1 files changed, 128 insertions, 0 deletions
diff --git a/src/mmo/md5more.cpp b/src/mmo/md5more.cpp
new file mode 100644
index 0000000..51ff5c4
--- /dev/null
+++ b/src/mmo/md5more.cpp
@@ -0,0 +1,128 @@
+#include "md5more.hpp"
+
+#include "../compat/rawmem.hpp"
+
+#include "../generic/random.hpp"
+
+#include "../io/cxxstdio.hpp"
+
+#include "../poison.hpp"
+
+#define X block.data
+
+// TODO - refactor MD5 into a stream, and merge the implementations
+// I once implemented an ostream that does it ...
+MD5_state MD5_from_FILE(io::ReadFile& in)
+{
+    uint64_t total_len = 0;
+
+    uint8_t buf[0x40];
+    uint8_t block_len = 0;
+
+    MD5_state state;
+    MD5_init(&state);
+
+    MD5_block block;
+
+    while (true)
+    {
+        size_t rv = in.get(sign_cast<char *>(buf + block_len), 0x40 - block_len);
+        if (!rv)
+            break;
+        total_len += 8 * rv; // in bits
+        block_len += rv;
+        if (block_len != 0x40)
+            continue;
+        for (int i = 0; i < 0x10; i++)
+            X[i] = buf[4 * i + 0] | buf[4 * i + 1] << 8 | buf[4 * i + 2] << 16 | buf[4 * i + 3] << 24;
+        MD5_do_block(&state, block);
+        block_len = 0;
+    }
+    // no more input, just pad and append the length
+    buf[block_len] = 0x80;
+    really_memset0(buf + block_len + 1, 0x40 - block_len - 1);
+    if (block_len < 0x38)
+    {
+        for (int i = 0; i < 8; i++)
+            buf[0x38 + i] = total_len >> i * 8;
+    }
+    for (int i = 0; i < 0x10; i++)
+        X[i] = buf[4 * i + 0] | buf[4 * i + 1] << 8 | buf[4 * i + 2] << 16 | buf[4 * i + 3] << 24;
+    MD5_do_block(&state, block);
+    if (0x38 <= block_len)
+    {
+        really_memset0(buf, 0x38);
+        for (int i = 0; i < 8; i++)
+            buf[0x38 + i] = total_len >> i * 8;
+        for (int i = 0; i < 0x10; i++)
+            X[i] = buf[4 * i + 0] | buf[4 * i + 1] << 8 | buf[4 * i + 2] << 16 | buf[4 * i + 3] << 24;
+        MD5_do_block(&state, block);
+    }
+    return state;
+}
+
+
+// Hash a password with a salt.
+// Whoever wrote this FAILS programming
+AccountCrypt MD5_saltcrypt(AccountPass key, SaltString salt)
+{
+    char cbuf[64] {};
+
+    // hash the key then the salt
+    // buf ends up as a 64-char NUL-terminated string
+    md5_string tbuf, tbuf2;
+    MD5_to_str(MD5_from_string(key), tbuf);
+    MD5_to_str(MD5_from_string(salt), tbuf2);
+    const auto it = std::copy(tbuf.begin(), tbuf.end(), std::begin(cbuf));
+    auto it2 = std::copy(tbuf2.begin(), tbuf2.end(), it);
+    assert(it2 == std::end(cbuf));
+
+    md5_string tbuf3;
+    MD5_to_str(MD5_from_string(XString(std::begin(cbuf), it2, nullptr)), tbuf3);
+
+    VString<31> obuf;
+
+    // This truncates the string, but we have to keep it like that for compatibility
+    SNPRINTF(obuf, 32, "!%s$%s", salt, tbuf3);
+    return stringish<AccountCrypt>(obuf);
+}
+
+SaltString make_salt(void)
+{
+    char salt[5];
+    for (int i = 0; i < 5; i++)
+        // 126 would probably actually be okay
+        salt[i] = random_::in(48, 125);
+    return stringish<SaltString>(XString(salt + 0, salt + 5, nullptr));
+}
+
+bool pass_ok(AccountPass password, AccountCrypt crypted)
+{
+    // crypted is like !salt$hash
+    auto begin = crypted.begin() + 1;
+    auto end = std::find(begin, crypted.end(), '$');
+    SaltString salt = stringish<SaltString>(crypted.xislice(begin, end));
+
+    return crypted == MD5_saltcrypt(password, salt);
+}
+
+// [M|h]ashes up an IP address and a secret key
+// to return a hopefully unique masked IP.
+IP4Address MD5_ip(IP4Address ip)
+{
+    static SaltString secret = make_salt();
+
+    // MD5sum a secret + the IP address
+    VString<31> ipbuf;
+    SNPRINTF(ipbuf, 32, "%s %s", ip, secret);
+    md5_binary obuf;
+    MD5_to_bin(MD5_from_string(ipbuf), obuf);
+
+    // Fold the md5sum to 32 bits, pack the bytes to an in_addr
+    return IP4Address({
+            static_cast<uint8_t>(obuf[0] ^ obuf[1] ^ obuf[8] ^ obuf[9]),
+            static_cast<uint8_t>(obuf[2] ^ obuf[3] ^ obuf[10] ^ obuf[11]),
+            static_cast<uint8_t>(obuf[4] ^ obuf[5] ^ obuf[12] ^ obuf[13]),
+            static_cast<uint8_t>(obuf[6] ^ obuf[7] ^ obuf[14] ^ obuf[15]),
+    });
+}