+/* $OpenBSD: arc4random.c,v 1.58 2022/07/31 13:41:45 tb Exp $ */
+
/*
- * Arc4 random number generator for OpenBSD.
- * Copyright 1996 David Mazieres <dm@lcs.mit.edu>.
+ * Copyright (c) 1996, David Mazieres <dm@uun.org>
+ * Copyright (c) 2008, Damien Miller <djm@openbsd.org>
+ * Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
+ * Copyright (c) 2014, Theo de Raadt <deraadt@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.
*
- * Modification and redistribution in source and binary forms is
- * permitted provided that due credit is given to the author and the
- * OpenBSD project by leaving this copyright notice intact.
+ * 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.
*/
/*
- * This code is derived from section 17.1 of Applied Cryptography,
- * second edition, which describes a stream cipher allegedly
- * compatible with RSA Labs "RC4" cipher (the actual description of
- * which is a trade secret). The same algorithm is used as a stream
- * cipher called "arcfour" in Tatu Ylonen's ssh package.
- *
- * Here the stream cipher has been modified always to include the time
- * when initializing the state. That makes it impossible to
- * regenerate the same random sequence twice, so this can't be used
- * for encryption, but will generate good random numbers.
- *
- * RC4 is a registered trademark of RSA Laboratories.
+ * ChaCha based random number generator for OpenBSD.
*/
-#include <sys/time.h>
+/*
+ * OPENBSD ORIGINAL: lib/libc/crypt/arc4random.c
+ * lib/libc/crypt/arc4random.h
+ */
+
+#include "config.h"
#include <fcntl.h>
+#include <limits.h>
+#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
+#include <string.h>
#include <unistd.h>
+#include <sys/types.h>
+#include <sys/time.h>
-#include "arc4random.h"
+#define KEYSTREAM_ONLY
+#include "chacha_private.h"
-struct arc4_stream {
- uint8_t i;
- uint8_t j;
- uint8_t s[256];
- size_t count;
- pid_t stir_pid;
- int fd;
-};
+#define minimum(a, b) ((a) < (b) ? (a) : (b))
-#define S(n) (n)
-#define S4(n) S(n), S(n + 1), S(n + 2), S(n + 3)
-#define S16(n) S4(n), S4(n + 4), S4(n + 8), S4(n + 12)
-#define S64(n) S16(n), S16(n + 16), S16(n + 32), S16(n + 48)
-#define S256 S64(0), S64(64), S64(128), S64(192)
+#if defined(__GNUC__) || defined(_MSC_VER)
+#define inline __inline
+#else /* __GNUC__ || _MSC_VER */
+#define inline
+#endif /* !__GNUC__ && !_MSC_VER */
-static struct arc4_stream rs = { .i = 0xff, .j = 0, .s = { S256 },
- .count = 0, .stir_pid = 0, .fd = -1 };
+#define KEYSZ 32
+#define IVSZ 8
+#define BLOCKSZ 64
+#define RSBUFSZ (16*BLOCKSZ)
-#undef S
-#undef S4
-#undef S16
-#undef S64
-#undef S256
+#define REKEY_BASE (1024*1024) /* NB. should be a power of 2 */
-static void
-arc4_addrandom(struct arc4_stream *as, unsigned char *dat, int datlen)
+/* Marked MAP_INHERIT_ZERO, so zero'd out in fork children. */
+static struct _rs {
+ size_t rs_have; /* valid bytes at end of rs_buf */
+ size_t rs_count; /* bytes till reseed */
+} *rs;
+
+/* Maybe be preserved in fork children, if _rs_allocate() decides. */
+static struct _rsx {
+ chacha_ctx rs_chacha; /* chacha context for random keystream */
+ u_char rs_buf[RSBUFSZ]; /* keystream blocks */
+} *rsx;
+
+static int _dhcpcd_rand_fd = -1; /* /dev/urandom fd */
+
+static int _dhcpcd_getentropy(void *, size_t);
+static inline int _rs_allocate(struct _rs **, struct _rsx **);
+static inline void _rs_forkdetect(void);
+
+/* Inline "arc4random.h" */
+#include <sys/types.h>
+#include <sys/mman.h>
+
+static inline void _rs_rekey(u_char *dat, size_t datlen);
+
+/* dhcpcd isn't multithreaded */
+#define _ARC4_LOCK()
+#define _ARC4_UNLOCK()
+#define _ARC4_ATFORK(f)
