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102 err("the primary key was revoked!\n");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 err("the primary key can be used for authentication\n");
122 algo = gnutls_openpgp_crt_get_pk_algorithm(openpgp_crt, &bits);
124 err("failed to get the algorithm of the OpenPGP public key (error: %d)\n", algo);
126 } else if (algo == GNUTLS_PK_RSA) {
128 err("OpenPGP RSA certificate, with %d bits\n", bits);
129 ret = gnutls_openpgp_crt_get_pk_rsa_raw(openpgp_crt, &m, &e);
130 if (GNUTLS_E_SUCCESS != ret) {
131 err ("failed to export RSA key parameters (error: %d)\n", ret);
134 } else if (algo == GNUTLS_PK_DSA) {
135 err("OpenPGP DSA Key, with %d bits\n", bits);
136 ret = gnutls_openpgp_crt_get_pk_dsa_raw(openpgp_crt, &p, &q, &g, &y);
137 if (GNUTLS_E_SUCCESS != ret) {
138 err ("failed to export DSA key parameters (error: %d)\n", ret);
142 err("OpenPGP Key was not RSA or DSA -- can't deal! (actual algorithm was: %d)\n", algo);
147 err("primary key is only good for: 0x%08x. Trying subkeys...\n", usage);
149 if (ret = gnutls_openpgp_crt_get_auth_subkey(openpgp_crt, keyid, 0), ret) {
150 err("failed to find a subkey capable of authentication (error: %d)\n", ret);
153 make_keyid_printable(p_keyid, keyid);
154 err("found authentication subkey %.16s\n", p_keyid);
156 ret = gnutls_openpgp_crt_get_subkey_idx(openpgp_crt, keyid);
158 err("could not get the index of subkey %.16s (error: %d)\n", ret);
163 if (gnutls_openpgp_crt_get_subkey_revoked_status(openpgp_crt, keyidx)) {
164 err("The authentication subkey was revoked!\n");
168 if (ret = gnutls_openpgp_crt_get_subkey_usage(openpgp_crt, keyidx, &usage), ret) {
169 err("could not figure out usage of subkey %.16s (error: %d)\n", p_keyid, ret);
172 if ((usage & GNUTLS_KEY_KEY_AGREEMENT) == 0) {
173 err("could not find a subkey with authentication privileges.\n");
177 /* switch, based on the algorithm in question, to extract the MPI
180 algo = gnutls_openpgp_crt_get_subkey_pk_algorithm(openpgp_crt, keyidx, &bits);
182 err("failed to get the algorithm of the authentication subkey (error: %d)\n", algo);
184 } else if (algo == GNUTLS_PK_RSA) {
186 err("OpenPGP RSA subkey, with %d bits\n", bits);
187 ret = gnutls_openpgp_crt_get_subkey_pk_rsa_raw(openpgp_crt, keyidx, &m, &e);
188 if (GNUTLS_E_SUCCESS != ret) {
189 err ("failed to export RSA subkey parameters (error: %d)\n", ret);
192 } else if (algo == GNUTLS_PK_DSA) {
193 err("OpenPGP DSA subkey, with %d bits\n", bits);
194 ret = gnutls_openpgp_crt_get_subkey_pk_dsa_raw(openpgp_crt, keyidx, &p, &q, &g, &y);
195 if (GNUTLS_E_SUCCESS != ret) {
196 err ("failed to export DSA subkey parameters (error: %d)\n", ret);
200 err("OpenPGP subkey was not RSA or DSA -- can't deal! (actual algorithm was: %d)\n", algo);
205 /* make sure userid is NULL-terminated */
206 userid[sizeof(userid) - 1] = 0;
209 /* FIXME: we're just choosing the first UserID from the certificate:
210 instead, we should be selecting every User ID that is adequately
211 signed and matches the spec, and aggregating them with commas for
212 known_hosts output */
214 if (ret = gnutls_openpgp_crt_get_name(openpgp_crt, 0, userid, &uidsz), ret) {
215 err("Failed to fetch the first UserID (error: %d)\n", ret);
219 if (ret = validate_ssh_host_userid(userid), ret) {
220 err("bad userid: not a valid ssh host.\n");
224 /* remove ssh:// from the beginning of userid */
225 memmove(userid, userid + strlen("ssh://"), 1 + strlen(userid) - strlen("ssh://"));
228 /* now we have algo, and the various MPI data are set. Can we
229 export them cleanly? */
231 /* for the moment, we'll just dump the info raw, and pipe it
232 externally through coreutils' /usr/bin/base64 */
234 if (algo == GNUTLS_PK_RSA) {
235 algoname = "ssh-rsa";
241 } else if (algo == GNUTLS_PK_DSA) {
242 algoname = "ssh-dss";
251 err("no idea what this algorithm is: %d\n", algo);
255 if (ret = datum_from_string(&algolabel, algoname), ret) {
256 err("couldn't label string (error: %d)\n", ret);
260 snprintf(output_data, sizeof(output_data), "%s %s ", userid, algoname);
262 pipefd = create_writing_pipe(&child_pid, args[0], args);
264 err("failed to create a writing pipe (returned %d)\n", pipefd);
268 write(1, output_data, strlen(output_data));
270 if (0 != write_data_fd_with_length(pipefd, all, mpicount)) {
271 err("was not able to write out RSA key data\n");
275 if (child_pid != waitpid(child_pid, &pipestatus, 0)) {
276 err("could not wait for child process to return for some reason.\n");
279 if (pipestatus != 0) {
280 err("base64 pipe died with return code %d\n", pipestatus);
288 gnutls_openpgp_crt_deinit(openpgp_crt);
289 gnutls_global_deinit();