2 * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file crypt.h Public crypto interface. */
10 /* These are used to distinguish between loading of private/public key. */
12 /** The key to load is a public key. */
13 #define LOAD_PUBLIC_KEY 0
14 /** The key to load is a private key. */
15 #define LOAD_PRIVATE_KEY 1
16 /** The size of the challenge sent to the client. */
17 #define CHALLENGE_SIZE 64
19 /** Opaque structure for public and private keys. */
20 struct asymmetric_key;
23 * Encrypt a buffer using asymmetric keys.
25 * \param pub: The public key.
26 * \param inbuf The input buffer.
27 * \param len The length of \a inbuf.
28 * \param outbuf The output buffer.
30 * \return The size of the encrypted data on success, negative on errors.
32 int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
33 unsigned len, unsigned char *outbuf);
36 * Decrypt a buffer using a private key.
38 * \param key_file Full path of the key.
39 * \param outbuf The output buffer.
40 * \param inbuf The encrypted input buffer.
41 * \param inlen The length of \a inbuf.
43 * The \a outbuf must be large enough to hold at least 512 bytes.
45 * \return The size of the recovered plaintext on success, negative on errors.
47 int priv_decrypt(const char *key_file, unsigned char *outbuf,
48 unsigned char *inbuf, int inlen);
51 * Read an asymmetric key from a file.
53 * \param key_file The file containing the key.
54 * \param result The key structure is returned here.
56 * \return The size of the key on success, negative on errors.
58 int get_public_key(const char *key_file, struct asymmetric_key **result);
61 * Deallocate a public key.
63 * \param key Pointer to the key structure to free.
65 * This should be called for keys obtained by get_public_key() if the key is no
68 void free_public_key(struct asymmetric_key *key);
72 * Fill a buffer with random content.
74 * \param buf The buffer to fill.
75 * \param num The size of \a buf in bytes.
77 * This function puts \a num cryptographically strong pseudo-random bytes into
78 * buf. If it can not guarantee an unpredictable byte sequence (for example
79 * because the PRNG has not been seeded with enough randomness) the function
80 * logs an error message and calls exit().
82 void get_random_bytes_or_die(unsigned char *buf, int num);
85 * Seed pseudo random number generators.
87 * This function seeds the PRNG used by random() with a random seed obtained
88 * from the crypto implementation. On errors, an error message is logged and
89 * the function calls exit().
91 * \sa \ref get_random_bytes_or_die(), srandom(3), random(3), \ref
94 void init_random_seed_or_die(void);
97 /** Opaque structure for stream ciphers. */
100 /** Number of bytes of the session key for stream ciphers. */
101 #define SESSION_KEY_LEN 32
104 * Used for client-server communication encryption.
106 * The traffic between (the forked child of) para_server and the remote client
107 * process is crypted by a symmetric session key. This structure contains the
108 * keys for the stream cipher and the file descriptor for which these keys
111 struct stream_cipher_context {
112 /** The socket file descriptor. */
114 /** Key used for receiving data. */
115 struct stream_cipher *recv;
116 /** Key used for sending data. */
117 struct stream_cipher *send;
121 * Allocate and initialize an aes_ctr128 stream cipher structure.
123 * \param data The key.
124 * \param len The size of the key.
126 * \return A new stream cipher structure.
128 struct stream_cipher *sc_new(const unsigned char *data, int len);
131 * Encrypt or decrypt a buffer using a stream cipher.
133 * \param sc Crypto key.
134 * \param src The source buffer and length.
135 * \param dst The destination buffer and length, filled out by the function.
137 * It is up to the implementation to decide whether the crypt operation is
138 * performed in place. The caller can tell by looking if the buffers given by
139 * \a src and \a dst coincide after the call. If (and only if) the crypt
140 * operation was not performed in place, the function allocated a new buffer
141 * for the result, so dst->iov_base is different from src->iov_base. In this
142 * case, the destination buffer must be freed by the caller when it is no
145 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst);
148 * Wrapper for \ref sc_crypt() that can be used as a sideband transformation.
150 * \param src Passed verbatim to \ref sc_crypt().
151 * \param dst Passed verbatim to \ref sc_crypt().
152 * \param trafo_context Must point to an initialized stream cipher.
154 _static_inline_ void sc_trafo(struct iovec *src, struct iovec *dst,
157 sc_crypt(trafo_context, src, dst);
161 * Deallocate a stream cipher structure.
163 * \param sc A stream cipher previously obtained by sc_new().
165 void sc_free(struct stream_cipher *sc);
167 /** Size of the hash value in bytes. */
171 * Compute the hash of the given input data.
173 * \param data Pointer to the data to compute the hash value from.
174 * \param len The length of \a data in bytes.
175 * \param hash Result pointer.
177 * \a hash must point to an area at least \p HASH_SIZE bytes large.
179 * \sa sha(3), openssl(1).
181 void hash_function(const char *data, unsigned long len, unsigned char *hash);
184 * Convert a hash value to ascii format.
186 * \param hash the hash value.
187 * \param asc Result pointer.
189 * \a asc must point to an area of at least 2 * \p HASH_SIZE + 1 bytes which
190 * will be filled by the function with the ascii representation of the hash
191 * value given by \a hash, and a terminating \p NULL byte.
193 void hash_to_asc(unsigned char *hash, char *asc);
196 * Compare two hashes.
198 * \param h1 Pointer to the first hash value.
199 * \param h2 Pointer to the second hash value.
201 * \return 1, -1, or zero, depending on whether \a h1 is greater than,
202 * less than or equal to h2, respectively.
204 int hash_compare(unsigned char *h1, unsigned char *h2);