,16 @@ static bool error_shall_fallback(const char *error_id) {
                           VARLINK_ERROR_METHOD_NOT_IMPLEMENTED);
 }
 
+static bool error_shall_try_again(const char *error_id) {
+        /* The Varlink errors where we shall signal "can't answer now but might be able to later" back to the
+         * NSS stack. These are all errors that indicate lack of configuration or network problems. */
+        return STR_IN_SET(error_id,
+                          "io.systemd.Resolve.NoNameServers",
+                          "io.systemd.Resolve.QueryTimedOut",
+                          "io.systemd.Resolve.MaxAttemptsReached",
+                          "io.systemd.Resolve.NetworkDown");
+}
+
 static int connect_to_resolved(Varlink **ret) {
         _cleanup_(varlink_unrefp) Varlink *link = NULL;
         int r;
@@ -81,11 +95,10 @@ static uint32_t ifindex_to_scopeid(int family, const void *a, int ifindex) {
 }
 
 static int json_dispatch_ifindex(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata) {
-        int *ifi = userdata;
-        intmax_t t;
+        int *ifi = ASSERT_PTR(userdata);
+        int64_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));
@@ -99,11 +112,10 @@ static int json_dispatch_ifindex(const char *name, JsonVariant *variant, JsonDis
 }
 
 static int json_dispatch_family(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata) {
-        int *family = userdata;
-        intmax_t t;
+        int *family = ASSERT_PTR(userdata);
+        int64_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));
@@ -130,9 +142,9 @@ static void resolve_hostname_reply_destroy(ResolveHostnameReply *p) {
 }
 
 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              },
+        { "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_TYPE_INVALID, json_dispatch_uint64,  offsetof(ResolveHostnameReply, flags),     0              },
         {}
 };
 
@@ -144,13 +156,12 @@ typedef struct AddressParameters {
 } AddressParameters;
 
 static int json_dispatch_address(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata) {
-        AddressParameters *p = userdata;
+        AddressParameters *p = ASSERT_PTR(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));
@@ -160,14 +171,16 @@ static int json_dispatch_address(const char *name, JsonVariant *variant, JsonDis
                 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;
+                int64_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));
+                        return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL),
+                                        "Element %zu of JSON field '%s' is out of range 0%s255.",
+                                        k, strna(name), special_glyph(SPECIAL_GLYPH_ELLIPSIS));
 
                 buf.bytes[k++] = (uint8_t) b;
         }
@@ -185,19 +198,30 @@ static const JsonDispatch address_parameters_dispatch_table[] = {
         {}
 };
 
-static uint64_t query_flags(void) {
-        uint64_t f = 0;
-        int r;
+static uint64_t query_flag(
+                const char *name,
+                const int value,
+                uint64_t flag) {
 
-        /* Allow callers to turn off validation, when we resolve via nss-resolve */
+        int r;
 
-        r = getenv_bool_secure("SYSTEMD_NSS_RESOLVE_VALIDATE");
-        if (r < 0 && r != -ENXIO)
-                log_debug_errno(r, "Failed to parse $SYSTEMD_NSS_RESOLVE_VALIDATE value, ignoring.");
-        else if (r == 0)
-                f |= SD_RESOLVED_NO_VALIDATE;
+        r = secure_getenv_bool(name);
+        if (r >= 0)
+                return r == value ? flag : 0;
+        if (r != -ENXIO)
+                log_debug_errno(r, "Failed to parse $%s, ignoring.", name);
+        return 0;
+}
 
-        return f;
+static uint64_t query_flags(void) {
+        /* Allow callers to turn off validation, synthetization, caching, etc., when we resolve via
+         * nss-resolve. */
+        return  query_flag("SYSTEMD_NSS_RESOLVE_VALIDATE", 0, SD_RESOLVED_NO_VALIDATE) |
+                query_flag("SYSTEMD_NSS_RESOLVE_SYNTHESIZE", 0, SD_RESOLVED_NO_SYNTHESIZE) |
+                query_flag("SYSTEMD_NSS_RESOLVE_CACHE", 0, SD_RESOLVED_NO_CACHE) |
+                query_flag("SYSTEMD_NSS_RESOLVE_ZONE", 0, SD_RESOLVED_NO_ZONE) |
+                query_flag("SYSTEMD_NSS_RESOLVE_TRUST_ANCHOR", 0, SD_RESOLVED_NO_TRUST_ANCHOR) |
+                query_flag("SYSTEMD_NSS_RESOLVE_NETWORK", 0, SD_RESOLVED_NO_NETWORK);
 }
 
