Merge branch 't/crypt_cleanups'

[paraslash.git] / crypt.h

diff --git a/crypt.h b/crypt.h
index 6bd8179bbe90b8162bcc7d3a9af5736cd21d2677..21abe41f68cd8c5b335cc133b5c6f3050869c4ee 100644 (file)
--- a/crypt.h
+++ b/crypt.h
@@ -4,42 +4,108 @@
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
-/** \file crypt.h prototypes for the RSA crypt functions */
+/** \file crypt.h Prototypes for paraslash crypto functions. */
 
-#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);
+/** Opaque structure for public and private keys. */
+struct asymmetric_key;
+
+int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
+               unsigned len, unsigned char *outbuf);
+int priv_decrypt(const char *key_file, unsigned char *outbuf,
+               unsigned char *inbuf, int inlen);
+int get_asymmetric_key(const char *key_file, int private,
+               struct asymmetric_key **result);
+void free_asymmetric_key(struct asymmetric_key *key);
 
-void rsa_free(RSA *rsa);
 void get_random_bytes_or_die(unsigned char *buf, int num);
 void init_random_seed_or_die(void);
 
+/** Opaque structure for stream cipher crypto. */
+struct stream_cipher;
+
+/** Number of bytes of the session key. */
+#define SESSION_KEY_LEN 32
+
 /**
  * Used on the server-side for client-server communication encryption.
  *
- * The traffic between (the forked child of) para_server and the remote
- * client process is crypted by a RC4 session key. This structure contains
- * the RC4 keys and the file descriptor for which these keys should be used.
+ * 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 rc4_context {
+struct stream_cipher_context {
        /** The socket file descriptor. */
        int fd;
-       /** Key used for sending data. */
-       RC4_KEY recv_key;
        /** Key used for receiving data. */
-       RC4_KEY send_key;
+       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);
+
+struct stream_cipher *sc_new(const unsigned char *data, int len);
+void sc_free(struct stream_cipher *sc);
+
+int sc_send_bin_buffer(struct stream_cipher_context *scc, const char *buf,
+               size_t len);
+int sc_send_buffer(struct stream_cipher_context *scc, const char *buf);
+__printf_2_3 int sc_send_va_buffer(struct stream_cipher_context *scc,
+               const char *fmt, ...);
+int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf,
+               size_t size);
+int sc_recv_buffer(struct stream_cipher_context *scc, 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 **/
+
+/** Size of the hash value in bytes. */
+#define HASH_SIZE 20
+
+void hash_function(const char *data, unsigned long len, unsigned char *hash);
+
+/**
+ * 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.
+ */
+_static_inline_ int hash_compare(unsigned char *h1, unsigned char *h2)
+{
+       int i;
+
+       for (i = 0; i < HASH_SIZE; i++) {
+               if (h1[i] < h2[i])
+                       return -1;
+               if (h1[i] > h2[i])
+                       return 1;
+       }
+       return 0;
+}
+
+/**
+ * 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.
+ */
+_static_inline_ void hash_to_asc(unsigned char *hash, char *asc)
+{
+       int i;
+       const char hexchar[] = "0123456789abcdef";
+
+       for (i = 0; i < HASH_SIZE; i++) {
+               asc[2 * i] = hexchar[hash[i] >> 4];
+               asc[2 * i + 1] = hexchar[hash[i] & 0xf];
+       }
+       asc[2 * HASH_SIZE] = '\0';
+}