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7e2f51940b
Since arc4random seeds from getentropy, and we use OpenSSL for that if enabled, there's the possibility that if we build on a system that does not have getentropy then run on a system that does have it, then OpenSSL could end up calling our getentropy and getting stuck in a loop. Pointed out by deraadt@, ok djm@
83 lines
2.2 KiB
C
83 lines
2.2 KiB
C
/*
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* Copyright (c) 1996, David Mazieres <dm@uun.org>
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* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
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* Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#ifndef HAVE_GETENTROPY
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#ifndef SSH_RANDOM_DEV
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# define SSH_RANDOM_DEV "/dev/urandom"
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#endif /* SSH_RANDOM_DEV */
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#include <sys/types.h>
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#ifdef HAVE_SYS_RANDOM_H
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# include <sys/random.h>
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#endif
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#ifdef WITH_OPENSSL
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#include <openssl/rand.h>
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#include <openssl/err.h>
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#endif
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#include "log.h"
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int
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_ssh_compat_getentropy(void *s, size_t len)
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{
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#ifdef WITH_OPENSSL
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if (RAND_bytes(s, len) <= 0)
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fatal("Couldn't obtain random bytes (error 0x%lx)",
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(unsigned long)ERR_get_error());
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#else
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int fd, save_errno;
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ssize_t r;
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size_t o = 0;
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#ifdef HAVE_GETRANDOM
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if ((r = getrandom(s, len, 0)) > 0 && (size_t)r == len)
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return 0;
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#endif /* HAVE_GETRANDOM */
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if ((fd = open(SSH_RANDOM_DEV, O_RDONLY)) == -1) {
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save_errno = errno;
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/* Try egd/prngd before giving up. */
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if (seed_from_prngd(s, len) == 0)
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return 0;
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fatal("Couldn't open %s: %s", SSH_RANDOM_DEV,
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strerror(save_errno));
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}
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while (o < len) {
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r = read(fd, (u_char *)s + o, len - o);
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if (r < 0) {
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if (errno == EAGAIN || errno == EINTR ||
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errno == EWOULDBLOCK)
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continue;
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fatal("read %s: %s", SSH_RANDOM_DEV, strerror(errno));
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}
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o += r;
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}
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close(fd);
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#endif /* WITH_OPENSSL */
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return 0;
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}
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#endif /* WITH_GETENTROPY */
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