1 files changed, 9 insertions, 0 deletions
diff --git a/src/options.cpp b/src/options.cpp
index b77af24..f78d8de 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -77,6 +77,15 @@ int zmq::options_t::setsockopt (int option_, const void *optval_,
         return 0;
 
     case ZMQ_IDENTITY:
+
+        //  Empty identity is invalid as well as identity longer than
+        //  255 bytes. Identity starting with binary zero is invalid
+        //  as these are used for auto-generated identities.
+        if (optvallen_ < 1 || optvallen_ > 255 ||
+              *((const unsigned char*) optval_) == 0) {
+            errno = EINVAL;
+            return -1;
+        }
         identity.assign ((const unsigned char*) optval_, optvallen_);
         return 0;