reorganizing to prepare for transition to openpgp2ssh.

6 files changed, 1190 insertions, 0 deletions

diff --git a/src/keytrans/Makefile b/src/keytrans/Makefile
new file mode 100644
index 0000000..fdd4ccd
--- /dev/null
+++ b/src/keytrans/Makefile
@@ -0,0 +1,19 @@
+all: openpgp2ssh
+
+openpgp2ssh: openpgp2ssh.c gnutls-helpers.o
+	gcc -g -Wall --pedantic -o openpgp2ssh openpgp2ssh.c `libgnutls-config --libs --cflags` -lgnutls-extra gnutls-helpers.o
+
+%.o: %.c
+	gcc -g -Wall --pedantic -o $@ -c $<
+
+clean: 
+	rm -f openpgp2ssh gpg2ssh ssh2gpg *.o
+
+# deprecated:
+gpg2ssh: gpg2ssh.c gnutls-helpers.o
+	gcc -g -Wall --pedantic -o gpg2ssh gpg2ssh.c `libgnutls-config --libs --cflags` -lgnutls-extra gnutls-helpers.o
+
+ssh2gpg: ssh2gpg.c gnutls-helpers.o
+	gcc -g -Wall --pedantic -o ssh2gpg ssh2gpg.c `libgnutls-config --libs --cflags` -lgnutls-extra gnutls-helpers.o
+
+.PHONY: clean all
diff --git a/src/keytrans/gnutls-helpers.c b/src/keytrans/gnutls-helpers.c
new file mode 100644
index 0000000..6eae29e
--- /dev/null
+++ b/src/keytrans/gnutls-helpers.c
@@ -0,0 +1,364 @@
+/* Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net> */
+/* Date: Fri, 04 Apr 2008 19:31:16 -0400 */
+/* License: GPL v3 or later */
+
+#include "gnutls-helpers.h"
+/* for htonl() */
+#include <arpa/inet.h>
+
+/* for setlocale() */
+#include <locale.h>
+
+/* for isalnum() */
+#include <ctype.h>
+
+int loglevel = 0;
+
+
+void err(const char* fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  vfprintf(stderr, fmt, ap);
+  va_end(ap);
+  fflush(stderr);
+}
+
+void logfunc(int level, const char* string) {
+  fprintf(stderr, "GnuTLS Logging (%d): %s\n", level, string);
+}
+
+void init_keyid(gnutls_openpgp_keyid_t keyid) {
+  memset(keyid, 'x', sizeof(gnutls_openpgp_keyid_t));
+}
+
+
+
+void make_keyid_printable(printable_keyid out, gnutls_openpgp_keyid_t keyid)
+{
+  static const char hex[16] = "0123456789ABCDEF";
+  unsigned int kix = 0, outix = 0;
+  
+  while (kix < sizeof(gnutls_openpgp_keyid_t)) {
+    out[outix] = hex[(keyid[kix] >> 4) & 0x0f];
+    out[outix + 1] = hex[keyid[kix] & 0x0f];
+    kix++;
+    outix += 2;
+  }
+}
+
+
+int init_gnutls() {
+  const char* version = NULL;
+  const char* debug_string = NULL;
+  int ret;
+
+  if (ret = gnutls_global_init(), ret) {
+    err("Failed to do gnutls_global_init() (error: %d)\n", ret);
+    return 1;
+  }
+
+  version = gnutls_check_version(NULL);
+
+  if (version) 
+    err("gnutls version: %s\n", version);
+  else {
+    err("no version found!\n");
+    return 1;
+  }
+
+  if (debug_string = getenv("MONKEYSPHERE_DEBUG"), debug_string) {
+    loglevel = atoi(debug_string);
+    gnutls_global_set_log_function(logfunc);
+    
+    gnutls_global_set_log_level(loglevel);
+    err("set log level to %d\n", loglevel);
+  }
+  return 0;
+}
+
+void init_datum(gnutls_datum_t* d) {
+  d->data = NULL;
+  d->size = 0;
+}
+void copy_datum(gnutls_datum_t* dest, const gnutls_datum_t* src) {
+  dest->data = gnutls_realloc(dest->data, src->size);
+  dest->size = src->size;
+  memcpy(dest->data, src->data, src->size);
+}
+int compare_data(const gnutls_datum_t* a, const gnutls_datum_t* b) {
+  if (a->size > b->size) {
+    err("a is larger\n");
+    return 1;
+  }
+  if (a->size < b->size) {
+    err("b is larger\n");
+    return -1;
+  }
+  return memcmp(a->data, b->data, a->size);
+}