 enum nss_status _nss_resolve_gethostbyname4_r(
@@ -238,16 +262,20 @@ enum nss_status _nss_resolve_gethostbyname4_r(
          * configuration can distinguish such executed but negative replies from complete failure to
          * talk to resolved). */
         const char *error_id;
-        r = varlink_call(link, "io.systemd.Resolve.ResolveHostname", cparams, &rparams, &error_id, NULL);
+        r = varlink_call(link, "io.systemd.Resolve.ResolveHostname", cparams, &rparams, &error_id);
         if (r < 0)
                 goto fail;
         if (!isempty(error_id)) {
-                if (!error_shall_fallback(error_id))
-                        goto not_found;
-                goto fail;
+                if (error_shall_try_again(error_id))
+                        goto try_again;
+                if (error_shall_fallback(error_id))
+                        goto fail;
+                if (streq(error_id, "io.systemd.Resolve.NoSuchResourceRecord"))
+                        goto no_data;
+                goto not_found;
         }
 
-        r = json_dispatch(rparams, resolve_hostname_reply_dispatch_table, NULL, json_dispatch_flags, &p);
+        r = json_dispatch(rparams, resolve_hostname_reply_dispatch_table, json_dispatch_flags, &p);
         if (r < 0)
                 goto fail;
         if (json_variant_is_blank_object(p.addresses))
@@ -257,7 +285,7 @@ enum nss_status _nss_resolve_gethostbyname4_r(
         JSON_VARIANT_ARRAY_FOREACH(entry, p.addresses) {
                 AddressParameters q = {};
 
-                r = json_dispatch(entry, address_parameters_dispatch_table, NULL, json_dispatch_flags, &q);
+                r = json_dispatch(entry, address_parameters_dispatch_table, json_dispatch_flags, &q);
                 if (r < 0)
                         goto fail;
 
@@ -295,7 +323,7 @@ enum nss_status _nss_resolve_gethostbyname4_r(
         JSON_VARIANT_ARRAY_FOREACH(entry, p.addresses) {
                 AddressParameters q = {};
 
-                r = json_dispatch(entry, address_parameters_dispatch_table, NULL, json_dispatch_flags, &q);
+                r = json_dispatch(entry, address_parameters_dispatch_table, json_dispatch_flags, &q);
                 if (r < 0)
                         goto fail;
 
@@ -341,6 +369,16 @@ fail:
 not_found:
         *h_errnop = HOST_NOT_FOUND;
         return NSS_STATUS_NOTFOUND;
+
+no_data:
+        *h_errnop = NO_DATA;
+        return NSS_STATUS_NOTFOUND;
+
+try_again:
+        UNPROTECT_ERRNO;
+        *errnop = -r;
+        *h_errnop = TRY_AGAIN;
+        return NSS_STATUS_TRYAGAIN;
 }
 
 enum nss_status _nss_resolve_gethostbyname3_r(
@@ -386,16 +424,20 @@ enum nss_status _nss_resolve_gethostbyname3_r(
                 goto fail;
 
         const char *error_id;
-        r = varlink_call(link, "io.systemd.Resolve.ResolveHostname", cparams, &rparams, &error_id, NULL);
+        r = varlink_call(link, "io.systemd.Resolve.ResolveHostname", cparams, &rparams, &error_id);
         if (r < 0)
                 goto fail;
         if (!isempty(error_id)) {
-                if (!error_shall_fallback(error_id))
-                        goto not_found;
-                goto fail;
+                if (error_shall_try_again(error_id))
+                        goto try_again;
+                if (error_shall_fallback(error_id))
+                        goto fail;
+                if (streq(error_id, "io.systemd.Resolve.NoSuchResourceRecord"))
+                        goto no_data;
+                goto not_found;
         }
 
-        r = json_dispatch(rparams, resolve_hostname_reply_dispatch_table, NULL, json_dispatch_flags, &p);
+        r = json_dispatch(rparams, resolve_hostname_reply_dispatch_table, json_dispatch_flags, &p);
         if (r < 0)
                 goto fail;
         if (json_variant_is_blank_object(p.addresses))
@@ -405,7 +447,7 @@ enum nss_status _nss_resolve_gethostbyname3_r(
         JSON_VARIANT_ARRAY_FOREACH(entry, p.addresses) {
                 AddressParameters q = {};
 
