/************************************************************************
  *   IRC - Internet Relay Chat, random.c
  *   (C) 2004-2019 Bram Matthys (Syzop) and the UnrealIRCd Team
  *
  *   See file AUTHORS in IRC package for additional names of
  *   the programmers. 
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation; either version 1, or (at your option)
  *   any later version.
  *
  *   This program 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 General Public License for more details.
  *
  *   You should have received a copy of the GNU General Public License
  *   along with this program; if not, write to the Free Software
  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  *
  */
 
 #include "unrealircd.h"
 
 #ifndef HAVE_ARC4RANDOM
 
 #define KEYSTREAM_ONLY
 
 /* chacha_private.h from openssh/openssh-portable
  * "chacha-merged.c version 20080118
  *  D. J. Bernstein
  *  Public domain."
  */
 
 /* $OpenBSD: chacha_private.h,v 1.2 2013/10/04 07:02:27 djm Exp $ */
 
 typedef unsigned char u8;
 typedef unsigned int u32;
 
 typedef struct
 {
   u32 input[16]; /* could be compressed */
 } chacha_ctx;
 
 #define U8C(v) (v##U)
 #define U32C(v) (v##U)
 
 #define U8V(v) ((u8)(v) & U8C(0xFF))
 #define U32V(v) ((u32)(v) & U32C(0xFFFFFFFF))
 
 #define ROTL32(v, n) \
   (U32V((v) << (n)) | ((v) >> (32 - (n))))
 
 #define U8TO32_LITTLE(p) \
   (((u32)((p)[0])      ) | \
    ((u32)((p)[1]) <<  8) | \
    ((u32)((p)[2]) << 16) | \
    ((u32)((p)[3]) << 24))
 
 #define U32TO8_LITTLE(p, v) \
   do { \
     (p)[0] = U8V((v)      ); \
     (p)[1] = U8V((v) >>  8); \
     (p)[2] = U8V((v) >> 16); \
     (p)[3] = U8V((v) >> 24); \
   } while (0)
 
 #define ROTATE(v,c) (ROTL32(v,c))
 #define XOR(v,w) ((v) ^ (w))
 #define PLUS(v,w) (U32V((v) + (w)))
 #define PLUSONE(v) (PLUS((v),1))
 
 #define QUARTERROUND(a,b,c,d) \
   a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \
   c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \
   a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \
   c = PLUS(c,d); b = ROTATE(XOR(b,c), 7);
 
 static const char sigma[16] = "expand 32-byte k";
 static const char tau[16] = "expand 16-byte k";
 
 static void
 chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits,u32 ivbits)
 {
   const char *constants;
 
   x->input[4] = U8TO32_LITTLE(k + 0);
   x->input[5] = U8TO32_LITTLE(k + 4);
   x->input[6] = U8TO32_LITTLE(k + 8);
   x->input[7] = U8TO32_LITTLE(k + 12);
   if (kbits == 256) { /* recommended */
     k += 16;
     constants = sigma;
   } else { /* kbits == 128 */
     constants = tau;
   }
   x->input[8] = U8TO32_LITTLE(k + 0);
   x->input[9] = U8TO32_LITTLE(k + 4);
   x->input[10] = U8TO32_LITTLE(k + 8);
   x->input[11] = U8TO32_LITTLE(k + 12);
   x->input[0] = U8TO32_LITTLE(constants + 0);
   x->input[1] = U8TO32_LITTLE(constants + 4);
   x->input[2] = U8TO32_LITTLE(constants + 8);
   x->input[3] = U8TO32_LITTLE(constants + 12);
 }
 
 static void
 chacha_ivsetup(chacha_ctx *x,const u8 *iv)
 {
   x->input[12] = 0;
   x->input[13] = 0;
   x->input[14] = U8TO32_LITTLE(iv + 0);
   x->input[15] = U8TO32_LITTLE(iv + 4);
 }
 
 static void
 chacha_encrypt_bytes(chacha_ctx *x,const u8 *m,u8 *c,u32 bytes)
 {
   u32 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15;
   u32 j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15;
   u8 *ctarget = NULL;
   u8 tmp[64];
   u_int i;
 
   if (!bytes) return;
 
