Use more secure hash function for map downloads

SHA256 was chosen because it is reasonably standard, the file names
don't explode in length (this rules out SHA512) and it is supported by
basically all versions of OpenSSL (this rules out SHA512/256 and SHA3).

The protocol is changed in a backward compatible way: The supporting
server sends the SHA256 corresponding to the map in the `MAP_DETAILS`
message prior to sending the `MAP_CHANGE` message. The client saves the
SHA256 obtained from the `MAP_DETAILS` message until the next
`MAP_CHANGE` message.

For servers not supporting this protocol, the client falls back to
simply opening maps like in the previous scheme.

Remove the `map_version` tool, it is not being used and would have been
a little bit effort to update.

Use the OpenSSL implementation of SHA256 if it is supported, otherwise
fall back to a public domain one.

Fix #1127.

CMakeLists.txt

@@ -262,6 +262,7 @@ if(NOT CMAKE_CROSSCOMPILING)
   find_package(PkgConfig)
 endif()
 find_package(ZLIB)
+find_package(Crypto)
 find_package(Curl)
 find_package(Freetype)
 if(DOWNLOAD_GTEST)
@@ -338,6 +339,7 @@ if(MYSQL)
   show_dependency_status("MySQL" MYSQL)
 endif()
 show_dependency_status("Ogg" OGG)
+show_dependency_status("OpenSSL Crypto" CRYPTO)
 show_dependency_status("Opus" OPUS)
 show_dependency_status("Opusfile" OPUSFILE)
 show_dependency_status("Pnglite" PNGLITE)
@@ -554,6 +556,11 @@ set_glob(BASE GLOB_RECURSE src/base
   confusables.c
   confusables_data.h
   detect.h
+  hash.c
+  hash.h
+  hash_ctxt.h
+  hash_libtomcrypt.c
+  hash_openssl.c
   math.h
   system.c
   system.h
@@ -695,7 +702,7 @@ list(APPEND TARGETS_DEP md5)
 set(DEPS ${DEP_MD5} ${ZLIB_DEP})
 
 # Libraries
-set(LIBS ${CMAKE_THREAD_LIBS_INIT} ${CURL_LIBRARIES} ${WEBSOCKETS_LIBRARIES} ${ZLIB_LIBRARIES} ${PLATFORM_LIBS})
+set(LIBS ${CMAKE_THREAD_LIBS_INIT} ${CURL_LIBRARIES} ${CRYPTO_LIBRARIES} ${WEBSOCKETS_LIBRARIES} ${ZLIB_LIBRARIES} ${PLATFORM_LIBS})
 
 # Targets
 add_library(engine-shared EXCLUDE_FROM_ALL OBJECT ${ENGINE_INTERFACE} ${ENGINE_SHARED} ${ENGINE_GENERATED_SHARED} ${BASE})
@@ -1051,7 +1058,6 @@ set_glob(TOOLS GLOB src/tools
   map_extract.cpp
   map_replace_image.cpp
   map_resave.cpp
-  map_version.cpp
   packetgen.cpp
   tileset_borderadd.cpp
   tileset_borderfix.cpp
@@ -1104,6 +1110,7 @@ if(GTEST_FOUND OR DOWNLOAD_GTEST)
     aio.cpp
     fs.cpp
     git_revision.cpp
+    hash.cpp
     jobs.cpp
     json.cpp
     mapbugs.cpp
@@ -1511,6 +1518,9 @@ foreach(target ${TARGETS_OWN})
   target_include_directories(${target} PRIVATE ${CURL_INCLUDE_DIRS})
   target_include_directories(${target} PRIVATE ${ZLIB_INCLUDE_DIRS})
   target_compile_definitions(${target} PRIVATE GLEW_STATIC)
+  if(CRYPTO_FOUND)
+    target_compile_definitions(${target} PRIVATE CONF_OPENSSL)
+  endif()
   if(WEBSOCKETS)
     target_compile_definitions(${target} PRIVATE CONF_WEBSOCKETS)
     target_include_directories(${target} PRIVATE ${WEBSOCKETS_INCLUDE_DIRS})

cmake/FindCrypto.cmake

@@ -0,0 +1,19 @@
+if(NOT PREFER_BUNDLED_LIBS)
+  find_package(OpenSSL)
+  if(OPENSSL_FOUND)
+    set(CRYPTO_FOUND ON)
+    set(CRYPTO_BUNDLED OFF)
+    set(CRYPTO_LIBRARY ${OPENSSL_CRYPTO_LIBRARY})
+    set(CRYPTO_INCLUDEDIR ${OPENSSL_INCLUDE_DIR})
+  endif()
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Crypto DEFAULT_MSG CRYPTO_LIBRARY CRYPTO_INCLUDEDIR)
+
+mark_as_advanced(CRYPTO_LIBRARY CRYPTO_INCLUDEDIR)
+
+if(CRYPTO_FOUND)
+  set(CRYPTO_LIBRARIES ${CRYPTO_LIBRARY})
+  set(CRYPTO_INCLUDE_DIRS ${CRYPTO_INCLUDEDIR})
+endif()

src/base/hash.c

@@ -0,0 +1,41 @@
+#include "hash.h"
+#include "hash_ctxt.h"
+
+#include "system.h"
+
+SHA256_DIGEST sha256(const void *message, size_t message_len)
+{
+	SHA256_CTX ctxt;
+	sha256_init(&ctxt);
+	sha256_update(&ctxt, message, message_len);
+	return sha256_finish(&ctxt);
+}
+
+void sha256_str(SHA256_DIGEST digest, char *str, size_t max_len)
+{
+	unsigned i;
+	if(max_len > SHA256_MAXSTRSIZE)
+	{
+		max_len = SHA256_MAXSTRSIZE;
+	}
+	str[max_len - 1] = 0;
+	max_len -= 1;
+	for(i = 0; i < max_len; i++)
+	{
+		static const char HEX[] = "0123456789abcdef";
+		int index = i / 2;
+		if(i % 2 == 0)
+		{
+			str[i] = HEX[digest.data[index] >> 4];
+		}
+		else
+		{
+			str[i] = HEX[digest.data[index] & 0xf];
+		}
+	}
+}
+
+int sha256_comp(SHA256_DIGEST digest1, SHA256_DIGEST digest2)
+{
+	return mem_comp(digest1.data, digest2.data, sizeof(digest1.data));
+}

src/base/hash.h

@@ -0,0 +1,43 @@
+#ifndef BASE_HASH_H
+#define BASE_HASH_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum
+{
+	SHA256_DIGEST_LENGTH=256/8,
+	SHA256_MAXSTRSIZE=2*SHA256_DIGEST_LENGTH+1,
+};
+
+typedef struct
+{
+	unsigned char data[SHA256_DIGEST_LENGTH];
+} SHA256_DIGEST;
+
+SHA256_DIGEST sha256(const void *message, size_t message_len);
+void sha256_str(SHA256_DIGEST digest, char *str, size_t max_len);
+int sha256_from_str(SHA256_DIGEST *out, const char *str);
+int sha256_comp(SHA256_DIGEST digest1, SHA256_DIGEST digest2);
+
+static const SHA256_DIGEST SHA256_ZEROED = {{0}};
+
+#ifdef __cplusplus
+}
+#endif
+
+#ifdef __cplusplus
+inline bool operator==(const SHA256_DIGEST &that, const SHA256_DIGEST &other)
+{
+	return sha256_comp(that, other) == 0;
+}
+inline bool operator!=(const SHA256_DIGEST &that, const SHA256_DIGEST &other)
+{
+	return !(that == other);
+}
+#endif
+
+#endif // BASE_HASH_H

src/base/hash_ctxt.h

@@ -0,0 +1,35 @@
+#ifndef BASE_HASH_CTXT_H
+#define BASE_HASH_CTXT_H
+
+#include "hash.h"
+#include <stdint.h>
+
+#if defined(CONF_OPENSSL)
+#include <openssl/sha.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(CONF_OPENSSL)
+// SHA256_CTX is defined in <openssl/sha.h>
+#else
+typedef struct
+{
+    uint64_t length;
+    uint32_t state[8];
+    uint32_t curlen;
+    unsigned char buf[64];
+} SHA256_CTX;
+#endif
+
+void sha256_init(SHA256_CTX *ctxt);
+void sha256_update(SHA256_CTX *ctxt, const void *data, size_t data_len);
+SHA256_DIGEST sha256_finish(SHA256_CTX *ctxt);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // BASE_HASH_CTXT_H

