implement md5 password hashing (untested)

disable test for case-insensitive password test
fix faction/checkpasswd test

src/kernel/faction.test.c

@@ -126,8 +126,8 @@ static void test_check_passwd(CuTest *tc) {
     f = test_create_faction(0);
     faction_setpassword(f, password_hash("password"));
     CuAssertIntEquals(tc, true, checkpasswd(f, "password"));
-    CuAssertIntEquals(tc, true, checkpasswd(f, "PASSWORD"));
     CuAssertIntEquals(tc, false, checkpasswd(f, "assword"));
+    CuAssertIntEquals(tc, false, checkpasswd(f, "PASSWORD"));
 }
 
 static void test_get_monsters(CuTest *tc) {

src/util/password.c

@@ -1,9 +1,12 @@
 #include <platform.h>
 #include "password.h"
 
+#include <md5.h>
+
 #include <assert.h>
 #include <string.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #define PASSWORD_PLAIN  0
 #define PASSWORD_MD5 1
@@ -11,6 +14,8 @@
 #define PASSWORD_BCRYPT 3 // not implemented
 #define PASSWORD_DEFAULT PASSWORD_PLAIN
 
+#define MAXSALTLEN 32 // maximum length in characters of any salt
+
 static const char * password_hash_i(const char * passwd, const char *salt, int algo) {
     static char result[64]; // TODO: static result buffers are bad mojo!
     assert(passwd);
@@ -18,6 +23,15 @@ static const char * password_hash_i(const char * passwd, const char *salt, int a
     if (algo==PASSWORD_PLAIN) {
         _snprintf(result, sizeof(result), "$0$%s$%s", salt, passwd);
     }
+    else if (algo == PASSWORD_MD5) {
+        md5_state_t ms;
+        md5_byte_t digest[16];
+        md5_init(&ms);
+        md5_append(&ms, (const md5_byte_t *)passwd, strlen(passwd));
+        md5_append(&ms, (const md5_byte_t *)salt, strlen(salt));
+        md5_finish(&ms, digest);
+        _snprintf(result, sizeof(result), "$1$%s$%s", salt, digest); // FIXME: need to build a hex string first!
+    } 
     else {
         return NULL;
     }
@@ -28,8 +42,34 @@ const char * password_hash(const char * passwd) {
     return password_hash_i(passwd, "saltyfish", PASSWORD_DEFAULT);
 }
 
-int password_verify(const char * hash, const char * passwd) {
-    assert(hash);
-    assert(passwd);
-    return VERIFY_UNKNOWN;
+static bool password_is_implemented(int algo) {
+    return algo==PASSWORD_PLAIN;
+}
+
+int password_verify(const char * pwhash, const char * passwd) {
+    char salt[MAXSALTLEN+1];
+    size_t len;
+    int algo;
+    char *pos;
+    const char *dol, *hash;
+    assert(pwhash);
+    assert(passwd);
+    assert(pwhash[0] == '$');
+    algo = (int)strtol(pwhash + 1, &pos, 16);
+    assert(pos[0] == '$');
+    ++pos;
+    dol = strchr(pos, '$');
+    assert(dol>pos && dol[0] == '$');
+    len = dol - pos;
+    assert(len <= MAXSALTLEN);
+    strncpy(salt, pos, len);
+    salt[len] = 0;
+    hash = password_hash_i(passwd, salt, algo);
+    if (!password_is_implemented(algo)) {
+        return VERIFY_UNKNOWN;
+    }
+    if (strcmp(pwhash, hash) == 0) {
+        return VERIFY_OK;
+    }
+    return VERIFY_FAIL;
 }