upstream) and a number of security fixes which we had already backported. MFC after: 1 week
556 lines
13 KiB
C
556 lines
13 KiB
C
/* $OpenBSD: authfile.c,v 1.107 2014/06/24 01:13:21 djm Exp $ */
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/*
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* Copyright (c) 2000, 2013 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/param.h>
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#include <sys/uio.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdarg.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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#include "cipher.h"
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#include "key.h"
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#include "ssh.h"
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#include "log.h"
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#include "authfile.h"
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#include "rsa.h"
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#include "misc.h"
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#include "atomicio.h"
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#include "sshbuf.h"
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#include "ssherr.h"
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#define MAX_KEY_FILE_SIZE (1024 * 1024)
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/* Save a key blob to a file */
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static int
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sshkey_save_private_blob(struct sshbuf *keybuf, const char *filename)
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{
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int fd, oerrno;
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if ((fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0)
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return SSH_ERR_SYSTEM_ERROR;
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if (atomicio(vwrite, fd, (u_char *)sshbuf_ptr(keybuf),
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sshbuf_len(keybuf)) != sshbuf_len(keybuf)) {
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oerrno = errno;
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close(fd);
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unlink(filename);
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errno = oerrno;
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return SSH_ERR_SYSTEM_ERROR;
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}
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close(fd);
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return 0;
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}
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int
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sshkey_save_private(struct sshkey *key, const char *filename,
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const char *passphrase, const char *comment,
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int force_new_format, const char *new_format_cipher, int new_format_rounds)
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{
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struct sshbuf *keyblob = NULL;
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int r;
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if ((keyblob = sshbuf_new()) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((r = sshkey_private_to_fileblob(key, keyblob, passphrase, comment,
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force_new_format, new_format_cipher, new_format_rounds)) != 0)
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goto out;
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if ((r = sshkey_save_private_blob(keyblob, filename)) != 0)
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goto out;
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r = 0;
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out:
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sshbuf_free(keyblob);
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return r;
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}
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/* Load a key from a fd into a buffer */
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int
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sshkey_load_file(int fd, const char *filename, struct sshbuf *blob)
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{
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u_char buf[1024];
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size_t len;
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struct stat st;
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int r;
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if (fstat(fd, &st) < 0)
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return SSH_ERR_SYSTEM_ERROR;
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if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
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st.st_size > MAX_KEY_FILE_SIZE)
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return SSH_ERR_INVALID_FORMAT;
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for (;;) {
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if ((len = atomicio(read, fd, buf, sizeof(buf))) == 0) {
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if (errno == EPIPE)
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break;
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r = SSH_ERR_SYSTEM_ERROR;
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goto out;
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}
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if ((r = sshbuf_put(blob, buf, len)) != 0)
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goto out;
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if (sshbuf_len(blob) > MAX_KEY_FILE_SIZE) {
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r = SSH_ERR_INVALID_FORMAT;
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goto out;
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}
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}
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if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
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st.st_size != (off_t)sshbuf_len(blob)) {
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r = SSH_ERR_FILE_CHANGED;
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goto out;
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}
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r = 0;
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out:
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explicit_bzero(buf, sizeof(buf));
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if (r != 0)
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sshbuf_reset(blob);
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return r;
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}
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#ifdef WITH_SSH1
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/*
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* Loads the public part of the ssh v1 key file. Returns NULL if an error was
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* encountered (the file does not exist or is not readable), and the key
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* otherwise.