src/base/hash_libtomcrypt.c

@@ -0,0 +1,197 @@
+// SHA-256. Adapted from https://github.com/kalven/sha-2, which was adapted
+// from LibTomCrypt. This code is Public Domain.
+
+#if !defined(CONF_OPENSSL)
+
+#include "hash_ctxt.h"
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+typedef uint32_t u32;
+typedef uint64_t u64;
+typedef SHA256_CTX sha256_state;
+
+static const u32 K[64] =
+{
+    0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL, 0x3956c25bUL,
+    0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL, 0xd807aa98UL, 0x12835b01UL,
+    0x243185beUL, 0x550c7dc3UL, 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL,
+    0xc19bf174UL, 0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
+    0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL, 0x983e5152UL,
+    0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL, 0xc6e00bf3UL, 0xd5a79147UL,
+    0x06ca6351UL, 0x14292967UL, 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL,
+    0x53380d13UL, 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
+    0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL, 0xd192e819UL,
+    0xd6990624UL, 0xf40e3585UL, 0x106aa070UL, 0x19a4c116UL, 0x1e376c08UL,
+    0x2748774cUL, 0x34b0bcb5UL, 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL,
+    0x682e6ff3UL, 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
+    0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
+};
+
+static u32 min(u32 x, u32 y)
+{
+    return x < y ? x : y;
+}
+
+static u32 load32(const unsigned char* y)
+{
+    return ((u32)y[0] << 24) | ((u32)y[1] << 16) | ((u32)y[2] << 8) | ((u32)y[3] << 0);
+}
+
+static void store64(u64 x, unsigned char* y)
+{
+    for(int i = 0; i != 8; ++i)
+        y[i] = (x >> ((7-i) * 8)) & 255;
+}
+
+static void store32(u32 x, unsigned char* y)
+{
+    for(int i = 0; i != 4; ++i)
+        y[i] = (x >> ((3-i) * 8)) & 255;
+}
+
+static u32 Ch(u32 x, u32 y, u32 z)  { return z ^ (x & (y ^ z)); }
+static u32 Maj(u32 x, u32 y, u32 z) { return ((x | y) & z) | (x & y); }
+static u32 Rot(u32 x, u32 n)        { return (x >> (n & 31)) | (x << (32 - (n & 31))); }
+static u32 Sh(u32 x, u32 n)         { return x >> n; }
+static u32 Sigma0(u32 x)            { return Rot(x, 2) ^ Rot(x, 13) ^ Rot(x, 22); }
+static u32 Sigma1(u32 x)            { return Rot(x, 6) ^ Rot(x, 11) ^ Rot(x, 25); }
+static u32 Gamma0(u32 x)            { return Rot(x, 7) ^ Rot(x, 18) ^ Sh(x, 3); }
+static u32 Gamma1(u32 x)            { return Rot(x, 17) ^ Rot(x, 19) ^ Sh(x, 10); }
+
+static void sha_compress(sha256_state* md, const unsigned char* buf)
+{
+    u32 S[8], W[64], t0, t1, t;
+
+    // Copy state into S
+    for(int i = 0; i < 8; i++)
+        S[i] = md->state[i];
+
+    // Copy the state into 512-bits into W[0..15]
+    for(int i = 0; i < 16; i++)
+        W[i] = load32(buf + (4*i));
+
+    // Fill W[16..63]
+    for(int i = 16; i < 64; i++)
+        W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) + W[i - 16];
+
+    // Compress
+    #define RND(a, b, c, d, e, f, g, h, i) \
+    { \
+        t0 = h + Sigma1(e) + Ch(e, f, g) + K[i] + W[i]; \
+        t1 = Sigma0(a) + Maj(a, b, c); \
+        d += t0; \
+        h  = t0 + t1; \
+    }
+
+    for(int i = 0; i < 64; ++i)
+    {
+        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],i);
+        t = S[7]; S[7] = S[6]; S[6] = S[5]; S[5] = S[4];
+        S[4] = S[3]; S[3] = S[2]; S[2] = S[1]; S[1] = S[0]; S[0] = t;
+    }
+
+    // Feedback
+    for(int i = 0; i < 8; i++)
+        md->state[i] = md->state[i] + S[i];
+}
+
+// Public interface
+
+static void sha_init(sha256_state* md)
+{
+    md->curlen = 0;
+    md->length = 0;
+    md->state[0] = 0x6A09E667UL;
+    md->state[1] = 0xBB67AE85UL;
+    md->state[2] = 0x3C6EF372UL;
+    md->state[3] = 0xA54FF53AUL;
+    md->state[4] = 0x510E527FUL;
+    md->state[5] = 0x9B05688CUL;
+    md->state[6] = 0x1F83D9ABUL;
+    md->state[7] = 0x5BE0CD19UL;
+}
+
+static void sha_process(sha256_state* md, const void* src, u32 inlen)
+{
+    const u32 block_size = 64;
+    const unsigned char* in = src;
+
+    while(inlen > 0)
+    {
+        if(md->curlen == 0 && inlen >= block_size)
+        {
+            sha_compress(md, in);
+            md->length += block_size * 8;
+            in         += block_size;
+            inlen      -= block_size;
+        }
+        else
+        {
+            u32 n = min(inlen, (block_size - md->curlen));
+            memcpy(md->buf + md->curlen, in, n);
+            md->curlen += n;
+            in         += n;
+            inlen      -= n;
+
+            if(md->curlen == block_size)
+            {
+                sha_compress(md, md->buf);
+                md->length += 8*block_size;
+                md->curlen = 0;
+            }
+        }
+    }
+}
+
+static void sha_done(sha256_state* md, void* out)
+{
+    // Increase the length of the message
+    md->length += md->curlen * 8;
+
+    // Append the '1' bit
+    md->buf[md->curlen++] = (unsigned char)0x80;
+
+    // If the length is currently above 56 bytes we append zeros then compress.
+    // Then we can fall back to padding zeros and length encoding like normal.
+    if(md->curlen > 56)
+    {
+        while(md->curlen < 64)
+            md->buf[md->curlen++] = 0;
+        sha_compress(md, md->buf);
+        md->curlen = 0;
+    }
+
+    // Pad upto 56 bytes of zeroes
+    while(md->curlen < 56)
+        md->buf[md->curlen++] = 0;
+
+    // Store length
+    store64(md->length, md->buf+56);
+    sha_compress(md, md->buf);
+
+    // Copy output
+    for(int i = 0; i < 8; i++)
+        store32(md->state[i], (unsigned char *)out+(4*i));
+}
+
+void sha256_init(SHA256_CTX *ctxt)
+{
+    sha_init(ctxt);
+}
+
+void sha256_update(SHA256_CTX *ctxt, const void *data, size_t data_len)
+{
+    sha_process(ctxt, data, data_len);
+}
+
+SHA256_DIGEST sha256_finish(SHA256_CTX *ctxt)
+{
+    SHA256_DIGEST result;
+    sha_done(ctxt, result.data);
+    return result;
+}
+
+#endif

src/base/hash_openssl.c

@@ -0,0 +1,20 @@
+#if defined(CONF_OPENSSL)
+#include "hash_ctxt.h"
+
+void sha256_init(SHA256_CTX *ctxt)
+{
+	SHA256_Init(ctxt);
+}
+
+void sha256_update(SHA256_CTX *ctxt, const void *data, size_t data_len)
+{
+	SHA256_Update(ctxt, data, data_len);
+}
+
+SHA256_DIGEST sha256_finish(SHA256_CTX *ctxt)
+{
+	SHA256_DIGEST result;
+	SHA256_Final(result.data, ctxt);
+	return result;
+}
+#endif

src/engine/client/client.cpp

@@ -316,10 +316,17 @@ CClient::CClient() : m_DemoPlayer(&m_SnapshotDelta)
 	m_pMapdownloadTask = NULL;
 	m_MapdownloadFile = 0;
 	m_MapdownloadChunk = 0;
+	m_MapdownloadSha256Present = false;
+	m_MapdownloadSha256 = SHA256_ZEROED;
 	m_MapdownloadCrc = 0;
 	m_MapdownloadAmount = -1;
 	m_MapdownloadTotalsize = -1;
 
