diff options
Diffstat (limited to 'crypto/openssh/openbsd-compat/bsd-arc4random.c')
-rw-r--r-- | crypto/openssh/openbsd-compat/bsd-arc4random.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/crypto/openssh/openbsd-compat/bsd-arc4random.c b/crypto/openssh/openbsd-compat/bsd-arc4random.c new file mode 100644 index 0000000..d45fb18 --- /dev/null +++ b/crypto/openssh/openbsd-compat/bsd-arc4random.c @@ -0,0 +1,84 @@ +/* + * Copyright (c) 1999,2000,2004 Damien Miller <djm@mindrot.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. + */ + +#include "includes.h" + +#include <sys/types.h> + +#include <string.h> +#include <stdarg.h> + +#include "log.h" + +#ifndef HAVE_ARC4RANDOM + +#include <openssl/rand.h> +#include <openssl/rc4.h> +#include <openssl/err.h> + +/* Size of key to use */ +#define SEED_SIZE 20 + +/* Number of bytes to reseed after */ +#define REKEY_BYTES (1 << 24) + +static int rc4_ready = 0; +static RC4_KEY rc4; + +unsigned int +arc4random(void) +{ + unsigned int r = 0; + static int first_time = 1; + + if (rc4_ready <= 0) { + if (first_time) + seed_rng(); + first_time = 0; + arc4random_stir(); + } + + RC4(&rc4, sizeof(r), (unsigned char *)&r, (unsigned char *)&r); + + rc4_ready -= sizeof(r); + + return(r); +} + +void +arc4random_stir(void) +{ + unsigned char rand_buf[SEED_SIZE]; + int i; + + memset(&rc4, 0, sizeof(rc4)); + if (RAND_bytes(rand_buf, sizeof(rand_buf)) <= 0) + fatal("Couldn't obtain random bytes (error %ld)", + ERR_get_error()); + RC4_set_key(&rc4, sizeof(rand_buf), rand_buf); + + /* + * Discard early keystream, as per recommendations in: + * http://www.wisdom.weizmann.ac.il/~itsik/RC4/Papers/Rc4_ksa.ps + */ + for(i = 0; i <= 256; i += sizeof(rand_buf)) + RC4(&rc4, sizeof(rand_buf), rand_buf, rand_buf); + + memset(rand_buf, 0, sizeof(rand_buf)); + + rc4_ready = REKEY_BYTES; +} +#endif /* !HAVE_ARC4RANDOM */ |