+
+static int
+_dhcpcd_getentropy(void *buf, size_t length)
{
- int n;
- uint8_t si;
-
- as->i--;
- for (n = 0; n < 256; n++) {
- as->i = (uint8_t)(as->i + 1);
- si = as->s[as->i];
- as->j = (uint8_t)(as->j + si + dat[n % datlen]);
- as->s[as->i] = as->s[as->j];
- as->s[as->j] = si;
+ struct timeval tv;
+ uint8_t *rand = (uint8_t *)buf;
+
+ if (length < sizeof(tv)) {
+ gettimeofday(&tv, NULL);
+ memcpy(buf, &tv, sizeof(tv));
+ length -= sizeof(tv);
+ rand += sizeof(tv);
+ }
+ if (_dhcpcd_rand_fd == -1)
+ _dhcpcd_rand_fd = open("/dev/urandom", O_RDONLY | O_NONBLOCK);
+ if (_dhcpcd_rand_fd != -1) {
+ /* coverity[check_return] */
+ (void)read(_dhcpcd_rand_fd, rand, length);
}
- as->j = as->i;
+
+ /* Never fail. If there is an error reading from /dev/urandom,
+ * just use what is on the stack. */
+ return (0);
}
-static uint8_t
-arc4_getbyte(struct arc4_stream *as)
+static inline void
+_getentropy_fail(void)
{
- uint8_t si, sj;
-
- as->i = (uint8_t)(as->i + 1);
- si = as->s[as->i];
- as->j = (uint8_t)(as->j + si);
- sj = as->s[as->j];
- as->s[as->i] = sj;
- as->s[as->j] = si;
- return (as->s[(si + sj) & 0xff]);
+ raise(SIGKILL);
}
-static uint32_t
-arc4_getword(struct arc4_stream *as)
+static volatile sig_atomic_t _rs_forked;
+
+static inline void
+_rs_forkhandler(void)
{
- int val;
+ _rs_forked = 1;
+}
- val = (int)((unsigned int)arc4_getbyte(as) << 24);
- val |= arc4_getbyte(as) << 16;
- val |= arc4_getbyte(as) << 8;
- val |= arc4_getbyte(as);
- return (uint32_t)val;
+static inline void
+_rs_forkdetect(void)
+{
+ static pid_t _rs_pid = 0;
+ pid_t pid = getpid();
+
+ /* XXX unusual calls to clone() can bypass checks */
+ if (_rs_pid == 0 || _rs_pid == 1 || _rs_pid != pid || _rs_forked) {
+ _rs_pid = pid;
+ _rs_forked = 0;
+ if (rs)
+ memset(rs, 0, sizeof(*rs));
+ }
}
-/* We don't care about any error on read, just use what we have
- * on the stack. So mask off this GCC warning. */
-#pragma GCC diagnostic ignored "-Wunused-result"
-static void
-arc4_stir(struct arc4_stream *as)
+static inline int
+_rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
{
- struct {
- struct timeval tv;
- unsigned int rnd[(128 - sizeof(struct timeval)) /
- sizeof(unsigned int)];
- } rdat;
- size_t n;
-
- gettimeofday(&rdat.tv, NULL);
- if (as->fd == -1) {
-#ifndef O_CLOEXEC
- int fd_opts;
-#endif
+ if ((*rsp = mmap(NULL, sizeof(**rsp), PROT_READ|PROT_WRITE,
+ MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED)
+ return (-1);
- as->fd = open("/dev/urandom", O_RDONLY | O_NONBLOCK
-#ifdef O_CLOEXEC
- | O_CLOEXEC
-#endif
- );
-#ifndef O_CLOEXEC
- if (as->fd != -1 &&
- (fd_opts = fcntl(as->fd, F_GETFD)))
- fcntl(as->fd, F_SETFD, fd_opts | FD_CLOEXEC);
-#endif
+ if ((*rsxp = mmap(NULL, sizeof(**rsxp), PROT_READ|PROT_WRITE,
+ MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) {
+ munmap(*rsp, sizeof(**rsp));
+ *rsp = NULL;
+ return (-1);
}
- if (as->fd != -1) {
- /* If there is an error reading, just use what is
- * on the stack. */
- /* coverity[check_return] */
- (void)read(as->fd, rdat.rnd, sizeof(rdat.rnd));
+ _ARC4_ATFORK(_rs_forkhandler);
+ return (0);
+}
+
+static inline void
+_rs_init(u_char *buf, size_t n)
+{
+ if (n < KEYSZ + IVSZ)
+ return;
+
+ if (rs == NULL) {
+ if (_rs_allocate(&rs, &rsx) == -1)
+ _exit(1);
}
- /* fd < 0? Ah, what the heck. We'll just take
- * whatever was on the stack... */
- /* coverity[uninit_use_in_call] */
- arc4_addrandom(as, (void *) &rdat, sizeof(rdat));
-
- /*
- * Throw away the first N words of output, as suggested in the
- * paper "Weaknesses in the Key Scheduling Algorithm of RC4"
- * by Fluher, Mantin, and Shamir. (N = 256 in our case.)