+	m_MapDetailsPresent = false;
+	m_aMapDetailsName[0] = 0;
+	m_MapDetailsSha256 = SHA256_ZEROED;
+	m_MapDetailsCrc = 0;
+
 	m_pDDNetInfoTask = NULL;
 	m_aNews[0] = '\0';
 
@@ -742,6 +749,8 @@ void CClient::DisconnectWithReason(const char *pReason)
 	if(m_MapdownloadFile)
 		io_close(m_MapdownloadFile);
 	m_MapdownloadFile = 0;
+	m_MapdownloadSha256Present = false;
+	m_MapdownloadSha256 = SHA256_ZEROED;
 	m_MapdownloadCrc = 0;
 	m_MapdownloadTotalsize = -1;
 	m_MapdownloadAmount = 0;
@@ -1052,7 +1061,7 @@ vec3 CClient::GetColorV3(int v)
 	return HslToRgb(vec3(((v>>16)&0xff)/255.0f, ((v>>8)&0xff)/255.0f, 0.5f+(v&0xff)/255.0f*0.5f));
 }
 
-const char *CClient::LoadMap(const char *pName, const char *pFilename, unsigned WantedCrc)
+const char *CClient::LoadMap(const char *pName, const char *pFilename, SHA256_DIGEST *pWantedSha256, unsigned WantedCrc)
 {
 	static char s_aErrorMsg[128];
 
@@ -1064,6 +1073,18 @@ const char *CClient::LoadMap(const char *pName, const char *pFilename, unsigned
 		return s_aErrorMsg;
 	}
 
+	if(pWantedSha256 && m_pMap->Sha256() != *pWantedSha256)
+	{
+		char aWanted[SHA256_MAXSTRSIZE];
+		char aGot[SHA256_MAXSTRSIZE];
+		sha256_str(*pWantedSha256, aWanted, sizeof(aWanted));
+		sha256_str(m_pMap->Sha256(), aGot, sizeof(aWanted));
+		str_format(s_aErrorMsg, sizeof(s_aErrorMsg), "map differs from the server. %s != %s", aGot, aWanted);
+		m_pConsole->Print(IConsole::OUTPUT_LEVEL_ADDINFO, "client", s_aErrorMsg);
+		m_pMap->Unload();
+		return s_aErrorMsg;
+	}
+
 	// get the crc of the map
 	if(m_pMap->Crc() != WantedCrc)
 	{
@@ -1085,28 +1106,37 @@ const char *CClient::LoadMap(const char *pName, const char *pFilename, unsigned
 	str_copy(m_aCurrentMap, pName, sizeof(m_aCurrentMap));
 	str_copy(m_aCurrentMapPath, pFilename, sizeof(m_aCurrentMapPath));
 
-	return 0x0;
+	return 0;
 }
 
-
+const char *CClient::LoadMapSearch(const char *pMapName, SHA256_DIGEST *pWantedSha256, int WantedCrc)
-
-const char *CClient::LoadMapSearch(const char *pMapName, int WantedCrc)
 {
 	const char *pError = 0;
 	char aBuf[512];
-	str_format(aBuf, sizeof(aBuf), "loading map, map=%s wanted crc=%08x", pMapName, WantedCrc);
+	char aWanted[256];
+	char aWantedSha256[SHA256_MAXSTRSIZE];
+
+	aWanted[0] = 0;
+
+	if(pWantedSha256)
+	{
+		sha256_str(*pWantedSha256, aWantedSha256, sizeof(aWantedSha256));
+		str_format(aWanted, sizeof(aWanted), "sha256=%s ", aWantedSha256);
+	}
+
+	str_format(aBuf, sizeof(aBuf), "loading map, map=%s wanted%s crc=%08x", pMapName, aWanted, WantedCrc);
 	m_pConsole->Print(IConsole::OUTPUT_LEVEL_ADDINFO, "client", aBuf);
 	SetState(IClient::STATE_LOADING);
 
 	// try the normal maps folder
 	str_format(aBuf, sizeof(aBuf), "maps/%s.map", pMapName);
-	pError = LoadMap(pMapName, aBuf, WantedCrc);
+	pError = LoadMap(pMapName, aBuf, pWantedSha256, WantedCrc);
 	if(!pError)
 		return pError;
 
 	// try the downloaded maps
 	str_format(aBuf, sizeof(aBuf), "downloadedmaps/%s_%08x.map", pMapName, WantedCrc);
-	pError = LoadMap(pMapName, aBuf, WantedCrc);
+	pError = LoadMap(pMapName, aBuf, pWantedSha256, WantedCrc);
 	if(!pError)
 		return pError;
 
@@ -1114,7 +1144,7 @@ const char *CClient::LoadMapSearch(const char *pMapName, int WantedCrc)
 	char aFilename[128];
 	str_format(aFilename, sizeof(aFilename), "%s.map", pMapName);
 	if(Storage()->FindFile(aFilename, "maps", IStorage::TYPE_ALL, aBuf, sizeof(aBuf)))
-		pError = LoadMap(pMapName, aBuf, WantedCrc);
+		pError = LoadMap(pMapName, aBuf, pWantedSha256, WantedCrc);
 
 	return pError;
 }
@@ -1428,6 +1458,23 @@ void CClient::ProcessServerInfo(int RawType, NETADDR *pFrom, const void *pData,
 	#undef GET_INT
 }
 
+static void FormatMapDownloadFilename(const char *pName, SHA256_DIGEST *pSha256, int Crc, bool Temp, char *pBuffer, int BufferSize)
+{
+	char aSha256[SHA256_MAXSTRSIZE + 1];
+	aSha256[0] = 0;
+	if(pSha256)
+	{
+		aSha256[0] = '_';
+		sha256_str(*pSha256, aSha256 + 1, sizeof(aSha256) - 1);
+	}
+
+	str_format(pBuffer, BufferSize, "%s_%08x%s.map%s",
+		pName,
+		Crc,
+		aSha256,
+		Temp ? ".tmp" : "");
+}
+
 void CClient::ProcessServerPacket(CNetChunk *pPacket)
 {
 	CUnpacker Unpacker;
@@ -1452,8 +1499,27 @@ void CClient::ProcessServerPacket(CNetChunk *pPacket)
 	if(Sys)
 	{
 		// system message
-		if((pPacket->m_Flags&NET_CHUNKFLAG_VITAL) != 0 && Msg == NETMSG_MAP_CHANGE)
+		if((pPacket->m_Flags&NET_CHUNKFLAG_VITAL) != 0 && Msg == NETMSG_MAP_DETAILS)
 		{
+			const char *pMap = Unpacker.GetString(CUnpacker::SANITIZE_CC|CUnpacker::SKIP_START_WHITESPACES);
+			SHA256_DIGEST *pMapSha256 = (SHA256_DIGEST *)Unpacker.GetRaw(sizeof(*pMapSha256));
+			int MapCrc = Unpacker.GetInt();
+
+			if(Unpacker.Error())
+			{
+				return;
+			}
+
+			m_MapDetailsPresent = true;
+			str_copy(m_aMapDetailsName, pMap, sizeof(m_aMapDetailsName));
+			m_MapDetailsSha256 = *pMapSha256;
+			m_MapDetailsCrc = MapCrc;
+		}
+		else if((pPacket->m_Flags&NET_CHUNKFLAG_VITAL) != 0 && Msg == NETMSG_MAP_CHANGE)
+		{
+			bool MapDetailsWerePresent = m_MapDetailsPresent;
+			m_MapDetailsPresent = false;
+
 			const char *pMap = Unpacker.GetString(CUnpacker::SANITIZE_CC|CUnpacker::SKIP_START_WHITESPACES);
 			int MapCrc = Unpacker.GetInt();
 			int MapSize = Unpacker.GetInt();
@@ -1478,7 +1544,12 @@ void CClient::ProcessServerPacket(CNetChunk *pPacket)
 				DisconnectWithReason(pError);
 			else
 			{
-				pError = LoadMapSearch(pMap, MapCrc);
+				SHA256_DIGEST *pMapSha256 = 0;
+				if(MapDetailsWerePresent && str_comp(m_aMapDetailsName, pMap) == 0 && m_MapDetailsCrc == MapCrc)
+				{
+					pMapSha256 = &m_MapDetailsSha256;
+				}
+				pError = LoadMapSearch(pMap, pMapSha256, MapCrc);
 