+void free_datum(gnutls_datum_t* d) {
+  gnutls_free(d->data);
+  d->data = NULL;
+  d->size = 0;
+}
+
+/* read the passed-in string, store in a single datum */
+int set_datum_string(gnutls_datum_t* d, const char* s) {
+  unsigned int x = strlen(s)+1;
+  unsigned char* c = NULL;
+
+  c = gnutls_realloc(d->data, x);
+  if (NULL == c)
+    return -1;
+  d->data = c;
+  d->size = x;
+  memcpy(d->data, s, x);
+  return 0;
+}
+
+/* read the passed-in file descriptor until EOF, store in a single
+   datum */
+int set_datum_fd(gnutls_datum_t* d, int fd) {
+  unsigned int bufsize = 1024;
+  unsigned int len = 0;
+
+  FILE* f = fdopen(fd, "r");
+  if (bufsize > d->size) {
+    bufsize = 1024;
+    d->data = gnutls_realloc(d->data, bufsize);
+    if (d->data == NULL) {
+      err("out of memory!\n");
+      return -1;
+    }
+    d->size = bufsize;
+  } else {
+    bufsize = d->size;
+  }
+  f = fdopen(fd, "r");
+  if (NULL == f) {
+    err("could not fdopen FD %d\n", fd);
+  }
+  clearerr(f);
+  while (!feof(f) && !ferror(f)) { 
+    if (len == bufsize) {
+      /* allocate more space by doubling: */
+      bufsize *= 2;
+      d->data = gnutls_realloc(d->data, bufsize);
+      if (d->data == NULL) {
+	err("out of memory!\n"); 
+	return -1;
+      };
+      d->size = bufsize;
+    }
+    len += fread(d->data + len, 1, bufsize - len, f);
+    /*     err("read %d bytes\n", len); */
+  }
+  if (ferror(f)) {
+    err("Error reading from fd %d (error: %d) (error: %d '%s')\n", fd, ferror(f), errno, strerror(errno));
+    return -1;
+  }
+    
+  /* touch up buffer size to match reality: */
+  d->data = gnutls_realloc(d->data, len);
+  d->size = len;
+  return 0;
+}
+
+/* read the file indicated (by name) in the fname parameter.  store
+   its entire contents in a single datum. */
+int set_datum_file(gnutls_datum_t* d, const char* fname) {
+  struct stat sbuf;
+  unsigned char* c = NULL;
+  FILE* file = NULL;
+  size_t x = 0;
+
+  if (0 != stat(fname, &sbuf)) {
+    err("failed to stat '%s'\n", fname);
+    return -1;
+  }
+  
+  c = gnutls_realloc(d->data, sbuf.st_size);
+  if (NULL == c) {
+    err("failed to allocate %d bytes for '%s'\n", sbuf.st_size, fname);
+    return -1;
+  }
+
+  d->data = c;
+  d->size = sbuf.st_size;
+  file = fopen(fname, "r");
+  if (NULL == file) {
+    err("failed to open '%s' for reading\n",  fname);
+    return -1;
+  }
+
+  x = fread(d->data, d->size, 1, file);
+  if (x != 1) {
+    err("tried to read %d bytes, read %d instead from '%s'\n", d->size, x, fname);
+    fclose(file);
+    return -1;
+  }
+  fclose(file);
+  return 0;
+}
+
+int write_datum_fd(int fd, const gnutls_datum_t* d) {
+  if (d->size != write(fd, d->data, d->size)) {
+    err("failed to write body of datum.\n");
+    return -1;
+  }
+  return 0;
+}
+
+
+int write_datum_fd_with_length(int fd, const gnutls_datum_t* d) {
+  uint32_t len;
+  int looks_negative = (d->data[0] & 0x80);
+  unsigned char zero = 0;
+
+  /* if the first bit is 1, then the datum will appear negative in the
+     MPI encoding style used by OpenSSH.  In that case, we'll increase
+     the length by one, and dump out one more byte */
+
+  if (looks_negative) {
+    len = htonl(d->size + 1);
+  } else {
+    len = htonl(d->size);
+  }
+  if (write(fd, &len, sizeof(len)) != sizeof(len)) {
+    err("failed to write size of datum.\n");
+    return -2;
