diff --git a/src/basic/util.h b/src/basic/util.h
index f009d37d4c..dc33d66067 100644
--- a/src/basic/util.h
+++ b/src/basic/util.h
@@ -174,12 +174,21 @@ static inline void *mempset(void *s, int c, size_t n) {
 }
 
 static inline void _reset_errno_(int *saved_errno) {
+        if (*saved_errno < 0) /* Invalidated by UNPROTECT_ERRNO? */
+                return;
+
         errno = *saved_errno;
 }
 
 #define PROTECT_ERRNO                                                   \
         _cleanup_(_reset_errno_) _unused_ int _saved_errno_ = errno
 
+#define UNPROTECT_ERRNO                         \
+        do {                                    \
+                errno = _saved_errno_;          \
+                _saved_errno_ = -1;             \
+        } while (false)
+
 static inline int negative_errno(void) {
         /* This helper should be used to shut up gcc if you know 'errno' is
          * negative. Instead of "return -errno;", use "return negative_errno();"
diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c
index 5abc0c91bf..e491351dee 100644
--- a/src/nss-myhostname/nss-myhostname.c
+++ b/src/nss-myhostname/nss-myhostname.c
@@ -74,6 +74,7 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
         } else {
                 hn = gethostname_malloc();
                 if (!hn) {
+                        UNPROTECT_ERRNO;
                         *errnop = ENOMEM;
                         *h_errnop = NO_RECOVERY;
                         return NSS_STATUS_TRYAGAIN;
@@ -96,6 +97,7 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
         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;
@@ -186,6 +188,8 @@ static enum nss_status fill_in_hostent(
         assert(errnop);
         assert(h_errnop);
 
+        PROTECT_ERRNO;
+
         alen = FAMILY_ADDRESS_SIZE(af);
 
         for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++)
@@ -202,6 +206,7 @@ static enum nss_status fill_in_hostent(
                 (c > 0 ? c+1 : 2) * sizeof(char*);
 
         if (buflen < ms) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 *h_errnop = NETDB_INTERNAL;
                 return NSS_STATUS_TRYAGAIN;
@@ -321,6 +326,7 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
                 af = AF_INET;
 
         if (!IN_SET(af, AF_INET, AF_INET6)) {
+                UNPROTECT_ERRNO;
                 *errnop = EAFNOSUPPORT;
                 *h_errnop = NO_DATA;
                 return NSS_STATUS_UNAVAIL;
@@ -343,6 +349,7 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
         } else {
                 hn = gethostname_malloc();
                 if (!hn) {
+                        UNPROTECT_ERRNO;
                         *errnop = ENOMEM;
                         *h_errnop = NO_RECOVERY;
                         return NSS_STATUS_TRYAGAIN;
@@ -362,6 +369,8 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
                 local_address_ipv4 = LOCALADDRESS_IPV4;
         }
 
+        UNPROTECT_ERRNO;
+
         return fill_in_hostent(
                         canonical, additional,
                         af,
@@ -401,12 +410,14 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r(
         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;
@@ -461,6 +472,7 @@ found:
         if (!canonical || additional_from_hostname) {
                 hn = gethostname_malloc();
                 if (!hn) {
+                        UNPROTECT_ERRNO;
                         *errnop = ENOMEM;
                         *h_errnop = NO_RECOVERY;
                         return NSS_STATUS_TRYAGAIN;
@@ -472,6 +484,7 @@ found:
                         additional = hn;
         }
 
+        UNPROTECT_ERRNO;
         return fill_in_hostent(
                         canonical, additional,
                         af,
diff --git a/src/nss-mymachines/nss-mymachines.c b/src/nss-mymachines/nss-mymachines.c
index 3d1fc28353..486a658958 100644
--- a/src/nss-mymachines/nss-mymachines.c
+++ b/src/nss-mymachines/nss-mymachines.c
@@ -153,6 +153,7 @@ enum nss_status _nss_mymachines_gethostbyname4_r(
         l = strlen(name);
         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;
@@ -227,6 +228,7 @@ enum nss_status _nss_mymachines_gethostbyname4_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         *h_errnop = NO_DATA;
         return NSS_STATUS_UNAVAIL;
@@ -313,6 +315,7 @@ enum nss_status _nss_mymachines_gethostbyname3_r(
         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;
@@ -396,6 +399,7 @@ enum nss_status _nss_mymachines_gethostbyname3_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         *h_errnop = NO_DATA;
         return NSS_STATUS_UNAVAIL;
@@ -484,6 +488,7 @@ enum nss_status _nss_mymachines_getpwnam_r(
 