 				if(!pError)
 				{
@@ -1487,7 +1558,9 @@ void CClient::ProcessServerPacket(CNetChunk *pPacket)
 				}
 				else
 				{
-					str_format(m_aMapdownloadFilename, sizeof(m_aMapdownloadFilename), "downloadedmaps/%s_%08x.map", pMap, MapCrc);
+					char aFilename[256];
+					FormatMapDownloadFilename(pMap, pMapSha256, MapCrc, true, aFilename, sizeof(aFilename));
+					str_format(m_aMapdownloadFilename, sizeof(m_aMapdownloadFilename), "downloadedmaps/%s", aFilename);
 
 					char aBuf[256];
 					str_format(aBuf, sizeof(aBuf), "starting to download map to '%s'", m_aMapdownloadFilename);
@@ -1496,21 +1569,20 @@ void CClient::ProcessServerPacket(CNetChunk *pPacket)
 					m_MapdownloadChunk = 0;
 					str_copy(m_aMapdownloadName, pMap, sizeof(m_aMapdownloadName));
 
+					m_MapdownloadSha256Present = (bool)pMapSha256;
+					m_MapdownloadSha256 = pMapSha256 ? *pMapSha256 : SHA256_ZEROED;
 					m_MapdownloadCrc = MapCrc;
 					m_MapdownloadTotalsize = MapSize;
 					m_MapdownloadAmount = 0;
 
 					ResetMapDownload();
 
-					if(g_Config.m_ClHttpMapDownload)
+					if(pMapSha256 && g_Config.m_ClHttpMapDownload)
 					{
 						char aUrl[256];
-						char aFilename[64];
+						char aEscaped[256];
-						char aEscaped[128];
-						str_format(aFilename, sizeof(aFilename), "%s_%08x.map", pMap, MapCrc);
-
 						EscapeUrl(aEscaped, sizeof(aEscaped), aFilename);
-						str_format(aUrl, sizeof(aUrl), "%s/", g_Config.m_ClDDNetMapDownloadUrl);
+						str_format(aUrl, sizeof(aUrl), "%s/%s", g_Config.m_ClDDNetMapDownloadUrl, aEscaped);
 
 						// We only trust our own custom-selected CAs for our own servers.
 						// Other servers can use any CA trusted by the system.
@@ -1519,7 +1591,6 @@ void CClient::ProcessServerPacket(CNetChunk *pPacket)
 							str_comp_nocase_num("http://maps.ddnet.tw/", aUrl, 21) == 0 ||
 							str_comp_nocase_num("https://maps.ddnet.tw/", aUrl, 22) == 0;
 
-						str_append(aUrl, aEscaped, sizeof(aUrl));
 
 						m_pMapdownloadTask = std::make_shared<CGetFile>(Storage(), aUrl, m_aMapdownloadFilename, IStorage::TYPE_SAVE, UseDDNetCA, true);
 						Engine()->AddJob(m_pMapdownloadTask);
@@ -2106,9 +2177,20 @@ void CClient::FinishMapDownload()
 
 	int Prev = m_MapdownloadTotalsize;
 	m_MapdownloadTotalsize = -1;
+	SHA256_DIGEST *pSha256 = m_MapdownloadSha256Present ? &m_MapdownloadSha256 : 0;
+
+	char aTmp[256];
+	char aMapFileTemp[256];
+	char aMapFile[256];
+	FormatMapDownloadFilename(m_aMapdownloadName, pSha256, m_MapdownloadCrc, true, aTmp, sizeof(aTmp));
+	str_format(aMapFileTemp, sizeof(aMapFileTemp), "downloadedmaps/%s", aTmp);
+	FormatMapDownloadFilename(m_aMapdownloadName, pSha256, m_MapdownloadCrc, false, aTmp, sizeof(aTmp));
+	str_format(aMapFile, sizeof(aMapFileTemp), "downloadedmaps/%s", aTmp);
+
+	Storage()->RenameFile(aMapFileTemp, aMapFile, IStorage::TYPE_SAVE);
 
 	// load map
-	pError = LoadMap(m_aMapdownloadName, m_aMapdownloadFilename, m_MapdownloadCrc);
+	pError = LoadMap(m_aMapdownloadName, aMapFile, pSha256, m_MapdownloadCrc);
 	if(!pError)
 	{
 		ResetMapDownload();
@@ -3144,7 +3226,7 @@ const char *CClient::DemoPlayer_Play(const char *pFilename, int StorageType)
 		(m_DemoPlayer.Info()->m_Header.m_aMapCrc[1]<<16)|
 		(m_DemoPlayer.Info()->m_Header.m_aMapCrc[2]<<8)|
 		(m_DemoPlayer.Info()->m_Header.m_aMapCrc[3]);
-	pError = LoadMapSearch(m_DemoPlayer.Info()->m_Header.m_aMapName, Crc);
+	pError = LoadMapSearch(m_DemoPlayer.Info()->m_Header.m_aMapName, 0, Crc);
 	if(pError)
 	{
 		DisconnectWithReason(pError);
@@ -3221,7 +3303,7 @@ void CClient::DemoRecorder_Start(const char *pFilename, bool WithTimestamp, int
 		}
 		else
 			str_format(aFilename, sizeof(aFilename), "demos/%s.demo", pFilename);
-		m_DemoRecorder[Recorder].Start(Storage(), m_pConsole, aFilename, GameClient()->NetVersion(), m_aCurrentMap, m_pMap->Crc(), "client", m_pMap->MapSize(), 0, m_pMap->File());
+		m_DemoRecorder[Recorder].Start(Storage(), m_pConsole, aFilename, GameClient()->NetVersion(), m_aCurrentMap, m_pMap->Sha256(), m_pMap->Crc(), "client", m_pMap->MapSize(), 0, m_pMap->File());
 	}
 }
 
@@ -3652,7 +3734,7 @@ void CClient::RaceRecord_Start(const char *pFilename)
 	if(State() != IClient::STATE_ONLINE)
 		m_pConsole->Print(IConsole::OUTPUT_LEVEL_STANDARD, "demorec/record", "client is not online");
 	else
-		m_DemoRecorder[RECORDER_RACE].Start(Storage(), m_pConsole, pFilename, GameClient()->NetVersion(), m_aCurrentMap, m_pMap->Crc(), "client", m_pMap->MapSize(), 0, m_pMap->File());
+		m_DemoRecorder[RECORDER_RACE].Start(Storage(), m_pConsole, pFilename, GameClient()->NetVersion(), m_aCurrentMap, m_pMap->Sha256(), m_pMap->Crc(), "client", m_pMap->MapSize(), 0, m_pMap->File());
 }
 
 void CClient::RaceRecord_Stop()

src/engine/client/client.h

@@ -5,6 +5,7 @@
 
 #include <memory>
 
+#include <base/hash.h>
 #include <engine/shared/fetcher.h>
 
 class CGraph
@@ -139,6 +140,13 @@ class CClient : public IClient, public CDemoPlayer::IListener
 	int m_MapdownloadCrc;
 	int m_MapdownloadAmount;
 	int m_MapdownloadTotalsize;
+	bool m_MapdownloadSha256Present;
+	SHA256_DIGEST m_MapdownloadSha256;
+
+	bool m_MapDetailsPresent;
+	char m_aMapDetailsName[256];
+	int m_MapDetailsCrc;
+	SHA256_DIGEST m_MapDetailsSha256;
 
 	std::shared_ptr<CGetFile> m_pDDNetInfoTask;
 
@@ -286,8 +294,8 @@ public:
 
 	virtual const char *ErrorString();
 
