Merge pull request #15 from Colby-Coffman/agnostic-hash

Add support for alternate hashing algorithms and minor bug fixes

Author: 1to5pc

.gitignore

@@ -1,2 +1,3 @@
 usrlist
-__pycache__/usrcheck.cpython-310.pyc
+# Ignore the whole cache
+__pycache__/

backendtest.py

@@ -1,12 +1,16 @@
 import usrcheck
-import hashlib
+import hash
 def test_auth():
-    usr_list=[['testusr',hashlib.sha256(str('testPSWD'+'1QgF35ws').encode()).hexdigest(),'1QgF35ws']]
-    usrcheck.save_users(usr_list,True)
-    assert usrcheck.load_users() == usr_list, "Userlist loading failed"
-    assert usrcheck.usr_check('testusr', 'testPSWD',usr_list) == (True,True), "User check failed"
-    #Wrong username
-    assert usrcheck.usr_check('wrongusr', 'testPSWD',usr_list) == (False,False), "User check failed"
-    #Wrong password
-    assert usrcheck.usr_check('testusr', 'wrongPSWD',usr_list) == (True,False), "User check failed"
+    # Updated test to support new implementation
+    for hash_method in hash.SUPPORTED_HASHES:
+        hasher = hash.Hasher(hash_method, ('testPSWD' + '1QgF35ws').encode())
+        usr_list = [['testusr', hasher.hexdigest(), '1QgF35ws']]
+        hasher.clear_hasher()
+        usrcheck.save_users(usr_list, True)
+        assert usrcheck.load_users() == usr_list, "UserList loading failed"
+        assert usrcheck.usr_check('testusr', 'testPSWD', usr_list, test_hasher=hasher) == (True,True), "User check failed"
+        #Wrong username
+        assert usrcheck.usr_check('wrongusr', 'testPSWD', usr_list, test_hasher=hasher) == (False,False), "User check failed"
+        #Wrong password
+        assert usrcheck.usr_check('testusr', 'wrongPSWD', usr_list, test_hasher=hasher) == (True,False), "User check failed"
 test_auth()

hash.py

@@ -0,0 +1,28 @@
+import hashlib
+
+SUPPORTED_HASHES = hashlib.algorithms_available 
+
+class Hasher():
+    def __init__(self, hash_name: str, initial_data: bytes = b'', **kwargs):
+        if not (hash_name in SUPPORTED_HASHES):
+            raise ValueError(f"{hash_name} is not a supported hashing algorithm")
+        self.__hash_implementation: hashlib._Hash = hashlib.new(hash_name, initial_data, **kwargs)
+        self.__kwargs = kwargs
+    
+    # Convenient but wont show up in lsp, might have to define each method later
+    def __getattr__(self, name):
+        return getattr(self.__hash_implementation, name)
+    
+    def hexdigest(self, shake_output_size: int=None) -> bytes:
+        if self.__hash_implementation.name in ('shake_128', 'shake_256'):
+            if shake_output_size:
+                return self.__hash_implementation.hexdigest(shake_output_size)
+            # Good default output sizes for shake
+            elif self.__hash_implementation.name == 'shake_128':
+                return self.__hash_implementation.hexdigest(32)
+            elif self.__hash_implementation.name == 'shake_256':
+                return self.__hash_implementation.hexdigest(64)
+        return self.__hash_implementation.hexdigest()
+    
+    def clear_hasher(self) -> None:
+        self.__hash_implementation = hashlib.new(self.__hash_implementation.name, b'', **self.__kwargs)

