From de41ab367fd0bf21c481175086d8f59bdb5d9ef6 Mon Sep 17 00:00:00 2001
From: s1lentq <s1lentsk@yandex.ru>
Date: Fri, 21 Jun 2024 21:26:22 +0700
Subject: [PATCH] Fixed collisions of SteamIDs issued to non-unique serial
 numbers "0000_0000_0000_0000_0000_0100_0000_0000". For these non-steam
 clients, SteamIDs will now be generated based on IP.

---
 reunion/src/client_auth.cpp         |  9 ++++++++-
 reunion/src/reunion_authorizers.cpp |  6 ++++--
 reunion/src/reunion_utils.cpp       | 13 +++++++++++++
 reunion/src/reunion_utils.h         |  1 +
 4 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/reunion/src/client_auth.cpp b/reunion/src/client_auth.cpp
index 20b88c4..3f4d56d 100644
--- a/reunion/src/client_auth.cpp
+++ b/reunion/src/client_auth.cpp
@@ -97,6 +97,7 @@ uint64_t SteamByIp(uint32_t ip)
 bool Reunion_FinishClientAuth(CReunionPlayer* reunionPlr, USERID_t* userid, client_auth_context_t* ctx)
 {
 	client_auth_kind authkind;
+	client_id_kind idkind = CI_UNKNOWN;
 
 	if (!ctx->authentificatedInSteam) {
 		// native auth failed, try authorize by emulators
@@ -125,6 +126,10 @@ bool Reunion_FinishClientAuth(CReunionPlayer* reunionPlr, USERID_t* userid, clie
 				authkind = CA_STEAM_PENDING;
 			}
 			else {
+				// check for bad authkey
+				if (!IsValidHddsnNumber(authdata.authKey, authdata.authKeyLen))
+					idkind = CI_VALVE_BY_IP;
+
 				// salt steamid
 				if (g_ReunionConfig->getSteamIdSaltLen()) {
 					SaltSteamId(&authdata);
@@ -162,7 +167,9 @@ bool Reunion_FinishClientAuth(CReunionPlayer* reunionPlr, USERID_t* userid, clie
 	}
 
 	// add prefix
-	client_id_kind idkind = g_ReunionConfig->getIdGenOptions(authkind)->id_kind;
+	if (idkind == CI_UNKNOWN)
+		idkind = g_ReunionConfig->getIdGenOptions(authkind)->id_kind;
+
 	switch (idkind) {
 	// check for deprecation
 	case CI_DEPRECATED:
diff --git a/reunion/src/reunion_authorizers.cpp b/reunion/src/reunion_authorizers.cpp
index 6d861e7..0b05008 100644
--- a/reunion/src/reunion_authorizers.cpp
+++ b/reunion/src/reunion_authorizers.cpp
@@ -58,14 +58,16 @@ void RevEmuFinishAuthorization(authdata_t* authdata, const char* authStr, bool s
 	if (IsHddsnNumber(authStr)) {
 		authdata->authKeyKind = AK_HDDSN;
 
-		LCPrintf(false, "RevEmu raw auth string: '%s' (HDDSN)\n", authStr);
-
 		if (stripSpecialChars) {
 			authdata->authKeyLen = strecpy(hddsn, authStr, authKeyMaxLen, " \\/-");
 			authStr = hddsn;
 		}
 		else
 			authdata->authKeyLen = min(strlen(authStr), authKeyMaxLen);
+
+		LCPrintf(false, "RevEmu raw auth string: '%s' (HDDSN)%s\n", authStr,
+			IsValidHddsnNumber(authStr, authdata->authKeyLen) ? "" : " (INVALID)"
+		);
 	}
 	else {
 		authdata->authKeyKind = AK_VOLUMEID;
diff --git a/reunion/src/reunion_utils.cpp b/reunion/src/reunion_utils.cpp
index bd259bb..19919bd 100644
--- a/reunion/src/reunion_utils.cpp
+++ b/reunion/src/reunion_utils.cpp
@@ -145,6 +145,19 @@ bool IsHddsnNumber(const char* authstring)
 	return strtoull(authstring, nullptr, 10) >= UINT32_MAX; // SSD
 }
 
+// This serial number is actually not a valid serial number
+// it is a system bug that provides an incorrect serial number for NVMe solid-state drives (Netac NVMe SSD),
+// retrieved from the Storage Descriptor instead of reading it from the driver.
+// Therefore, obtaining the serial number from the Storage Descriptor means we should not generate a SteamID based on such serial numbers,
+// as it increases the risk of SteamID collisions.
+// Instead, it is better to generate a SteamID based on the client's IP.
+const char *BadHddsnNumber = "0000_0000_0000_0000_0000_0100_0";
+
+bool IsValidHddsnNumber(const void* data, size_t maxlen)
+{
+	return memcmp(data, BadHddsnNumber, min(strlen(BadHddsnNumber), maxlen)) != 0;
+}
+
 void util_console_print(const char* fmt, ...)
 {
 	char buf[1024];
diff --git a/reunion/src/reunion_utils.h b/reunion/src/reunion_utils.h
index 2f6bcd9..5f150de 100644
--- a/reunion/src/reunion_utils.h
+++ b/reunion/src/reunion_utils.h
@@ -16,6 +16,7 @@ extern bool IsUniqueIdKind(client_id_kind idkind);
 extern bool IsValidId(uint32 authId);
 extern bool IsValidSteamTicket(const uint8 *pvSteam2Key, size_t ucbSteam2Key);
 extern bool IsHddsnNumber(const char* authstring);
+extern bool IsValidHddsnNumber(const void* data, size_t maxlen);
 
 extern void util_console_print(const char* fmt, ...);
 extern void util_syserror(const char* fmt, ...);