1 files changed, 3 insertions, 0 deletions
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index cbd3dd86ce..0e7b539588 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -476,6 +476,9 @@ s_recvfrom(sock, argc, argv, from)
   retry:
     rb_str_locktmp(str);
     rb_thread_wait_fd(fd);
+    if (buflen != RSTRING(str)->len) {
+	rb_raise(rb_eRuntimeError, "buffer modified");
+    }
     TRAP_BEG;
     slen = recvfrom(fd, RSTRING(str)->ptr, buflen, flags, (struct sockaddr*)buf, &alen);
     TRAP_END;