added ft decryption routine

libretroshare/src/crypto/chacha20.cpp

@@ -28,10 +28,13 @@
 #include <string>
 #include <stdio.h>
 #include <string.h>
+#include <openssl/crypto.h>
 
 #include <iostream>
 #include <stdlib.h>
 
+#pragma once
+
 #define rotl(x,n) { x = (x << n) | (x >> (-n & 31)) ;}
 
 namespace librs {
@@ -431,10 +434,16 @@ void poly1305_tag(uint8_t key[32],uint8_t *message,uint32_t size,uint8_t tag[16]
     tag[12] = (acc.b[3] >> 0) & 0xff ; tag[13] = (acc.b[3] >> 8) & 0xff ; tag[14] = (acc.b[3] >>16) & 0xff ; tag[15] = (acc.b[3] >>24) & 0xff ;
 }
 
-void AEAD_chacha20_poly1305(uint8_t key[32], uint8_t nonce[12],uint8_t *data,uint32_t data_size,uint8_t *aad,uint32_t aad_size,uint8_t tag[16])
+bool AEAD_chacha20_poly1305(uint8_t key[32], uint8_t nonce[12],uint8_t *data,uint32_t data_size,uint8_t *aad,uint32_t aad_size,uint8_t tag[16])
 {
 #warning this part is not implemented yet.
     memset(tag,0xff,16) ;
+    return false;
+}
+
+bool constant_time_memory_compare(const uint8_t *m1,const uint8_t *m2,uint32_t size)
+{
+    return !CRYPTO_memcmp(m1,m2,size) ;
 }
 
 void perform_tests()
@@ -658,7 +667,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0xa8,0x06,0x1d,0xc1,0x30,0x51,0x36,0xc6,0xc2,0x2b,0x8b,0xaf,0x0c,0x01,0x27,0xa9 };
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
 
     std::cerr << "  RFC7539 poly1305 test vector #001     OK" << std::endl;
@@ -676,7 +685,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 };
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
 
     std::cerr << "  RFC7539 poly1305 test vector #002     OK" << std::endl;
@@ -695,7 +704,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0x36,0xe5,0xf6,0xb5,0xc5,0xe0,0x60,0x70,0xf0,0xef,0xca,0x96,0x22,0x7a,0x86,0x3e };
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
 
     std::cerr << "  RFC7539 poly1305 test vector #003     OK" << std::endl;
@@ -714,7 +723,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0xf3,0x47,0x7e,0x7c,0xd9,0x54,0x17,0xaf,0x89,0xa6,0xb8,0x79,0x4c,0x31,0x0c,0xf0 } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
 
     std::cerr << "  RFC7539 poly1305 test vector #004     OK" << std::endl;
@@ -731,7 +740,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0x45,0x41,0x66,0x9a,0x7e,0xaa,0xee,0x61,0xe7,0x08,0xdc,0x7c,0xbc,0xc5,0xeb,0x62 } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
 
     std::cerr << "  RFC7539 poly1305 test vector #005     OK" << std::endl;
@@ -749,7 +758,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0x03,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
 
     std::cerr << "  RFC7539 poly1305 test vector #006     OK" << std::endl;
@@ -767,7 +776,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0x03,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
     std::cerr << "  RFC7539 poly1305 test vector #007     OK" << std::endl;
 
@@ -786,7 +795,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0x05,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
     std::cerr << "  RFC7539 poly1305 test vector #008     OK" << std::endl;
 
@@ -805,7 +814,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
     std::cerr << "  RFC7539 poly1305 test vector #009     OK" << std::endl;
 
@@ -822,7 +831,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0xfa,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
     std::cerr << "  RFC7539 poly1305 test vector #010     OK" << std::endl;
 
@@ -843,7 +852,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0x14,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x55,0x00,0x00,0x00,0x00,0x00,0x00,0x00 } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
     std::cerr << "  RFC7539 poly1305 test vector #011     OK" << std::endl;
 
@@ -863,7 +872,7 @@ void perform_tests()
 
         uint8_t test_tag[16] = { 0x13,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 } ;
 
-        assert(!memcmp(tag,test_tag,16)) ;
+        assert(constant_time_memory_compare(tag,test_tag,16)) ;
     }
 }
 

libretroshare/src/crypto/chacha20.h

@@ -37,7 +37,7 @@ namespace librs
          * \param data				data that gets encrypted/decrypted in place
          * \param size				size of the data.
          */
-        static void chacha20_encrypt(uint8_t key[32], uint32_t block_counter, uint8_t nonce[12], uint8_t *data, uint32_t size) ;
+        void chacha20_encrypt(uint8_t key[32], uint32_t block_counter, uint8_t nonce[12], uint8_t *data, uint32_t size) ;
 
