--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/random.c	Tue Jun 01 02:46:09 2004 +0000
@@ -0,0 +1,178 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#include "includes.h"
+#include "buffer.h"
+#include "dbutil.h"
+
+int donerandinit = 0;
+
+/* this is used to generate unique output from the same hashpool */
+unsigned int counter = 0;
+#define MAX_COUNTER 1000000/* the max value for the counter, so it won't loop */
+
+unsigned char hashpool[SHA1_HASH_SIZE];
+
+#define INIT_SEED_SIZE 32 /* 256 bits */
+
+static void readrand(unsigned char* buf, unsigned int buflen);
+
+/* The basic setup is we read some data from DEV_URANDOM or PRNGD and hash it
+ * into hashpool. To read data, we hash together current hashpool contents,
+ * and a counter. We feed more data in by hashing the current pool and new
+ * data into the pool.
+ *
+ * It is important to ensure that counter doesn't wrap around before we
+ * feed in new entropy.
+ *
+ */
+
+static void readrand(unsigned char* buf, unsigned int buflen) {
+
+	int readfd;
+	unsigned int readpos;
+	int readlen;
+#ifdef DROPBEAR_EGD
+	struct sockaddr_un egdsock;
+	char egdcmd[2];
+#endif
+
+#ifdef DROPBEAR_DEV_URANDOM
+	readfd = open(DEV_URANDOM, O_RDONLY);
+	if (!readfd) {
+		dropbear_exit("couldn't open random device");
+	}
+#endif
+
+#ifdef DROPBEAR_EGD
+	memset((void*)&egdsock, 0x0, sizeof(egdsock));
+	egdsock.sun_family = AF_UNIX;
+	strlcpy(egdsock.sun_path, DROPBEAR_EGD_SOCKET,
+			sizeof(egdsock.sun_path));
+
+	if ((readfd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
+		dropbear_exit("couldn't open random device");
+	}
+	/* todo - try various common locations */
+	if (connect(readfd, (struct sockaddr*)&egdsock, 
+			sizeof(struct sockaddr_un)) < 0) {
+		dropbear_exit("couldn't open random device");
+	}
+
+	if (buflen > 255)
+		dropbear_exit("can't request more than 255 bytes from egd");
+	egdcmd[0] = 0x02;	/* blocking read */
+	egdcmd[1] = (unsigned char)buflen;
+	if (write(readfd, egdcmd, 2) < 0)
+		dropbear_exit("can't send command to egd");
+#endif
+
+	/* read the actual random data */
+	readpos = 0;
+	do {
+		readlen = read(readfd, &buf[readpos], buflen - readpos);
+		if (readlen <= 0) {
+			if (readlen < 0 && errno == EINTR) {
+				continue;
+			}
+			dropbear_exit("error reading random source");
+		}
+		readpos += readlen;
+	} while (readpos < buflen);
+
+	close (readfd);
+}
+
+/* initialise the prng from /dev/urandom or prngd */
+void seedrandom() {
+		
+	unsigned char readbuf[INIT_SEED_SIZE];
+
+	hash_state hs;
+
+	/* initialise so compilers will be happy about hashing it */
+	if (!donerandinit) {
+		m_burn(hashpool, sizeof(hashpool));
+	}
+
+	/* get the seed data */
+	readrand(readbuf, sizeof(readbuf));
+
+	/* hash in the new seed data */
+	sha1_init(&hs);
+	sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
+	sha1_process(&hs, (void*)readbuf, sizeof(readbuf));
+	sha1_done(&hs, hashpool);
+
+	counter = 0;
+	donerandinit = 1;
+}
+
+/* return len bytes of pseudo-random data */
+void genrandom(unsigned char* buf, unsigned int len) {
+
+	hash_state hs;
+	unsigned char hash[SHA1_HASH_SIZE];
+	unsigned int copylen;
+
+	if (!donerandinit) {
+		dropbear_exit("seedrandom not done");
+	}
+
+	while (len > 0) {
+		sha1_init(&hs);
+		sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
+		sha1_process(&hs, (void*)&counter, sizeof(counter));
+		sha1_done(&hs, hash);
+
+		counter++;
+		if (counter > MAX_COUNTER) {
+			seedrandom();
+		}
+
+		copylen = MIN(len, SHA1_HASH_SIZE);
+		memcpy(buf, hash, copylen);
+		len -= copylen;
+		buf += copylen;
+	}
+	m_burn(hash, sizeof(hash));
+}
+
+/* Adds entropy to the PRNG state. As long as the hash is strong, then we
+ * don't need to worry about entropy being added "diluting" the current
+ * state - it should only make it stronger. */
+void addrandom(unsigned char* buf, unsigned int len) {
+
+	hash_state hs;
+	if (!donerandinit) {
+		dropbear_exit("seedrandom not done");
+	}
+
+	sha1_init(&hs);
+	sha1_process(&hs, (void*)buf, len);
+	sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
+	sha1_done(&hs, hashpool);
+	counter = 0;
+
+}