*: don't build with Go versions with known security vulnerabilities

env

-GOVERSION=$( go version | grep -o 'go1\.[0-9]')
+MAJOR_GOVERSION=$( go version | grep -o 'go1\.[0-9]')
+FULL_GOVERSION=$( go version| grep -o 'go1\.[0-9|\.]*' )
 
+# The list of unsupported major go versions.
 UNSUPPORTED=( "go1.0" "go1.1" "go1.2" "go1.3" "go1.4" )
 
+# Minor go verisons which have known security vulnerabilities. Refuse to build with these.
+KNOWN_INSECURE=( "go1.5" "go1.5.1" "go1.5.2" )
+
 for V in "${UNSUPPORTED[@]}"; do
-    if [ "$V" = "$GOVERSION" ]; then
-        echo "dex requires go version 1.5+. Please update your go version."
+    if [ "$V" = "$MAJOR_GOVERSION" ]; then
+        echo "dex requires Go version 1.5.3+. Please update your Go version."
+        exit 2
+    fi
+done
+
+for V in "${KNOWN_INSECURE[@]}"; do
+    if [ "$V" = "$FULL_GOVERSION" ]; then
+        echo "Go version ${V} has known security vulnerabilities which impact dex. Plesae update your Go verison."
         exit 2
     fi
 done