Add base domain patch

docs/README.md

@@ -5,4 +5,5 @@ Contents:
  - [`opcacrt6.yml`](opcacrt6.yml): A [Kaitai](https://kaitai.io) structure describing a very basic `opcacrt6.dat`.
 It does not attempt to handle things such as client certificates or user passwords.
  - [`patch_overwrite_ios.md`](patch_overwrite_ios.md): An explanation over why and how IOS is patched for operation of the Wii Shop Channel.
- - [`patch_custom_ca_ios.md`](patch_custom_ca_ios.md): The logistics of inserting our custom CA into IOS as well for EC usage.
+ - [`patch_custom_ca_ios.md`](patch_custom_ca_ios.md): The logistics of inserting our custom CA into IOS as well for EC usage.
+ - [`patch_base_domain.md`](patch_base_domain.md): Information about what URLs are present within the main DOL and information about patching them.

docs/patch_base_domain.md

@@ -0,0 +1,29 @@
+# Patch: Change Base Domain
+
+## Motivation
+Ranging from HTML/JS/etc loaded from the browser portion of the shop channel to ES underneath, traffic points to Nintendo's servers without other modifications.
+
+We need to have all traffic directed to our controlled servers.
+
+## Explanation
+With Opera's `myfilter.ini`, we simply insert our custom URL to the allowed domains on the filter list.
+
+Unfortunately, we cannot simply `s/shop.wii.com/$USER_BASE_DOMAIN/` in the main DOL, no matter how appealing as that sounds. Most prominently, we need to handle padding for domain names shorter than `shop.wii.com`.
+
+Thankfully, for all types present, we can replace the domain name replaced and add padding to match if necessary.
+
+We can identify five types of URLs within the main DOL to patch:
+  - `https://oss-auth.shop.wii.com/startup?initpage=showManual&titleId=`
+    - For an unknown reason, this specific URL (alongside several others) is present 9 times within the main DOL. It is only referenced once. The other 8 occurrences appear to be directly after the data segment for other JS plugins.
+  - `https://oss-auth.shop.wii.com/oss/getLog`
+    - It is unclear on what this is for, as it is never requested whatsoever or accessed during normal runtime. Perhaps an earlier version of the Wii Shop Channel posted `ec.getLog()` to it.
+    - It appears directly after the data for `wiiShop`'s JS plugin, implying it goes unused. The similarly-named `getLogUrl` Setter within `wiiShop` appears to be stubbed out.
+  - `.shop.wii.com`
+    - This suffix is compared on all pages. If the loaded page's domain does not match, most EC functionality is disabled.
+  - `https://oss-auth.shop.wii.com`
+    - Similar to the first, this appears 9 times and is only referenced once.
+  - `https://ecs.a.taur.cloud/ecs/services/ECommerceSOAP`
+    - Appears to be present for `GetECConfig`, which is most likely not called within the Wii Shop channel. Instead, `ECommerceInterface#setWebSvcUrls` is preferred.
+
+## Execution
+We simply iterate through these 5 types of URLs, replace the domain, and pad if appropiate. Doing so allows us to not fragment the rest of the URL with null bytes should padding be added.

modify_dol.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+
 	"github.com/logrusorgru/aurora/v3"
 )
 
@@ -20,6 +21,9 @@ type Patch struct {
 	Name string
 
 	// AtOffset is the offset within the file this patch should be applied at.
+	// If not present, the patch will be recursively applied across the entire file.
+	// Relying on this behavior is highly discouraged, as it may damage other parts of the binary
+	// if gone unchecked.
 	AtOffset int
 
 	// Before is an array of the bytes to find for, i.e. present within the original file.
@@ -43,21 +47,28 @@ func applyPatch(patch Patch) error {
 	if len(patch.Before) != len(patch.After) {
 		return ErrInconsistentPatch
 	}
-	if patch.AtOffset > len(mainDol) {
+	if patch.AtOffset != 0 && patch.AtOffset > len(mainDol) {
 		return ErrPatchOutOfRange
 	}
 