   j0 = x->input[0];
   j1 = x->input[1];
   j2 = x->input[2];
   j3 = x->input[3];
   j4 = x->input[4];
   j5 = x->input[5];
   j6 = x->input[6];
   j7 = x->input[7];
   j8 = x->input[8];
   j9 = x->input[9];
   j10 = x->input[10];
   j11 = x->input[11];
   j12 = x->input[12];
   j13 = x->input[13];
   j14 = x->input[14];
   j15 = x->input[15];
 
   for (;;) {
     if (bytes < 64) {
       for (i = 0;i < bytes;++i) tmp[i] = m[i];
       m = tmp;
       ctarget = c;
       c = tmp;
     }
     x0 = j0;
     x1 = j1;
     x2 = j2;
     x3 = j3;
     x4 = j4;
     x5 = j5;
     x6 = j6;
     x7 = j7;
     x8 = j8;
     x9 = j9;
     x10 = j10;
     x11 = j11;
     x12 = j12;
     x13 = j13;
     x14 = j14;
     x15 = j15;
     for (i = 20;i > 0;i -= 2) {
       QUARTERROUND( x0, x4, x8,x12)
       QUARTERROUND( x1, x5, x9,x13)
       QUARTERROUND( x2, x6,x10,x14)
       QUARTERROUND( x3, x7,x11,x15)
       QUARTERROUND( x0, x5,x10,x15)
       QUARTERROUND( x1, x6,x11,x12)
       QUARTERROUND( x2, x7, x8,x13)
       QUARTERROUND( x3, x4, x9,x14)
     }
     x0 = PLUS(x0,j0);
     x1 = PLUS(x1,j1);
     x2 = PLUS(x2,j2);
     x3 = PLUS(x3,j3);
     x4 = PLUS(x4,j4);
     x5 = PLUS(x5,j5);
     x6 = PLUS(x6,j6);
     x7 = PLUS(x7,j7);
     x8 = PLUS(x8,j8);
     x9 = PLUS(x9,j9);
     x10 = PLUS(x10,j10);
     x11 = PLUS(x11,j11);
     x12 = PLUS(x12,j12);
     x13 = PLUS(x13,j13);
     x14 = PLUS(x14,j14);
     x15 = PLUS(x15,j15);
 
 #ifndef KEYSTREAM_ONLY
     x0 = XOR(x0,U8TO32_LITTLE(m + 0));
     x1 = XOR(x1,U8TO32_LITTLE(m + 4));
     x2 = XOR(x2,U8TO32_LITTLE(m + 8));
     x3 = XOR(x3,U8TO32_LITTLE(m + 12));
     x4 = XOR(x4,U8TO32_LITTLE(m + 16));
     x5 = XOR(x5,U8TO32_LITTLE(m + 20));
     x6 = XOR(x6,U8TO32_LITTLE(m + 24));
     x7 = XOR(x7,U8TO32_LITTLE(m + 28));
     x8 = XOR(x8,U8TO32_LITTLE(m + 32));
     x9 = XOR(x9,U8TO32_LITTLE(m + 36));
     x10 = XOR(x10,U8TO32_LITTLE(m + 40));
     x11 = XOR(x11,U8TO32_LITTLE(m + 44));
     x12 = XOR(x12,U8TO32_LITTLE(m + 48));
     x13 = XOR(x13,U8TO32_LITTLE(m + 52));
     x14 = XOR(x14,U8TO32_LITTLE(m + 56));
     x15 = XOR(x15,U8TO32_LITTLE(m + 60));
 #endif
 
     j12 = PLUSONE(j12);
     if (!j12) {
       j13 = PLUSONE(j13);
       /* stopping at 2^70 bytes per nonce is user's responsibility */
     }
 
     U32TO8_LITTLE(c + 0,x0);
     U32TO8_LITTLE(c + 4,x1);
     U32TO8_LITTLE(c + 8,x2);
     U32TO8_LITTLE(c + 12,x3);
     U32TO8_LITTLE(c + 16,x4);
     U32TO8_LITTLE(c + 20,x5);
     U32TO8_LITTLE(c + 24,x6);
     U32TO8_LITTLE(c + 28,x7);
     U32TO8_LITTLE(c + 32,x8);
     U32TO8_LITTLE(c + 36,x9);
     U32TO8_LITTLE(c + 40,x10);
     U32TO8_LITTLE(c + 44,x11);
     U32TO8_LITTLE(c + 48,x12);
     U32TO8_LITTLE(c + 52,x13);
     U32TO8_LITTLE(c + 56,x14);
     U32TO8_LITTLE(c + 60,x15);
 
     if (bytes <= 64) {
       if (bytes < 64) {
         for (i = 0;i < bytes;++i) ctarget[i] = c[i];
       }
       x->input[12] = j12;
       x->input[13] = j13;
       return;
     }
     bytes -= 64;
     c += 64;
 #ifndef KEYSTREAM_ONLY
     m += 64;
 #endif
   }
 }
 