usrcheck.py

@@ -1,3 +1,8 @@
+import hash
+
+# TODO: Encapsulate this later
+hasher = None
+
 def configRead():
     import configparser
     config = configparser.ConfigParser()
@@ -8,11 +13,16 @@ def configRead():
     except KeyError:
         quiet = False
     try:
-        alg = config['Config']['alg']
-        alg = str(quiet).lower()
+        alg = config['Config']['alg'].lower()
+        # alg = str(quiet).lower() Not really sure the purpose of this line
+        # Not the most elegant but trying to hit the KeyError on unsupported hash algs
+        if not (alg in hash.SUPPORTED_HASHES):
+            raise KeyError
     except KeyError:
         print("ERROR: Algorithm not defined. Reverting to SHA256")
         alg = 'sha256'
+    global hasher
+    hasher = hash.Hasher(alg)
     try:
         saltSize = config['Salt']['saltSize']
         saltSize = int(saltSize)
@@ -29,7 +39,6 @@ def salter(pswd,saltsize):
     return pswd+salt,salt
 
 def init_usrs(nUsr, saltSize):
-    import hashlib
     usrlist=[]
     for index in range(nUsr):
         usrname=''
@@ -39,7 +48,10 @@ def init_usrs(nUsr, saltSize):
         while pswd=='':
             pswd = input("Enter password: ")
         pswd,salt = salter(pswd,saltSize)
-        pswd = hashlib.sha256(pswd.encode()).hexdigest()
+        hasher.update(pswd.encode())
+        pswd = hasher.hexdigest()
+        # We have to clear the hasher every time with the new implementation, later we could define this behaviour automatically
+        hasher.clear_hasher()
         usrlist.append([])
         usrlist[index].append(usrname)
         usrlist[index].append(pswd)
@@ -78,15 +90,35 @@ def save_users(usrlist,overWrite):
         saveFile.write('')
     saveFile.close()
 
-def usr_check(usrn,pswd,usrlist):
-    import hashlib
+def usr_check(usrn,pswd,usrlist, test_hasher: hash.Hasher=None):
+    if test_hasher:
+        hasher = test_hasher
+    # TODO:
+    # Supporting different hashes means we have to figure out what hash was used for the usrlist
+    # This basic solution simply reads what hash was specified in the config file.
+    # The config file will need additional information, and this logic will have to be changed, if variable
+    # output for shake is allowed.
+    else:
+        import configparser
+        config = configparser.ConfigParser()
+        config.read('config.ini')
+        try:
+            alg = config['Config']['alg'].lower()
+            if not (alg in hash.SUPPORTED_HASHES):
+                raise KeyError
+        except KeyError:
+            print("No algorithm specified to read usrlist or unsuporrted algorithm\nDefaulting to sha256")
+            alg = 'sha256'
+        hasher = hash.Hasher(alg)
     index=0
     Ufound=False
     Pfound=False
     while Ufound==False and index<len(usrlist):
         if usrlist[index][0]==usrn:
             Ufound=True
-            pswd=hashlib.sha256(str(pswd+str(usrlist[index][2])).encode()).hexdigest()
+            hasher.update(str(pswd+str(usrlist[index][2])).encode())
+            pswd = hasher.hexdigest()
+            hasher.clear_hasher()
             if usrlist[index][1]==pswd:
                 Pfound=True
             break
@@ -118,11 +150,14 @@ def login_init(usrname,pswd,overWrite,quiet,saltSize):
         print("Userfile does not exist! Execute with overWrite set to 'True'")
         sys.exit()
     elif overWrite==True:
-        if input("Do you want to overwrite the existing user list[y/N]? ").upper()=='Y':
-            newFile=True
-        else:
-            newFile=False
+        # Bug fix for when no usrlist exists but the user asks not to overwrite user list
+        newFile = True
+        if os.path.isfile("usrlist") and (input("Do you want to overwrite the existing user list [Y/N]? ").upper() == 'N'):
+            newFile = False
         while True:
+            # TODO: 
+            # Seems to me redundant to ask if they want to clear the database when "overwriting" the existing database does
+            # the same thing.
             nUsr=input("Enter the number of users to initialize ('0' Clears the database): ")
             try:
                 nUsr=int(nUsr)