+  }
+  if (looks_negative) {
+    if (write(fd, &zero, 1) != 1) {
+      err("failed to write padding byte for MPI.\n");
+      return -2;
+    }
+  }
+  return write_datum_fd(fd, d);
+}
+
+int write_data_fd_with_length(int fd, const gnutls_datum_t** d, unsigned int num) {
+  unsigned int i;
+  int ret;
+
+  for (i = 0; i < num; i++)
+    if (ret = write_datum_fd_with_length(fd, d[i]), ret != 0)
+      return ret;
+
+  return 0;
+}
+
+
+int datum_from_string(gnutls_datum_t* d, const char* str) {
+  d->size = strlen(str);
+  d->data = gnutls_realloc(d->data, d->size);
+  if (d->data == 0)
+    return ENOMEM;
+  memcpy(d->data, str, d->size);
+  return 0;
+}
+
+
+int create_writing_pipe(pid_t* pid, const char* path, char* const argv[]) {
+  int p[2];
+  int ret;
+
+  if (pid == NULL) {
+    err("bad pointer passed to create_writing_pipe()\n");
+    return -1;
+  }
+
+  if (ret = pipe(p), ret == -1) {
+    err("failed to create a pipe (error: %d \"%s\")\n", errno, strerror(errno));
+    return -1;
+  }
+
+  *pid = fork();
+  if (*pid == -1) {
+    err("Failed to fork (error: %d \"%s\")\n", errno, strerror(errno));
+    return -1;
+  }
+  if (*pid == 0) { /* this is the child */
+    close(p[1]); /* close unused write end */
+    
+    if (0 != dup2(p[0], 0)) { /* map the reading end into stdin */
+      err("Failed to transfer reading file descriptor to stdin (error: %d \"%s\")\n", errno, strerror(errno));
+      exit(1);
+    }
+    execv(path, argv);
+    err("exec %s failed (error: %d \"%s\")\n", path, errno, strerror(errno));
+    /* close the open file descriptors */
+    close(p[0]);
+    close(0);
+
+    exit(1);
+  } else { /* this is the parent */
+    close(p[0]); /* close unused read end */
+    return p[1];
+  }
+}
+
+int validate_ssh_host_userid(const char* userid) {
+  char* oldlocale = setlocale(LC_ALL, "C");
+  
+  /* choke if userid does not match the expected format
+     ("ssh://fully.qualified.domain.name") */
+  if (strncmp("ssh://", userid, strlen("ssh://")) != 0) {
+    err("The user ID should start with ssh:// for a host key\n");
+    goto fail;
+  }
+  /* so that isalnum will work properly */
+  userid += strlen("ssh://");
+  while (0 != (*userid)) {
+    if (!isalnum(*userid)) {
+      err("label did not start with a letter or a digit! (%s)\n", userid);
+      goto fail;
+    }
+    userid++;
+    while (isalnum(*userid) || ('-' == (*userid)))
+      userid++;
+    if (('.' == (*userid)) || (0 == (*userid))) { /* clean end of label:
+						 check last char
+						 isalnum */
+      if (!isalnum(*(userid - 1))) {
+	err("label did not end with a letter or a digit!\n");
+	goto fail;
+      }
+      if ('.' == (*userid)) /* advance to the start of the next label */
+	userid++;
+    } else {
+      err("invalid character in domain name: %c\n", *userid);
+      goto fail;
+    }
+  }
+  /* ensure that the last character is valid: */
+  if (!isalnum(*(userid - 1))) {
+    err("hostname did not end with a letter or a digit!\n");
+    goto fail;
+  }
+  /* FIXME: fqdn's can be unicode now, thanks to RFC 3490 -- how do we
+     make sure that we've got an OK string? */
+
+  return 0;
+
+ fail:
+  setlocale(LC_ALL, oldlocale);
+  return 1;
+}
+
+/* http://tools.ietf.org/html/rfc4880#section-5.5.2 */
+size_t get_openpgp_mpi_size(gnutls_datum_t* d) {
+  return 2 + d->size;
+}
+