 /* The following is taken from arc4random.c
  * from openssh/openssh-portable/, which has an ISC license,
  * which is GPL compatible.
  */
 
 /* OPENBSD ORIGINAL: lib/libc/crypto/arc4random.c */
 /* $OpenBSD: arc4random.c,v 1.25 2013/10/01 18:34:57 markus Exp $	*/
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
  * Copyright (c) 2008, Damien Miller <djm@openbsd.org>
  * Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
 /* Modified for UnrealIRCd by Bram Matthys ("Syzop") in 2019.
  * Things like taking out #if (n)def's for openssl (which we always
  * compile with), re-indenting, removing various stuff, etc.
  */
 
 
 
 #define KEYSZ	32
 #define IVSZ	8
 #define BLOCKSZ	64
 #define RSBUFSZ	(16*BLOCKSZ)
 static int rs_initialized;
 static chacha_ctx rs;		/* chacha context for random keystream */
 static u_char rs_buf[RSBUFSZ];	/* keystream blocks */
 static size_t rs_have;		/* valid bytes at end of rs_buf */
 static size_t rs_count;		/* bytes till reseed */
 
 static inline void _rs_rekey(u_char *dat, size_t datlen);
 
 static inline void _rs_init(u_char *buf, size_t n)
 {
 	if (n < KEYSZ + IVSZ)
 		return;
 	chacha_keysetup(&rs, buf, KEYSZ * 8, 0);
 	chacha_ivsetup(&rs, buf + KEYSZ);
 }
 
 static void _rs_stir(void)
 {
 	u_char rnd[KEYSZ + IVSZ];
 
 	if (RAND_bytes(rnd, sizeof(rnd)) <= 0)
 	{
 		unreal_log(ULOG_FATAL, "random", "RANDOM_OUT_OF_BYTES", NULL,
 		           "Could not obtain random bytes, error $tls_error_code",
 		           log_data_integer("tls_error_code", ERR_get_error()));
 		abort();
 	}
 
 	if (!rs_initialized) {
 		rs_initialized = 1;
 		_rs_init(rnd, sizeof(rnd));
 	} else
 		_rs_rekey(rnd, sizeof(rnd));
 #ifdef HAVE_EXPLICIT_BZERO
 	explicit_bzero(rnd, sizeof(rnd));
 #else
 	/* Not terribly important in this case */
 	memset(rnd, 0, sizeof(rnd));
 #endif
 	/* invalidate rs_buf */
 	rs_have = 0;
 	memset(rs_buf, 0, RSBUFSZ);
 
 	rs_count = 1600000;
 }
 
 static inline void _rs_stir_if_needed(size_t len)
 {
 	if (rs_count <= len || !rs_initialized) {
 		_rs_stir();
 	} else
 		rs_count -= len;
 }
 
 static inline void _rs_rekey(u_char *dat, size_t datlen)
 {
 #ifndef KEYSTREAM_ONLY
 	memset(rs_buf, 0,RSBUFSZ);
 #endif
 	/* fill rs_buf with the keystream */
 	chacha_encrypt_bytes(&rs, rs_buf, rs_buf, RSBUFSZ);
 	/* mix in optional user provided data */
 	if (dat) {
 		size_t i, m;
 
 		m = MIN(datlen, KEYSZ + IVSZ);
 		for (i = 0; i < m; i++)
 			rs_buf[i] ^= dat[i];
 	}
 	/* immediately reinit for backtracking resistance */
 	_rs_init(rs_buf, KEYSZ + IVSZ);
 	memset(rs_buf, 0, KEYSZ + IVSZ);
 	rs_have = RSBUFSZ - KEYSZ - IVSZ;
 }
 
 static inline void _rs_random_buf(void *_buf, size_t n)
 {
 	u_char *buf = (u_char *)_buf;
 	size_t m;
 
