New functions to compute an ssh style fingerprint.

5 files changed, 473 insertions, 1 deletions

diff --git a/common/ChangeLog b/common/ChangeLog
index 4f8b5414f..c56bc4d8f 100644
--- a/common/ChangeLog
+++ b/common/ChangeLog
@@ -1,3 +1,10 @@
+2011-07-20  Werner Koch  <wk@g10code.com>
+
+	* ssh-utils.c, ssh-utils.h: New.
+	* t-ssh-utils.c: New.
+	* Makefile.am (t_ssh_utils_LDADD): New.
+	(module_tests): Add t-ssh-utils.c
+
 2011-06-01  Marcus Brinkmann  <mb@g10code.com>
 
 	* util.h: Undef snprintf before redefining it.
diff --git a/common/Makefile.am b/common/Makefile.am
index 5d7f22496..555d0881d 100644
--- a/common/Makefile.am
+++ b/common/Makefile.am
@@ -91,6 +91,7 @@ common_sources = \
 	session-env.c session-env.h \
 	userids.c userids.h \
 	openpgp-oid.c \
+	ssh-utils.c ssh-utils.h \
 	helpfile.c
 
 # To make the code easier to read we have split home some code into
@@ -161,7 +162,7 @@ if HAVE_W32_SYSTEM
 jnlib_tests += t-w32-reg
 endif
 module_tests = t-convert t-percent t-gettime t-sysutils t-sexputil \
-	       t-session-env t-openpgp-oid
+	       t-session-env t-openpgp-oid t-ssh-utils
 if !HAVE_W32CE_SYSTEM
 module_tests += t-exechelp
 endif
@@ -194,3 +195,4 @@ t_b64_LDADD = $(t_common_ldadd)
 t_exechelp_LDADD = $(t_common_ldadd)
 t_session_env_LDADD = $(t_common_ldadd)
 t_openpgp_oid_LDADD = $(t_common_ldadd)
+t_ssh_utils_LDADD = $(t_common_ldadd)
diff --git a/common/ssh-utils.c b/common/ssh-utils.c
new file mode 100644
index 000000000..e2de80258
--- /dev/null
+++ b/common/ssh-utils.c
@@ -0,0 +1,187 @@
+/* ssh-utils.c - Secure Shell helper functions
+ * Copyright (C) 2011 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <ctype.h>
+#include <assert.h>
+
+#include "util.h"
+#include "ssh-utils.h"
+
+
+
+/* Return the Secure Shell type fingerprint for KEY.  The length of
+   the fingerprint is returned at R_LEN and the fingerprint itself at
+   R_FPR.  In case of a error code is returned and NULL stored at
+   R_FPR.  This function is usually called via the ssh_get_fingerprint
+   macro which makes sure to use the correct value for ERRSOURCE. */
+static gpg_error_t
+get_fingerprint (gcry_sexp_t key, void **r_fpr, size_t *r_len,
+                 gpg_err_source_t errsource, int as_string)
+{
+  gpg_error_t err;
+  gcry_sexp_t list = NULL;
+  gcry_sexp_t l2 = NULL;
+  const char *s;
+  char *name = NULL;
+  int idx;
+  const char *elems;
+  gcry_md_hd_t md = NULL;
+
+  *r_fpr = NULL;
+  *r_len = 0;
+
+  /* Check that the first element is valid. */
+  list = gcry_sexp_find_token (key, "public-key", 0);
+  if (!list)
+    list = gcry_sexp_find_token (key, "private-key", 0);
+  if (!list)
+    list = gcry_sexp_find_token (key, "protected-private-key", 0);
+  if (!list)
+    list = gcry_sexp_find_token (key, "shadowed-private-key", 0);
+  if (!list)
+    {
+      err = gpg_err_make (errsource, GPG_ERR_UNKNOWN_SEXP);
+      goto leave;
+    }
+
+  l2 = gcry_sexp_cadr (list);
+  gcry_sexp_release (list);
+  list = l2;
+  l2 = NULL;
