diff options
author | Daniel Kahn Gillmor <dkg@fifthhorseman.net> | 2008-06-12 13:31:13 -0400 |
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committer | Daniel Kahn Gillmor <dkg@fifthhorseman.net> | 2008-06-12 13:31:13 -0400 |
commit | 00719770b7608af0c37dfd6c14a04eb7ebc4cad0 (patch) | |
tree | c698e08c03c93cbc81cb23434445035c083e2a6c /src/keytrans/gpg2ssh.c | |
parent | e2314e2105e02ec0d2684a3b68b9187982ca812b (diff) |
reorganizing to prepare for transition to openpgp2ssh.
Diffstat (limited to 'src/keytrans/gpg2ssh.c')
-rw-r--r-- | src/keytrans/gpg2ssh.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/src/keytrans/gpg2ssh.c b/src/keytrans/gpg2ssh.c new file mode 100644 index 0000000..c99f03f --- /dev/null +++ b/src/keytrans/gpg2ssh.c @@ -0,0 +1,293 @@ +#include "gnutls-helpers.h" + +#include <gnutls/openpgp.h> +#include <gnutls/x509.h> + +/* for waitpid() */ +#include <sys/types.h> +#include <sys/wait.h> + +/* + Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net> + Date: Tue, 08 Apr 2008 + License: GPL v3 or later + + monkeysphere public key translator: execute this with an GPG + certificate (public key(s) + userid(s)) on stdin. It currently + only works with RSA keys. + + It will spit out a version of the first key capable of being used + for authentication on stdout. The output format should be suitable + for appending a known_hosts file. + + Requirements: I've only built this so far with GnuTLS v2.3.4 -- + version 2.2.0 does not contain the appropriate pieces. + + */ + +int main(int argc, char* argv[]) { + gnutls_datum_t data; + int ret; + gnutls_openpgp_crt_t openpgp_crt; + gnutls_openpgp_keyid_t keyid; + printable_keyid p_keyid; + unsigned int keyidx; + unsigned int usage, bits; + gnutls_pk_algorithm_t algo; + + gnutls_datum_t m, e, p, q, g, y; + gnutls_datum_t algolabel; + + char output_data[10240]; + char userid[10240]; + size_t uidsz = sizeof(userid); + + const gnutls_datum_t* all[5]; + int pipefd; + pid_t child_pid; + char* const args[] = {"/usr/bin/base64", "--wrap=0", NULL}; + const char* algoname; + int mpicount; + int pipestatus; + + init_gnutls(); + + init_datum(&data); + + init_datum(&m); + init_datum(&e); + init_datum(&p); + init_datum(&q); + init_datum(&g); + init_datum(&y); + + init_datum(&algolabel); + + init_keyid(keyid); + + /* slurp in the private key from stdin */ + if (ret = set_datum_fd(&data, 0), ret) { + err("didn't read file descriptor 0\n"); + return 1; + } + + + if (ret = gnutls_openpgp_crt_init(&openpgp_crt), ret) { + err("Failed to initialize OpenPGP certificate (error: %d)\n", ret); + return 1; + } + + /* format could be either: GNUTLS_OPENPGP_FMT_RAW, + GNUTLS_OPENPGP_FMT_BASE64; if MONKEYSPHERE_RAW is set, use RAW, + otherwise, use BASE64: */ + + /* FIXME: we should be auto-detecting the input format, and + translating it as needed. */ + + if (getenv("MONKEYSPHERE_RAW")) { + err("assuming RAW formatted certificate\n"); + if (ret = gnutls_openpgp_crt_import(openpgp_crt, &data, GNUTLS_OPENPGP_FMT_RAW), ret) { + err("failed to import the OpenPGP certificate in RAW format (error: %d)\n", ret); + return ret; + } + } else { + err("assuming BASE64 formatted certificate\n"); + if (ret = gnutls_openpgp_crt_import (openpgp_crt, &data, GNUTLS_OPENPGP_FMT_BASE64), ret) { + err("failed to import the OpenPGP certificate in BASE64 format (error: %d)\n", ret); + return ret; + } + } + + if (gnutls_openpgp_crt_get_revoked_status(openpgp_crt)) { + err("the primary key was revoked!\n"); + return 1; + } + + /* FIXME: We're currently looking at the primary key or maybe the + first authentication-capable subkey. + + Instead, we should be iterating through the primary key and all + subkeys: for each one with the authentication usage flag set of a + algorithm we can handle, we should output matching UserIDs and + the SSH version of the key. */ + + + if (ret = gnutls_openpgp_crt_get_key_usage(openpgp_crt, &usage), ret) { + err("failed to get the usage flags for the primary key (error: %d)\n", ret); + return ret; + } + if (usage & GNUTLS_KEY_KEY_AGREEMENT && + usage & GNUTLS_KEY_KEY_ENCIPHERMENT) { + err("the primary key can be used for authentication and communication encryption!\n"); + + algo = gnutls_openpgp_crt_get_pk_algorithm(openpgp_crt, &bits); + if (algo < 0) { + err("failed to get the algorithm of the OpenPGP public key (error: %d)\n", algo); + return algo; + } else if (algo == GNUTLS_PK_RSA) { + + err("OpenPGP RSA certificate, with %d bits\n", bits); + ret = gnutls_openpgp_crt_get_pk_rsa_raw(openpgp_crt, &m, &e); + if (GNUTLS_E_SUCCESS != ret) { + err ("failed to export RSA key parameters (error: %d)\n", ret); + return 1; + } + } else if (algo == GNUTLS_PK_DSA) { + err("OpenPGP DSA Key, with %d bits\n", bits); + ret = gnutls_openpgp_crt_get_pk_dsa_raw(openpgp_crt, &p, &q, &g, &y); + if (GNUTLS_E_SUCCESS != ret) { + err ("failed to export DSA key parameters (error: %d)\n", ret); + return 1; + } + } else { + err("OpenPGP Key was not RSA or DSA -- can't deal! (actual algorithm was: %d)\n", algo); + return 1; + } + + } else { + err("primary key is not good for authentication and communication encryption. Trying subkeys...