userdb: when doing client-side NSS look-ups optionally avoid shadow look-ups

9 files changed, 87 insertions, 54 deletions

diff --git a/src/nss-systemd/nss-systemd.c b/src/nss-systemd/nss-systemd.c
index 581b7959bd..058119742f 100644
--- a/src/nss-systemd/nss-systemd.c
+++ b/src/nss-systemd/nss-systemd.c
@@ -482,7 +482,7 @@ enum nss_status _nss_systemd_getgrent_r(
                                 }
                         }
 
-                        r = nss_group_record_by_name(group_name, &gr);
+                        r = nss_group_record_by_name(group_name, false, &gr);
                         if (r == -ESRCH)
                                 continue;
                         if (r < 0) {
diff --git a/src/nss-systemd/userdb-glue.c b/src/nss-systemd/userdb-glue.c
index 58915c3d23..a88b0d7502 100644
--- a/src/nss-systemd/userdb-glue.c
+++ b/src/nss-systemd/userdb-glue.c
@@ -251,7 +251,7 @@ enum nss_status userdb_getgrnam(
                 if (lock_fd < 0 && lock_fd != -EBUSY)
                         return lock_fd;
 
-                r = nss_group_record_by_name(name, &g);
+                r = nss_group_record_by_name(name, false, &g);
                 if (r == -ESRCH)
                         return NSS_STATUS_NOTFOUND;
                 if (r < 0) {
@@ -310,7 +310,7 @@ enum nss_status userdb_getgrgid(
                 if (lock_fd < 0 && lock_fd != -EBUSY)
                         return lock_fd;
 
-                r = nss_group_record_by_gid(gid, &g);
+                r = nss_group_record_by_gid(gid, false, &g);
                 if (r == -ESRCH)
                         return NSS_STATUS_NOTFOUND;
 
diff --git a/src/shared/group-record-nss.c b/src/shared/group-record-nss.c
index 77924f1c40..5c4fae865a 100644
--- a/src/shared/group-record-nss.c
+++ b/src/shared/group-record-nss.c
@@ -106,12 +106,16 @@ int nss_sgrp_for_group(const struct group *grp, struct sgrp *ret_sgrp, char **re
         }
 }
 
-int nss_group_record_by_name(const char *name, GroupRecord **ret) {
+int nss_group_record_by_name(
+                const char *name,
+                bool with_shadow,
+                GroupRecord **ret) {
+
         _cleanup_free_ char *buf = NULL, *sbuf = NULL;
         struct group grp, *result;
         bool incomplete = false;
         size_t buflen = 4096;
-        struct sgrp sgrp;
+        struct sgrp sgrp, *sresult = NULL;
         int r;
 
         assert(name);
@@ -141,13 +145,17 @@ int nss_group_record_by_name(const char *name, GroupRecord **ret) {
                 buf = mfree(buf);
         }
 
-        r = nss_sgrp_for_group(result, &sgrp, &sbuf);
-        if (r < 0) {
-                log_debug_errno(r, "Failed to do shadow lookup for group %s, ignoring: %m", result->gr_name);
-                incomplete = ERRNO_IS_PRIVILEGE(r);
-        }
-
-        r = nss_group_to_group_record(result, r >= 0 ? &sgrp : NULL, ret);
+        if (with_shadow) {
+                r = nss_sgrp_for_group(result, &sgrp, &sbuf);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to do shadow lookup for group %s, ignoring: %m", result->gr_name);
+                        incomplete = ERRNO_IS_PRIVILEGE(r);
+                } else
+                        sresult = &sgrp;
+        } else
+                incomplete = true;
+
+        r = nss_group_to_group_record(result, sresult, ret);
         if (r < 0)
                 return r;
 
@@ -155,12 +163,16 @@ int nss_group_record_by_name(const char *name, GroupRecord **ret) {
         return 0;
 }
 