+int write_openpgp_mpi_to_fd(int fd, gnutls_datum_t* d) {
+  uint16_t x;
+
+  x = d->size * 8;
+  x = htons(x);
+  
+  write(fd, &x, sizeof(x));
+  write(fd, d->data, d->size);
+  
+  return 0;
+}
diff --git a/src/keytrans/gnutls-helpers.h b/src/keytrans/gnutls-helpers.h
new file mode 100644
index 0000000..9ea22a3
--- /dev/null
+++ b/src/keytrans/gnutls-helpers.h
@@ -0,0 +1,72 @@
+/* Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net> */
+/* Date: Fri, 04 Apr 2008 19:31:16 -0400 */
+/* License: GPL v3 or later */
+
+
+#include <gnutls/gnutls.h>
+#include <gnutls/openpgp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdarg.h>
+
+/* Functions to help dealing with GnuTLS for monkeysphere key
+   translation projects: */
+
+/* set everything up, including logging levels.  Return 0 on
+   success */
+int init_gnutls();
+
+/* logging and output functions: */
+
+void err(const char* fmt, ...);
+void logfunc(int level, const char* string);
+
+/* basic datum manipulations: */
+
+void init_datum(gnutls_datum_t* d);
+void copy_datum(gnutls_datum_t* dest, const gnutls_datum_t* src);
+int compare_data(const gnutls_datum_t* a, const gnutls_datum_t* b);
+void free_datum(gnutls_datum_t* d);
+int write_datum_fd(int fd, const gnutls_datum_t* d);
+int write_datum_fd_with_length(int fd, const gnutls_datum_t* d);
+int write_data_fd_with_length(int fd, const gnutls_datum_t** d, unsigned int num);
+
+/* set up a datum from a null-terminated string */
+int datum_from_string(gnutls_datum_t* d, const char* str);
+
+/* keyid manipulations: */
+typedef unsigned char printable_keyid[16];
+
+void init_keyid(gnutls_openpgp_keyid_t keyid);
+void make_keyid_printable(printable_keyid out, gnutls_openpgp_keyid_t keyid);
+
+/* functions to get data into datum objects: */
+
+/* read the passed-in string, store in a single datum */
+int set_datum_string(gnutls_datum_t* d, const char* s);
+
+/* read the passed-in file descriptor until EOF, store in a single
+   datum */
+int set_datum_fd(gnutls_datum_t* d, int fd);
+
+/* read the file indicated (by name) in the fname parameter.  store
+   its entire contents in a single datum. */
+int set_datum_file(gnutls_datum_t* d, const char* fname);
+
+/* set up file descriptor pipe for writing (child process pid gets
+   stored in pid, fd is returned)*/
+int create_writing_pipe(pid_t* pid, const char* path, char* const argv[]);
+
+/* return 0 if userid matches the monkeysphere spec for ssh host user IDs */
+int validate_ssh_host_userid(const char* userid);
+
+/* how many bytes will it take to write out this datum in OpenPGP MPI form? */
+size_t get_openpgp_mpi_size(gnutls_datum_t* d);
+
+/* write the MPI stored in gnutls_datum_t to file descriptor fd: */
+int write_openpgp_mpi_to_fd(int fd, gnutls_datum_t* d);
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;
+}
diff --git a/src/keytrans/openpgp2ssh.c b/src/keytrans/openpgp2ssh.c
new file mode 100644
index 0000000..d6bac68
--- /dev/null
+++ b/src/keytrans/openpgp2ssh.c
@@ -0,0 +1,271 @@
+#include "gnutls-helpers.h"
+
+#include <gnutls/openpgp.h>
+#include <gnutls/x509.h>
+
+/* 
+   Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
+   Date: Tue, 01 Apr 2008
+   License: GPL v3 or later
+
+   monkeysphere private key translator: execute this with an GPG
+   secret key on stdin (at the moment, only passphraseless RSA keys
+   work).