+
+  name = gcry_sexp_nth_string (list, 0);
+  if (!name)
+    {
+      err = gpg_err_make (errsource, GPG_ERR_INV_SEXP);
+      goto leave;
+    }
+
+  err = gcry_md_open (&md, GCRY_MD_MD5, 0);
+  if (err)
+    goto leave;
+
+  switch (gcry_pk_map_name (name))
+    {
+    case GCRY_PK_RSA:
+      elems = "en";
+      gcry_md_write (md, "\0\0\0\x07ssh-rsa", 11);
+      break;
+    case GCRY_PK_DSA:
+      elems = "pqgy";
+      gcry_md_write (md, "\0\0\0\x07ssh-dss", 11);
+      break;
+    default:
+      elems = "";
+      err = gpg_err_make (errsource, GPG_ERR_PUBKEY_ALGO);
+      break;
+    }
+  if (err)
+    goto leave;
+
+  for (idx = 0, s = elems; *s; s++, idx++)
+    {
+      gcry_mpi_t a;
+      unsigned char *buf;
+      size_t buflen;
+
+      l2 = gcry_sexp_find_token (list, s, 1);
+      if (!l2)
+        {
+          err = gpg_err_make (errsource, GPG_ERR_INV_SEXP);
+          goto leave;
+        }
+      a = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
+      gcry_sexp_release (l2);
+      l2 = NULL;
+      if (!a)
+        {
+          err = gpg_err_make (errsource, GPG_ERR_INV_SEXP);
+          goto leave;
+        }
+
+      err = gcry_mpi_aprint (GCRYMPI_FMT_SSH, &buf, &buflen, a);
+      gcry_mpi_release (a);
+      if (err)
+        goto leave;
+      gcry_md_write (md, buf, buflen);
+      gcry_free (buf);
+    }
+
+  *r_fpr = gcry_malloc (as_string? 61:20);
+  if (!*r_fpr)
+    {
+      err = gpg_err_make (errsource, gpg_err_code_from_syserror ());
+      goto leave;
+    }
+
+  if (as_string)
+    {
+      bin2hexcolon (gcry_md_read (md, GCRY_MD_MD5), 16, *r_fpr);
+      *r_len = 3*16+1;
+      strlwr (*r_fpr);
+    }
+  else
+    {
+      memcpy (*r_fpr, gcry_md_read (md, GCRY_MD_MD5), 16);
+      *r_len = 16;
+    }
+  err = 0;
+
+ leave:
+  gcry_free (name);
+  gcry_sexp_release (l2);
+  gcry_md_close (md);
+  gcry_sexp_release (list);
+  return err;
+}
+
+/* Return the Secure Shell type fingerprint for KEY.  The length of
+   the fingerprint is returned at R_LEN and the fingerprint itself at
+   R_FPR.  In case of an error an error code is returned and NULL
+   stored at R_FPR.  This function is usually called via the
+   ssh_get_fingerprint macro which makes sure to use the correct value
+   for ERRSOURCE. */
+gpg_error_t
+_ssh_get_fingerprint (gcry_sexp_t key, void **r_fpr, size_t *r_len,
+                      gpg_err_source_t errsource)
+{
+  return get_fingerprint (key, r_fpr, r_len, errsource, 0);
+}
+
+
+/* Return the Secure Shell type fingerprint for KEY as a string.  The
+   fingerprint is mallcoed and stored at R_FPRSTR.  In case of an
+   error an error code is returned and NULL stored at R_FPRSTR.  This
+   function is usually called via the ssh_get_fingerprint_string macro
+   which makes sure to use the correct value for ERRSOURCE. */
+gpg_error_t
+_ssh_get_fingerprint_string (gcry_sexp_t key, char **r_fprstr,
+                             gpg_err_source_t errsource)
+{
+  gpg_error_t err;