-int nss_group_record_by_gid(gid_t gid, GroupRecord **ret) {
+int nss_group_record_by_gid(
+                gid_t gid,
+                bool with_shadow,
+                GroupRecord **ret) {
+
         _cleanup_free_ char *buf = NULL, *sbuf = NULL;
         struct group grp, *result;
         bool incomplete = false;
         size_t buflen = 4096;
-        struct sgrp sgrp;
+        struct sgrp sgrp, *sresult = NULL;
         int r;
 
         assert(ret);
@@ -188,13 +200,17 @@ int nss_group_record_by_gid(gid_t gid, GroupRecord **ret) {
                 buf = mfree(buf);
         }
 
-        r = nss_sgrp_for_group(result, &sgrp, &sbuf);
-        if (r < 0) {
-                log_debug_errno(r, "Failed to do shadow lookup for group %s, ignoring: %m", result->gr_name);
-                incomplete = ERRNO_IS_PRIVILEGE(r);
-        }
-
-        r = nss_group_to_group_record(result, r >= 0 ? &sgrp : NULL, ret);
+        if (with_shadow) {
+                r = nss_sgrp_for_group(result, &sgrp, &sbuf);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to do shadow lookup for group %s, ignoring: %m", result->gr_name);
+                        incomplete = ERRNO_IS_PRIVILEGE(r);
+                } else
+                        sresult = &sgrp;
+        } else
+                incomplete = true;
+
+        r = nss_group_to_group_record(result, sresult, ret);
         if (r < 0)
                 return r;
 
diff --git a/src/shared/group-record-nss.h b/src/shared/group-record-nss.h
index 38b2995178..077c22d89f 100644
--- a/src/shared/group-record-nss.h
+++ b/src/shared/group-record-nss.h
@@ -11,5 +11,5 @@
 int nss_group_to_group_record(const struct group *grp, const struct sgrp *sgrp, GroupRecord **ret);
 int nss_sgrp_for_group(const struct group *grp, struct sgrp *ret_sgrp, char **ret_buffer);
 
-int nss_group_record_by_name(const char *name, GroupRecord **ret);
-int nss_group_record_by_gid(gid_t gid, GroupRecord **ret);
+int nss_group_record_by_name(const char *name, bool with_shadow, GroupRecord **ret);
+int nss_group_record_by_gid(gid_t gid, bool with_shadow, GroupRecord **ret);
diff --git a/src/shared/user-record-nss.c b/src/shared/user-record-nss.c
index 0ff6d17117..f265a2af93 100644
--- a/src/shared/user-record-nss.c
+++ b/src/shared/user-record-nss.c
@@ -161,12 +161,16 @@ int nss_spwd_for_passwd(const struct passwd *pwd, struct spwd *ret_spwd, char **
         }
 }
 
-int nss_user_record_by_name(const char *name, UserRecord **ret) {
+int nss_user_record_by_name(
+                const char *name,
+                bool with_shadow,
+                UserRecord **ret) {
+
         _cleanup_free_ char *buf = NULL, *sbuf = NULL;
         struct passwd pwd, *result;
         bool incomplete = false;
         size_t buflen = 4096;
-        struct spwd spwd;
+        struct spwd spwd, *sresult = NULL;
         int r;
 
         assert(name);
@@ -197,13 +201,17 @@ int nss_user_record_by_name(const char *name, UserRecord **ret) {
                 buf = mfree(buf);
         }
 
-        r = nss_spwd_for_passwd(result, &spwd, &sbuf);
-        if (r < 0) {
-                log_debug_errno(r, "Failed to do shadow lookup for user %s, ignoring: %m", name);
-                incomplete = ERRNO_IS_PRIVILEGE(r);
-        }
+        if (with_shadow) {
+                r = nss_spwd_for_passwd(result, &spwd, &sbuf);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to do shadow lookup for user %s, ignoring: %m", name);
+                        incomplete = ERRNO_IS_PRIVILEGE(r);
+                } else
+                        sresult = &spwd;
+        } else
+                incomplete = true;
 
-        r = nss_passwd_to_user_record(result, r >= 0 ? &spwd : NULL, ret);
+        r = nss_passwd_to_user_record(result, sresult, ret);
         if (r < 0)
                 return r;
 
@@ -211,12 +219,16 @@ int nss_user_record_by_name(const char *name, UserRecord **ret) {
         return 0;
 }
 