         l = strlen(name);
         if (buflen < l+1) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
@@ -501,6 +506,7 @@ enum nss_status _nss_mymachines_getpwnam_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         return NSS_STATUS_UNAVAIL;
 }
@@ -564,6 +570,7 @@ enum nss_status _nss_mymachines_getpwuid_r(
                 return NSS_STATUS_NOTFOUND;
 
         if (snprintf(buffer, buflen, "vu-%s-" UID_FMT, machine, (uid_t) mapped) >= (int) buflen) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
@@ -579,6 +586,7 @@ enum nss_status _nss_mymachines_getpwuid_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         return NSS_STATUS_UNAVAIL;
 }
@@ -662,6 +670,7 @@ enum nss_status _nss_mymachines_getgrnam_r(
 
         l = sizeof(char*) + strlen(name) + 1;
         if (buflen < l) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
@@ -677,6 +686,7 @@ enum nss_status _nss_mymachines_getgrnam_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         return NSS_STATUS_UNAVAIL;
 }
@@ -740,12 +750,14 @@ enum nss_status _nss_mymachines_getgrgid_r(
                 return NSS_STATUS_NOTFOUND;
 
         if (buflen < sizeof(char*) + 1) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
 
         memzero(buffer, sizeof(char*));
         if (snprintf(buffer + sizeof(char*), buflen - sizeof(char*), "vg-%s-" GID_FMT, machine, (gid_t) mapped) >= (int) buflen) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
@@ -758,6 +770,7 @@ enum nss_status _nss_mymachines_getgrgid_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         return NSS_STATUS_UNAVAIL;
 }
diff --git a/src/nss-resolve/nss-resolve.c b/src/nss-resolve/nss-resolve.c
index a28b5d8ba8..8370fed076 100644
--- a/src/nss-resolve/nss-resolve.c
+++ b/src/nss-resolve/nss-resolve.c
@@ -186,6 +186,7 @@ enum nss_status _nss_resolve_gethostbyname4_r(
         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;
@@ -267,6 +268,7 @@ enum nss_status _nss_resolve_gethostbyname4_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         *h_errnop = NO_RECOVERY;
         return ret;
@@ -364,6 +366,7 @@ enum nss_status _nss_resolve_gethostbyname3_r(
         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;
@@ -455,6 +458,7 @@ enum nss_status _nss_resolve_gethostbyname3_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         *h_errnop = NO_RECOVERY;
         return ret;
@@ -492,12 +496,14 @@ enum nss_status _nss_resolve_gethostbyaddr2_r(
         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;
@@ -576,6 +582,7 @@ enum nss_status _nss_resolve_gethostbyaddr2_r(
               c * sizeof(char*);        /* pointers to aliases, plus trailing NULL */
 
         if (buflen < ms) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 *h_errnop = NETDB_INTERNAL;
                 return NSS_STATUS_TRYAGAIN;
@@ -636,6 +643,7 @@ enum nss_status _nss_resolve_gethostbyaddr2_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         *h_errnop = NO_RECOVERY;
         return ret;
diff --git a/src/nss-systemd/nss-systemd.c b/src/nss-systemd/nss-systemd.c
index f554828d49..f8db27ae27 100644
--- a/src/nss-systemd/nss-systemd.c
+++ b/src/nss-systemd/nss-systemd.c
@@ -210,6 +210,7 @@ enum nss_status _nss_systemd_getpwnam_r(
 
