crypt.h

   1 /*
   2  * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file crypt.h Prototypes for paraslash crypto functions. */
   8
   9 /** Opaque structure for public and private keys. */
  10 struct asymmetric_key;
  11
  12 int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
  13                 unsigned len, unsigned char *outbuf);
  14 int priv_decrypt(const char *key_file, unsigned char *outbuf,
  15                 unsigned char *inbuf, int inlen);
  16 int get_asymmetric_key(const char *key_file, int private,
  17                 struct asymmetric_key **result);
  18 void free_asymmetric_key(struct asymmetric_key *key);
  19
  20 void get_random_bytes_or_die(unsigned char *buf, int num);
  21 void init_random_seed_or_die(void);
  22
  23 /** Opaque structure for stream cipher crypto. */
  24 struct stream_cipher;
  25
  26 /** Number of bytes of the session key. */
  27 #define SESSION_KEY_LEN 32
  28
  29 /**
  30  * Used on the server-side for client-server communication encryption.
  31  *
  32  * The traffic between (the forked child of) para_server and the remote client
  33  * process is crypted by a symmetric session key. This structure contains the
  34  * keys for the stream cipher and the file descriptor for which these keys
  35  * should be used.
  36  */
  37 struct stream_cipher_context {
  38         /** The socket file descriptor. */
  39         int fd;
  40         /** Key used for receiving data. */
  41         struct stream_cipher *recv;
  42         /** Key used for sending data. */
  43         struct stream_cipher *send;
  44 };
  45
  46 struct stream_cipher *sc_new(const unsigned char *data, int len);
  47 void sc_free(struct stream_cipher *sc);
  48
  49 int sc_send_bin_buffer(struct stream_cipher_context *scc, const char *buf,
  50                 size_t len);
  51 int sc_send_buffer(struct stream_cipher_context *scc, const char *buf);
  52 __printf_2_3 int sc_send_va_buffer(struct stream_cipher_context *scc,
  53                 const char *fmt, ...);
  54 int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf,
  55                 size_t size);
  56 int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size);
  57
  58 /** \cond used to distinguish between loading of private/public key */
  59 #define LOAD_PUBLIC_KEY 0
  60 #define LOAD_PRIVATE_KEY 1
  61 #define CHALLENGE_SIZE 64
  62 /** \endcond **/
  63
  64 /** Size of the hash value in bytes. */
  65 #define HASH_SIZE 20
  66
  67 void hash_function(const char *data, unsigned long len, unsigned char *hash);
  68
  69 /**
  70  * Compare two hashes.
  71  *
  72  * \param h1 Pointer to the first hash value.
  73  * \param h2 Pointer to the second hash value.
  74  *
  75  * \return 1, -1, or zero, depending on whether \a h1 is greater than,
  76  * less than or equal to h2, respectively.
  77  */
  78 _static_inline_ int hash_compare(unsigned char *h1, unsigned char *h2)
  79 {
  80         int i;
  81
  82         for (i = 0; i < HASH_SIZE; i++) {
  83                 if (h1[i] < h2[i])
  84                         return -1;
  85                 if (h1[i] > h2[i])
  86                         return 1;
  87         }
  88         return 0;
  89 }
  90
  91 /**
  92  * Convert a hash value to ascii format.
  93  *
  94  * \param hash the hash value.
  95  * \param asc Result pointer.
  96  *
  97  * \a asc must point to an area of at least 2 * \p HASH_SIZE + 1 bytes which
  98  * will be filled by the function with the ascii representation of the hash
  99  * value given by \a hash, and a terminating \p NULL byte.
 100  */
 101 _static_inline_ void hash_to_asc(unsigned char *hash, char *asc)
 102 {
 103         int i;
 104         const char hexchar[] = "0123456789abcdef";
 105
 106         for (i = 0; i < HASH_SIZE; i++) {
 107                 asc[2 * i] = hexchar[hash[i] >> 4];
 108                 asc[2 * i + 1] = hexchar[hash[i] & 0xf];
 109         }
 110         asc[2 * HASH_SIZE] = '\0';
 111 }