/*
- * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2012 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file crypt.h prototypes for the RSA crypt functions */
+/** \file crypt.h Public crypto interface. */
-#include <openssl/pem.h>
-int para_encrypt_buffer(RSA* rsa, unsigned char *inbuf, unsigned len,
- unsigned char *outbuf);
-int para_decrypt_buffer(char *key_file, unsigned char *outbuf, unsigned char *inbuf,
- unsigned rsa_inlen);
-int get_rsa_key(char *key_file, RSA **rsa, int private);
-void rsa_free(RSA *rsa);
+/* These are used to distinguish between loading of private/public key. */
+
+/** The key to load is a public key. */
+#define LOAD_PUBLIC_KEY 0
+/** The key to load is a private key. */
+#define LOAD_PRIVATE_KEY 1
+/** The size of the challenge sent to the client. */
+#define CHALLENGE_SIZE 64
+
+/** Opaque structure for public and private keys. */
+struct asymmetric_key;
+
+/**
+ * Encrypt a buffer using asymmetric keys.
+ *
+ * \param pub: The public key.
+ * \param inbuf The input buffer.
+ * \param len The length of \a inbuf.
+ * \param outbuf The output buffer.
+ *
+ * \return The size of the encrypted data on success, negative on errors.
+ */
+int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
+ unsigned len, unsigned char *outbuf);
+
+/**
+ * Decrypt a buffer using a private key.
+ *
+ * \param key_file Full path of the key.
+ * \param outbuf The output buffer.
+ * \param inbuf The encrypted input buffer.
+ * \param inlen The length of \a inbuf.
+ *
+ * The \a outbuf must be large enough to hold at least 512 bytes.
+ *
+ * \return The size of the recovered plaintext on success, negative on errors.
+ */
+int priv_decrypt(const char *key_file, unsigned char *outbuf,
+ unsigned char *inbuf, int inlen);
+
+/**
+ * Read an asymmetric key from a file.
+ *
+ * \param key_file The file containing the key.
+ * \param private if non-zero, read the private key, otherwise the public key.
+ * \param result The key structure is returned here.
+ *
+ * \return The size of the key on success, negative on errors.
+ */
+int get_asymmetric_key(const char *key_file, int private,
+ struct asymmetric_key **result);
+
+/**
+ * Deallocate an asymmetric key structure.
+ *
+ * \param key Pointer to the key structure to free.
+ *
+ * This must be called for any key obtained by get_asymmetric_key().
+ */
+void free_asymmetric_key(struct asymmetric_key *key);
+
+
+/**
+ * Fill a buffer with random content.
+ *
+ * \param buf The buffer to fill.
+ * \param num The size of \a buf in bytes.
+ *
+ * This function puts \a num cryptographically strong pseudo-random bytes into
+ * buf. If it can not guarantee an unpredictable byte sequence (for example
+ * because the PRNG has not been seeded with enough randomness) the function
+ * logs an error message and calls exit().
+ */
void get_random_bytes_or_die(unsigned char *buf, int num);
+
+/**
+ * Seed pseudo random number generators.
+ *
+ * This function seeds the PRNG used by random() with a random seed obtained
+ * from the crypto implementation. On errors, an error message is logged and
+ * the function calls exit().
+ *
+ * \sa \ref get_random_bytes_or_die(), srandom(3), random(3), \ref
+ * para_random().
+ */
void init_random_seed_or_die(void);
-struct rc4_context {
+
+/** Opaque structure for stream ciphers. */
+struct stream_cipher;
+
+/** Number of bytes of the session key for stream ciphers. */
+#define SESSION_KEY_LEN 32
+
+/**
+ * Used for client-server communication encryption.
+ *
+ * The traffic between (the forked child of) para_server and the remote client
+ * process is crypted by a symmetric session key. This structure contains the
+ * keys for the stream cipher and the file descriptor for which these keys
+ * should be used.
