diff options
Diffstat (limited to 'usr.bin/ssh/ssh-keysign.c')
| -rw-r--r-- | usr.bin/ssh/ssh-keysign.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/usr.bin/ssh/ssh-keysign.c b/usr.bin/ssh/ssh-keysign.c new file mode 100644 index 00000000000..a309852d3d7 --- /dev/null +++ b/usr.bin/ssh/ssh-keysign.c @@ -0,0 +1,185 @@ +/* + * Copyright (c) 2002 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" +RCSID("$OpenBSD: ssh-keysign.c,v 1.1 2002/05/23 19:24:30 markus Exp $"); + +#include <openssl/evp.h> + +#include "log.h" +#include "key.h" +#include "ssh2.h" +#include "misc.h" +#include "xmalloc.h" +#include "buffer.h" +#include "bufaux.h" +#include "authfile.h" +#include "msg.h" +#include "pathnames.h" + +static int +valid_request(struct passwd *pw, Key **ret, u_char *data, u_int datalen) +{ + Buffer b; + Key *key; + u_char *p, *pkblob; + u_int blen; + char *pkalg; + int pktype, fail; + + fail = 0; + + buffer_init(&b); + buffer_append(&b, data, datalen); + + /* session id */ + buffer_skip_string(&b); + if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) + fail++; + + /* server user */ + buffer_skip_string(&b); + + /* service */ + p = buffer_get_string(&b, NULL); + if (strcmp("ssh-connection", p) != 0) + fail++; + xfree(p); + + /* method */ + p = buffer_get_string(&b, NULL); + if (strcmp("hostbased", p) != 0) + fail++; + xfree(p); + + /* pubkey */ + pkalg = buffer_get_string(&b, NULL); + pkblob = buffer_get_string(&b, &blen); + + pktype = key_type_from_name(pkalg); + if (pktype == KEY_UNSPEC) + fail++; + else if ((key = key_from_blob(pkblob, blen)) == NULL) + fail++; + else if (key->type != pktype) + fail++; + xfree(pkalg); + xfree(pkblob); + + /* chost */ + buffer_skip_string(&b); + + /* local user */ + p = buffer_get_string(&b, NULL); + if (strcmp(pw->pw_name, p) != 0) + fail++; + xfree(p); + + /* end of message */ + if (buffer_len(&b) != 0) + fail++; + + debug3("valid_request: fail %d", fail); + + if (fail && key != NULL) + key_free(key); + else + *ret = key; + + return (fail ? -1 : 0); +} + +int +main(int argc, char **argv) +{ + Buffer b; + Key *keys[2], *key; + struct passwd *pw; + int key_fd[2], i, found, version = 1; + u_char *signature, *data; + u_int slen, dlen; + + key_fd[0] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY); + key_fd[1] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY); + + seteuid(getuid()); + setuid(getuid()); + +#ifdef DEBUG_SSH_KEYSIGN + log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0); +#endif + + if (key_fd[0] == -1 && key_fd[1] == -1) + fatal("could not open any host key"); + + if ((pw = getpwuid(getuid())) == NULL) + fatal("getpwuid failed"); + pw = pwcopy(pw); + + SSLeay_add_all_algorithms(); + + found = 0; + for (i = 0; i < 2; i++) { + keys[i] = NULL; + if (key_fd[i] == -1) + continue; + keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC, + NULL, NULL); + close(key_fd[i]); + if (keys[i] != NULL) + found = 1; + } + if (!found) + fatal("no hostkey found"); + + buffer_init(&b); + if (msg_recv(STDIN_FILENO, &b) < 0) + fatal("msg_recv failed"); + if (buffer_get_char(&b) != version) + fatal("bad version"); + data = buffer_get_string(&b, &dlen); + if (valid_request(pw, &key, data, dlen) < 0) + fatal("not a valid request"); + xfree(data); + + found = 0; + for (i = 0; i < 2; i++) { + if (keys[i] != NULL && + key_equal(key, keys[i])) { + found = 1; + break; + } + } + if (!found) + fatal("no matching hostkey found"); + + if (key_sign(keys[i], &signature, &slen, data, dlen) != 0) + fatal("key_sign failed"); + + /* send reply */ + buffer_clear(&b); + buffer_put_string(&b, signature, slen); + msg_send(STDOUT_FILENO, version, &b); + + return (0); +} |