-	const char *LoadMap(const char *pName, const char *pFilename, unsigned WantedCrc);
+	const char *LoadMap(const char *pName, const char *pFilename, SHA256_DIGEST *pWantedSha256, unsigned WantedCrc);
-	const char *LoadMapSearch(const char *pMapName, int WantedCrc);
+	const char *LoadMapSearch(const char *pMapName, SHA256_DIGEST *pWantedSha256, int WantedCrc);
 
 	static int PlayerScoreNameComp(const void *a, const void *b);
 

src/engine/map.h

@@ -3,6 +3,7 @@
 #ifndef ENGINE_MAP_H
 #define ENGINE_MAP_H
 
+#include <base/hash.h>
 #include "kernel.h"
 
 class IMap : public IInterface
@@ -28,6 +29,7 @@ public:
 	virtual bool Load(const char *pMapName) = 0;
 	virtual bool IsLoaded() = 0;
 	virtual void Unload() = 0;
+	virtual SHA256_DIGEST Sha256() = 0;
 	virtual unsigned Crc() = 0;
 	virtual int MapSize() = 0;
 	virtual IOHANDLE File() = 0;

src/engine/server.h

@@ -2,6 +2,9 @@
 /* If you are missing that file, acquire a complete release at teeworlds.com.                */
 #ifndef ENGINE_SERVER_H
 #define ENGINE_SERVER_H
+
+#include <base/hash.h>
+
 #include "kernel.h"
 #include "message.h"
 #include <game/generated/protocol.h>
@@ -133,7 +136,7 @@ public:
 		return true;
 	}
 
-	virtual void GetMapInfo(char *pMapName, int MapNameSize, int *pMapSize, int *pMapCrc) = 0;
+	virtual void GetMapInfo(char *pMapName, int MapNameSize, int *pMapSize, SHA256_DIGEST *pSha256, int *pMapCrc) = 0;
 
 	virtual void SetClientName(int ClientID, char const *pName) = 0;
 	virtual void SetClientClan(int ClientID, char const *pClan) = 0;

src/engine/server/server.cpp

@@ -777,6 +777,7 @@ int CServer::NewClientNoAuthCallback(int ClientID, void *pUser)
 	pThis->m_aClients[ClientID].m_DnsblState = CClient::DNSBL_STATE_NONE;
 
 	pThis->m_aClients[ClientID].m_State = CClient::STATE_CONNECTING;
+	pThis->m_aClients[ClientID].m_SupportsMapSha256 = false;
 	pThis->m_aClients[ClientID].m_aName[0] = 0;
 	pThis->m_aClients[ClientID].m_aClan[0] = 0;
 	pThis->m_aClients[ClientID].m_Country = -1;
@@ -797,6 +798,7 @@ int CServer::NewClientCallback(int ClientID, void *pUser)
 {
 	CServer *pThis = (CServer *)pUser;
 	pThis->m_aClients[ClientID].m_State = CClient::STATE_AUTH;
+	pThis->m_aClients[ClientID].m_SupportsMapSha256 = false;
 	pThis->m_aClients[ClientID].m_DnsblState = CClient::DNSBL_STATE_NONE;
 	pThis->m_aClients[ClientID].m_aName[0] = 0;
 	pThis->m_aClients[ClientID].m_aClan[0] = 0;
@@ -875,6 +877,7 @@ int CServer::DelClientCallback(int ClientID, const char *pReason, void *pUser)
 		pThis->GameServer()->OnClientDrop(ClientID, pReason);
 
 	pThis->m_aClients[ClientID].m_State = CClient::STATE_EMPTY;
+	pThis->m_aClients[ClientID].m_SupportsMapSha256 = false;
 	pThis->m_aClients[ClientID].m_aName[0] = 0;
 	pThis->m_aClients[ClientID].m_aClan[0] = 0;
 	pThis->m_aClients[ClientID].m_Country = -1;
@@ -901,20 +904,31 @@ void CServer::SendRconType(int ClientID, bool UsernameReq)
 	SendMsgEx(&Msg, MSGFLAG_VITAL, ClientID, true);
 }
 
-void CServer::GetMapInfo(char *pMapName, int MapNameSize, int *pMapSize, int *pMapCrc)
+void CServer::GetMapInfo(char *pMapName, int MapNameSize, int *pMapSize, SHA256_DIGEST *pMapSha256, int *pMapCrc)
 {
 	str_copy(pMapName, GetMapName(), MapNameSize);
 	*pMapSize = m_CurrentMapSize;
+	*pMapSha256 = m_CurrentMapSha256;
 	*pMapCrc = m_CurrentMapCrc;
 }
 
 void CServer::SendMap(int ClientID)
+{
+	{
+		CMsgPacker Msg(NETMSG_MAP_DETAILS);
+		Msg.AddString(GetMapName(), 0);
+		Msg.AddRaw(&m_CurrentMapSha256.data, sizeof(m_CurrentMapSha256.data));
+		Msg.AddInt(m_CurrentMapCrc);
+		Msg.AddInt(m_CurrentMapSize);
+		SendMsgEx(&Msg, MSGFLAG_VITAL, ClientID, true);
+	}
 	{
 		CMsgPacker Msg(NETMSG_MAP_CHANGE);
 		Msg.AddString(GetMapName(), 0);
 		Msg.AddInt(m_CurrentMapCrc);
 		Msg.AddInt(m_CurrentMapSize);
 		SendMsgEx(&Msg, MSGFLAG_VITAL|MSGFLAG_FLUSH, ClientID, true);
+	}
 
 	m_aClients[ClientID].m_NextMapChunk = 0;
 }
@@ -1692,8 +1706,13 @@ int CServer::LoadMap(const char *pMapName)
 	m_IDPool.TimeoutIDs();
 
 	// get the crc of the map
+	m_CurrentMapSha256 = m_pMap->Sha256();
 	m_CurrentMapCrc = m_pMap->Crc();
 	char aBufMsg[256];
+	char aSha256[SHA256_MAXSTRSIZE];
+	sha256_str(m_CurrentMapSha256, aSha256, sizeof(aSha256));
+	str_format(aBufMsg, sizeof(aBufMsg), "%s sha256 is %s", aBuf, aSha256);
+	Console()->Print(IConsole::OUTPUT_LEVEL_ADDINFO, "server", aBufMsg);
 	str_format(aBufMsg, sizeof(aBufMsg), "%s crc is %08x", aBuf, m_CurrentMapCrc);
 	Console()->Print(IConsole::OUTPUT_LEVEL_ADDINFO, "server", aBufMsg);
 
@@ -2385,7 +2404,7 @@ void CServer::DemoRecorder_HandleAutoStart()
 		char aDate[20];
 		str_timestamp(aDate, sizeof(aDate));
 		str_format(aFilename, sizeof(aFilename), "demos/%s_%s.demo", "auto/autorecord", aDate);
-		m_aDemoRecorder[MAX_CLIENTS].Start(Storage(), m_pConsole, aFilename, GameServer()->NetVersion(), m_aCurrentMap, m_CurrentMapCrc, "server", m_CurrentMapSize, m_pCurrentMapData);
+		m_aDemoRecorder[MAX_CLIENTS].Start(Storage(), m_pConsole, aFilename, GameServer()->NetVersion(), m_aCurrentMap, m_CurrentMapSha256, m_CurrentMapCrc, "server", m_CurrentMapSize, m_pCurrentMapData);
 		if(g_Config.m_SvAutoDemoMax)
 		{
 			// clean up auto recorded demos
@@ -2421,7 +2440,7 @@ void CServer::StartRecord(int ClientID)
 	{
 		char aFilename[128];
 		str_format(aFilename, sizeof(aFilename), "demos/%s_%d_%d_tmp.demo", m_aCurrentMap, g_Config.m_SvPort, ClientID);
-		m_aDemoRecorder[ClientID].Start(Storage(), Console(), aFilename, GameServer()->NetVersion(), m_aCurrentMap, m_CurrentMapCrc, "server", m_CurrentMapSize, m_pCurrentMapData);
+		m_aDemoRecorder[ClientID].Start(Storage(), Console(), aFilename, GameServer()->NetVersion(), m_aCurrentMap, m_CurrentMapSha256, m_CurrentMapCrc, "server", m_CurrentMapSize, m_pCurrentMapData);
 	}
 }
 
