1 #include "gnutls-helpers.h"
3 #include <gnutls/openpgp.h>
4 #include <gnutls/x509.h>
11 Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
12 Date: Tue, 08 Apr 2008
13 License: GPL v3 or later
15 monkeysphere public key translator: execute this with an GPG
16 certificate (public key(s) + userid(s)) on stdin. It currently
17 only works with RSA keys.
19 It will spit out a version of the first key capable of being used
20 for authentication on stdout. The output format should be suitable
21 for appending a known_hosts file.
23 Requirements: I've only built this so far with GnuTLS v2.3.4 --
24 version 2.2.0 does not contain the appropriate pieces.
28 int main(int argc, char* argv[]) {
31 gnutls_openpgp_crt_t openpgp_crt;
32 gnutls_openpgp_keyid_t keyid;
33 printable_keyid p_keyid;
35 unsigned int usage, bits;
36 gnutls_pk_algorithm_t algo;
38 gnutls_datum_t m, e, p, q, g, y;
39 gnutls_datum_t algolabel;
41 char output_data[10240];
43 size_t uidsz = sizeof(userid);
45 const gnutls_datum_t* all[5];
48 char* const args[] = {"/usr/bin/base64", "--wrap=0", NULL};
64 init_datum(&algolabel);
68 /* slurp in the private key from stdin */
69 if (ret = set_datum_fd(&data, 0), ret) {
70 err("didn't read file descriptor 0\n");
75 if (ret = gnutls_openpgp_crt_init(&openpgp_crt), ret) {
76 err("Failed to initialize OpenPGP certificate (error: %d)\n", ret);
80 /* format could be either: GNUTLS_OPENPGP_FMT_RAW,
81 GNUTLS_OPENPGP_FMT_BASE64; if MONKEYSPHERE_RAW is set, use RAW,
82 otherwise, use BASE64: */
84 /* FIXME: we should be auto-detecting the input format, and
85 translating it as needed. */
87 if (getenv("MONKEYSPHERE_RAW")) {
88 err("assuming RAW formatted certificate\n");
89 if (ret = gnutls_openpgp_crt_import(openpgp_crt, &data, GNUTLS_OPENPGP_FMT_RAW), ret) {
90 err("failed to import the OpenPGP certificate in RAW format (error: %d)\n", ret);
94 err("assuming BASE64 formatted certificate\n");
95 if (ret = gnutls_openpgp_crt_import (openpgp_crt, &data, GNUTLS_OPENPGP_FMT_BASE64), ret) {
96 err("failed to import the OpenPGP certificate in BASE64 format (error: %d)\n", ret);
101 if (gnutls_openpgp_crt_get_revoked_status(openpgp_crt)) {
102 err("the primary key was revoked!\n");
106 /* FIXME: We're currently looking at the primary key or maybe the
107 first authentication-capable subkey.
109 Instead, we should be iterating through the primary key and all
110 subkeys: for each one with the authentication usage flag set of a
111 algorithm we can handle, we should output matching UserIDs and
112 the SSH version of the key. */
115 if (ret = gnutls_openpgp_crt_get_key_usage(openpgp_crt, &usage), ret) {
116 err("failed to get the usage flags for the primary key (error: %d)\n", ret);
119 if (usage & GNUTLS_KEY_KEY_AGREEMENT &&
120 usage & GNUTLS_KEY_KEY_ENCIPHERMENT) {
121 err("the primary key can be used for authentication and communication encryption!\n");
123 algo = gnutls_openpgp_crt_get_pk_algorithm(openpgp_crt, &bits);
125 err("failed to get the algorithm of the OpenPGP public key (error: %d)\n", algo);
127 } else if (algo == GNUTLS_PK_RSA) {
129 err("OpenPGP RSA certificate, with %d bits\n", bits);
130 ret = gnutls_openpgp_crt_get_pk_rsa_raw(openpgp_crt, &m, &e);
131 if (GNUTLS_E_SUCCESS != ret) {
132 err ("failed to export RSA key parameters (error: %d)\n", ret);
135 } else if (algo == GNUTLS_PK_DSA) {
136 err("OpenPGP DSA Key, with %d bits\n", bits);
137 ret = gnutls_openpgp_crt_get_pk_dsa_raw(openpgp_crt, &p, &q, &g, &y);
138 if (GNUTLS_E_SUCCESS != ret) {
139 err ("failed to export DSA key parameters (error: %d)\n", ret);
143 err("OpenPGP Key was not RSA or DSA -- can't deal! (actual algorithm was: %d)\n", algo);
148 err("primary key is not good for authentication and communication encryption. Trying subkeys...\n");
