diff --git a/src/libsystemd-daemon/sd-daemon.c b/src/libsystemd-daemon/sd-daemon.c
index 863ac75290..480db3bbb9 100644
--- a/src/libsystemd-daemon/sd-daemon.c
+++ b/src/libsystemd-daemon/sd-daemon.c
@@ -88,7 +88,7 @@ _sd_export_ int sd_listen_fds(int unset_environment) {
                 goto finish;
         }
 
-        if (!p || *p || l <= 0) {
+        if (!p || p == e || *p || l <= 0) {
                 r = -EINVAL;
                 goto finish;
         }
@@ -112,7 +112,7 @@ _sd_export_ int sd_listen_fds(int unset_environment) {
                 goto finish;
         }
 
-        if (!p || *p) {
+        if (!p || p == e || *p) {
                 r = -EINVAL;
                 goto finish;
         }
diff --git a/src/shared/conf-parser.c b/src/shared/conf-parser.c
index 4bf3147f2d..9f5c07c761 100644
--- a/src/shared/conf-parser.c
+++ b/src/shared/conf-parser.c
@@ -865,7 +865,7 @@ int config_parse_mode(
 
         errno = 0;
         l = strtol(rvalue, &x, 8);
-        if (!x || *x || errno) {
+        if (!x || x == rvalue || *x || errno) {
                 log_error("[%s:%u] Failed to parse mode value, ignoring: %s", filename, line, rvalue);
                 return 0;
         }
diff --git a/src/shared/util.c b/src/shared/util.c
index 8ec83e49a8..23832fe16a 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -377,7 +377,7 @@ int safe_atou(const char *s, unsigned *ret_u) {
         errno = 0;
         l = strtoul(s, &x, 0);
 
-        if (!x || *x || errno)
+        if (!x || x == s || *x || errno)
                 return errno ? -errno : -EINVAL;
 
         if ((unsigned long) (unsigned) l != l)
@@ -397,7 +397,7 @@ int safe_atoi(const char *s, int *ret_i) {
         errno = 0;
         l = strtol(s, &x, 0);
 
-        if (!x || *x || errno)
+        if (!x || x == s || *x || errno)
                 return errno ? -errno : -EINVAL;
 
         if ((long) (int) l != l)
@@ -417,7 +417,7 @@ int safe_atollu(const char *s, long long unsigned *ret_llu) {
         errno = 0;
         l = strtoull(s, &x, 0);
 
-        if (!x || *x || errno)
+        if (!x || x == s || *x || errno)
                 return errno ? -errno : -EINVAL;
 
         *ret_llu = l;
@@ -434,7 +434,7 @@ int safe_atolli(const char *s, long long int *ret_lli) {
         errno = 0;
         l = strtoll(s, &x, 0);
 
-        if (!x || *x || errno)
+        if (!x || x == s || *x || errno)
                 return errno ? -errno : -EINVAL;
 
         *ret_lli = l;