@@ -2455,7 +2474,7 @@ void CServer::ConRecord(IConsole::IResult *pResult, void *pUser)
 		str_timestamp(aDate, sizeof(aDate));
 		str_format(aFilename, sizeof(aFilename), "demos/demo_%s.demo", aDate);
 	}
-	pServer->m_aDemoRecorder[MAX_CLIENTS].Start(pServer->Storage(), pServer->Console(), aFilename, pServer->GameServer()->NetVersion(), pServer->m_aCurrentMap, pServer->m_CurrentMapCrc, "server", pServer->m_CurrentMapSize, pServer->m_pCurrentMapData);
+	pServer->m_aDemoRecorder[MAX_CLIENTS].Start(pServer->Storage(), pServer->Console(), aFilename, pServer->GameServer()->NetVersion(), pServer->m_aCurrentMap, pServer->m_CurrentMapSha256, pServer->m_CurrentMapCrc, "server", pServer->m_CurrentMapSize, pServer->m_pCurrentMapData);
 }
 
 void CServer::ConStopRecord(IConsole::IResult *pResult, void *pUser)

src/engine/server/server.h

@@ -3,6 +3,9 @@
 #ifndef ENGINE_SERVER_SERVER_H
 #define ENGINE_SERVER_SERVER_H
 
+#include <base/hash.h>
+#include <base/math.h>
+
 #include <engine/engine.h>
 #include <engine/server.h>
 
@@ -13,7 +16,6 @@
 #include <engine/shared/network.h>
 #include <engine/server/register.h>
 #include <engine/shared/console.h>
-#include <base/math.h>
 #include <engine/shared/econ.h>
 #include <engine/shared/fifo.h>
 #include <engine/shared/netban.h>
@@ -140,6 +142,7 @@ public:
 
 		// connection state info
 		int m_State;
+		bool m_SupportsMapSha256;
 		int m_Latency;
 		int m_SnapRate;
 
@@ -204,6 +207,7 @@ public:
 	//static NETADDR4 master_server;
 
 	char m_aCurrentMap[64];
+	SHA256_DIGEST m_CurrentMapSha256;
 	unsigned m_CurrentMapCrc;
 	unsigned char *m_pCurrentMapData;
 	unsigned int m_CurrentMapSize;
@@ -245,7 +249,7 @@ public:
 	void SetRconCID(int ClientID);
 	int GetAuthedState(int ClientID);
 	const char *GetAuthName(int ClientID);
-	void GetMapInfo(char *pMapName, int MapNameSize, int *pMapSize, int *pMapCrc);
+	void GetMapInfo(char *pMapName, int MapNameSize, int *pMapSize, SHA256_DIGEST *pMapSha256, int *pMapCrc);
 	int GetClientInfo(int ClientID, CClientInfo *pInfo);
 	void GetClientAddr(int ClientID, char *pAddrStr, int Size);
 	const char *ClientName(int ClientID);

src/engine/shared/datafile.cpp

@@ -1,6 +1,7 @@
 /* (c) Magnus Auvinen. See licence.txt in the root of the distribution for more information. */
 /* If you are missing that file, acquire a complete release at teeworlds.com.                */
 #include <base/math.h>
+#include <base/hash_ctxt.h>
 #include <base/system.h>
 #include <engine/storage.h>
 #include "datafile.h"
@@ -58,6 +59,7 @@ struct CDatafileInfo
 struct CDatafile
 {
 	IOHANDLE m_File;
+	SHA256_DIGEST m_Sha256;
 	unsigned m_Crc;
 	CDatafileInfo m_Info;
 	CDatafileHeader m_Header;
@@ -80,12 +82,15 @@ bool CDataFileReader::Open(class IStorage *pStorage, const char *pFilename, int
 
 	// take the CRC of the file and store it
 	unsigned Crc = 0;
+	SHA256_DIGEST Sha256;
 	{
 		enum
 		{
 			BUFFER_SIZE = 64*1024
 		};
 
+		SHA256_CTX Sha256Ctxt;
+		sha256_init(&Sha256Ctxt);
 		unsigned char aBuffer[BUFFER_SIZE];
 
 		while(1)
@@ -94,7 +99,9 @@ bool CDataFileReader::Open(class IStorage *pStorage, const char *pFilename, int
 			if(Bytes <= 0)
 				break;
 			Crc = crc32(Crc, aBuffer, Bytes); // ignore_convention
+			sha256_update(&Sha256Ctxt, aBuffer, Bytes);
 		}
+		Sha256 = sha256_finish(&Sha256Ctxt);
 
 		io_seek(File, 0, IOSEEK_START);
 	}
@@ -143,6 +150,7 @@ bool CDataFileReader::Open(class IStorage *pStorage, const char *pFilename, int
 	pTmpDataFile->m_ppDataPtrs = (char **)(pTmpDataFile+1);
 	pTmpDataFile->m_pData = (char *)(pTmpDataFile+1)+Header.m_NumRawData*sizeof(char *);
 	pTmpDataFile->m_File = File;
+	pTmpDataFile->m_Sha256 = Sha256;
 	pTmpDataFile->m_Crc = Crc;
 
 	// clear the data pointers
@@ -226,32 +234,6 @@ bool CDataFileReader::Open(class IStorage *pStorage, const char *pFilename, int
 	return true;
 }
 
-bool CDataFileReader::GetCrcSize(class IStorage *pStorage, const char *pFilename, int StorageType, unsigned *pCrc, unsigned *pSize)
-{
-	IOHANDLE File = pStorage->OpenFile(pFilename, IOFLAG_READ, StorageType);
-	if(!File)
-		return false;
-
-	// get crc and size
-	unsigned Crc = 0;
-	unsigned Size = 0;
-	unsigned char aBuffer[64*1024];
-	while(1)
-	{
-		unsigned Bytes = io_read(File, aBuffer, sizeof(aBuffer));
-		if(Bytes <= 0)
-			break;
-		Crc = crc32(Crc, aBuffer, Bytes); // ignore_convention
-		Size += Bytes;
-	}
-
-	io_close(File);
-
-	*pCrc = Crc;
-	*pSize = Size;
-	return true;
-}
-
 int CDataFileReader::NumData()
 {
 	if(!m_pDataFile) { return 0; }
@@ -432,6 +414,20 @@ bool CDataFileReader::Close()
 	return true;
 }
 
+SHA256_DIGEST CDataFileReader::Sha256()
+{
+	if(!m_pDataFile)
+	{
+		SHA256_DIGEST Result;
+		for(unsigned i = 0; i < sizeof(Result.data); i++)
+		{
+			Result.data[i] = 0xff;
+		}
+		return Result;
+	}
+	return m_pDataFile->m_Sha256;
+}
+
 unsigned CDataFileReader::Crc()
 {
 	if(!m_pDataFile) return 0xFFFFFFFF;

src/engine/shared/datafile.h

@@ -3,6 +3,8 @@
 #ifndef ENGINE_SHARED_DATAFILE_H
 #define ENGINE_SHARED_DATAFILE_H
 
+#include <base/hash.h>
+
 // raw datafile access
 class CDataFileReader
 {
@@ -18,8 +20,6 @@ public:
 	bool Open(class IStorage *pStorage, const char *pFilename, int StorageType);
 	bool Close();
 
-	static bool GetCrcSize(class IStorage *pStorage, const char *pFilename, int StorageType, unsigned *pCrc, unsigned *pSize);
-
 	void *GetData(int Index);
 	void *GetDataSwapped(int Index); // makes sure that the data is 32bit LE ints when saved
 	int GetDataSize(int Index);
@@ -32,6 +32,7 @@ public:
 	int NumData();
 	void Unload();
 
+	SHA256_DIGEST Sha256();
 	unsigned Crc();
 	int MapSize();
 	IOHANDLE File();

src/engine/shared/demo.cpp

@@ -33,7 +33,7 @@ CDemoRecorder::CDemoRecorder(class CSnapshotDelta *pSnapshotDelta, bool NoMapDat
 }
 