150 if (ret = gnutls_openpgp_crt_get_auth_subkey(openpgp_crt, keyid, 0), ret) {
151 err("failed to find a subkey capable of authentication and communication encryption (error: %d)\n", ret);
154 make_keyid_printable(p_keyid, keyid);
155 err("found authentication subkey %.16s\n", p_keyid);
157 ret = gnutls_openpgp_crt_get_subkey_idx(openpgp_crt, keyid);
159 err("could not get the index of subkey %.16s (error: %d)\n", ret);
164 if (gnutls_openpgp_crt_get_subkey_revoked_status(openpgp_crt, keyidx)) {
165 err("The authentication subkey was revoked!\n");
169 if (ret = gnutls_openpgp_crt_get_subkey_usage(openpgp_crt, keyidx, &usage), ret) {
170 err("could not figure out usage of subkey %.16s (error: %d)\n", p_keyid, ret);
173 if ((usage & GNUTLS_KEY_KEY_AGREEMENT) == 0 &&
174 usage & GNUTLS_KEY_KEY_ENCIPHERMENT) {
175 err("could not find a subkey with authentication and communication encryption.\n");
179 /* switch, based on the algorithm in question, to extract the MPI
182 algo = gnutls_openpgp_crt_get_subkey_pk_algorithm(openpgp_crt, keyidx, &bits);
184 err("failed to get the algorithm of the authentication subkey (error: %d)\n", algo);
186 } else if (algo == GNUTLS_PK_RSA) {
188 err("OpenPGP RSA subkey, with %d bits\n", bits);
189 ret = gnutls_openpgp_crt_get_subkey_pk_rsa_raw(openpgp_crt, keyidx, &m, &e);
190 if (GNUTLS_E_SUCCESS != ret) {
191 err ("failed to export RSA subkey parameters (error: %d)\n", ret);
194 } else if (algo == GNUTLS_PK_DSA) {
195 err("OpenPGP DSA subkey, with %d bits\n", bits);
196 ret = gnutls_openpgp_crt_get_subkey_pk_dsa_raw(openpgp_crt, keyidx, &p, &q, &g, &y);
197 if (GNUTLS_E_SUCCESS != ret) {
198 err ("failed to export DSA subkey parameters (error: %d)\n", ret);
202 err("OpenPGP subkey was not RSA or DSA -- can't deal! (actual algorithm was: %d)\n", algo);
207 /* make sure userid is NULL-terminated */
208 userid[sizeof(userid) - 1] = 0;
211 /* FIXME: we're just choosing the first UserID from the certificate:
212 instead, we should be selecting every User ID that is adequately
213 signed and matches the spec, and aggregating them with commas for
214 known_hosts output */
216 if (ret = gnutls_openpgp_crt_get_name(openpgp_crt, 0, userid, &uidsz), ret) {
217 err("Failed to fetch the first UserID (error: %d)\n", ret);
221 if (ret = validate_ssh_host_userid(userid), ret) {
222 err("bad userid: not a valid ssh host.\n");
226 /* remove ssh:// from the beginning of userid */
227 memmove(userid, userid + strlen("ssh://"), 1 + strlen(userid) - strlen("ssh://"));
230 /* now we have algo, and the various MPI data are set. Can we
231 export them cleanly? */
233 /* for the moment, we'll just dump the info raw, and pipe it
234 externally through coreutils' /usr/bin/base64 */
236 if (algo == GNUTLS_PK_RSA) {
237 algoname = "ssh-rsa";
243 } else if (algo == GNUTLS_PK_DSA) {
244 algoname = "ssh-dss";
253 err("no idea what this algorithm is: %d\n", algo);
257 if (ret = datum_from_string(&algolabel, algoname), ret) {
258 err("couldn't label string (error: %d)\n", ret);
262 snprintf(output_data, sizeof(output_data), "%s %s ", userid, algoname);
264 pipefd = create_writing_pipe(&child_pid, args[0], args);
266 err("failed to create a writing pipe (returned %d)\n", pipefd);
270 write(1, output_data, strlen(output_data));
272 if (0 != write_data_fd_with_length(pipefd, all, mpicount)) {
273 err("was not able to write out RSA key data\n");
277 if (child_pid != waitpid(child_pid, &pipestatus, 0)) {
278 err("could not wait for child process to return for some reason.\n");
281 if (pipestatus != 0) {
282 err("base64 pipe died with return code %d\n", pipestatus);
290 gnutls_openpgp_crt_deinit(openpgp_crt);
291 gnutls_global_deinit();