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|
/* $OpenBSD: authfile.c,v 1.130 2018/07/09 21:59:10 markus Exp $ */
/*
* Copyright (c) 2000, 2013 Markus Friedl. 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/stat.h>
#include <sys/uio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include "cipher.h"
#include "ssh.h"
#include "log.h"
#include "authfile.h"
#include "misc.h"
#include "atomicio.h"
#include "sshkey.h"
#include "sshbuf.h"
#include "ssherr.h"
#include "krl.h"
#define MAX_KEY_FILE_SIZE (1024 * 1024)
/* Save a key blob to a file */
static int
sshkey_save_private_blob(struct sshbuf *keybuf, const char *filename)
{
int fd, oerrno;
if ((fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0)
return SSH_ERR_SYSTEM_ERROR;
if (atomicio(vwrite, fd, sshbuf_mutable_ptr(keybuf),
sshbuf_len(keybuf)) != sshbuf_len(keybuf)) {
oerrno = errno;
close(fd);
unlink(filename);
errno = oerrno;
return SSH_ERR_SYSTEM_ERROR;
}
close(fd);
return 0;
}
int
sshkey_save_private(struct sshkey *key, const char *filename,
const char *passphrase, const char *comment,
int force_new_format, const char *new_format_cipher, int new_format_rounds)
{
struct sshbuf *keyblob = NULL;
int r;
if ((keyblob = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_private_to_fileblob(key, keyblob, passphrase, comment,
force_new_format, new_format_cipher, new_format_rounds)) != 0)
goto out;
if ((r = sshkey_save_private_blob(keyblob, filename)) != 0)
goto out;
r = 0;
out:
sshbuf_free(keyblob);
return r;
}
/* Load a key from a fd into a buffer */
int
sshkey_load_file(int fd, struct sshbuf *blob)
{
u_char buf[1024];
size_t len;
struct stat st;
int r;
if (fstat(fd, &st) < 0)
return SSH_ERR_SYSTEM_ERROR;
if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
st.st_size > MAX_KEY_FILE_SIZE)
return SSH_ERR_INVALID_FORMAT;
for (;;) {
if ((len = atomicio(read, fd, buf, sizeof(buf))) == 0) {
if (errno == EPIPE)
break;
r = SSH_ERR_SYSTEM_ERROR;
goto out;
}
if ((r = sshbuf_put(blob, buf, len)) != 0)
goto out;
if (sshbuf_len(blob) > MAX_KEY_FILE_SIZE) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
}
if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
st.st_size != (off_t)sshbuf_len(blob)) {
r = SSH_ERR_FILE_CHANGED;
goto out;
}
r = 0;
out:
explicit_bzero(buf, sizeof(buf));
if (r != 0)
sshbuf_reset(blob);
return r;
}
/* XXX remove error() calls from here? */
int
sshkey_perm_ok(int fd, const char *filename)
{
struct stat st;
if (fstat(fd, &st) < 0)
return SSH_ERR_SYSTEM_ERROR;
/*
* if a key owned by the user is accessed, then we check the
* permissions of the file. if the key owned by a different user,
* then we don't care.
*/
#ifdef HAVE_CYGWIN
if (check_ntsec(filename))
#endif
if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("Permissions 0%3.3o for '%s' are too open.",
(u_int)st.st_mode & 0777, filename);
error("It is required that your private key files are NOT accessible by others.");
error("This private key will be ignored.");
return SSH_ERR_KEY_BAD_PERMISSIONS;
}
return 0;
}
/* XXX kill perm_ok now that we have SSH_ERR_KEY_BAD_PERMISSIONS? */
int
sshkey_load_private_type(int type, const char *filename, const char *passphrase,
struct sshkey **keyp, char **commentp, int *perm_ok)
{
int fd, r;
if (keyp != NULL)
*keyp = NULL;
if (commentp != NULL)
*commentp = NULL;
if ((fd = open(filename, O_RDONLY)) < 0) {
if (perm_ok != NULL)
*perm_ok = 0;
return SSH_ERR_SYSTEM_ERROR;
}
if (sshkey_perm_ok(fd, filename) != 0) {
if (perm_ok != NULL)
*perm_ok = 0;
r = SSH_ERR_KEY_BAD_PERMISSIONS;
goto out;
}
if (perm_ok != NULL)
*perm_ok = 1;
r = sshkey_load_private_type_fd(fd, type, passphrase, keyp, commentp);
if (r == 0 && keyp && *keyp)
r = sshkey_set_filename(*keyp, filename);
out:
close(fd);
return r;
}
int
sshkey_load_private_type_fd(int fd, int type, const char *passphrase,
struct sshkey **keyp, char **commentp)
{
struct sshbuf *buffer = NULL;
int r;
if (keyp != NULL)
*keyp = NULL;
if ((buffer = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshkey_load_file(fd, buffer)) != 0 ||
(r = sshkey_parse_private_fileblob_type(buffer, type,
passphrase, keyp, commentp)) != 0)
goto out;
/* success */
r = 0;
out
|