 	// Either Before or After should return the same length.
 	patchLen := len(patch.Before)
 
-	// Ensure original bytes are present
-	originalBytes := mainDol[patch.AtOffset : patch.AtOffset+patchLen]
-	if !bytes.Equal(originalBytes, patch.Before) {
-		return ErrInvalidPatch
-	}
+	// Determine our patching behavior.
+	if patch.AtOffset != 0 {
+		// Ensure original bytes are present
+		originalBytes := mainDol[patch.AtOffset : patch.AtOffset+patchLen]
+		if !bytes.Equal(originalBytes, patch.Before) {
+			return ErrInvalidPatch
+		}
 
-	// Apply patch
-	copy(mainDol[patch.AtOffset:], patch.After)
+		// Apply patch at the specified offset
+		copy(mainDol[patch.AtOffset:], patch.After)
+	} else {
+		// Recursively apply this patch.
+		// We cannot verify if the original contents are present via this.
+		mainDol = bytes.ReplaceAll(mainDol, patch.Before, patch.After)
+	}
 
 	return nil
 }
@@ -80,5 +91,6 @@ func emptyBytes(length int) []byte {
 // applyDefaultPatches iterates through a list of default patches.
 func applyDefaultPatches() {
 	applyPatchSet("Overwrite IOS Syscall for ES", OverwriteIOSPatch)
-	applyPatchSet("Load Custom CA within IOS", LoadCustomCA(rootCertificate))
+	applyPatchSet("Load Custom CA within IOS", LoadCustomCA())
+	applyPatchSet("Change Base Domain", PatchBaseDomain())
 }

patch_base_domain.go

@@ -0,0 +1,64 @@
+package main
+
+import "strings"
+
+const (
+	NintendoBaseDomain = "shop.wii.com"
+	ShowManualURL      = "https://oss-auth.shop.wii.com/startup?initpage=showManual&titleId="
+	GetLogURL          = "https://oss-auth.shop.wii.com/oss/getLog"
+	TrustedDomain      = ".shop.wii.com"
+	ECommerceBaseURL   = "https://ecs.shop.wii.com/ecs/services/ECommerceSOAP"
+)
+
+// PatchBaseDomain replaces all Nintendo domains to be the user's
+// specified base domain.
+// See docs/patch_base_domain.md for more information.
+func PatchBaseDomain() PatchSet {
+	return PatchSet{
+		Patch{
+			Name: "Modify /startup domain",
+
+			Before: []byte(ShowManualURL),
+			After:  padReplace(ShowManualURL),
+		},
+		Patch{
+			Name:     "Modify oss-auth URL",
+			AtOffset: 3180692,
+
+			Before: []byte(GetLogURL),
+			After:  padReplace(GetLogURL),
+		},
+		Patch{
+			Name:     "Modify trusted base domain prefix",
+			AtOffset: 3323432,
+
+			Before: []byte(TrustedDomain),
+			After:  padReplace(TrustedDomain),
+		},
+		Patch{
+			Name:     "Modify ECS SOAP endpoint URL",
+			AtOffset: 3268896,
+
+			Before: []byte(ECommerceBaseURL),
+			After:  padReplace(ECommerceBaseURL),
+		},
+		Patch{
+			Name: "Wildcard replace other instances",
+
+			Before: []byte(NintendoBaseDomain),
+			After:  padReplace(baseDomain),
+		},
+	}
+}
+
+func padReplace(url string) []byte {
+	replaced := strings.ReplaceAll(url, NintendoBaseDomain, baseDomain)
+
+	// See if we truly need to pad.
+	if len(url) == len(replaced) {
+		return []byte(replaced)
+	}
+
+	padding := len(url) - len(replaced)
+	return append([]byte(replaced), emptyBytes(padding)...)
+}