From 9dcaab0819b8b5e345bb4bd8b8acac17ae5b2b85 Mon Sep 17 00:00:00 2001
From: lda <lda@freetards.xyz>
Date: Sun, 19 May 2024 19:11:33 +0200
Subject: [PATCH] [ADD/FIX/WIP] Fix content hashing, respect creation_content.

Oops, I *should* have known sha256 are stored as raw unpadded b64!base64!
---
 src/CanonicalJson.c         |  7 ++-----
 src/Room.c                  | 39 +++++++++++++++++++++++++++++++------
 src/include/CanonicalJson.h |  4 ++--
 3 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/src/CanonicalJson.c b/src/CanonicalJson.c
index 5847ef2..0de8abc 100644
--- a/src/CanonicalJson.c
+++ b/src/CanonicalJson.c
@@ -199,23 +199,20 @@ static const IoFunctions Functions = {
     .close = NULL,
     .seek = NULL
 };
-char *
+unsigned char *
 CanonicalJsonHash(HashMap *json)
 {
     char *string = NULL;
     unsigned char *sha;
-    char *shastr;
     Io *string_writer = IoCreate(&string, Functions);
     Stream *io_stream = StreamIo(string_writer);
     CanonicalJsonEncode(json, io_stream);
     StreamFlush(io_stream);
 
     sha = Sha256(string);
-    shastr = ShaToHex(sha);
 
     Free(string);
-    Free(sha);
     StreamClose(io_stream);
 
-    return shastr;
+    return sha;
 }
diff --git a/src/Room.c b/src/Room.c
index d13dfc9..ce99bae 100644
--- a/src/Room.c
+++ b/src/Room.c
@@ -32,6 +32,7 @@
 #include <Room.h>
 
 #include <Cytoplasm/Memory.h>
+#include <Cytoplasm/Base64.h>
 #include <Cytoplasm/Util.h>
 #include <Cytoplasm/Str.h>
 #include <Cytoplasm/Db.h>
@@ -82,7 +83,7 @@ static void
 RoomPopulate(Room *room, User *user, RoomCreateRequest *req, ServerPart s)
 {
     CommonID sender;
-    char *sender_str, *key;
+    char *sender_str, *key, *version;
     HashMap *content, *event, *override;
     Array *initial_states;
     JsonValue *val;
@@ -104,6 +105,23 @@ RoomPopulate(Room *room, User *user, RoomCreateRequest *req, ServerPart s)
     {
         JsonSet(content, JsonValueString(sender_str), 1, "creator");
     }
+
+    version = req->room_version ? 
+        StrDuplicate(req->room_version) : StrInt(room->version);
+    JsonSet(content, JsonValueString(version), 1, "room_version");
+    Free(version);
+
+    while (HashMapIterate(req->creation_content, &key, (void **) &val))
+    {
+        JsonValue *content_v = HashMapGet(content, key);
+        if (content_v &&
+            !StrEquals(key, "creator") &&
+            !StrEquals(key, "room_version"))
+        {
+            continue;
+        }
+        JsonValueFree(HashMapSet(content, key, JsonValueDuplicate(val)));
+    }
     event = RoomEventCreate(sender_str, "m.room.create", "", content);
     JsonFree(RoomEventSend(room, event));
     JsonFree(event);
@@ -1428,23 +1446,32 @@ char *
 EventContentHash(HashMap * pdu_json)
 {
     HashMap * copy = JsonDuplicate(pdu_json);
-    char *hash;
+    unsigned char *sha;
+    char *b64;
+
     JsonValueFree(HashMapDelete(copy, "unsigned"));
     JsonValueFree(HashMapDelete(copy, "signatures"));
     JsonValueFree(HashMapDelete(copy, "hashes"));
     
-    hash = CanonicalJsonHash(copy);
+    sha = CanonicalJsonHash(copy);
+    b64 = Base64Encode((const char *) sha, 32);
+    Base64Unpad(b64, strlen(b64));
+
+    Free(sha);
     JsonFree(copy);
-    return hash;
+
+    return b64;
 }
 static char *
 RoomHashEventV1(PduV1 pdu)
 {
     HashMap *json = PduV1ToJson(&pdu);
-    char *sha = EventContentHash(json);
+    char *b64;
+    
+    b64 = EventContentHash(json);
 
     JsonFree(json);
-    return sha;
+    return b64;
 }
 static bool
 EventFits(HashMap *pdu)
diff --git a/src/include/CanonicalJson.h b/src/include/CanonicalJson.h
index 978de40..fad9371 100644
--- a/src/include/CanonicalJson.h
+++ b/src/include/CanonicalJson.h
@@ -83,11 +83,11 @@ extern int CanonicalJsonEncode(HashMap *, Stream *);
  * Computes a JSON object encoded as Canonical JSON's SHA-256 
  * hash.
  *
- * This function returns a SHA-256 string stored on the heap, 
+ * This function returns a SHA-256 hexstream stored on the heap, 
  * which will need to be freed with 
  * .Fn Free .
  */
-extern char * CanonicalJsonHash(HashMap *);
+extern unsigned char * CanonicalJsonHash(HashMap *);
 
 /**
  * Encode a JSON value following the rules of Canonical JSON.