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- /*
- * 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.
- */
-
- #include "includes.h"
-
- #ifndef SSH_RANDOM_DEV
- # define SSH_RANDOM_DEV "/dev/urandom"
- #endif /* SSH_RANDOM_DEV */
-
- #include <sys/types.h>
- #ifdef HAVE_SYS_RANDOM_H
- # include <sys/random.h>
- #endif
-
- #include <fcntl.h>
- #include <stdlib.h>
- #include <string.h>
- #include <unistd.h>
- #ifdef WITH_OPENSSL
- #include <openssl/rand.h>
- #include <openssl/err.h>
- #endif
-
- #include "log.h"
-
- int
- _ssh_compat_getentropy(void *s, size_t len)
- {
- #if defined(WITH_OPENSSL) && defined(OPENSSL_PRNG_ONLY)
- if (RAND_bytes(s, len) <= 0)
- fatal("Couldn't obtain random bytes (error 0x%lx)",
- (unsigned long)ERR_get_error());
- #else
- int fd, save_errno;
- ssize_t r;
- size_t o = 0;
-
- #ifdef WITH_OPENSSL
- if (RAND_bytes(s, len) == 1)
- return 0;
- #endif
- #ifdef HAVE_GETENTROPY
- if ((r = getentropy(s, len)) == 0)
- return 0;
- #endif /* HAVE_GETENTROPY */
- #ifdef HAVE_GETRANDOM
- if ((r = getrandom(s, len, 0)) > 0 && (size_t)r == len)
- return 0;
- #endif /* HAVE_GETRANDOM */
-
- if ((fd = open(SSH_RANDOM_DEV, O_RDONLY)) == -1) {
- save_errno = errno;
- /* Try egd/prngd before giving up. */
- if (seed_from_prngd(s, len) == 0)
- return 0;
- fatal("Couldn't open %s: %s", SSH_RANDOM_DEV,
- strerror(save_errno));
- }
- while (o < len) {
- r = read(fd, (u_char *)s + o, len - o);
- if (r < 0) {
- if (errno == EAGAIN || errno == EINTR ||
- errno == EWOULDBLOCK)
- continue;
- fatal("read %s: %s", SSH_RANDOM_DEV, strerror(errno));
- }
- o += r;
- }
- close(fd);
- #endif /* WITH_OPENSSL */
- return 0;
- }
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