dist_utils: Eliminate crash when list_to_existing_atom/1 fails

In the following scenario list_to_existing_atom/1 may crash
during handshake:

  Start a node in one window:

     erl -sname adam@localhost

  Start another node in another window:

     erl -sname bertil

  In this node, ping the first node (use the actual hostname
  in the command):

    net:ping(adam@hostname).

There will be an error report similar to:

=ERROR REPORT==== 27-May-2010::15:03:14 ===
Error in process <0.40.0> on node 'bertil@hostname' with exit value: {badarg,[{erlang,list_to_existing_atom,
["adam@localhost"]},{dist_util,recv_challenge,1},{dist_util,handshake_we_started,1}]}

Eliminate the crash and the error report by catching the call to
list_to_existing_atom/1 and do a clean shutdown if it fails.

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/kernel/src/dist_util.erl b/lib/kernel/src/dist_util.erl
index a2937d60b8..8fc4934f1f 100644
--- a/lib/kernel/src/dist_util.erl
+++ b/lib/kernel/src/dist_util.erl
@@ -564,7 +564,7 @@ recv_challenge(#hs_data{socket=Socket,other_node=Node,
     case Recv(Socket, 0, infinity) of
 	{ok,[$n,V1,V0,Fl1,Fl2,Fl3,Fl4,CA3,CA2,CA1,CA0 | Ns]} ->
 	    Flags = ?u32(Fl1,Fl2,Fl3,Fl4),
-	    case {list_to_existing_atom(Ns),?u16(V1,V0)} of
+	    try {list_to_existing_atom(Ns),?u16(V1,V0)} of
 		{Node,Version} ->
 		    Challenge = ?u32(CA3,CA2,CA1,CA0),
 		    ?trace("recv: node=~w, challenge=~w version=~w\n",
@@ -572,6 +572,9 @@ recv_challenge(#hs_data{socket=Socket,other_node=Node,
 		    {Flags,Challenge};
 		_ ->
 		    ?shutdown(no_node)
+	    catch
+		error:badarg ->
+		    ?shutdown(no_node)
 	    end;
 	_ ->
 	    ?shutdown(no_node)