         /*!
          * \brief poly1305_tag
@@ -48,7 +48,7 @@ namespace librs
          * \param tag				place where the tag is stored.
          */
 
-        static void poly1305_tag(uint8_t key[32],uint8_t *message,uint32_t size,uint8_t tag[16]);
+        void poly1305_tag(uint8_t key[32],uint8_t *message,uint32_t size,uint8_t tag[16]);
 
         /*!
          * \brief AEAD_chacha20_poly1305
@@ -62,24 +62,26 @@ namespace librs
          * \param size			size of the data
          * \param tag			generated poly1305 tag.
          */
-        static void AEAD_chacha20_poly1305(uint8_t key[32], uint8_t nonce[12],uint8_t *data,uint32_t data_size,uint8_t *aad,uint32_t aad_size,uint8_t tag[16]) ;
+        bool AEAD_chacha20_poly1305(uint8_t key[32], uint8_t nonce[12],uint8_t *data,uint32_t data_size,uint8_t *aad,uint32_t aad_size,uint8_t tag[16]) ;
 
         /*!
          * \brief constant_time_memcmp
-         * 			Provides a constant time comparison of two memory chunks. The implementation comes from the FreeBSD implementation.
+         * 			Provides a constant time comparison of two memory chunks. Calls CRYPTO_memcmp.
          *
          * \param m1    memory block 1
          * \param m2	memory block 2
          * \param size  common size of m1 and m2
          * \return
+         * 			false  if the two chunks are different
+         * 			true   if the two chunks are different
          */
-        static bool constant_time_memcmp(const uint8_t *m1,const uint8_t *m2,uint32_t size) ;
+        bool constant_time_memory_compare(const uint8_t *m1,const uint8_t *m2,uint32_t size) ;
 
         /*!
          * \brief perform_tests
          *          Tests all methods in this class, using the tests supplied in RFC7539
          */
 
-        static void perform_tests() ;
+        void perform_tests() ;
 	}
 }

libretroshare/src/ft/ftserver.cc

@@ -1014,13 +1014,13 @@ void ftServer::deriveEncryptionKey(const RsFileHash& hash, uint8_t *key)
     SHA256_Final (key, &sha_ctx);
 }
 
+static const uint32_t ENCRYPTED_FT_INITIALIZATION_VECTOR_SIZE = 12 ;
+static const uint32_t ENCRYPTED_FT_AUTHENTICATION_TAG_SIZE    = 16 ;
+static const uint32_t ENCRYPTED_FT_HEADER_SIZE                =  4 ;
+static const uint32_t ENCRYPTED_FT_EDATA_SIZE                 =  4 ;
+
 bool ftServer::encryptItem(RsTurtleGenericTunnelItem *clear_item,const RsFileHash& hash,RsTurtleGenericDataItem *& encrypted_item)
 {
-    static const uint32_t ENCRYPTED_FT_INITIALIZATION_VECTOR_SIZE = 12 ;
-    static const uint32_t ENCRYPTED_FT_AUTHENTICATION_TAG_SIZE    = 16 ;
-    static const uint32_t ENCRYPTED_FT_HEADER_SIZE                =  4 ;
-    static const uint32_t ENCRYPTED_FT_EDATA_SIZE                 =  4 ;
-
     uint8_t initialization_vector[ENCRYPTED_FT_INITIALIZATION_VECTOR_SIZE] ;
 
     RSRandom::random_bytes(initialization_vector,ENCRYPTED_FT_INITIALIZATION_VECTOR_SIZE) ;
@@ -1088,9 +1088,59 @@ bool ftServer::encryptItem(RsTurtleGenericTunnelItem *clear_item,const RsFileHas
 
