Big thanks to Solar Designer who pointed out a bug in bcrypt

salt generation code.  He also urged using better random source
and making possible to choose using bcrypt and xdes rounds more
easily.  So, here's patch:

* For all salt generation, use Solar Designer's own code.  This
  is mostly due fact that his code is more fit for get_random_bytes()
  style interface.
* New function: gen_salt(type, rounds).  This lets specify iteration
  count for algorithm.
* random.c: px_get_random_bytes() function.
  Supported randomness soure: /dev/urandom, OpenSSL PRNG, libc random()
  Default: /dev/urandom.
* Draft description of C API for pgcrypto functions.

New files: API, crypt-gensalt.c, random.c

Marko Kreen

contrib/pgcrypto/random.c

@@ -0,0 +1,127 @@
+/*
+ * random.c
+ *		Random functions.
+ *
+ * Copyright (c) 2001 Marko Kreen
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *	  notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *	  notice, this list of conditions and the following disclaimer in the
+ *	  documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.	IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $Id: random.c,v 1.1 2001/09/23 04:12:44 momjian Exp $
+ */
+
+
+#include <postgres.h>
+
+#include "px.h"
+
+
+#ifdef RAND_DEV
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+static int
+safe_read(int fd, void *buf, size_t count)
+{
+	int done = 0;
+	char *p = buf;
+	int res;
+	
+	while (count) {
+		res = read(fd, p, count);
+		if (res <= 0) {
+			if (errno == EINTR)
+				continue;
+			return -1;
+		}
+		p += res;
+		done += res;
+		count -= res;
+	}
+	return done;
+}
+
+int
+px_get_random_bytes(uint8 *dst, unsigned count)
+{
+	int fd;
+	int res;
+
+	fd = open(RAND_DEV, O_RDONLY);
+	if (fd == -1)
+		return -1;
+	res = safe_read(fd, dst, count);
+	close(fd);
+	return res;
+}
+
+#endif /* RAND_DEV */
+
+#ifdef RAND_SILLY
+
+int px_get_random_bytes(char *dst, unsigned count)
+{
+	int i;
+	for (i = 0; i < count; i++) {
+		*dst++ = random();
+	}
+	return i;
+}
+
+#endif /* RAND_SILLY */
+
+#ifdef RAND_OPENSSL
+
+#include <openssl/evp.h>
+#include <openssl/blowfish.h>
+#include <openssl/rand.h>
+#include <openssl/err.h>
+
+static int openssl_random_init = 0;
+
+int px_get_random_bytes(uint8 *dst, unsigned count)
+{
+	int res;
+
+	if (!openssl_random_init) {
+		if (RAND_get_rand_method() == NULL) {
+			RAND_set_rand_method(RAND_SSLeay());
+		}
+		openssl_random_init = 1;
+	}
+	
+	/*
+	 * OpenSSL random should re-feeded occasionally.
+	 * From /dev/urandom preferrably.
+	 */
+	
+	res = RAND_bytes(dst, count);
+	if (res > 0)
+		return count;
+
+	return -1;
+}
+
+#endif /* RAND_OPENSSL */
+