Expand EC title check patch scope

docs/patch_ec_title_check.md

@@ -13,13 +13,24 @@ Within this, four conditions are checked:
   - Is the channel a game channel? This checks two types: 
     - `00010000`, typically used for discs
     - `00010004`.
-  - Is the channel a "service title"?  (`00010100`)
+  - Is the channel a service title?  (`00010100`)
-    - Name taken from `ec::isServiceTitle`.
 
 If any of these are true, installation of the title is permitted.
 Otherwise, installation is forbidden.
 
-## Execution
+Two other functions perform these four conditionals as well: `ec::isManagedTitle`, and `ec::isManagedTicket`. They are invoked when retrieving title information and when deleting titles.
-This behavior is not ideal. `ec::allowDownloadByApp` is patched to immediately return `1`, or true.
 
-In the future, `ec::isManagedTitle` and `ec::isManagedTicket` may wish to be patched as well due to similar reasons.
+It was identified that upon unregistration, a function named `ec::removeAllTitles` is called. This function loops through all installed titles, checking whether they are managed titles. If the title is managed, its ticket is removed and its title contents are deleted.
+
+Simply returning that all titles are managed exposes a large risk of deletion. Several options were discussed on how to approach this:
+  - Have all titles and tickets be managed, and ensure that the user is never unregistered
+    - While possible, not worth the risk.
+  - Possibly add hidden titles as managed (since we'll have the installation stub there)
+    - While far more safe than the first bullet point, we will still delete all NAND channels upon unregistration.
+  - Nullify the deletion function on unregister and hope that nothing else is like this
+    - This approach was chosen. This patch set will be refined if other mass-deletion functions are identified.
+
+## Execution
+This behavior is not ideal. Four patches are applied:
+  - `ec::allowDownloadByApp`, `ec::isManagedTitle`, and `ec::isManagedTicket` are all patched to immediately return `1`, or true.
+  - `ec::removeAllTitles` immediately returns `0`, preventing all damage. Its return value is seemingly the amount of titles remaining.

patch_ec_title_check.go

@@ -2,7 +2,7 @@ package main
 
 var NegateECTitle = PatchSet{
 	Patch{
-		Name:     "Allow all titles",
+		Name:     "Permit downloading all titles",
 		AtOffset: 619648,
 
 		// Generic function prolog
@@ -17,4 +17,41 @@ var NegateECTitle = PatchSet{
 			BLR(),
 		}.toBytes(),
 	},
+	Patch{
+		Name:     "Mark all titles as managed",
+		AtOffset: 620656,
+
+		Before: Instructions{
+			STWU(R1, R1, 0xfff0),
+			MFSPR(),
+		}.toBytes(),
+		After: Instructions{
+			LI(R3, 1),
+			BLR(),
+		}.toBytes(),
+	},
+	Patch{
+		Name:     "Mark all tickets as managed",
+		AtOffset: 619904,
+		Before: Instructions{
+			STWU(R1, R1, 0xfff0),
+			MFSPR(),
+		}.toBytes(),
+		After: Instructions{
+			LI(R3, 1),
+			BLR(),
+		}.toBytes(),
+	},
+	Patch{
+		Name:     "Nullify ec::removeAllTitles",
+		AtOffset: 588368,
+		Before: Instructions{
+			STWU(R1, R1, 0xffc0),
+			MFSPR(),
+		}.toBytes(),
+		After: Instructions{
+			LI(R3, 0),
+			BLR(),
+		}.toBytes(),
+	},
 }