+
+   It will spit out a PEM-encoded version of the key on stdout, which
+   can be fed into ssh-add like this:
+
+    gpg --export-secret-keys $KEYID | monkeysphere | ssh-add -c /dev/stdin
+
+   Requirements: I've only built this so far with GnuTLS v2.3.4 --
+   version 2.2.0 does not contain the appropriate pieces.
+
+   Notes: gpgkey2ssh doesn't seem to provide the same public
+   keys. Mighty weird!
+
+0 wt215@squeak:~/monkeysphere$ gpg --export-secret-keys 1DCDF89F | ~dkg/src/monkeysphere/monkeysphere  | ssh-add -c /dev/stdin
+gnutls version: 2.3.4
+OpenPGP RSA Key, with 1024 bits
+Identity added: /dev/stdin (/dev/stdin)
+The user has to confirm each use of the key
+0 wt215@squeak:~/monkeysphere$ ssh-add -L
+ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgQC9gWQqfrnhQKDQnND/3eOexpddE64J+1zp9fcyCje7H5LKclb6DBV2HS6WgW32PJhIzvP+fYZM3dzXea3fpv14y1SicXiRBDgF9SnsNA1qWn2RyzkLcKy7PmM0PDYtU1oiLTcQj/xkWcqW2sLKHT/WW+vZP5XP7RMGN/yWNMfE2Q== /dev/stdin
+0 wt215@squeak:~/monkeysphere$ gpgkey2ssh 1DCDF89F
+ssh-rsa AAAAB3NzaC1yc2EAAACBAL2BZCp+ueFAoNCc0P/d457Gl10Trgn7XOn19zIKN7sfkspyVvoMFXYdLpaBbfY8mEjO8/59hkzd3Nd5rd+m/XjLVKJxeJEEOAX1Kew0DWpafZHLOQtwrLs+YzQ8Ni1TWiItNxCP/GRZypbawsodP9Zb69k/lc/tEwY3/JY0x8TZAAAAAwEAAQ== COMMENT
+0 wt215@squeak:~/monkeysphere$ 
+
+ */
+
+
+int convert_pgp_to_x509(gnutls_x509_privkey_t* output, gnutls_datum_t* input) {
+  gnutls_openpgp_privkey_t pgp_privkey;
+  gnutls_datum_t m, e, d, p, q, u, g, y, x;
+  gnutls_pk_algorithm_t pgp_algo;
+  unsigned int pgp_bits;
+  int ret;
+
+  init_datum(&m);
+  init_datum(&e);
+  init_datum(&d);
+  init_datum(&p);
+  init_datum(&q);
+  init_datum(&u);
+  init_datum(&g);
+  init_datum(&y);
+  init_datum(&x);
+
+  if (ret = gnutls_openpgp_privkey_init(&pgp_privkey), ret) {
+    err("Failed to initialized OpenPGP private key (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: */
+
+  if (getenv("MONKEYSPHERE_RAW")) {
+    err("assuming RAW formatted private keys\n");
+    if (ret = gnutls_openpgp_privkey_import(pgp_privkey, input, GNUTLS_OPENPGP_FMT_RAW, NULL, 0), ret)
+      err("failed to import the OpenPGP private key in RAW format (error: %d)\n", ret);
+  } else {
+    err("assuming BASE64 formatted private keys\n");
+    if (ret = gnutls_openpgp_privkey_import (pgp_privkey, input, GNUTLS_OPENPGP_FMT_BASE64, NULL, 0), ret)
+      err("failed to import the OpenPGP private key in BASE64 format (error: %d)\n", ret);
+  }
+
+  pgp_algo = gnutls_openpgp_privkey_get_pk_algorithm(pgp_privkey, &pgp_bits);
+  if (pgp_algo < 0) {
+    err("failed to get OpenPGP key algorithm (error: %d)\n", pgp_algo);
+    return 1;
+  }
+  if (pgp_algo == GNUTLS_PK_RSA) {
+    err("OpenPGP RSA Key, with %d bits\n", pgp_bits);
+    ret = gnutls_openpgp_privkey_export_rsa_raw(pgp_privkey, &m, &e, &d, &p, &q, &u);
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to export RSA key parameters (error: %d)\n", ret);
+      return 1;
+    }
+