\n"); + + if (ret = gnutls_openpgp_crt_get_auth_subkey(openpgp_crt, keyid, 0), ret) { + err("failed to find a subkey capable of authentication and communication encryption (error: %d)\n", ret); + return ret; + } + make_keyid_printable(p_keyid, keyid); + err("found authentication subkey %.16s\n", p_keyid); + + ret = gnutls_openpgp_crt_get_subkey_idx(openpgp_crt, keyid); + if (ret < 0) { + err("could not get the index of subkey %.16s (error: %d)\n", ret); + return ret; + } + keyidx = ret; + + if (gnutls_openpgp_crt_get_subkey_revoked_status(openpgp_crt, keyidx)) { + err("The authentication subkey was revoked!\n"); + return 1; + } + + if (ret = gnutls_openpgp_crt_get_subkey_usage(openpgp_crt, keyidx, &usage), ret) { + err("could not figure out usage of subkey %.16s (error: %d)\n", p_keyid, ret); + return ret; + } + if ((usage & GNUTLS_KEY_KEY_AGREEMENT) == 0 && + usage & GNUTLS_KEY_KEY_ENCIPHERMENT) { + err("could not find a subkey with authentication and communication encryption.\n"); + return 1; + } + + /* switch, based on the algorithm in question, to extract the MPI + components: */ + + algo = gnutls_openpgp_crt_get_subkey_pk_algorithm(openpgp_crt, keyidx, &bits); + if (algo < 0) { + err("failed to get the algorithm of the authentication subkey (error: %d)\n", algo); + return algo; + } else if (algo == GNUTLS_PK_RSA) { + + err("OpenPGP RSA subkey, with %d bits\n", bits); + ret = gnutls_openpgp_crt_get_subkey_pk_rsa_raw(openpgp_crt, keyidx, &m, &e); + if (GNUTLS_E_SUCCESS != ret) { + err ("failed to export RSA subkey parameters (error: %d)\n", ret); + return 1; + } + } else if (algo == GNUTLS_PK_DSA) { + err("OpenPGP DSA subkey, with %d bits\n", bits); + ret = gnutls_openpgp_crt_get_subkey_pk_dsa_raw(openpgp_crt, keyidx, &p, &q, &g, &y); + if (GNUTLS_E_SUCCESS != ret) { + err ("failed to export DSA subkey parameters (error: %d)\n", ret); + return 1; + } + } else { + err("OpenPGP subkey was not RSA or DSA -- can't deal! (actual algorithm was: %d)\n", algo); + return 1; + } + } + + /* make sure userid is NULL-terminated */ + userid[sizeof(userid) - 1] = 0; + uidsz--; + + /* FIXME: we're just choosing the first UserID from the certificate: + instead, we should be selecting every User ID that is adequately + signed and matches the spec, and aggregating them with commas for + known_hosts output */ + + if (ret = gnutls_openpgp_crt_get_name(openpgp_crt, 0, userid, &uidsz), ret) { + err("Failed to fetch the first UserID (error: %d)\n", ret); + return ret; + } + + if (ret = validate_ssh_host_userid(userid), ret) { + err("bad userid: not a valid ssh host.\n"); + return ret; + } + + /* remove ssh:// from the beginning of userid */ + memmove(userid, userid + strlen("ssh://"), 1 + strlen(userid) - strlen("ssh://")); + + + /* now we have algo, and the various MPI data are set. Can we + export them cleanly? */ + + /* for the moment, we'll just dump the info raw, and pipe it + externally through coreutils' /usr/bin/base64 */ + + if (algo == GNUTLS_PK_RSA) { + algoname = "ssh-rsa"; + mpicount = 3; + + all[0] = &algolabel; + all[1] = &e; + all[2] = &m; + } else if (algo == GNUTLS_PK_DSA) { + algoname = "ssh-dss"; + mpicount = 5; + + all[0] = &algolabel; + all[1] = &p; + all[2] = &q; + all[3] = &g; + all[4] = &y; + } else { + err("no idea what this algorithm is: %d\n", algo); + return 1; + } + + if (ret = datum_from_string(&algolabel, algoname), ret) { + err("couldn't label string (error: %d)\n", ret); + return ret; + } + + snprintf(output_data, sizeof(output_data), "%s %s ", userid, algoname); + + pipefd = create_writing_pipe(&child_pid, args[0], args); + if (pipefd < 0) { + err("failed to create a writing pipe (returned %d)\n", pipefd); + return pipefd; + } + + write(1, output_data, strlen(output_data)); + + if (0 != write_data_fd_with_length(pipefd, all, mpicount)) { + err("was not able to write out RSA key data\n"); + return 1; + } + close(pipefd); + if (child_pid != waitpid(child_pid, &pipestatus, 0)) { + err("could not wait for child process to return for some reason.\n"); + return 1; + } + if (pipestatus != 0) { + err("base64 pipe died with return code %d\n", pipestatus); + return pipestatus; + } + + write(1, "\n", 1); + + + + gnutls_openpgp_crt_deinit(openpgp_crt); + gnutls_global_deinit(); + return 0; +} |