mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-24 11:29:10 +00:00
d4af9e693f
I have worked hard to reduce diffs against the vendor branch. One notable change in that respect is that we no longer prefer DSA over RSA - the reasons for doing so went away years ago. This may cause some surprises, as ssh will warn about unknown host keys even for hosts whose keys haven't changed. MFC after: 6 weeks
195 lines
5.2 KiB
C
195 lines
5.2 KiB
C
/*
|
|
* Copyright (c) 2001 Damien Miller. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#include "includes.h"
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/wait.h>
|
|
|
|
#ifdef HAVE_SYS_STAT_H
|
|
# include <sys/stat.h>
|
|
#endif
|
|
|
|
#ifdef HAVE_FCNTL_H
|
|
# include <fcntl.h>
|
|
#endif
|
|
#include <stdarg.h>
|
|
#include <string.h>
|
|
#include <signal.h>
|
|
#include <unistd.h>
|
|
|
|
#include <openssl/rand.h>
|
|
#include <openssl/crypto.h>
|
|
#include <openssl/err.h>
|
|
|
|
#include "ssh.h"
|
|
#include "misc.h"
|
|
#include "xmalloc.h"
|
|
#include "atomicio.h"
|
|
#include "pathnames.h"
|
|
#include "log.h"
|
|
#include "buffer.h"
|
|
|
|
/*
|
|
* Portable OpenSSH PRNG seeding:
|
|
* If OpenSSL has not "internally seeded" itself (e.g. pulled data from
|
|
* /dev/random), then we execute a "ssh-rand-helper" program which
|
|
* collects entropy and writes it to stdout. The child program must
|
|
* write at least RANDOM_SEED_SIZE bytes. The child is run with stderr
|
|
* attached, so error/debugging output should be visible.
|
|
*
|
|
* XXX: we should tell the child how many bytes we need.
|
|
*/
|
|
|
|
#ifndef OPENSSL_PRNG_ONLY
|
|
#define RANDOM_SEED_SIZE 48
|
|
static uid_t original_uid, original_euid;
|
|
#endif
|
|
|
|
void
|
|
seed_rng(void)
|
|
{
|
|
#ifndef OPENSSL_PRNG_ONLY
|
|
int devnull;
|
|
int p[2];
|
|
pid_t pid;
|
|
int ret;
|
|
unsigned char buf[RANDOM_SEED_SIZE];
|
|
mysig_t old_sigchld;
|
|
|
|
if (RAND_status() == 1) {
|
|
debug3("RNG is ready, skipping seeding");
|
|
return;
|
|
}
|
|
|
|
debug3("Seeding PRNG from %s", SSH_RAND_HELPER);
|
|
|
|
if ((devnull = open("/dev/null", O_RDWR)) == -1)
|
|
fatal("Couldn't open /dev/null: %s", strerror(errno));
|
|
if (pipe(p) == -1)
|
|
fatal("pipe: %s", strerror(errno));
|
|
|
|
old_sigchld = signal(SIGCHLD, SIG_DFL);
|
|
if ((pid = fork()) == -1)
|
|
fatal("Couldn't fork: %s", strerror(errno));
|
|
if (pid == 0) {
|
|
dup2(devnull, STDIN_FILENO);
|
|
dup2(p[1], STDOUT_FILENO);
|
|
/* Keep stderr open for errors */
|
|
close(p[0]);
|
|
close(p[1]);
|
|
close(devnull);
|
|
|
|
if (original_uid != original_euid &&
|
|
( seteuid(getuid()) == -1 ||
|
|
setuid(original_uid) == -1) ) {
|
|
fprintf(stderr, "(rand child) setuid(%li): %s\n",
|
|
(long int)original_uid, strerror(errno));
|
|
_exit(1);
|
|
}
|
|
|
|
execl(SSH_RAND_HELPER, "ssh-rand-helper", NULL);
|
|
fprintf(stderr, "(rand child) Couldn't exec '%s': %s\n",
|
|
SSH_RAND_HELPER, strerror(errno));
|
|
_exit(1);
|
|
}
|
|
|
|
close(devnull);
|
|
close(p[1]);
|
|
|
|
memset(buf, '\0', sizeof(buf));
|
|
ret = atomicio(read, p[0], buf, sizeof(buf));
|
|
if (ret == -1)
|
|
fatal("Couldn't read from ssh-rand-helper: %s",
|
|
strerror(errno));
|
|
if (ret != sizeof(buf))
|
|
fatal("ssh-rand-helper child produced insufficient data");
|
|
|
|
close(p[0]);
|
|
|
|
if (waitpid(pid, &ret, 0) == -1)
|
|
fatal("Couldn't wait for ssh-rand-helper completion: %s",
|
|
strerror(errno));
|
|
signal(SIGCHLD, old_sigchld);
|
|
|
|
/* We don't mind if the child exits upon a SIGPIPE */
|
|
if (!WIFEXITED(ret) &&
|
|
(!WIFSIGNALED(ret) || WTERMSIG(ret) != SIGPIPE))
|
|
fatal("ssh-rand-helper terminated abnormally");
|
|
if (WEXITSTATUS(ret) != 0)
|
|
fatal("ssh-rand-helper exit with exit status %d", ret);
|
|
|
|
RAND_add(buf, sizeof(buf), sizeof(buf));
|
|
memset(buf, '\0', sizeof(buf));
|
|
|
|
#endif /* OPENSSL_PRNG_ONLY */
|
|
if (RAND_status() != 1)
|
|
fatal("PRNG is not seeded");
|
|
}
|
|
|
|
void
|
|
init_rng(void)
|
|
{
|
|
/*
|
|
* OpenSSL version numbers: MNNFFPPS: major minor fix patch status
|
|
* We match major, minor, fix and status (not patch)
|
|
*/
|
|
if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L)
|
|
fatal("OpenSSL version mismatch. Built against %lx, you "
|
|
"have %lx", OPENSSL_VERSION_NUMBER, SSLeay());
|
|
|
|
#ifndef OPENSSL_PRNG_ONLY
|
|
original_uid = getuid();
|
|
original_euid = geteuid();
|
|
#endif
|
|
}
|
|
|
|
#ifndef OPENSSL_PRNG_ONLY
|
|
void
|
|
rexec_send_rng_seed(Buffer *m)
|
|
{
|
|
u_char buf[RANDOM_SEED_SIZE];
|
|
|
|
if (RAND_bytes(buf, sizeof(buf)) <= 0) {
|
|
error("Couldn't obtain random bytes (error %ld)",
|
|
ERR_get_error());
|
|
buffer_put_string(m, "", 0);
|
|
} else
|
|
buffer_put_string(m, buf, sizeof(buf));
|
|
}
|
|
|
|
void
|
|
rexec_recv_rng_seed(Buffer *m)
|
|
{
|
|
u_char *buf;
|
|
u_int len;
|
|
|
|
buf = buffer_get_string_ret(m, &len);
|
|
if (buf != NULL) {
|
|
debug3("rexec_recv_rng_seed: seeding rng with %u bytes", len);
|
|
RAND_add(buf, len, len);
|
|
}
|
|
}
|
|
#endif
|