ssl: Make PQC groups most preferred

Author: IngelaAndin

lib/ssl/src/ssl.erl

@@ -1392,7 +1392,7 @@ The following options are specific to the client side, or have
 different semantics for the client and server:
 
 - **`{psk_groups, Groups}`** - key exchange groups that the client
-will send pre share keys for, defaults to first group in
+will send pre shared keys for, defaults to the first group in
 supported_groups. Must be a subset of supported_groups and will
 be sent in the same order as they appear in supported_groups.
 

lib/ssl/src/ssl_config.erl

@@ -1469,10 +1469,10 @@ opt_supported_groups(UserOpts, #{versions := TlsVsns} = Opts, Env) ->
 
 opt_psk_groups(undefined, _,  _, _) ->
     undefined;
-opt_psk_groups(#supported_groups{supported_groups = SupportedGroups},  UserOpts, Opts, _Env) ->
+opt_psk_groups(#supported_groups{supported_groups = [First| _] = SupportedGroups},
+               UserOpts, Opts, _Env) ->
     %% Version dependency already asserted when SupportedGroups is supported
-    %% so is psk_groups
-    First = hd(SupportedGroups),
+    %% hence so is psk_groups
     case get_opt_list(psk_groups, [First], UserOpts, Opts) of
         {default, Default} ->
             Default;

lib/ssl/src/tls_v1.erl

@@ -68,6 +68,7 @@
          rsa_schemes/0,
          groups/0,
          groups/1,
+         pqc_groups/0,
          group_to_enum/1,
          enum_to_group/1,
          default_groups/0,
@@ -1251,48 +1252,38 @@ ecc_curves(Version) when is_tuple(Version) ->
     ecc_curves(TLSCurves);
 ecc_curves(TLSCurves) ->
     [pubkey_cert_records:namedCurves(Curve) || Curve <- TLSCurves].
-    
+ 
 groups() ->
     TLSGroups = groups(all),
     groups(TLSGroups).
 
 -spec groups(all | default | TLSGroups :: list()) -> [ssl:group()].
 groups(all) ->
-    [x25519,
-     x448,
-     secp521r1,
-     secp384r1,
-     secp256r1,
-     brainpoolP256r1tls13,
-     brainpoolP384r1tls13,
-     brainpoolP512r1tls13,
-     mlkem512,
-     mlkem768,
-     mlkem1024,
-     x25519mlkem768,
-     secp384r1mlkem1024,
-     secp256r1mlkem768,
-     ffdhe2048,
-     ffdhe3072,
-     ffdhe4096,
-     ffdhe6144,
-     ffdhe8192];
+    pqc_groups() ++
+        [x25519,
+         x448,
+         secp521r1,
+         secp384r1,
+         secp256r1,
+         brainpoolP256r1tls13,
+         brainpoolP384r1tls13,
+         brainpoolP512r1tls13,
+         ffdhe2048,
+         ffdhe3072,
+         ffdhe4096,
+         ffdhe6144,
+         ffdhe8192];
 groups(default) ->
-    [x25519,
-     x448,
-     secp521r1,
-     secp384r1,
-     secp256r1,
-     brainpoolP512r1tls13,
-     brainpoolP384r1tls13,
-     brainpoolP256r1tls13,
-     mlkem512,
-     mlkem768,
-     mlkem1024,
-     x25519mlkem768,
-     secp384r1mlkem1024,
-     secp256r1mlkem768
-    ];
+    pqc_groups() ++
+        [x25519,
+         x448,
+         secp521r1,
+         secp384r1,
+         secp256r1,
+         brainpoolP512r1tls13,
+         brainpoolP384r1tls13,
+         brainpoolP256r1tls13
+        ];
 groups(TLSGroups) when is_list(TLSGroups) ->
     CryptoGroups = crypto_supported_groups(),
     lists:filter(fun(x25519mlkem768) ->
@@ -1307,6 +1298,13 @@ groups(TLSGroups) when is_list(TLSGroups) ->
                     (Group) ->
                          proplists:get_bool(maybe_group_to_curve(Group), CryptoGroups)
                  end, TLSGroups).
+pqc_groups() ->
+    [x25519mlkem768,
+     mlkem1024,
+     mlkem768,
+     mlkem512,
+     secp384r1mlkem1024,
+     secp256r1mlkem768].
 
 default_groups() ->
     TLSGroups = groups(default),