- */
- for (n = 0; n < 256 * sizeof(uint32_t); n++)
- arc4_getbyte(as);
- as->count = 1600000;
+ chacha_keysetup(&rsx->rs_chacha, buf, KEYSZ * 8);
+ chacha_ivsetup(&rsx->rs_chacha, buf + KEYSZ);
}
static void
-arc4_stir_if_needed(struct arc4_stream *as)
+_rs_stir(void)
+{
+ u_char rnd[KEYSZ + IVSZ];
+ uint32_t rekey_fuzz = 0;
+
+ if (_dhcpcd_getentropy(rnd, sizeof rnd) == -1)
+ _getentropy_fail();
+
+ if (!rs)
+ _rs_init(rnd, sizeof(rnd));
+ else
+ _rs_rekey(rnd, sizeof(rnd));
+ explicit_bzero(rnd, sizeof(rnd)); /* discard source seed */
+
+ /* invalidate rs_buf */
+ rs->rs_have = 0;
+ memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
+
+ /* rekey interval should not be predictable */
+ chacha_encrypt_bytes(&rsx->rs_chacha, (uint8_t *)&rekey_fuzz,
+ (uint8_t *)&rekey_fuzz, sizeof(rekey_fuzz));
+ rs->rs_count = REKEY_BASE + (rekey_fuzz % REKEY_BASE);
+}
+
+static inline void
+_rs_stir_if_needed(size_t len)
+{
+ _rs_forkdetect();
+ if (!rs || rs->rs_count <= len)
+ _rs_stir();
+ if (rs->rs_count <= len)
+ rs->rs_count = 0;
+ else
+ rs->rs_count -= len;
+}
+
+static inline void
+_rs_rekey(u_char *dat, size_t datlen)
{
- pid_t pid;
-
- pid = getpid();
- if (as->count <= sizeof(uint32_t) || as->stir_pid != pid) {
- as->stir_pid = pid;
- arc4_stir(as);
- } else
- as->count -= sizeof(uint32_t);
+#ifndef KEYSTREAM_ONLY
+ memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
+#endif
+ /* fill rs_buf with the keystream */
+ chacha_encrypt_bytes(&rsx->rs_chacha, rsx->rs_buf,
+ rsx->rs_buf, sizeof(rsx->rs_buf));
+ /* mix in optional user provided data */
+ if (dat) {
+ size_t i, m;
+
+ m = minimum(datlen, KEYSZ + IVSZ);
+ for (i = 0; i < m; i++)
+ rsx->rs_buf[i] ^= dat[i];
+ }
+ /* immediately reinit for backtracking resistance */
+ _rs_init(rsx->rs_buf, KEYSZ + IVSZ);
+ memset(rsx->rs_buf, 0, KEYSZ + IVSZ);
+ rs->rs_have = sizeof(rsx->rs_buf) - KEYSZ - IVSZ;
+}
+
+static inline void
+_rs_random_buf(void *_buf, size_t n)
+{
+ u_char *buf = (u_char *)_buf;
+ u_char *keystream;
+ size_t m;
+
+ _rs_stir_if_needed(n);
+ while (n > 0) {
+ if (rs->rs_have > 0) {
+ m = minimum(n, rs->rs_have);
+ keystream = rsx->rs_buf + sizeof(rsx->rs_buf)
+ - rs->rs_have;
+ memcpy(buf, keystream, m);
+ memset(keystream, 0, m);
+ buf += m;
+ n -= m;
+ rs->rs_have -= m;
+ }
+ if (rs->rs_have == 0)
+ _rs_rekey(NULL, 0);
+ }
+}
+
+static inline void
+_rs_random_u32(uint32_t *val)
+{
+ u_char *keystream;
+
+ _rs_stir_if_needed(sizeof(*val));
+ if (rs->rs_have < sizeof(*val))
+ _rs_rekey(NULL, 0);
+ keystream = rsx->rs_buf + sizeof(rsx->rs_buf) - rs->rs_have;
+ memcpy(val, keystream, sizeof(*val));
+ memset(keystream, 0, sizeof(*val));
+ rs->rs_have -= sizeof(*val);
}
uint32_t
-arc4random()
+arc4random(void)
{
+ uint32_t val;
- arc4_stir_if_needed(&rs);
- return arc4_getword(&rs);
+ _ARC4_LOCK();
+ _rs_random_u32(&val);
+ _ARC4_UNLOCK();
+ return val;
+}
+
+void
+arc4random_buf(void *buf, size_t n)
+{
+ _ARC4_LOCK();
+ _rs_random_buf(buf, n);
+ _ARC4_UNLOCK();
}
--- /dev/null
+/*
+chacha-merged.c version 20080118
+D. J. Bernstein
+Public domain.
+*/
+
+/* $OpenBSD: chacha_private.h,v 1.3 2022/02/28 21:56:29 dtucker 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)
+{
+ 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
+ }
+}
projects / thirdparty / dhcpcd.git / commitdiff
