inet_dns: support TSIG (TO BE SQUASHED)

erlang#6985 (review)
jimdigriz · Aug 8, 2023 · 0d7b763 · 0d7b763
1 parent 172c0cf
commit 0d7b763
Showing 1 changed file with 25 additions and 25 deletions.
diff --git a/lib/kernel/src/inet_dns_tsig.erl b/lib/kernel/src/inet_dns_tsig.erl
@@ -54,18 +54,18 @@
 -type tsig_error() :: ?BADSIG | ?BADKEY | ?BADTIME | ?BADTRUNC.
 
 -record(tsig_state, {
-    key       :: tsig_key() | list(tsig_key()),
-    alg       :: tsig_alg(), % client only
-    fudge     :: 0..65535,
+    key                         :: tsig_key() | list(tsig_key()),
+    alg                         :: tsig_alg(), % client only
+    fudge                       :: 0..65535,
 
-    qr    = 0 :: 0..100, % 0 (false): request, 1+ (true): response
-                         % this value is overloaded to handle TSIG
-                         % over TCP where we need to accept up to
-                         % 99 messages without TSIG so each time a
-                         % response with a TSIG RR is received this
-                         % value is reset to 2
-    id        :: undefined | 0..65535,
-    mac       :: undefined | binary() | crypto:mac_state()
+    qr    = 0                   :: 0..100, % 0 (false): request, 1+ (true): response
+                                           % this value is overloaded to handle TSIG
+                                           % over TCP where we need to accept up to
+                                           % 99 messages without TSIG so each time a
+                                           % response with a TSIG RR is received this
+                                           % value is reset to 2
+    id                          :: undefined | 0..65535,
+    mac   = {?MODULE,undefined} :: {?MODULE,undefined | binary()} | {crypto,crypto:mac_state()}
 }).
 -opaque tsig_state() :: #tsig_state{}.
 -export_type([tsig_state/0]).
@@ -135,7 +135,7 @@ sign(Pkt0 = <<_Id:16, QR:1, _:15, _/binary>>,
         binary:part(Pkt0, {12,byte_size(Pkt0) - 12}),
         TSigRRB
     ]),
-    TS = TS0#tsig_state{ qr = TSQR + 1, mac = MAC },
+    TS = TS0#tsig_state{ qr = TSQR + 1, mac = {?MODULE,MAC} },
     {ok,Pkt,TS}.
 
 % this function needs to work with the original response binary as the MAC
@@ -233,7 +233,7 @@ do_verify(Pkt, _Response, TS, TSigRR) ->
         binary:part(Pkt, {12,Offset - 12})
     ]),
     MACCalc = if
-        TS#tsig_state.mac == undefined; is_binary(TS#tsig_state.mac) ->
+        element(1, TS#tsig_state.mac) == ?MODULE ->
             mac(PktS, TS, Error, Now, OtherData);
         % RFC8945, section 5.3.1: TSIG on TCP Connections
         true ->
@@ -243,7 +243,7 @@ do_verify(Pkt, _Response, TS, TSigRR) ->
         % RFC8945, section 5.2 - MUST check time after MAC
         MAC == MACCalc, NowSigned - Fudge < Now, NowSigned + Fudge > Now ->
             QR = if TS#tsig_state.qr == 0 -> 1; true -> 2 end,
-            {ok,TS#tsig_state{ qr = QR, mac = MAC }};
+            {ok,TS#tsig_state{ qr = QR, mac = {?MODULE,MAC} }};
         MAC == MACCalc ->
             {error,{notauth,badtime}};
         true ->
@@ -293,33 +293,33 @@ encode_algname(Alg) ->
 otherdata(?BADTIME, Now) -> <<Now:48>>;
 otherdata(_Error, _Now) -> <<>>.
 
-mac0(TS) ->
+mac0(TS = #tsig_state{ mac = {?MODULE,MAC} }) ->
     {_Name,Secret} = TS#tsig_state.key,
     {Alg,_MACSize} = TS#tsig_state.alg,
     MACState = crypto:mac_init(hmac, Alg, Secret),
-    if
+    {crypto,if
         % RFC8945, section 5.3.1: TSIG on TCP Connections
-        is_binary(TS#tsig_state.mac) ->
-            MS = byte_size(TS#tsig_state.mac),
-            crypto:mac_update(MACState, [<<MS:16>>, TS#tsig_state.mac]);
+        is_binary(MAC) ->
+            MS = byte_size(MAC),
+            crypto:mac_update(MACState, [<<MS:16>>, MAC]);
         true ->
             MACState
-    end.
-macN(Pkt, TS) ->
-    crypto:mac_update(TS#tsig_state.mac, [
+    end}.
+macN(Pkt, TS = #tsig_state{ mac = {crypto,MACState} }) ->
+    {crypto,crypto:mac_update(MACState, [
        <<(TS#tsig_state.id):16>>,
        binary:part(Pkt, {2,byte_size(Pkt) - 2})
-    ]).
+    ])}.
 % RFC8945, section 5.3.2: Generation of TSIG on Error Returns
 mac(_TS, Error, _Now, _OtherData)
   when Error == ?BADSIG; Error == ?BADKEY ->
     <<>>;
-mac(TS, Error, Now, OtherData) ->
+mac(TS = #tsig_state{ mac = {crypto,MACState0} }, Error, Now, OtherData) ->
     {Name,_Secret} = TS#tsig_state.key,
     {Alg,MACSize} = TS#tsig_state.alg,
     Fudge = TS#tsig_state.fudge,
     OtherLen = byte_size(OtherData),
-    MACState = crypto:mac_update(TS#tsig_state.mac, if
+    MACState = crypto:mac_update(MACState0, if
         TS#tsig_state.qr =< 1 ->
             [
                 % TSIG RR