 // Record
-int CDemoRecorder::Start(class IStorage *pStorage, class IConsole *pConsole, const char *pFilename, const char *pNetVersion, const char *pMap, unsigned Crc, const char *pType, unsigned int MapSize, unsigned char *pMapData, IOHANDLE MapFile, DEMOFUNC_FILTER pfnFilter, void *pUser)
+int CDemoRecorder::Start(class IStorage *pStorage, class IConsole *pConsole, const char *pFilename, const char *pNetVersion, const char *pMap, SHA256_DIGEST Sha256, unsigned Crc, const char *pType, unsigned int MapSize, unsigned char *pMapData, IOHANDLE MapFile, DEMOFUNC_FILTER pfnFilter, void *pUser)
 {
 	m_pfnFilter = pfnFilter;
 	m_pUser = pUser;
@@ -963,7 +963,12 @@ void CDemoEditor::Slice(const char *pDemo, const char *pDst, int StartTick, int
 		return;
 
 	const CDemoPlayer::CMapInfo *pMapInfo = m_pDemoPlayer->GetMapInfo();
-	if (m_pDemoRecorder->Start(m_pStorage, m_pConsole, pDst, m_pNetVersion, pMapInfo->m_aName, pMapInfo->m_Crc, "client", pMapInfo->m_Size, NULL, NULL, pfnFilter, pUser) == -1)
+	SHA256_DIGEST Fake;
+	for(unsigned i = 0; i < sizeof(Fake.data); i++)
+	{
+		Fake.data[i] = 0xff;
+	}
+	if (m_pDemoRecorder->Start(m_pStorage, m_pConsole, pDst, m_pNetVersion, pMapInfo->m_aName, Fake, pMapInfo->m_Crc, "client", pMapInfo->m_Size, NULL, NULL, pfnFilter, pUser) == -1)
 		return;
 
 

src/engine/shared/demo.h

@@ -3,6 +3,8 @@
 #ifndef ENGINE_SHARED_DEMO_H
 #define ENGINE_SHARED_DEMO_H
 
+#include <base/hash.h>
+
 #include <engine/demo.h>
 #include <engine/shared/protocol.h>
 
@@ -32,7 +34,7 @@ public:
 	CDemoRecorder(class CSnapshotDelta *pSnapshotDelta, bool NoMapData = false);
 	CDemoRecorder() {}
 
-	int Start(class IStorage *pStorage, class IConsole *pConsole, const char *pFilename, const char *pNetversion, const char *pMap, unsigned MapCrc, const char *pType, unsigned int MapSize, unsigned char *pMapData, IOHANDLE MapFile = 0, DEMOFUNC_FILTER pfnFilter = 0, void *pUser = 0);
+	int Start(class IStorage *pStorage, class IConsole *pConsole, const char *pFilename, const char *pNetversion, const char *pMap, SHA256_DIGEST Sha256, unsigned MapCrc, const char *pType, unsigned int MapSize, unsigned char *pMapData, IOHANDLE MapFile = 0, DEMOFUNC_FILTER pfnFilter = 0, void *pUser = 0);
 	int Stop();
 	void AddDemoMarker();
 
@@ -77,6 +79,7 @@ public:
 	struct CMapInfo
 	{
 		char m_aName[128];
+		SHA256_DIGEST m_Sha256;
 		int m_Crc;
 		int m_Size;
 	};

src/engine/shared/fetcher.h

@@ -20,7 +20,7 @@ private:
 	IStorage *m_pStorage;
 
 	char m_aUrl[256];
-	char m_aDest[128];
+	char m_aDest[256];
 	int m_StorageType;
 	bool m_UseDDNetCA;
 	bool m_CanTimeout;

src/engine/shared/map.cpp

@@ -39,6 +39,11 @@ public:
 		return m_DataFile.IsOpen();
 	}
 
+	virtual SHA256_DIGEST Sha256()
+	{
+		return m_DataFile.Sha256();
+	}
+
 	virtual unsigned Crc()
 	{
 		return m_DataFile.Crc();

src/engine/shared/protocol_ex_msgs.h

@@ -22,3 +22,4 @@ UUID(NETMSG_ITIS,         "it-is@ddnet.tw")
 UUID(NETMSG_IDONTKNOW,    "i-dont-know@ddnet.tw")
 
 UUID(NETMSG_RCONTYPE,     "rcon-type@ddnet.tw")
+UUID(NETMSG_MAP_DETAILS,  "map-details@ddnet.tw")

src/game/server/gamecontext.cpp

@@ -2632,8 +2632,9 @@ void CGameContext::OnInit(/*class IKernel *pKernel*/)
 
 	char aMapName[128];
 	int MapSize;
+	SHA256_DIGEST MapSha256;
 	int MapCrc;
-	Server()->GetMapInfo(aMapName, sizeof(aMapName), &MapSize, &MapCrc);
+	Server()->GetMapInfo(aMapName, sizeof(aMapName), &MapSize, &MapSha256, &MapCrc);
 	m_MapBugs = GetMapBugs(aMapName, MapSize, MapCrc);
 
 	// reset everything here
@@ -2743,6 +2744,7 @@ void CGameContext::OnInit(/*class IKernel *pKernel*/)
 
 		GameInfo.m_pMapName = aMapName;
 		GameInfo.m_MapSize = MapSize;
+		GameInfo.m_MapSha256 = MapSha256;
 		GameInfo.m_MapCrc = MapCrc;
 
 		m_TeeHistorian.Reset(&GameInfo, TeeHistorianWrite, this);

src/game/server/teehistorian.cpp

@@ -66,9 +66,11 @@ void CTeeHistorian::WriteHeader(const CGameInfo *pGameInfo)
 
 	char aGameUuid[UUID_MAXSTRSIZE];
 	char aStartTime[128];
+	char aMapSha256[SHA256_MAXSTRSIZE];
 
 	FormatUuid(pGameInfo->m_GameUuid, aGameUuid, sizeof(aGameUuid));
 	str_timestamp_ex(pGameInfo->m_StartTime, aStartTime, sizeof(aStartTime), "%Y-%m-%dT%H:%M:%S%z");
+	sha256_str(pGameInfo->m_MapSha256, aMapSha256, sizeof(aMapSha256));
 
 	char aCommentBuffer[128];
 	char aServerVersionBuffer[128];
@@ -76,12 +78,13 @@ void CTeeHistorian::WriteHeader(const CGameInfo *pGameInfo)
 	char aServerNameBuffer[128];
 	char aGameTypeBuffer[128];
 	char aMapNameBuffer[128];
+	char aMapSha256Buffer[256];
 
 	char aJson[2048];
 
 	#define E(buf, str) EscapeJson(buf, sizeof(buf), str)
 
-	str_format(aJson, sizeof(aJson), "{\"comment\":\"%s\",\"version\":\"%s\",\"game_uuid\":\"%s\",\"server_version\":\"%s\",\"start_time\":\"%s\",\"server_name\":\"%s\",\"server_port\":\"%d\",\"game_type\":\"%s\",\"map_name\":\"%s\",\"map_size\":\"%d\",\"map_crc\":\"%08x\",\"config\":{",
+	str_format(aJson, sizeof(aJson), "{\"comment\":\"%s\",\"version\":\"%s\",\"game_uuid\":\"%s\",\"server_version\":\"%s\",\"start_time\":\"%s\",\"server_name\":\"%s\",\"server_port\":\"%d\",\"game_type\":\"%s\",\"map_name\":\"%s\",\"map_size\":\"%d\",\"map_sha256\":\"%s\",\"map_crc\":\"%08x\",\"config\":{",
 		E(aCommentBuffer, TEEHISTORIAN_NAME),
 		TEEHISTORIAN_VERSION,
 		aGameUuid,
@@ -92,6 +95,7 @@ void CTeeHistorian::WriteHeader(const CGameInfo *pGameInfo)
 		E(aGameTypeBuffer, pGameInfo->m_pGameType),
 		E(aMapNameBuffer, pGameInfo->m_pMapName),
 		pGameInfo->m_MapSize,
+		E(aMapSha256Buffer, aMapSha256),
 		pGameInfo->m_MapCrc);
 	Write(aJson, str_length(aJson));
 

src/game/server/teehistorian.h

@@ -1,3 +1,4 @@
+#include <base/hash.h>
 #include <engine/console.h>
 #include <engine/shared/fetcher.h>
 #include <engine/shared/packer.h>
@@ -27,6 +28,7 @@ public:
 
 		const char *m_pMapName;
 		int m_MapSize;
+		SHA256_DIGEST m_MapSha256;
 		int m_MapCrc;
 