+    ret = gnutls_x509_privkey_import_rsa_raw (*output, &m, &e, &d, &p, &q, &u); 
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to import RSA key parameters (error: %d)\n", ret);
+      return 1;
+    }
+  } else if (pgp_algo == GNUTLS_PK_DSA) {
+    err("OpenPGP DSA Key, with %d bits\n", pgp_bits);
+    ret = gnutls_openpgp_privkey_export_dsa_raw(pgp_privkey, &p, &q, &g, &y, &x);
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to export DSA key parameters (error: %d)\n", ret);
+      return 1;
+    }
+
+    ret = gnutls_x509_privkey_import_dsa_raw (*output, &p, &q, &g, &y, &x); 
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to import 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", pgp_algo);
+    return 1;
+  }
+  
+  ret = gnutls_x509_privkey_fix(*output);
+  if (ret != 0) {
+    err("failed to fix up the private key in X.509 format (error: %d)\n", ret);
+    return 1; 
+  }
+
+  gnutls_openpgp_privkey_deinit(pgp_privkey);
+  return 0;
+}
+
+int convert_x509_to_pgp(gnutls_openpgp_privkey_t* output, gnutls_datum_t* input) {
+  gnutls_x509_privkey_t x509_privkey;
+  gnutls_datum_t m, e, d, p, q, u, g, y, x;
+  gnutls_pk_algorithm_t x509_algo;
+  int ret;
+
+  init_datum(&m);
+  init_datum(&e);
+  init_datum(&d);
+  init_datum(&p);
+  init_datum(&q);
+  init_datum(&u);
+  init_datum(&g);
+  init_datum(&y);
+  init_datum(&x);
+
+  if (ret = gnutls_x509_privkey_init(&x509_privkey), ret) {
+    err("Failed to initialized X.509 private key (error: %d)\n", ret);
+    return 1;
+  }
+
+
+  /* format could be either:     GNUTLS_X509_FMT_DER,
+    GNUTLS_X509_FMT_PEM; if MONKEYSPHERE_DER is set, use DER,
+     otherwise, use PEM: */
+
+  if (getenv("MONKEYSPHERE_DER")) {
+    err("assuming DER formatted private keys\n");
+    if (ret = gnutls_x509_privkey_import(x509_privkey, input, GNUTLS_X509_FMT_DER), ret)
+      err("failed to import the X.509 private key in DER format (error: %d)\n", ret);
+  } else {
+    err("assuming PEM formatted private keys\n");
+    if (ret = gnutls_x509_privkey_import (x509_privkey, input, GNUTLS_X509_FMT_PEM), ret)
+      err("failed to import the X.509 private key in PEM format (error: %d)\n", ret);
+  }
+
+  x509_algo = gnutls_x509_privkey_get_pk_algorithm(x509_privkey);
+  if (x509_algo < 0) {
+    err("failed to get X.509 key algorithm (error: %d)\n", x509_algo);
+    return 1;
+  }
+  if (x509_algo == GNUTLS_PK_RSA) {
+    err("X.509 RSA Key\n");
+    ret = gnutls_x509_privkey_export_rsa_raw(x509_privkey, &m, &e, &d, &p, &q, &u);
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to export RSA key parameters (error: %d)\n", ret);
+      return 1;
+    }
+
+    /*     ret = gnutls_openpgp_privkey_import_rsa_raw (*output, &m, &e, &d, &p, &q, &u);  */
+    ret = GNUTLS_E_UNIMPLEMENTED_FEATURE;
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to import RSA key parameters (error: %d)\n", ret);
+      return 1;
+    }
+  } else if (x509_algo == GNUTLS_PK_DSA) {
+    err("X.509 DSA Key\n");