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*/
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static int
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sshkey_load_public_rsa1(int fd, const char *filename,
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struct sshkey **keyp, char **commentp)
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{
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struct sshbuf *b = NULL;
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int r;
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*keyp = NULL;
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if (commentp != NULL)
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*commentp = NULL;
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if ((b = sshbuf_new()) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((r = sshkey_load_file(fd, filename, b)) != 0)
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goto out;
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if ((r = sshkey_parse_public_rsa1_fileblob(b, keyp, commentp)) != 0)
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goto out;
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r = 0;
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out:
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sshbuf_free(b);
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return r;
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}
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#endif /* WITH_SSH1 */
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#ifdef WITH_OPENSSL
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/* XXX Deprecate? */
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int
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sshkey_load_private_pem(int fd, int type, const char *passphrase,
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struct sshkey **keyp, char **commentp)
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{
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struct sshbuf *buffer = NULL;
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int r;
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*keyp = NULL;
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if (commentp != NULL)
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*commentp = NULL;
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if ((buffer = sshbuf_new()) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((r = sshkey_load_file(fd, NULL, buffer)) != 0)
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goto out;
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if ((r = sshkey_parse_private_pem_fileblob(buffer, type, passphrase,
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keyp, commentp)) != 0)
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goto out;
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r = 0;
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out:
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sshbuf_free(buffer);
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return r;
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}
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#endif /* WITH_OPENSSL */
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/* XXX remove error() calls from here? */
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int
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sshkey_perm_ok(int fd, const char *filename)
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{
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struct stat st;
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if (fstat(fd, &st) < 0)
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return SSH_ERR_SYSTEM_ERROR;
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/*
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* if a key owned by the user is accessed, then we check the
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* permissions of the file. if the key owned by a different user,
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* then we don't care.
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*/
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#ifdef HAVE_CYGWIN
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if (check_ntsec(filename))
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#endif
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if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
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error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
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error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
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error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
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error("Permissions 0%3.3o for '%s' are too open.",
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(u_int)st.st_mode & 0777, filename);
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error("It is recommended that your private key files are NOT accessible by others.");
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error("This private key will be ignored.");
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return SSH_ERR_KEY_BAD_PERMISSIONS;
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}
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return 0;
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}
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/* XXX kill perm_ok now that we have SSH_ERR_KEY_BAD_PERMISSIONS? */
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int
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sshkey_load_private_type(int type, const char *filename, const char *passphrase,
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struct sshkey **keyp, char **commentp, int *perm_ok)
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{
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int fd, r;
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struct sshbuf *buffer = NULL;
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*keyp = NULL;
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if (commentp != NULL)
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*commentp = NULL;
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if ((fd = open(filename, O_RDONLY)) < 0) {
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if (perm_ok != NULL)
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*perm_ok = 0;
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return SSH_ERR_SYSTEM_ERROR;
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}
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if (sshkey_perm_ok(fd, filename) != 0) {
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if (perm_ok != NULL)
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*perm_ok = 0;
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r = SSH_ERR_KEY_BAD_PERMISSIONS;
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goto out;
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}
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if (perm_ok != NULL)
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*perm_ok = 1;
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if ((buffer = sshbuf_new()) == NULL) {
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r = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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if ((r = sshkey_load_file(fd, filename, buffer)) != 0)
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goto out;
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if ((r = sshkey_parse_private_fileblob_type(buffer, type, passphrase,
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keyp, commentp)) != 0)
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goto out;
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r = 0;
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out:
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close(fd);
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if (buffer != NULL)
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sshbuf_free(buffer);
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return r;
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}
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/* XXX this is almost identical to sshkey_load_private_type() */
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int
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sshkey_load_private(const char *filename, const char *passphrase,
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struct sshkey **keyp, char **commentp)
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{