 // Decrypts the given item using aead-chacha20-poly1305
 
-bool ftServer::decryptItem(RsTurtleGenericTunnelItem *encrypted_item,const RsFileHash& hash,RsTurtleGenericDataItem *& decrypted_item)
+bool ftServer::decryptItem(RsTurtleGenericDataItem *encrypted_item,const RsFileHash& hash,RsTurtleGenericTunnelItem *& decrypted_item)
 {
-    decrypted_item = NULL ;
+    uint8_t encryption_key[32] ;
+    deriveEncryptionKey(hash,encryption_key) ;
+
+    uint8_t *edata = (uint8_t*)encrypted_item->data_bytes ;
+    uint32_t offset = 0;
+
+    if(encrypted_item->data_size < ENCRYPTED_FT_HEADER_SIZE + ENCRYPTED_FT_INITIALIZATION_VECTOR_SIZE + ENCRYPTED_FT_EDATA_SIZE) return false ;
+
+    if(edata[0] != 0xae) return false ;
+    if(edata[1] != 0xad) return false ;
+    if(edata[2] != 0x00) return false ;
+    if(edata[3] != 0x01) return false ;
+
+    offset += ENCRYPTED_FT_HEADER_SIZE ;
+    uint32_t aad_offset = offset ;
+    uint32_t aad_size = ENCRYPTED_FT_EDATA_SIZE + ENCRYPTED_FT_INITIALIZATION_VECTOR_SIZE ;
+
+    uint8_t *initialization_vector = &edata[offset] ;
+
+    std::cerr << "ftServer::decrypting ft item." << std::endl;
+    std::cerr << "  item data       : " << RsUtil::BinToHex(edata,std::min(50u,encrypted_item->data_size)) << "(...)" << std::endl;
+    std::cerr << "  hash            : " << hash << std::endl;
+    std::cerr << "  encryption key  : " << RsUtil::BinToHex(encryption_key,32) << std::endl;
+    std::cerr << "  random nonce    : " << RsUtil::BinToHex(initialization_vector,ENCRYPTED_FT_INITIALIZATION_VECTOR_SIZE) << std::endl;
+
+    offset += ENCRYPTED_FT_INITIALIZATION_VECTOR_SIZE ;
+
+    uint32_t edata_size = 0 ;
+    edata_size += ((uint32_t)edata[offset+0]) <<  0 ;
+    edata_size += ((uint32_t)edata[offset+1]) <<  8 ;
+    edata_size += ((uint32_t)edata[offset+2]) << 16 ;
+    edata_size += ((uint32_t)edata[offset+3]) << 24 ;
+
+    offset += ENCRYPTED_FT_EDATA_SIZE ;
+    uint32_t clear_item_offset = offset ;
+
+    uint32_t authentication_tag_offset = offset + edata_size ;
+    std::cerr << "  authen. tag     : " << RsUtil::BinToHex(&edata[authentication_tag_offset],ENCRYPTED_FT_AUTHENTICATION_TAG_SIZE) << std::endl;
+
+    if(!librs::crypto::AEAD_chacha20_poly1305(encryption_key,initialization_vector,&edata[clear_item_offset],edata_size, &edata[aad_offset],aad_size, &edata[authentication_tag_offset]))
+        return false;
+
+    std::cerr << "  authen. result  : ok" << std::endl;
+    std::cerr << "  decrypted daya  : ok" << RsUtil::BinToHex(&edata[clear_item_offset],std::min(50u,edata_size)) << "(...)" << std::endl;
+
+    decrypted_item = deserialiseItem(&edata[clear_item_offset],edata_size) ;
+
+    if(decrypted_item == NULL)
+        return false ;
+
+    return true ;
 }
 
 // Dont delete the item. The client (p3turtle) is doing it after calling this.

libretroshare/src/ft/ftserver.h

@@ -225,8 +225,9 @@ public:
     virtual bool sendSingleChunkCRC(const RsPeerId& peer_id,const RsFileHash& hash,uint32_t chunk_number,const Sha1CheckSum& crc) ;
 
     static void deriveEncryptionKey(const RsFileHash& hash, uint8_t *key);
-    static bool encryptItem(RsTurtleGenericTunnelItem *clear_item,const RsFileHash& hash,RsTurtleGenericDataItem *& encrypted_item);
+
-    static bool decryptItem(RsTurtleGenericTunnelItem *encrypted_item,const RsFileHash& hash,RsTurtleGenericDataItem *& decrypted_item);
+    bool encryptItem(RsTurtleGenericTunnelItem *clear_item,const RsFileHash& hash,RsTurtleGenericDataItem *& encrypted_item);
+    bool decryptItem(RsTurtleGenericDataItem *encrypted_item, const RsFileHash& hash, RsTurtleGenericTunnelItem *&decrypted_item);
 
     /*************** Internal Transfer Fns *************************/
     virtual int tick();