         l = strlen(name);
         if (buflen < l+1) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
@@ -227,6 +228,7 @@ enum nss_status _nss_systemd_getpwnam_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         return NSS_STATUS_UNAVAIL;
 }
@@ -310,6 +312,7 @@ enum nss_status _nss_systemd_getpwuid_r(
 
         l = strlen(translated) + 1;
         if (buflen < l) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
@@ -327,6 +330,7 @@ enum nss_status _nss_systemd_getpwuid_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         return NSS_STATUS_UNAVAIL;
 }
@@ -408,6 +412,7 @@ enum nss_status _nss_systemd_getgrnam_r(
 
         l = sizeof(char*) + strlen(name) + 1;
         if (buflen < l) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
@@ -423,6 +428,7 @@ enum nss_status _nss_systemd_getgrnam_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         return NSS_STATUS_UNAVAIL;
 }
@@ -506,6 +512,7 @@ enum nss_status _nss_systemd_getgrgid_r(
 
         l = sizeof(char*) + strlen(translated) + 1;
         if (buflen < l) {
+                UNPROTECT_ERRNO;
                 *errnop = ERANGE;
                 return NSS_STATUS_TRYAGAIN;
         }
@@ -521,6 +528,7 @@ enum nss_status _nss_systemd_getgrgid_r(
         return NSS_STATUS_SUCCESS;
 
 fail:
+        UNPROTECT_ERRNO;
         *errnop = -r;
         return NSS_STATUS_UNAVAIL;
 }
@@ -740,6 +748,7 @@ enum nss_status _nss_systemd_getpwent_r(struct passwd *result, char *buffer, siz
         LIST_FOREACH(entries, p, getpwent_data.position) {
                 len = strlen(p->name) + 1;
                 if (buflen < len) {
+                        UNPROTECT_ERRNO;
                         *errnop = ERANGE;
                         ret = NSS_STATUS_TRYAGAIN;
                         goto finalize;
@@ -791,6 +800,7 @@ enum nss_status _nss_systemd_getgrent_r(struct group *result, char *buffer, size
         LIST_FOREACH(entries, p, getgrent_data.position) {
                 len = sizeof(char*) + strlen(p->name) + 1;
                 if (buflen < len) {
+                        UNPROTECT_ERRNO;
                         *errnop = ERANGE;
                         ret = NSS_STATUS_TRYAGAIN;
                         goto finalize;
diff --git a/src/test/test-fs-util.c b/src/test/test-fs-util.c
index b3a4b1749c..e049abc4a4 100644
--- a/src/test/test-fs-util.c
+++ b/src/test/test-fs-util.c
@@ -361,11 +361,11 @@ static void test_unlink_noerrno(void) {
 
         {
                 PROTECT_ERRNO;
-                errno = -42;
+                errno = 42;
                 assert_se(unlink_noerrno(name) >= 0);
-                assert_se(errno == -42);
+                assert_se(errno == 42);
                 assert_se(unlink_noerrno(name) < 0);
-                assert_se(errno == -42);
+                assert_se(errno == 42);
         }
 }
 
diff --git a/src/test/test-util.c b/src/test/test-util.c
index 40c1f4a3aa..ffacd65669 100644
--- a/src/test/test-util.c
+++ b/src/test/test-util.c
@@ -213,6 +213,30 @@ static void test_protect_errno(void) {
         assert_se(errno == 12);
 }
 
+static void test_unprotect_errno_inner_function(void) {
+        PROTECT_ERRNO;
+
+        errno = 2222;
+}
+
+static void test_unprotect_errno(void) {
+        log_info("/* %s */", __func__);
+
+        errno = 4711;
+
+        PROTECT_ERRNO;
+
+        errno = 815;
+
+        UNPROTECT_ERRNO;
+
+        assert_se(errno == 4711);
+
+        test_unprotect_errno_inner_function();
+
+        assert_se(errno == 4711);
+}
+
 static void test_in_set(void) {
         log_info("/* %s */", __func__);
 
@@ -383,6 +407,7 @@ int main(int argc, char *argv[]) {
         test_div_round_up();
         test_u64log2();
         test_protect_errno();
+        test_unprotect_errno();
         test_in_set();
         test_log2i();
         test_eqzero();