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struct sshbuf *buffer = NULL;
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int r, fd;
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*keyp = NULL;
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if (commentp != NULL)
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*commentp = NULL;
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if ((fd = open(filename, O_RDONLY)) < 0)
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return SSH_ERR_SYSTEM_ERROR;
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if (sshkey_perm_ok(fd, filename) != 0) {
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r = SSH_ERR_KEY_BAD_PERMISSIONS;
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goto out;
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}
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if ((buffer = sshbuf_new()) == NULL) {
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r = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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if ((r = sshkey_load_file(fd, filename, buffer)) != 0 ||
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(r = sshkey_parse_private_fileblob(buffer, passphrase, filename,
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keyp, commentp)) != 0)
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goto out;
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r = 0;
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out:
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close(fd);
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if (buffer != NULL)
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sshbuf_free(buffer);
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return r;
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}
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static int
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sshkey_try_load_public(struct sshkey *k, const char *filename, char **commentp)
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{
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FILE *f;
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char line[SSH_MAX_PUBKEY_BYTES];
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char *cp;
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u_long linenum = 0;
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int r;
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if (commentp != NULL)
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*commentp = NULL;
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if ((f = fopen(filename, "r")) == NULL)
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return SSH_ERR_SYSTEM_ERROR;
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while (read_keyfile_line(f, filename, line, sizeof(line),
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&linenum) != -1) {
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cp = line;
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switch (*cp) {
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case '#':
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case '\n':
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case '\0':
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continue;
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}
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/* Abort loading if this looks like a private key */
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if (strncmp(cp, "-----BEGIN", 10) == 0 ||
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strcmp(cp, "SSH PRIVATE KEY FILE") == 0)
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break;
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/* Skip leading whitespace. */
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for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
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;
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if (*cp) {
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if ((r = sshkey_read(k, &cp)) == 0) {
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cp[strcspn(cp, "\r\n")] = '\0';
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if (commentp) {
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*commentp = strdup(*cp ?
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cp : filename);
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if (*commentp == NULL)
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r = SSH_ERR_ALLOC_FAIL;
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}
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fclose(f);
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return r;
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}
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}
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}
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fclose(f);
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return SSH_ERR_INVALID_FORMAT;
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}
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/* load public key from ssh v1 private or any pubkey file */
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int
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sshkey_load_public(const char *filename, struct sshkey **keyp, char **commentp)
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{
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struct sshkey *pub = NULL;
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char file[MAXPATHLEN];
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int r, fd;
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if (keyp != NULL)
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*keyp = NULL;
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if (commentp != NULL)
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*commentp = NULL;
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if ((fd = open(filename, O_RDONLY)) < 0)
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goto skip;
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#ifdef WITH_SSH1
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/* try rsa1 private key */
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r = sshkey_load_public_rsa1(fd, filename, keyp, commentp);
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close(fd);
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switch (r) {
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case SSH_ERR_INTERNAL_ERROR:
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case SSH_ERR_ALLOC_FAIL:
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case SSH_ERR_INVALID_ARGUMENT:
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case SSH_ERR_SYSTEM_ERROR:
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case 0:
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return r;
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}
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#endif /* WITH_SSH1 */
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/* try ssh2 public key */
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if ((pub = sshkey_new(KEY_UNSPEC)) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((r = sshkey_try_load_public(pub, filename, commentp)) == 0) {
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if (keyp != NULL)
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*keyp = pub;
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return 0;
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}
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sshkey_free(pub);
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#ifdef WITH_SSH1
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/* try rsa1 public key */
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if ((pub = sshkey_new(KEY_RSA1)) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((r = sshkey_try_load_public(pub, filename, commentp)) == 0) {
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if (keyp != NULL)
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*keyp = pub;
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return 0;
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}
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sshkey_free(pub);
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#endif /* WITH_SSH1 */
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skip:
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/* try .pub suffix */
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if ((pub = sshkey_new(KEY_UNSPEC)) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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r = SSH_ERR_ALLOC_FAIL; /* in case strlcpy or strlcat fail */
