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authorRene Mayrhofer <rene@mayrhofer.eu.org>2007-04-12 20:30:08 +0000
committerRene Mayrhofer <rene@mayrhofer.eu.org>2007-04-12 20:30:08 +0000
commitb0d8ed94fe9e74afb49fdf5f11e4add29879c65c (patch)
treeb20167235628771046e940a82a906a6d0991ee4a /src/libfreeswan/prng.c
parentea939d07c84d2a8e51215458063fc05e9c399290 (diff)
downloadvyos-strongswan-b0d8ed94fe9e74afb49fdf5f11e4add29879c65c.tar.gz
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[svn-upgrade] Integrating new upstream version, strongswan (4.1.1)
Diffstat (limited to 'src/libfreeswan/prng.c')
-rw-r--r--src/libfreeswan/prng.c202
1 files changed, 202 insertions, 0 deletions
diff --git a/src/libfreeswan/prng.c b/src/libfreeswan/prng.c
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+/*
+ * crypto-class pseudorandom number generator
+ * currently uses same algorithm as RC4(TM), from Schneier 2nd ed p397
+ * Copyright (C) 2002 Henry Spencer.
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Library General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. See <http://www.fsf.org/copyleft/lgpl.txt>.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
+ * License for more details.
+ *
+ * RCSID $Id: prng.c,v 1.1 2004/03/15 20:35:26 as Exp $
+ */
+#include "internal.h"
+#include "freeswan.h"
+
+/*
+ - prng_init - initialize PRNG from a key
+ */
+void
+prng_init(prng, key, keylen)
+struct prng *prng;
+const unsigned char *key;
+size_t keylen;
+{
+ unsigned char k[256];
+ int i, j;
+ unsigned const char *p;
+ unsigned const char *keyend = key + keylen;
+ unsigned char t;
+
+ for (i = 0; i <= 255; i++)
+ prng->sbox[i] = i;
+ p = key;
+ for (i = 0; i <= 255; i++) {
+ k[i] = *p++;
+ if (p >= keyend)
+ p = key;
+ }
+ j = 0;
+ for (i = 0; i <= 255; i++) {
+ j = (j + prng->sbox[i] + k[i]) & 0xff;
+ t = prng->sbox[i];
+ prng->sbox[i] = prng->sbox[j];
+ prng->sbox[j] = t;
+ k[i] = 0; /* clear out key memory */
+ }
+ prng->i = 0;
+ prng->j = 0;
+ prng->count = 0;
+}
+
+/*
+ - prng_bytes - get some pseudorandom bytes from PRNG
+ */
+void
+prng_bytes(prng, dst, dstlen)
+struct prng *prng;
+unsigned char *dst;
+size_t dstlen;
+{
+ int i, j, t;
+ unsigned char *p = dst;
+ size_t remain = dstlen;
+# define MAX 4000000000ul
+
+ while (remain > 0) {
+ i = (prng->i + 1) & 0xff;
+ prng->i = i;
+ j = (prng->j + prng->sbox[i]) & 0xff;
+ prng->j = j;
+ t = prng->sbox[i];
+ prng->sbox[i] = prng->sbox[j];
+ prng->sbox[j] = t;
+ t = (t + prng->sbox[i]) & 0xff;
+ *p++ = prng->sbox[t];
+ remain--;
+ }
+ if (prng->count < MAX - dstlen)
+ prng->count += dstlen;
+ else
+ prng->count = MAX;
+}
+
+/*
+ - prnt_count - how many bytes have been extracted from PRNG so far?
+ */
+unsigned long
+prng_count(prng)
+struct prng *prng;
+{
+ return prng->count;
+}
+
+/*
+ - prng_final - clear out PRNG to ensure nothing left in memory
+ */
+void
+prng_final(prng)
+struct prng *prng;
+{
+ int i;
+
+ for (i = 0; i <= 255; i++)
+ prng->sbox[i] = 0;
+ prng->i = 0;
+ prng->j = 0;
+ prng->count = 0; /* just for good measure */
+}
+
+
+
+#ifdef PRNG_MAIN
+
+#include <stdio.h>
+
+void regress();
+
+int
+main(argc, argv)
+int argc;
+char *argv[];
+{
+ struct prng pr;
+ unsigned char buf[100];
+ unsigned char *p;
+ size_t n;
+
+ if (argc < 2) {
+ fprintf(stderr, "Usage: %s {key|-r}\n", argv[0]);
+ exit(2);
+ }
+
+ if (strcmp(argv[1], "-r") == 0) {
+ regress();
+ fprintf(stderr, "regress() returned?!?\n");
+ exit(1);
+ }
+
+ prng_init(&pr, argv[1], strlen(argv[1]));
+ prng_bytes(&pr, buf, 32);
+ printf("0x");
+ for (p = buf, n = 32; n > 0; p++, n--)
+ printf("%02x", *p);
+ printf("\n%lu bytes\n", prng_count(&pr));
+ prng_final(&pr);
+ exit(0);
+}
+
+void
+regress()
+{
+ struct prng pr;
+ unsigned char buf[100];
+ unsigned char *p;
+ size_t n;
+ /* somewhat non-random sample key */
+ unsigned char key[] = "here we go gathering nuts in May";
+ /* first thirty bytes of output from that key */
+ unsigned char good[] = "\x3f\x02\x8e\x4a\x2a\xea\x23\x18\x92\x7c"
+ "\x09\x52\x83\x61\xaa\x26\xce\xbb\x9d\x71"
+ "\x71\xe5\x10\x22\xaf\x60\x54\x8d\x5b\x28";
+ int nzero, none;
+ int show = 0;
+
+ prng_init(&pr, key, strlen(key));
+ prng_bytes(&pr, buf, sizeof(buf));
+ for (p = buf, n = sizeof(buf); n > 0; p++, n--) {
+ if (*p == 0)
+ nzero++;
+ if (*p == 255)
+ none++;
+ }
+ if (nzero > 3 || none > 3) {
+ fprintf(stderr, "suspiciously non-random output!\n");
+ show = 1;
+ }
+ if (memcmp(buf, good, strlen(good)) != 0) {
+ fprintf(stderr, "incorrect output!\n");
+ show = 1;
+ }
+ if (show) {
+ fprintf(stderr, "0x");
+ for (p = buf, n = sizeof(buf); n > 0; p++, n--)
+ fprintf(stderr, "%02x", *p);
+ fprintf(stderr, "\n");
+ exit(1);
+ }
+ if (prng_count(&pr) != sizeof(buf)) {
+ fprintf(stderr, "got %u bytes, but count is %lu\n",
+ sizeof(buf), prng_count(&pr));
+ exit(1);
+ }
+ prng_final(&pr);
+ exit(0);
+}
+
+#endif /* PRNG_MAIN */