diff --git a/binlog.c b/binlog.c
index 00dc12b..5e908db 100644
--- a/binlog.c
+++ b/binlog.c
@@ -100,7 +100,7 @@ void replay_log_event (void) {
       if (verbosity) {
         logprintf ( "id = %d, name = %.*s ip = %.*s port = %d\n", id, l1, name, l2, ip, port);
       }
-      alloc_dc (id, strndup (ip, l2), port);
+      alloc_dc (id, tstrndup (ip, l2), port);
     }
     rptr = in_ptr;
     break;
diff --git a/interface.c b/interface.c
index 53a245c..71e699c 100644
--- a/interface.c
+++ b/interface.c
@@ -675,7 +675,7 @@ void interpreter (char *line UU) {
       printf ("Empty file name\n");
       RET;
     }
-    do_send_photo (CODE_input_media_uploaded_photo, id, strndup (s, t));
+    do_send_photo (CODE_input_media_uploaded_photo, id, tstrndup (s, t));
   } else if (IS_WORD("send_video")) {
     GET_PEER;
     int t;
@@ -684,7 +684,7 @@ void interpreter (char *line UU) {
       printf ("Empty file name\n");
       RET;
     }
-    do_send_photo (CODE_input_media_uploaded_video, id, strndup (s, t));
+    do_send_photo (CODE_input_media_uploaded_video, id, tstrndup (s, t));
   } else if (IS_WORD ("send_text")) {
     GET_PEER;
     int t;
@@ -693,7 +693,7 @@ void interpreter (char *line UU) {
       printf ("Empty file name\n");
       RET;
     }
-    do_send_text (id, strndup (s, t));
+    do_send_text (id, tstrndup (s, t));
   } else if (IS_WORD ("fwd")) {
     GET_PEER;
     int num = next_token_int ();
@@ -950,7 +950,7 @@ void interpreter (char *line UU) {
       printf ("Empty file name\n");
       RET;
     }
-    do_send_photo (CODE_input_media_uploaded_audio, id, strndup (s, t));
+    do_send_photo (CODE_input_media_uploaded_audio, id, tstrndup (s, t));
   } else if (IS_WORD("send_document")) {
     GET_PEER;
     int t;
@@ -959,7 +959,7 @@ void interpreter (char *line UU) {
       printf ("Empty file name\n");
       RET;
     }
-    do_send_photo (CODE_input_media_uploaded_document, id, strndup (s, t));
+    do_send_photo (CODE_input_media_uploaded_document, id, tstrndup (s, t));
   } else if (IS_WORD ("load_audio")) {
     long long num = next_token_int ();
     if (num == NOT_FOUND) {
diff --git a/queries.c b/queries.c
index 50fd1de..339e214 100644
--- a/queries.c
+++ b/queries.c
@@ -386,7 +386,7 @@ int send_code_on_answer (struct query *q UU) {
   if (phone_code_hash) {
     tfree_str (phone_code_hash);
   }
-  phone_code_hash = strndup (s, l);
+  phone_code_hash = tstrndup (s, l);
   want_dc_num = -1;
   return 0;
 }
diff --git a/tools.c b/tools.c
index badf812..f4a4c0a 100644
--- a/tools.c
+++ b/tools.c
@@ -166,6 +166,23 @@ char *tstrdup (const char *s) {
 #endif
 }
 
+char *tstrndup (const char *s, size_t n) {
+#ifdef DEBUG
+  size_t l = 0;
+  for (l = 0; l < n && s[l]; l++) { }
+  char *p = talloc (l + 1);
+  memcpy (p, s, l);
+  p[l] = 0;
+  return p;
+#else
+  char *p = strndup (s, n);
+  if (p == NULL) {
+    out_of_memory ();
+  }
+  return p;
+#endif
+}
+
 void ensure (int r) {
   if (!r) {
     logprintf ("Open SSL error\n");
diff --git a/tools.h b/tools.h
index 8105c27..09f2b2b 100644
--- a/tools.h
+++ b/tools.h
@@ -24,6 +24,7 @@ void *talloc (size_t size);
 void *trealloc (void *ptr, size_t old_size, size_t size);
 void *talloc0 (size_t size);
 char *tstrdup (const char *s);
+char *tstrndup (const char *s, size_t n);
 int tinflate (void *input, int ilen, void *output, int olen);
 void ensure (int r);
 void ensure_ptr (void *p);