-                r = json_dispatch(entry, address_parameters_dispatch_table, NULL, json_dispatch_flags, &q);
+                r = json_dispatch(entry, address_parameters_dispatch_table, json_dispatch_flags, &q);
                 if (r < 0)
                         goto fail;
 
@@ -451,7 +493,7 @@ enum nss_status _nss_resolve_gethostbyname3_r(
         JSON_VARIANT_ARRAY_FOREACH(entry, p.addresses) {
                 AddressParameters q = {};
 
-                r = json_dispatch(entry, address_parameters_dispatch_table, NULL, json_dispatch_flags, &q);
+                r = json_dispatch(entry, address_parameters_dispatch_table, json_dispatch_flags, &q);
                 if (r < 0)
                         goto fail;
 
@@ -508,6 +550,16 @@ fail:
 not_found:
         *h_errnop = HOST_NOT_FOUND;
         return NSS_STATUS_NOTFOUND;
+
+no_data:
+        *h_errnop = NO_DATA;
+        return NSS_STATUS_NOTFOUND;
+
+try_again:
+        UNPROTECT_ERRNO;
+        *errnop = -r;
+        *h_errnop = TRY_AGAIN;
+        return NSS_STATUS_TRYAGAIN;
 }
 
 typedef struct ResolveAddressReply {
@@ -522,8 +574,8 @@ static void resolve_address_reply_destroy(ResolveAddressReply *p) {
 }
 
 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              },
+        { "names", JSON_VARIANT_ARRAY,         json_dispatch_variant, offsetof(ResolveAddressReply, names), JSON_MANDATORY },
+        { "flags", _JSON_VARIANT_TYPE_INVALID, json_dispatch_uint64,  offsetof(ResolveAddressReply, flags), 0              },
         {}
 };
 
@@ -590,16 +642,18 @@ enum nss_status _nss_resolve_gethostbyaddr2_r(
                 goto fail;
 
         const char* error_id;
-        r = varlink_call(link, "io.systemd.Resolve.ResolveAddress", cparams, &rparams, &error_id, NULL);
+        r = varlink_call(link, "io.systemd.Resolve.ResolveAddress", cparams, &rparams, &error_id);
         if (r < 0)
                 goto fail;
         if (!isempty(error_id)) {
-                if (!error_shall_fallback(error_id))
-                        goto not_found;
-                goto fail;
+                if (error_shall_try_again(error_id))
+                        goto try_again;
+                if (error_shall_fallback(error_id))
+                        goto fail;
+                goto not_found;
         }
 
-        r = json_dispatch(rparams, resolve_address_reply_dispatch_table, NULL, json_dispatch_flags, &p);
+        r = json_dispatch(rparams, resolve_address_reply_dispatch_table, json_dispatch_flags, &p);
         if (r < 0)
                 goto fail;
         if (json_variant_is_blank_object(p.names))
@@ -610,7 +664,7 @@ enum nss_status _nss_resolve_gethostbyaddr2_r(
         JSON_VARIANT_ARRAY_FOREACH(entry, p.names) {
                 _cleanup_(name_parameters_destroy) NameParameters q = {};
 
-                r = json_dispatch(entry, name_parameters_dispatch_table, NULL, json_dispatch_flags, &q);
+                r = json_dispatch(entry, name_parameters_dispatch_table, json_dispatch_flags, &q);
                 if (r < 0)
                         goto fail;
 
@@ -651,7 +705,7 @@ enum nss_status _nss_resolve_gethostbyaddr2_r(
         JSON_VARIANT_ARRAY_FOREACH(entry, p.names) {
                 _cleanup_(name_parameters_destroy) NameParameters q = {};
 
-                r = json_dispatch(entry, name_parameters_dispatch_table, NULL, json_dispatch_flags, &q);
+                r = json_dispatch(entry, name_parameters_dispatch_table, json_dispatch_flags, &q);
                 if (r < 0)
                         goto fail;
 
@@ -694,6 +748,12 @@ fail:
 not_found:
         *h_errnop = HOST_NOT_FOUND;
         return NSS_STATUS_NOTFOUND;
+
+try_again:
+        UNPROTECT_ERRNO;
+        *errnop = -r;
+        *h_errnop = TRY_AGAIN;
+        return NSS_STATUS_TRYAGAIN;
 }
 
 NSS_GETHOSTBYNAME_FALLBACKS(resolve);