+    ret = gnutls_x509_privkey_export_dsa_raw(x509_privkey, &p, &q, &g, &y, &x);
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to export DSA key parameters (error: %d)\n", ret);
+      return 1;
+    }
+
+    /*    ret = gnutls_openpgp_privkey_import_dsa_raw (*output, &p, &q, &g, &y, &x);  */
+    ret = GNUTLS_E_UNIMPLEMENTED_FEATURE;
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to import 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", x509_algo);
+    return 1;
+  }
+  
+  gnutls_x509_privkey_deinit(x509_privkey);
+  return 0;
+}
+
+
+int main(int argc, char* argv[]) {
+  gnutls_datum_t data;
+  int ret;
+  gnutls_x509_privkey_t x509_privkey;
+
+  char output_data[10240];
+  size_t ods = sizeof(output_data);
+
+  init_gnutls();
+  
+  init_datum(&data);
+
+  /* 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;
+  }
+
+
+
+  /* Or, instead, read in key from a file name: 
+  if (ret = set_datum_file(&data, argv[1]), ret) {
+    err("didn't read file '%s'\n", argv[1]);
+    return 1;
+  }
+*/
+
+  /* treat the passed file as an X.509 private key, and extract its
+     component values: */
+
+/*   if (ret = gnutls_x509_privkey_import(x509_privkey, &data, GNUTLS_X509_FMT_PEM), ret) { */
+/*     err("Failed to import the X.509 key (error: %d)\n", ret); */
+/*     return 1; */
+/*   } */
+/*   gnutls_x509_privkey_export_rsa_raw(x509_privkey, &m, &e, &d, &p, &q, &u); */
+
+  /* try to print the PEM-encoded private key: */
+/*   ret = gnutls_x509_privkey_export (x509_privkey, */
+/* 				    GNUTLS_X509_FMT_PEM, */
+/* 				    output_data, */
+/* 				    &ods); */
+/*   printf("ret: %u; ods: %u;\n", ret, ods); */
+/*   if (ret == 0) { */
+/*     write(0, output_data, ods); */
+/*   } */
+
+
+  if (ret = gnutls_x509_privkey_init(&x509_privkey), ret) {
+    err("Failed to initialize X.509 private key (error: %d)\n", ret);
+    return 1;
+  }
+
+  if (ret = convert_pgp_to_x509(&x509_privkey, &data), ret) {
+    return ret;
+  }
+
+  ret = gnutls_x509_privkey_export (x509_privkey,
+				    GNUTLS_X509_FMT_PEM,
+				    output_data,
+				    &ods);
+  printf("ret: %u; ods: %u;\n", ret, ods);
+  if (ret == 0) {
+    write(1, output_data, ods);
+  }
+
+
+  gnutls_x509_privkey_deinit(x509_privkey);
+  gnutls_global_deinit();
+  return 0;
+}
diff --git a/src/keytrans/ssh2gpg.c b/src/keytrans/ssh2gpg.c
new file mode 100644
index 0000000..b14a540
--- /dev/null
+++ b/src/keytrans/ssh2gpg.c
@@ -0,0 +1,171 @@
+#include "gnutls-helpers.h"
+
+#include <gnutls/openpgp.h>
+#include <gnutls/x509.h>
+
+/* for waitpid() */
+#include <sys/types.h>
+#include <sys/wait.h>
+
+/* for time() */
+#include <time.h>
+
+/* for htons() */
+#include <arpa/inet.h>
+
+
+/* 
+   Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
+   Date: Sun, 2008-04-20
+   License: GPL v3 or later
+
+   monkeysphere public key translator: execute this with an ssh
+   private key on stdin.  It currently only works with RSA keys.