-int nss_user_record_by_uid(uid_t uid, UserRecord **ret) {
+int nss_user_record_by_uid(
+                uid_t uid,
+                bool with_shadow,
+                UserRecord **ret) {
+
         _cleanup_free_ char *buf = NULL, *sbuf = NULL;
         struct passwd pwd, *result;
         bool incomplete = false;
         size_t buflen = 4096;
-        struct spwd spwd;
+        struct spwd spwd, *sresult = NULL;
         int r;
 
         assert(ret);
@@ -245,13 +257,17 @@ int nss_user_record_by_uid(uid_t uid, UserRecord **ret) {
                 buf = mfree(buf);
         }
 
-        r = nss_spwd_for_passwd(result, &spwd, &sbuf);
-        if (r < 0) {
-                log_debug_errno(r, "Failed to do shadow lookup for UID " UID_FMT ", ignoring: %m", uid);
-                incomplete = ERRNO_IS_PRIVILEGE(r);
-        }
+        if (with_shadow)  {
+                r = nss_spwd_for_passwd(result, &spwd, &sbuf);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to do shadow lookup for UID " UID_FMT ", ignoring: %m", uid);
+                        incomplete = ERRNO_IS_PRIVILEGE(r);
+                } else
+                        sresult = &spwd;
+        } else
+                incomplete = true;
 
-        r = nss_passwd_to_user_record(result, r >= 0 ? &spwd : NULL, ret);
+        r = nss_passwd_to_user_record(result, sresult, ret);
         if (r < 0)
                 return r;
 
diff --git a/src/shared/user-record-nss.h b/src/shared/user-record-nss.h
index d5fb23ad2a..0eb78d5b52 100644
--- a/src/shared/user-record-nss.h
+++ b/src/shared/user-record-nss.h
@@ -11,5 +11,5 @@
 int nss_passwd_to_user_record(const struct passwd *pwd, const struct spwd *spwd, UserRecord **ret);
 int nss_spwd_for_passwd(const struct passwd *pwd, struct spwd *ret_spwd, char **ret_buffer);
 
-int nss_user_record_by_name(const char *name, UserRecord **ret);
-int nss_user_record_by_uid(uid_t uid, UserRecord **ret);
+int nss_user_record_by_name(const char *name, bool with_shadow, UserRecord **ret);
+int nss_user_record_by_uid(uid_t uid, bool with_shadow, UserRecord **ret);
diff --git a/src/shared/userdb.c b/src/shared/userdb.c
index 92f8796768..11ab267b03 100644
--- a/src/shared/userdb.c
+++ b/src/shared/userdb.c
@@ -614,7 +614,7 @@ int userdb_by_name(const char *name, UserDBFlags flags, UserRecord **ret) {
                         iterator->nss_lock = r;
 
                         /* Client-side NSS fallback */
-                        r = nss_user_record_by_name(name, ret);
+                        r = nss_user_record_by_name(name, !FLAGS_SET(flags, USERDB_AVOID_SHADOW), ret);
                         if (r >= 0)
                                 return r;
                 }
@@ -661,7 +661,7 @@ int userdb_by_uid(uid_t uid, UserDBFlags flags, UserRecord **ret) {
                         iterator->nss_lock = r;
 
                         /* Client-side NSS fallback */
-                        r = nss_user_record_by_uid(uid, ret);
+                        r = nss_user_record_by_uid(uid, !FLAGS_SET(flags, USERDB_AVOID_SHADOW), ret);
                         if (r >= 0)
                                 return r;
                 }
@@ -819,7 +819,7 @@ int groupdb_by_name(const char *name, UserDBFlags flags, GroupRecord **ret) {
                 if (r >= 0 || r == -EBUSY) {
                         iterator->nss_lock = r;
 
-                        r = nss_group_record_by_name(name, ret);
+                        r = nss_group_record_by_name(name, !FLAGS_SET(flags, USERDB_AVOID_SHADOW), ret);
                         if (r >= 0)
                                 return r;
                 }
@@ -865,7 +865,7 @@ int groupdb_by_gid(gid_t gid, UserDBFlags flags, GroupRecord **ret) {
                 if (r >= 0 || r == -EBUSY) {
                         iterator->nss_lock = r;
 
