Limit FQDN in DiameterURI to 255 octets

As for the port number in the parent commit, a FQDN can't be arbitrarily
long, at most 255 octets. Make decode fail if it's more.

3 files changed, 10 insertions, 13 deletions

diff --git a/lib/diameter/doc/src/diameter_dict.xml b/lib/diameter/doc/src/diameter_dict.xml
index 9db9bcffde..5cf1b174a0 100644
--- a/lib/diameter/doc/src/diameter_dict.xml
+++ b/lib/diameter/doc/src/diameter_dict.xml
@@ -529,7 +529,7 @@ answer record and passed to a &app_handle_request;
 callback upon reception of an incoming request.</p>
 
 <p>
-In cases in which there is a choice between list() and binary() types
+In cases in which there is a choice between string() and binary() types
 for OctetString() and derived types, the representation is determined
 by the value of &mod_string_decode;.</p>
 
diff --git a/lib/diameter/src/base/diameter_types.erl b/lib/diameter/src/base/diameter_types.erl
index 96407efc09..87a0f0663d 100644
--- a/lib/diameter/src/base/diameter_types.erl
+++ b/lib/diameter/src/base/diameter_types.erl
@@ -93,7 +93,7 @@
     case diameter_codec:getopt(string_decode) of
         true ->
             binary_to_list(Bin);
-        _ ->
+        false ->
             Bin
     end;
 
@@ -565,7 +565,7 @@ msb(false) -> ?TIME_2036.
 
 scan_uri(Bin) ->
     RE = "^(aaas?)://"
-         "([-a-zA-Z0-9.]+)"
+         "([-a-zA-Z0-9.]{1,255})"
          "(:0{0,5}([0-9]{1,5}))?"
          "(;transport=(tcp|sctp|udp))?"
          "(;protocol=(diameter|radius|tacacs\\+))?$",
@@ -575,6 +575,9 @@ scan_uri(Bin) ->
     %% [0-9]+ and it's not inconceivable that a value might be padded.
     %% Don't fantasize about this padding being more than the number
     %% of digits in the port number proper.
+    %%
+    %% Similarly, a FQDN can't be arbitrarily long: at most 255
+    %% octets.
     {match, [A, DN, PN, T, P]} = re:run(Bin,
                                         RE,
                                         [{capture, [1,2,4,6,8], binary}]),
@@ -583,7 +586,7 @@ scan_uri(Bin) ->
     PortNr = to_int(PN, PN0),
     0 = PortNr bsr 16,  %% assert
     #diameter_uri{type = Type,
-                  fqdn = from_bin(DN),
+                  fqdn = 'OctetString'(decode, DN),
                   port = PortNr,
                   transport = to_atom(T, T0),
                   protocol = to_atom(P, diameter)}.
@@ -596,14 +599,6 @@ defaults(6733, aaa) ->
 defaults(6733, aaas) ->
     {5658, tcp}.
 
-from_bin(B) ->
-    case diameter_codec:getopt(string_decode) of
-        true ->
-            binary_to_list(B);
-        false ->
-            B
-    end.
-
 to_int(<<>>, N) ->
     N;
 to_int(B, _) ->
diff --git a/lib/diameter/test/diameter_codec_test.erl b/lib/diameter/test/diameter_codec_test.erl
index 11fa82cfa1..5f1dbfbd61 100644
--- a/lib/diameter/test/diameter_codec_test.erl
+++ b/lib/diameter/test/diameter_codec_test.erl
@@ -358,11 +358,13 @@ values('DiameterURI') ->
          Pr <- ["" | [";protocol=" ++ X
                       || X <- ["diameter","radius","tacacs+"]]],
          Tr /= ";transport=udp"
-             orelse (Pr /= ";protocol=diameter" andalso Pr /= "")],
+             orelse (Pr /= ";protocol=diameter" andalso Pr /= "")]
+     ++ ["aaa://" ++ lists:duplicate(255, $x)],
      ["aaa://diameter.se:65536",
       "aaa://diameter.se:-1",
       "aaa://diameter.se;transport=udp;protocol=diameter",
       "aaa://diameter.se;transport=udp",
+      "aaa://" ++ lists:duplicate(256, $x),
       "aaa://:3868",
       "aaax://diameter.se",
       "aaa://diameter.se;transport=tcpx",