+
+   it should eventually work with OpenSSH-style public keys instead of
+   the full private key, but it was easier to do this way.
+
+   It shoud spit out a version of the public key suitable for acting
+   as an OpenPGP public sub key packet.
+
+ */
+
+int main(int argc, char* argv[]) {
+  gnutls_datum_t data;
+  int ret;
+  gnutls_x509_privkey_t x509_privkey;
+  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;
+
+  unsigned char packettag;
+  unsigned char openpgpversion;
+  time_t timestamp;
+  uint32_t clunkytime;
+  unsigned char openpgpalgo;
+  unsigned int packetlen;
+  uint16_t plen;
+
+  gnutls_datum_t m, e, d, p, q, u, 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(&d);
+  init_datum(&p);
+  init_datum(&q);
+  init_datum(&u);
+  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_x509_privkey_init(&x509_privkey), ret) {
+    err("Failed to initialize private key structure (error: %d)\n", ret);
+    return 1;
+  }
+
+  err("assuming PEM formatted private key\n");
+  if (ret = gnutls_x509_privkey_import(x509_privkey, &data, GNUTLS_X509_FMT_PEM), ret) {
+    err("failed to import the PEM-encoded private key (error: %d)\n", ret);
+    return ret;
+  }
+
+  algo = gnutls_x509_privkey_get_pk_algorithm(x509_privkey);
+  if (algo < 0) {
+    err("failed to get the algorithm of the PEM-encoded public key (error: %d)\n", algo);
+    return algo;
+  } else if (algo == GNUTLS_PK_RSA) {
+    err("RSA private key\n");
+    ret = gnutls_x509_privkey_export_rsa_raw(x509_privkey, &m, &e, &d, &p, &q, &u);
+    if (GNUTLS_E_SUCCESS != ret) {
+      err ("failed to export RSA key parameters (error: %d)\n", ret);
+      return 1;
+    }
+    err("Modulus size %d, exponent size %d\n", m.size, e.size);
+  } else if (algo == GNUTLS_PK_DSA) {
+    err("DSA Key, not implemented!!\n", bits);
+    return 1;
+  } else {
+    err("Key was not RSA or DSA -- can't deal! (actual algorithm was: %d)\n", algo);
+    return 1;
+  }
+
+  /* now we have algo, and the various MPI data are set.  Can we
+     export them as a public subkey packet? */
+
+  /* this packet should be tagged 14, and should contain:
+
+     1 octet: version (4)
+     4 octets: time of generation (seconds since 1970)
+     1 octet: algo (http://tools.ietf.org/html/rfc4880#section-5.5.2 implies 1 for RSA)
+ 
+     MPI: modulus
+     MPI: exponent
+  */
+
+  packetlen = 1 + 4 + 1;
+  /* FIXME: this is RSA only.  for DSA, there'll be more: */
+  packetlen += get_openpgp_mpi_size(&m) + get_openpgp_mpi_size(&e);
+
+  /* FIXME: we should generate this bound more cleanly -- i just
+     happen to know that 65535 is 2^16-1: */
+  if (packetlen > 65535) {
+    err("packet length is too long (%d)\n", packetlen);
+    return 1;
+  }
+
+  /* we're going to emit an old-style packet, with tag 14 (public
+     subkey), with a two-octet packet length */
+  packettag = 0x80 | (14 << 2) | 1;
+  
+  write(1, &packettag, sizeof(packettag));
+  plen = htons(packetlen);
+  write(1, &plen, sizeof(plen));
+
+  openpgpversion = 4;
+  write(1, &openpgpversion, 1);
+
+  timestamp = time(NULL);
+  clunkytime = htonl(timestamp);
+  write(1, &clunkytime, 4);
+
+  /* FIXME: handle things other than RSA */
+  openpgpalgo = 1;
+  write(1, &openpgpalgo, 1);
+  
+  write_openpgp_mpi_to_fd(1, &m);
+  write_openpgp_mpi_to_fd(1, &e);
+
+  gnutls_x509_privkey_deinit(x509_privkey);
+  gnutls_global_deinit();
+  return 0;
+}