+ */
+struct stream_cipher_context {
+ /** The socket file descriptor. */
int fd;
- RC4_KEY recv_key;
- RC4_KEY send_key;
+ /** Key used for receiving data. */
+ struct stream_cipher *recv;
+ /** Key used for sending data. */
+ struct stream_cipher *send;
};
-int rc4_send_bin_buffer(struct rc4_context *rc4c, const char *buf, size_t len);
-int rc4_send_buffer(struct rc4_context *rc4c, const char *buf);
-__printf_2_3 int rc4_send_va_buffer(struct rc4_context *rc4c, const char *fmt, ...);
-int rc4_recv_bin_buffer(struct rc4_context *rcc, char *buf, size_t size);
-int rc4_recv_buffer(struct rc4_context *rcc, char *buf, size_t size);
-/** \cond used to distinguish between loading of private/public key */
-#define LOAD_PUBLIC_KEY 0
-#define LOAD_PRIVATE_KEY 1
-#define CHALLENGE_SIZE 64
-/** \endcond **/
+/**
+ * Allocate and initialize a stream cipher structure.
+ *
+ * \param data The key.
+ * \param len The size of the key.
+ *
+ * \return A new stream cipher structure.
+ */
+struct stream_cipher *sc_new(const unsigned char *data, int len);
+
+/**
+ * Deallocate a stream cipher structure.
+ *
+ * \param sc A stream cipher previously obtained by sc_new().
+ */
+void sc_free(struct stream_cipher *sc);
+
+/**
+ * Encrypt and send a buffer.
+ *
+ * \param scc The context.
+ * \param buf The buffer to send.
+ * \param len The size of \a buf in bytes.
+ *
+ * \return The return value of the underyling call to write_all().
+ *
+ * \sa \ref write_all(), RC4(3).
+ */
+int sc_send_bin_buffer(struct stream_cipher_context *scc, char *buf,
+ size_t len);
+
+/**
+ * Encrypt and send a \p NULL-terminated buffer.
+ *
+ * \param scc The context.
+ * \param buf The buffer to send.
+ *
+ * \return The return value of the underyling call to sc_send_bin_buffer().
+ */
+int sc_send_buffer(struct stream_cipher_context *scc, char *buf);
+
+/**
+ * Format, encrypt and send a buffer.
+ *
+ * \param scc The context.
+ * \param fmt A format string.
+ *
+ * \return The return value of the underyling call to sc_send_buffer().
+ */
+__printf_2_3 int sc_send_va_buffer(struct stream_cipher_context *scc,
+ const char *fmt, ...);
+
+/**
+ * Receive a buffer and decrypt it.
+ *
+ * \param scc The context.
+ * \param buf The buffer to write the decrypted data to.
+ * \param size The size of \a buf.
+ *
+ * \return The number of bytes received on success, negative on errors, zero if
+ * the peer has performed an orderly shutdown.
+ *
+ * \sa recv(2), RC4(3).
+ */
+int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf,
+ size_t size);
+
+/**
+ * Receive a buffer, decrypt it and write terminating NULL byte.
+ *
+ * \param scc The context.
+ * \param buf The buffer to write the decrypted data to.
+ * \param size The size of \a buf.
+ *
+ * Read at most \a size - 1 bytes from file descriptor given by \a scc, decrypt
+ * the received data and write a NULL byte at the end of the decrypted data.
+ *
+ * \return The return value of the underlying call to \ref
+ * sc_recv_bin_buffer().
+ */
+int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size);
+
+
+/** Size of the hash value in bytes. */
+#define HASH_SIZE 20
+
+
+/**
+ * Compute the hash of the given input data.
+ *
+ * \param data Pointer to the data to compute the hash value from.
+ * \param len The length of \a data in bytes.
+ * \param hash Result pointer.
+ *
+ * \a hash must point to an area at least \p HASH_SIZE bytes large.
+ *
+ * \sa sha(3), openssl(1).
+ * */
+void hash_function(const char *data, unsigned long len, unsigned char *hash);
+
+/**
+ * Convert a hash value to ascii format.
+ *
+ * \param hash the hash value.
+ * \param asc Result pointer.
+ *
+ * \a asc must point to an area of at least 2 * \p HASH_SIZE + 1 bytes which
+ * will be filled by the function with the ascii representation of the hash
+ * value given by \a hash, and a terminating \p NULL byte.
+ */
+void hash_to_asc(unsigned char *hash, char *asc);
+
+/**
+ * Compare two hashes.
+ *
+ * \param h1 Pointer to the first hash value.
+ * \param h2 Pointer to the second hash value.
+ *
+ * \return 1, -1, or zero, depending on whether \a h1 is greater than,
+ * less than or equal to h2, respectively.
+ */
+int hash_compare(unsigned char *h1, unsigned char *h2);
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