Propagate precise encryption key length errors

lib/rex/proto/kerberos/crypto/aes_block_cipher_base.rb

@@ -16,7 +16,7 @@ class AesBlockCipherBase < BlockCipherBase
           HASH_FUNCTION = 'SHA1'
 
           # Subclasses must also define ENCRYPT_CIPHER_NAME and DECRYPT_CIPHER_NAME
-      
+
           # Derive an encryption key based on a password and salt for the given cipher type
           #
           # @param password [String] The password to use as the basis for key generation
@@ -30,11 +30,15 @@ def string_to_key(password, salt, params: nil)
             tkey = random_to_key(seed)
             derive(tkey, 'kerberos'.encode('utf-8'))
           end
-      
+
           def encrypt_basic(plaintext, key)
             raise Rex::Proto::Kerberos::Model::Error::KerberosError, 'Ciphertext too short' if plaintext.length < BLOCK_SIZE
 
             cipher = OpenSSL::Cipher.new(self.class::ENCRYPT_CIPHER_NAME)
+            if key.length != cipher.key_len
+              raise Rex::Proto::Kerberos::Model::Error::KerberosError, "Encryption key length must be #{cipher.key_len} for #{self.class::ENCRYPT_CIPHER_NAME}"
+            end
+
             cipher.encrypt
             cipher.key = key
             cipher.padding = 0
@@ -51,11 +55,15 @@ def encrypt_basic(plaintext, key)
 
             ciphertext
           end
-      
+
           def decrypt_basic(ciphertext, key)
             raise Rex::Proto::Kerberos::Model::Error::KerberosError, 'Ciphertext too short' if ciphertext.length < BLOCK_SIZE
 
             cipher = OpenSSL::Cipher.new(self.class::DECRYPT_CIPHER_NAME)
+            if key.length != cipher.key_len
+              raise Rex::Proto::Kerberos::Model::Error::KerberosError, "Decryption key length must be #{cipher.key_len} for #{self.class::ENCRYPT_CIPHER_NAME}"
+            end
+
             cipher.decrypt
             cipher.key = key
             cipher.padding = 0

lib/rex/proto/kerberos/crypto/des3_cbc_sha1.rb

@@ -39,7 +39,11 @@ def decrypt_asn1(ciphertext, key, msg_type)
           # Decrypts the cipher using DES3-CBC-SHA1 schema
           def decrypt_basic(ciphertext, key)
             raise Rex::Proto::Kerberos::Model::Error::KerberosError, 'Ciphertext is not a multiple of block length' unless ciphertext.length % BLOCK_SIZE == 0
+
             cipher = OpenSSL::Cipher.new('des-ede3-cbc')
+            if key.length != cipher.key_len
+              raise Rex::Proto::Kerberos::Model::Error::KerberosError, "Decryption key length must be #{cipher.key_len} for des-ede3-cbc"
+            end
             cipher.decrypt
             cipher.key = key
             cipher.padding = 0
@@ -51,6 +55,9 @@ def decrypt_basic(ciphertext, key)
           # Encrypts the cipher using DES3-CBC-SHA1 schema
           def encrypt_basic(plaintext, key)
             cipher = OpenSSL::Cipher.new('des-ede3-cbc')
+            if key.length != cipher.key_len
+              raise Rex::Proto::Kerberos::Model::Error::KerberosError, "Encryption key length must be #{cipher.key_len} for des-ede3-cbc"
+            end
             cipher.encrypt
             cipher.key = key
             cipher.padding = 0
@@ -66,22 +73,22 @@ def parity(b)
                 b &= ~1
                 b | (b.digits(2).count(1) + 1) % 2
               end
-              
+
               raise Rex::Proto::Kerberos::Model::Error::KerberosError unless seed.length == 7
-        
+
               firstbytes = seed.map {|b| parity(b & ~1)}
               tmp = 7.times.map { |i| (seed[i] & 1) << i+1 }
               lastbyte = parity(tmp.sum)
               keybytes = firstbytes + [lastbyte]
               if _is_weak_des_key(keybytes)
                 keybytes[7] = keybytes[7] ^ 0xF0
               end
-              
+
               keybytes
             end
-        
+
             raise Rex::Proto::Kerberos::Model::Error::KerberosError unless seed.length == 21
-            
+
             subkeys = seed.each_slice(7).map { |slice| expand(slice) }
             subkeys.flatten
           end

lib/rex/proto/kerberos/crypto/des_cbc_md5.rb

@@ -94,6 +94,9 @@ def decrypt(ciphertext, key, msg_type)
 
 
             cipher = OpenSSL::Cipher.new('des-cbc')
+            if key.length != cipher.key_len
+              raise Rex::Proto::Kerberos::Model::Error::KerberosError, "Decryption key length must be #{cipher.key_len} for des-cbc"
+            end
             cipher.decrypt
             cipher.padding = 0
             cipher.key = key
@@ -137,6 +140,9 @@ def encrypt(plaintext, key, msg_type, confounder: nil)
             plaintext = confounder + checksum + padded_data
 
             cipher = OpenSSL::Cipher.new('des-cbc')
+            if key.length != cipher.key_len
+              raise Rex::Proto::Kerberos::Model::Error::KerberosError, "Encryption key length must be #{cipher.key_len} for des-cbc"
+            end
             cipher.encrypt
             cipher.padding = 0
             cipher.key = key

lib/rex/proto/kerberos/crypto/rc4_hmac.rb

@@ -25,7 +25,7 @@ def string_to_key(password, salt=nil, params: nil)
             unicode_password = password.encode('utf-16le')
             password_digest = OpenSSL::Digest.digest('MD4', unicode_password)
           end
-          
+
           # Use this class's encryption routines to create a checksum of the data based on the key and message type
           #
           # @param key [String] the key to use to generate the checksum
@@ -261,7 +261,7 @@ def calculate_encrypted_length(plaintext_len)
 
           def usage_str(msg_type)
             usage_table = {
-              Rex::Proto::Kerberos::Crypto::KeyUsage::AS_REP_ENCPART => Rex::Proto::Kerberos::Crypto::KeyUsage::TGS_REP_ENCPART_SESSION_KEY, 
+              Rex::Proto::Kerberos::Crypto::KeyUsage::AS_REP_ENCPART => Rex::Proto::Kerberos::Crypto::KeyUsage::TGS_REP_ENCPART_SESSION_KEY,
               Rex::Proto::Kerberos::Crypto::KeyUsage::GSS_ACCEPTOR_SIGN => Rex::Proto::Kerberos::Crypto::KeyUsage::KRB_PRIV_ENCPART
             }
             usage_mapped = usage_table.fetch(msg_type) { msg_type }