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if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
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(strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
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(r = sshkey_try_load_public(pub, file, commentp)) == 0) {
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if (keyp != NULL)
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*keyp = pub;
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return 0;
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}
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sshkey_free(pub);
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return r;
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}
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/* Load the certificate associated with the named private key */
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int
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sshkey_load_cert(const char *filename, struct sshkey **keyp)
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{
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struct sshkey *pub = NULL;
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char *file = NULL;
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int r = SSH_ERR_INTERNAL_ERROR;
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*keyp = NULL;
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if (asprintf(&file, "%s-cert.pub", filename) == -1)
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return SSH_ERR_ALLOC_FAIL;
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if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
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goto out;
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}
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if ((r = sshkey_try_load_public(pub, file, NULL)) != 0)
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goto out;
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*keyp = pub;
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pub = NULL;
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r = 0;
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out:
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if (file != NULL)
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free(file);
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if (pub != NULL)
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sshkey_free(pub);
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return r;
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}
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/* Load private key and certificate */
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int
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sshkey_load_private_cert(int type, const char *filename, const char *passphrase,
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struct sshkey **keyp, int *perm_ok)
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{
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struct sshkey *key = NULL, *cert = NULL;
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int r;
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*keyp = NULL;
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switch (type) {
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#ifdef WITH_OPENSSL
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case KEY_RSA:
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case KEY_DSA:
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case KEY_ECDSA:
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case KEY_ED25519:
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#endif /* WITH_OPENSSL */
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case KEY_UNSPEC:
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break;
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default:
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return SSH_ERR_KEY_TYPE_UNKNOWN;
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}
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if ((r = sshkey_load_private_type(type, filename,
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passphrase, &key, NULL, perm_ok)) != 0 ||
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(r = sshkey_load_cert(filename, &cert)) != 0)
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goto out;
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/* Make sure the private key matches the certificate */
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if (sshkey_equal_public(key, cert) == 0) {
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r = SSH_ERR_KEY_CERT_MISMATCH;
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goto out;
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}
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if ((r = sshkey_to_certified(key, sshkey_cert_is_legacy(cert))) != 0 ||
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(r = sshkey_cert_copy(cert, key)) != 0)
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goto out;
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r = 0;
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*keyp = key;
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key = NULL;
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out:
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if (key != NULL)
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sshkey_free(key);
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if (cert != NULL)
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sshkey_free(cert);
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return r;
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}
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/*
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* Returns success if the specified "key" is listed in the file "filename",
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* SSH_ERR_KEY_NOT_FOUND: if the key is not listed or another error.
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* If strict_type is set then the key type must match exactly,
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* otherwise a comparison that ignores certficiate data is performed.
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*/
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int
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sshkey_in_file(struct sshkey *key, const char *filename, int strict_type)
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{
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FILE *f;
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char line[SSH_MAX_PUBKEY_BYTES];
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char *cp;
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u_long linenum = 0;
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int r = 0;
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struct sshkey *pub = NULL;
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int (*sshkey_compare)(const struct sshkey *, const struct sshkey *) =
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strict_type ? sshkey_equal : sshkey_equal_public;
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if ((f = fopen(filename, "r")) == NULL) {
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if (errno == ENOENT)
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return SSH_ERR_KEY_NOT_FOUND;
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else
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return SSH_ERR_SYSTEM_ERROR;
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}
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|
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while (read_keyfile_line(f, filename, line, sizeof(line),
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&linenum) != -1) {
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cp = line;
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|
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/* Skip leading whitespace. */
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|
for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
|
|
;
|
|
|
|
/* Skip comments and empty lines */
|
|
switch (*cp) {
|
|
case '#':
|
|
case '\n':
|
|
case '\0':
|
|
continue;
|
|
}
|
|
|
|
if ((pub = sshkey_new(KEY_UNSPEC)) == NULL) {
|
|
r = SSH_ERR_ALLOC_FAIL;
|
|
goto out;
|
|
}
|
|
if ((r = sshkey_read(pub, &cp)) != 0)
|
|
goto out;
|
|
if (sshkey_compare(key, pub)) {
|
|
r = 0;
|
|
goto out;
|
|
}
|
|
sshkey_free(pub);
|
|
pub = NULL;
|
|
}
|
|
r = SSH_ERR_KEY_NOT_FOUND;
|
|
out:
|
|
if (pub != NULL)
|
|
sshkey_free(pub);
|
|
fclose(f);
|
|
return r;
|
|
}
|
|
|