 	_rs_stir_if_needed(n);
 	while (n > 0) {
 		if (rs_have > 0) {
 			m = MIN(n, rs_have);
 			memcpy(buf, rs_buf + RSBUFSZ - rs_have, m);
 			memset(rs_buf + RSBUFSZ - rs_have, 0, m);
 			buf += m;
 			n -= m;
 			rs_have -= m;
 		}
 		if (rs_have == 0)
 			_rs_rekey(NULL, 0);
 	}
 }
 
 static inline void _rs_random_u32(uint32_t *val)
 {
 	_rs_stir_if_needed(sizeof(*val));
 	if (rs_have < sizeof(*val))
 		_rs_rekey(NULL, 0);
 	memcpy(val, rs_buf + RSBUFSZ - rs_have, sizeof(*val));
 	memset(rs_buf + RSBUFSZ - rs_have, 0, sizeof(*val));
 	rs_have -= sizeof(*val);
 	return;
 }
 
 void arc4random_stir(void)
 {
 	_rs_stir();
 }
 
 void arc4random_doaddrandom(u_char *dat, int datlen)
 {
 	int m;
 
 	if (!rs_initialized)
 		_rs_stir();
 	while (datlen > 0) {
 		m = MIN(datlen, KEYSZ + IVSZ);
 		_rs_rekey(dat, m);
 		dat += m;
 		datlen -= m;
 	}
 }
 
 #endif /* !HAVE_ARC4RANDOM */
 
 /* UnrealIRCd-specific functions follow */
 
 static void arc4_addrandom(void *dat, int datlen)
 {
 	arc4random_doaddrandom((unsigned char *)dat, datlen);
 	return;
 }
 
 void add_entropy_configfile(struct stat *st, char *buf)
 {
 	char sha256buf[SHA256_DIGEST_LENGTH];
 
 	arc4_addrandom(&st->st_size, sizeof(st->st_size));
 	arc4_addrandom(&st->st_mtime, sizeof(st->st_mtime));
 	sha256hash_binary(sha256buf, buf, strlen(buf));
 	arc4_addrandom(sha256buf, sizeof(sha256buf));
 }
 
 /*
  * init_random, written by Syzop.
  * This function tries to initialize the arc4 random number generator securely.
  */
 void init_random()
 {
 	struct {
 #ifndef _WIN32
 		struct timeval nowt;		/* time */
 		char rnd[32];			/* /dev/urandom */
 #else
 		struct _timeb nowt;		/* time */
 		MEMORYSTATUS mstat;		/* memory status */
 #endif
 	} rdat;
 
 #ifndef _WIN32
 	int fd;
 #endif
 
 	_rs_stir();
 
 	/* Grab OS specific "random" data */
 #ifndef _WIN32
 	gettimeofday(&rdat.nowt, NULL);
 	fd = open("/dev/urandom", O_RDONLY);
 	if (fd >= 0)
 	{
 		int n = read(fd, &rdat.rnd, sizeof(rdat.rnd));
 		close(fd);
 	}
 #else
 	_ftime(&rdat.nowt);
 	GlobalMemoryStatus (&rdat.mstat);
 #endif	
 
 	arc4_addrandom(&rdat, sizeof(rdat));
 
 	/* NOTE: addtional entropy is added by add_entropy_* function(s) */
 }
 
 uint32_t arc4random(void)
 {
 	uint32_t val;
 
 	_rs_random_u32(&val);
 	return val;
 }
 
 /** Get 8 bits (1 byte) of randomness */
 u_char getrandom8()
 {
 	return arc4random() & 0xff;
 }
 
 /** Get 16 bits (2 bytes) of randomness */
 uint16_t getrandom16()
 {
 	return arc4random() & 0xffff;
 }
 
 /** Get 32 bits (4 bytes) of randomness */
 uint32_t getrandom32()
 {
 	return arc4random();
 }
 
 /** Generate an alphanumeric string (eg: XzHe5G).
  * @param buf      The buffer
  * @param numbytes The number of random bytes.
  * @note  Note that numbytes+1 bytes are written to buf.
  *        In other words, numbytes does NOT include the NUL byte.
  */
 void gen_random_alnum(char *buf, int numbytes)
 {
 	for (; numbytes > 0; numbytes--)
 	{
 		unsigned char v = getrandom8() % (26+26+10);
 		if (v < 26)
 			*buf++ = 'a'+v;
 		else if (v < 52)
 			*buf++ = 'A'+(v-26);
 		else
 			*buf++ = '0'+(v-52);
 	}
 	*buf = '\0';
 }

© 2023 acidvegas, inc • generated with stagit