 		CConfiguration *m_pConfig;

src/test/hash.cpp

@@ -0,0 +1,42 @@
+#include <gtest/gtest.h>
+
+#include <base/hash_ctxt.h>
+#include <base/system.h>
+
+static void Expect(SHA256_DIGEST Actual, const char *pWanted)
+{
+	char aActual[SHA256_MAXSTRSIZE];
+	sha256_str(Actual, aActual, sizeof(aActual));
+	EXPECT_STREQ(aActual, pWanted);
+}
+
+TEST(Hash, Sha256)
+{
+	// https://en.wikipedia.org/w/index.php?title=SHA-2&oldid=840187620#Test_vectors
+	Expect(sha256("", 0), "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855");
+	SHA256_CTX ctxt;
+
+	sha256_init(&ctxt);
+	Expect(sha256_finish(&ctxt), "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855");
+
+	// printf 'The quick brown fox jumps over the lazy dog.' | sha256sum
+	char QUICK_BROWN_FOX[] = "The quick brown fox jumps over the lazy dog.";
+	Expect(sha256(QUICK_BROWN_FOX, str_length(QUICK_BROWN_FOX)), "ef537f25c895bfa782526529a9b63d97aa631564d5d789c2b765448c8635fb6c");
+
+	sha256_init(&ctxt);
+	sha256_update(&ctxt, "The ", 4);
+	sha256_update(&ctxt, "quick ", 6);
+	sha256_update(&ctxt, "brown ", 6);
+	sha256_update(&ctxt, "fox ", 4);
+	sha256_update(&ctxt, "jumps ", 6);
+	sha256_update(&ctxt, "over ", 5);
+	sha256_update(&ctxt, "the ", 4);
+	sha256_update(&ctxt, "lazy ", 5);
+	sha256_update(&ctxt, "dog.", 4);
+	Expect(sha256_finish(&ctxt), "ef537f25c895bfa782526529a9b63d97aa631564d5d789c2b765448c8635fb6c");
+}
+
+TEST(Hash, Sha256Eq)
+{
+	EXPECT_EQ(sha256("", 0), sha256("", 0));
+}

src/test/teehistorian.cpp

@@ -43,6 +43,13 @@ protected:
 		RegisterTeehistorianUuids(&m_UuidManager);
 		RegisterGameUuids(&m_UuidManager);
 
+		SHA256_DIGEST Sha256 = {{
+			0x01, 0x23, 0x45, 0x67, 0x89, 0x01, 0x23, 0x45, 0x67, 0x89,
+			0x01, 0x23, 0x45, 0x67, 0x89, 0x01, 0x23, 0x45, 0x67, 0x89,
+			0x01, 0x23, 0x45, 0x67, 0x89, 0x01, 0x23, 0x45, 0x67, 0x89,
+			0x01, 0x23,
+		}};
+
 		mem_zero(&m_GameInfo, sizeof(m_GameInfo));
 
 		m_GameInfo.m_GameUuid = CalculateUuid("test@ddnet.tw");
@@ -55,6 +62,7 @@ protected:
 
 		m_GameInfo.m_pMapName = "Kobra 3 Solo";
 		m_GameInfo.m_MapSize = 903514;
+		m_GameInfo.m_MapSha256 = Sha256;
 		m_GameInfo.m_MapCrc = 0xeceaf25c;
 
 		m_GameInfo.m_pConfig = &m_Config;
@@ -81,7 +89,7 @@ protected:
 	{
 		static CUuid TEEHISTORIAN_UUID = CalculateUuid("teehistorian@ddnet.tw");
 		static const char PREFIX1[] = "{\"comment\":\"teehistorian@ddnet.tw\",\"version\":\"2\",\"game_uuid\":\"a1eb7182-796e-3b3e-941d-38ca71b2a4a8\",\"server_version\":\"DDNet test\",\"start_time\":\"";
-		static const char PREFIX2[] = "\",\"server_name\":\"server name\",\"server_port\":\"8303\",\"game_type\":\"game type\",\"map_name\":\"Kobra 3 Solo\",\"map_size\":\"903514\",\"map_crc\":\"eceaf25c\",\"config\":{},\"tuning\":{},\"uuids\":[";
+		static const char PREFIX2[] = "\",\"server_name\":\"server name\",\"server_port\":\"8303\",\"game_type\":\"game type\",\"map_name\":\"Kobra 3 Solo\",\"map_size\":\"903514\",\"map_sha256\":\"0123456789012345678901234567890123456789012345678901234567890123\",\"map_crc\":\"eceaf25c\",\"config\":{},\"tuning\":{},\"uuids\":[";
 		static const char PREFIX3[] = "]}";
 
 		char aTimeBuf[64];

src/tools/map_version.cpp

@@ -1,70 +0,0 @@
-/* (c) Magnus Auvinen. See licence.txt in the root of the distribution for more information. */
-/* If you are missing that file, acquire a complete release at teeworlds.com.                */
-#include <base/math.h>
-#include <base/system.h>
-
-#include <engine/kernel.h>
-#include <engine/map.h>
-#include <engine/storage.h>
-
-
-static IOHANDLE s_File = 0;
-static IStorage *s_pStorage = 0;
-static IEngineMap *s_pEngineMap = 0;
-
-int MaplistCallback(const char *pName, int IsDir, int DirType, void *pUser)
-{
-	int l = str_length(pName);
-	if(l < 4 || IsDir || str_comp(pName+l-4, ".map") != 0)
-		return 0;
-
-	char aBuf[128];
-	str_format(aBuf, sizeof(aBuf), "maps/%s", pName);
-	if(!s_pEngineMap->Load(aBuf))
-		return 0;
-
-	unsigned MapCrc = s_pEngineMap->Crc();
-	s_pEngineMap->Unload();
-
-	IOHANDLE MapFile = s_pStorage->OpenFile(aBuf, IOFLAG_READ, DirType);
-	unsigned MapSize = io_length(MapFile);
-	io_close(MapFile);
-
-	char aMapName[8];
-	str_copy(aMapName, pName, min((int)sizeof(aMapName),l-3));
-
-	str_format(aBuf, sizeof(aBuf), "\t{\"%s\", {0x%02x, 0x%02x, 0x%02x, 0x%02x}, {0x%02x, 0x%02x, 0x%02x, 0x%02x}},\n", aMapName,
-		(MapCrc>>24)&0xff, (MapCrc>>16)&0xff, (MapCrc>>8)&0xff, MapCrc&0xff,
-		(MapSize>>24)&0xff, (MapSize>>16)&0xff, (MapSize>>8)&0xff, MapSize&0xff);
-	io_write(s_File, aBuf, str_length(aBuf));
-
-	return 0;
-}
-
-int main(int argc, const char **argv) // ignore_convention
-{
-	IKernel *pKernel = IKernel::Create();
-	s_pStorage = CreateStorage("Teeworlds", IStorage::STORAGETYPE_BASIC, argc, argv);
-	s_pEngineMap = CreateEngineMap();
-
-	bool RegisterFail = !pKernel->RegisterInterface(s_pStorage);
-	RegisterFail |= !pKernel->RegisterInterface(s_pEngineMap);
-
-	if(RegisterFail)
-	{
-		delete pKernel;
-		return -1;
-	}
-
-	s_File = s_pStorage->OpenFile("map_version.txt", IOFLAG_WRITE, 1);
-	if(s_File)
-	{
-		io_write(s_File, "static CMapVersion s_aMapVersionList[] = {\n", str_length("static CMapVersion s_aMapVersionList[] = {\n"));
-		s_pStorage->ListDirectory(1, "maps", MaplistCallback, 0);
-		io_write(s_File, "};\n", str_length("};\n"));
-		io_close(s_File);
-	}
-
-	delete pKernel;
-	return 0;
-}