+  size_t dummy;
+  void *string;
+
+  err = get_fingerprint (key, &string, &dummy, errsource, 1);
+  *r_fprstr = string;
+  return err;
+}
diff --git a/common/ssh-utils.h b/common/ssh-utils.h
new file mode 100644
index 000000000..1813c8b51
--- /dev/null
+++ b/common/ssh-utils.h
@@ -0,0 +1,36 @@
+/* ssh-utils.c - Secure Shell helper function definitions
+ * Copyright (C) 2011 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GNUPG_COMMON_SSH_UTILS_H
+#define GNUPG_COMMON_SSH_UTILS_H
+
+
+gpg_error_t _ssh_get_fingerprint (gcry_sexp_t key, void **r_fpr, size_t *r_len,
+                                  gpg_err_source_t errsource);
+#define ssh_get_fingerprint(a,b,c)                              \
+  _ssh_get_fingerprint ((a), (b), (c), GPG_ERR_SOURCE_DEFAULT)
+
+gpg_error_t _ssh_get_fingerprint_string (gcry_sexp_t key, char **r_fprstr,
+                                         gpg_err_source_t errsource);
+#define ssh_get_fingerprint_string(a,b)                         \
+  _ssh_get_fingerprint_string ((a), (b), GPG_ERR_SOURCE_DEFAULT)
+
+
+
+#endif /*GNUPG_COMMON_SSH_UTILS_H*/
diff --git a/common/t-ssh-utils.c b/common/t-ssh-utils.c
new file mode 100644
index 000000000..cd1252fd2
--- /dev/null
+++ b/common/t-ssh-utils.c
@@ -0,0 +1,240 @@
+/* t-ssh-utils.c - Module test for ssh-utils.c
+ * Copyright (C) 2011 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "util.h"
+#include "ssh-utils.h"
+
+#define pass()  do { ; } while(0)
+#define fail(a,e)                                                       \
+  do { fprintf (stderr, "%s:%d: test %d failed (%s)\n",                 \
+                __FILE__,__LINE__, (a), gpg_strerror (e));              \
+    exit (1);                                                           \
+  } while(0)
+
+
+static struct { const char *key; const char *fpr; } sample_keys[] = {
+  { "(protected-private-key "
+    "(rsa "
+    "(n #"
+    "00D88E47BCE0DA99D6180E8A9F4E6A673CC16F5BB6CF930E0E868BAABA715A8E1D3E2BEA"
+    "5477170E1F6CAFC0F8907B9892993C70AC476BBB301669F68EE0593532FB522DD60755A3"
+    "2F8B08649E856271A7F9BCB25F29554DF11707F812EA377683A99DD4698C4DBF797A0ABF"
+    "43C8EBB364B9FFC9EE78CBEA348C590507A4EA390312153DDD905EC4F1A63D5DA56C08FD"
+    "C3F6E5707BFC5DBDC09D19723B1AC6E466906F13AA2ECDBD258148F86C980D45CF233415"
+    "38C5857C2CF0B4C9AB2B4E6A4517FF084FDB009A33553A68907A29691B6FAE994E864F78"
+    "7B83F714730BEDB0AF1723D636E034D73EB7EC9BA127BB4BE80FD805813E3F45E7FAE514"
+    "AD2ECA9607#)"
+    "(e \"#\")"
+    "(protected openpgp-s2k3-sha1-aes-cbc "
+    "("
+    "(sha1 #B5847F9A2DB4E0C5# \"5242880\")"
+    "#342D81BDE21301F18FDCE169A99A47C5#)"
+    "#23512602219EC7A97DBA89347CCD59D2072D80CE3F7DD6C97A058B83DAB3C829D97DF5"
+    "DFE9181F27DBF58258C4CDBD562A5B20BB5BC35EDCA7B1E57B8CDBF92D798F46EE5567BD"
+    "8A67EF3BE09908A49D41AA166A3398B64227BC75021C69A8FE8354E2903EF52DC91B1FE3"
+    "EF9558E5C2D34CF38BFC29E99A49AE30B0C22CE81EE14FC71E986E7C7CB5FCF807433FDA"
