From f3413e94b990b472846c2e1c989f7f66ace5cbb4 Mon Sep 17 00:00:00 2001
From: Moonchild <moonchild@palemoon.org>
Date: Tue, 21 May 2024 12:30:47 +0200
Subject: [PATCH] [network] Make http digest auth cnonce length configurable.

---
 modules/libpref/init/all.js                |  6 ++++++
 netwerk/protocol/http/nsHttpDigestAuth.cpp | 15 ++++++++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 85aacfd61b..682000aaf2 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1646,6 +1646,12 @@ pref("network.http.keep_empty_response_headers_as_empty_string", true);
 // Max size, in bytes, for received HTTP response header.
 pref("network.http.max_response_header_size", 393216);
 
+// This sets the nonce length to verify the server response (via a
+// server-returned Authentication-Info header). Also used for session info.
+// Note: Range-checked to 4..256, if OOB defaults to 16.
+// Note: Chrome uses 16. Larger values may break sites. See Bug 1892449.
+pref("network.http.digest_auth_cnonce_length", 16);
+
 // default values for FTP
 // in a DSCP environment this should be 40 (0x28, or AF11), per RFC-4594,
 // Section 4.8 "High-Throughput Data Service Class", and 80 (0x50, or AF22)
diff --git a/netwerk/protocol/http/nsHttpDigestAuth.cpp b/netwerk/protocol/http/nsHttpDigestAuth.cpp
index ac2808fa8c..5f70b90e50 100644
--- a/netwerk/protocol/http/nsHttpDigestAuth.cpp
+++ b/netwerk/protocol/http/nsHttpDigestAuth.cpp
@@ -7,6 +7,7 @@
 // HttpLog.h should generally be included first
 #include "HttpLog.h"
 
+#include "mozilla/Preferences.h"
 #include "mozilla/Sprintf.h"
 
 #include "nsHttp.h"
@@ -20,6 +21,7 @@
 #include "nsCRT.h"
 #include "nsICryptoHash.h"
 #include "nsComponentManagerUtils.h"
+#include "pk11pub.h"
 
 namespace mozilla {
 namespace net {
@@ -302,9 +304,16 @@ nsHttpDigestAuth::GenerateCredentials(nsIHttpAuthenticableChannel *authChannel,
   // returned Authentication-Info header). also used for session info.
   //
   nsAutoCString cnonce;
-  static const char hexChar[] = "0123456789abcdef";
-  for (int i=0; i<16; ++i) {
-    cnonce.Append(hexChar[(int)(15.0 * rand()/(RAND_MAX + 1.0))]);
+  nsTArray<uint8_t> cnonceBuf;
+  int cnonceLength = Preferences::GetInt("network.http.digest_auth_cnonce_length", 16);
+  if (cnonceLength < 4 || cnonceLength > 256) {
+    cnonceLength = 16;
+  }
+  cnonceBuf.SetLength(cnonceLength / 2);
+  PK11_GenerateRandom(reinterpret_cast<unsigned char*>(cnonceBuf.Elements()),
+                      cnonceBuf.Length());
+  for (auto byte : cnonceBuf) {
+    cnonce.AppendPrintf("%02x", byte);
   }
   LOG(("   cnonce=%s\n", cnonce.get()));