-                        r = nss_group_record_by_gid(gid, ret);
+                        r = nss_group_record_by_gid(gid, !FLAGS_SET(flags, USERDB_AVOID_SHADOW), ret);
                         if (r >= 0)
                                 return r;
                 }
@@ -1046,7 +1046,7 @@ int membershipdb_by_group(const char *name, UserDBFlags flags, UserDBIterator **
                 return iterator->nss_lock;
 
         /* We ignore all errors here, since the group might be defined by a userdb native service, and we queried them already above. */
-        (void) nss_group_record_by_name(name, &gr);
+        (void) nss_group_record_by_name(name, false, &gr);
         if (gr) {
                 iterator->members_of_group = strv_copy(gr->members);
                 if (!iterator->members_of_group)
diff --git a/src/shared/userdb.h b/src/shared/userdb.h
index 4288b0ff95..8af31aa86c 100644
--- a/src/shared/userdb.h
+++ b/src/shared/userdb.h
@@ -16,9 +16,10 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(UserDBIterator*, userdb_iterator_free);
 
 typedef enum UserDBFlags {
         USERDB_AVOID_NSS          = 1 << 0,  /* don't do client-side nor server-side NSS */
-        USERDB_AVOID_DYNAMIC_USER = 1 << 1,  /* exclude looking up in io.systemd.DynamicUser */
-        USERDB_AVOID_MULTIPLEXER  = 1 << 2,  /* exclude looking up via io.systemd.Multiplexer */
-        USERDB_DONT_SYNTHESIZE    = 1 << 3,  /* don't synthesize root/nobody */
+        USERDB_AVOID_SHADOW       = 1 << 1,  /* don't do client-side shadow calls (server side might happen though) */
+        USERDB_AVOID_DYNAMIC_USER = 1 << 2,  /* exclude looking up in io.systemd.DynamicUser */
+        USERDB_AVOID_MULTIPLEXER  = 1 << 3,  /* exclude looking up via io.systemd.Multiplexer */
+        USERDB_DONT_SYNTHESIZE    = 1 << 4,  /* don't synthesize root/nobody */
 } UserDBFlags;
 
 int userdb_by_name(const char *name, UserDBFlags flags, UserRecord **ret);
diff --git a/src/userdb/userwork.c b/src/userdb/userwork.c
index 3bc5ecc1d0..053448a718 100644
--- a/src/userdb/userwork.c
+++ b/src/userdb/userwork.c
@@ -137,9 +137,9 @@ static int vl_method_get_user_record(Varlink *link, JsonVariant *parameters, Var
 
         if (streq_ptr(p.service, "io.systemd.NameServiceSwitch")) {
                 if (uid_is_valid(p.uid))
-                        r = nss_user_record_by_uid(p.uid, &hr);
+                        r = nss_user_record_by_uid(p.uid, true, &hr);
                 else if (p.user_name)
-                        r = nss_user_record_by_name(p.user_name, &hr);
+                        r = nss_user_record_by_name(p.user_name, true, &hr);
                 else {
                         _cleanup_(json_variant_unrefp) JsonVariant *last = NULL;
 
@@ -324,9 +324,9 @@ static int vl_method_get_group_record(Varlink *link, JsonVariant *parameters, Va
         if (streq_ptr(p.service, "io.systemd.NameServiceSwitch")) {
 
                 if (gid_is_valid(p.gid))
-                        r = nss_group_record_by_gid(p.gid, &g);
+                        r = nss_group_record_by_gid(p.gid, true, &g);
                 else if (p.group_name)
-                        r = nss_group_record_by_name(p.group_name, &g);
+                        r = nss_group_record_by_name(p.group_name, true, &g);
                 else {
                         _cleanup_(json_variant_unrefp) JsonVariant *last = NULL;
 
@@ -467,7 +467,7 @@ static int vl_method_get_memberships(Varlink *link, JsonVariant *parameters, Var
                         const char *last = NULL;
                         char **i;
 
-                        r = nss_group_record_by_name(p.group_name, &g);
+                        r = nss_group_record_by_name(p.group_name, true, &g);
                         if (r == -ESRCH)
                                 return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
                         if (r < 0)