+    "EF1D00985767265BA0BE333754E44CCF622CBB98A029D78A6A9AADBC24613127B6448350"
+    "23DA355ED31CF089DD11A7FC6003CEEB53FB327A05604D053C99996F9E01CB355983F66E"
+    "7BEB9687A9277BBF440ED5FAF1A8396C9B06C9B47BA7A994E1931B08DAD34449952CD343"
+    "9A691477682C324EA07CCCE5DF0F0E9DAEFAE3A4717AACA6DC18ED91DD5A820C924BD36B"
+    "B3BA85BD63B3180C7F94EE58956940621280B9628FA5CC560BB14331AF1A7B5B499F8F03"
+    "0ED464ABD4E26C5FD610697EDD0FD1203983E73418F3776568A613D3CEFF17199473052A"
+    "18807A6F5C52A2A643185801D087EE4DC930ABEEB67C5B8A1CB2F29D0ACBD855972BEC0B"
+    "DE6E52387CFCC54B4C2B87EE947C97173BFCAE3E2658EB819D87F542C9A9FE6C410D08F5"
+    "3CD5451FB50253F4A848DFE136B3A5861D58B76A26A7E3E4E7A8F8D4BD5B80430674A6B9"
+    "A2C8EDD53DB37865D1ACBB07E1758DFF64A944E0126F948BF088C0FC0C3607E39522EC94"
+    "91483A90D9498D7F6C3C8720124C7E3F6E271E78E1CFFB4EF64F070F7424F30372A07D02"
+    "2355D8B17BB0DEBCBE101F621E0526551A35A56830D74E0F5BD6313DF114D1E46D4844AA"
+    "E4EB6268637D04B27D200D7F40AFA9AD2CFAA5415E5FC08358FFA79A9E743CCDF6668FE5"
+    "D79FA03D61941E57244F066A31F1C9D6A34DC62BC738C52B604F00B19EB9FD0173F3B139"
+    "42932066B7DC94DC4C563392F798A1CE2D5D75B8FF93E440433263CFB7016143A9923CD9"
+    "634E964A8056946F462B06F320F44449D85B07FA26A324505C858274F89EDBD8346950DE"
+    "5F#)"
+    "(protected-at \"20110720T135431\")"
+    ")"
+    "(comment passphrase_is_abc)"
+    ")",
+    "c7:c6:a7:ec:04:6c:87:59:54:f2:88:58:09:e0:f2:b1"
+  },
+  {
+    "(protected-private-key "
+    "(dsa "
+    "(p #00FC7DC086F4517079BCCFA7FD229477FE88B0231038DFC21B29CCBD74C6F6FE04FD"
+    "7248C0473D5028BE106D7A7C8F54B269225789E781763527D1432CD46E416C2D14DDCA70"
+    "27DA4B92D1E222B5BDF4B9C8C761CACCFBD108F7729412E8835653BE5073447287A6BDEB"
+    "4645A5411752405EE7F503E44B1DFDCA6054CD3C44630B#)"
+    "(q #00D498505BF0E7EE01239EB51F2B400B8EF6329B17#)"
+    "(g #00A127B3DD5106F0A463312E42ECB83790E6F3BEA7AC3FAF7A42FB2C00F376323676"
+    "C9E48984F0D4AC3FE5856F1C2765E9BC3C8A5C9C9CD3166C057E82569D187C48591AA66B"
+    "8966BFF2B827BE36BD0BA4B895B42136F1381D52DDA708B2A3D181F648228DFFFEB153DA"
+    "ACCAEBB51EF08A7807CD628024CEFF96FEE97DE95C8CBE#)"
+    "(y #008E2B0915A3A299D83B4333C848C5D312F25903773E8C4D50691CAF81C3B768FA41"
+    "7D19F0FD437B377CCF51D3AE598649656D4D74D210CDBC2B76209B16EAAFCB14D6F4D691"
+    "20164885852AF1CEBB4D8602AD6755DFA7163645B4DB7926CD44D2DD9F840BFEF57F3DB0"
+    "933C85EB6B0AAC20BC67E73F47B8DDBEC8EFAA64286EF1#)"
+    "(protected openpgp-s2k3-sha1-aes-cbc "
+    "("
+    "(sha1  \"ü¿jy²üa4\" \"5242880\")"
+    "#FF12BEE0B03F842349717AE1AB6D7AC2#)"
+    "#95570487C8B5C49492D4E662259F2CF9B6D7E64F728F17A1FE1B2DA616E5976FE32861E"
+    "C4B1F0DA03D9006C432CF2136871266E9444377ACEF04340B36B4550B5C1E4CC69AD4380"
+    "A709FB0DAA5104A8B#)"
+    "(protected-at \"20110720T142801\")"
+    ")"
+    "(comment sample_dsa_passphrase_is_abc)"
+    ")",
+    "2d:b1:70:1a:04:9e:41:a3:ce:27:a5:c7:22:fe:3a:a3"
+  },
+  {
+    NULL,
+    NULL
+  }
+};
+
+
+
+static char *
+read_file (const char *fname, size_t *r_length)
+{
+  FILE *fp;
+  char *buf;
+  size_t buflen;
+  struct stat st;
+
+  fp = fopen (fname, "rb");
+  if (!fp)
+    {
+      fprintf (stderr, "%s:%d: can't open `%s': %s\n",
+               __FILE__, __LINE__, fname, strerror (errno));
+      exit (1);
+    }
+
+  if (fstat (fileno(fp), &st))
+    {
+      fprintf (stderr, "%s:%d: can't stat `%s': %s\n",
+               __FILE__, __LINE__, fname, strerror (errno));
+      exit (1);
+    }
+
+  buflen = st.st_size;
+  buf = xmalloc (buflen+1);
+  if (fread (buf, buflen, 1, fp) != 1)
+    {
+      fprintf (stderr, "%s:%d: error reading `%s': %s\n",
+               __FILE__, __LINE__, fname, strerror (errno));
+      exit (1);
+    }
+  fclose (fp);
+
+  *r_length = buflen;
+  return buf;
+}
+
+
+static gcry_sexp_t
+read_key (const char *fname)
+{
+  gpg_error_t err;
+  char *buf;
+  size_t buflen;
+  gcry_sexp_t key;
+
+  buf = read_file (fname, &buflen);
+
+  err = gcry_sexp_sscan (&key, NULL, buf, buflen);
+  if (err)
+    {
+      fprintf (stderr, "%s:%d: gcry_sexp_sscan failed: %s\n",
+               __FILE__, __LINE__, gpg_strerror (err));
+      exit (1);                                 \
+    }
+
+  xfree (buf);
+  return key;
+}
+
+
+int
+main (int argc, char **argv)
+{
+  gpg_error_t err;
+  gcry_sexp_t key;
+  char *string;
+  int idx;
+
+  if (argc == 2)
+    {
+      key = read_key (argv[1]);
+      err = ssh_get_fingerprint_string (key, &string);
+      if (err)
+        {
+          fprintf (stderr, "%s:%d: error getting fingerprint: %s\n",
+                   __FILE__, __LINE__, gpg_strerror (err));
+          exit (1);
+        }
+      puts (string);
+      xfree (string);
+      gcry_sexp_release (key);
+    }
+  else
+    {
+      for (idx=0; sample_keys[idx].key; idx++)
+        {
+          err = gcry_sexp_sscan (&key, NULL, sample_keys[idx].key,
+                                 strlen (sample_keys[idx].key));
+          if (err)
+            {
+              fprintf (stderr, "%s:%d: gcry_sexp_sscan failed for "
+                       "sample key %d: %s\n",
+                       __FILE__, __LINE__, idx, gpg_strerror (err));
+              exit (1);
+            }
+
+          err = ssh_get_fingerprint_string (key, &string);
+          gcry_sexp_release (key);
+          if (err)
+            {
+              fprintf (stderr, "%s:%d: error getting fingerprint for "
+                       "sample key %d: %s\n",
+                       __FILE__, __LINE__, idx, gpg_strerror (err));
+              exit (1);
+            }
+
+          if (strcmp (string, sample_keys[idx].fpr))
+            {
+              fprintf (stderr, "%s:%d: fingerprint mismatch for "
+                       "sample key %d\n",
+                       __FILE__, __LINE__, idx);
+              fprintf (stderr, "want: %s\n got: %s\n",
+                       sample_keys[idx].fpr, string);
+              exit (1);
+            }
+          xfree (string);
+        }
+    }
+
+  return 0;
+}