Add a new helper tool

1 files changed, 407 insertions, 0 deletions

diff --git a/tests/rsacvt.c b/tests/rsacvt.c
new file mode 100644
index 00000000..78dad70f
--- /dev/null
+++ b/tests/rsacvt.c
@@ -0,0 +1,407 @@
+/* rsacvt.c  -  A debug tool to convert RSA formats.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+
+   This file is part of Libgcrypt.
+  
+   Libgcrypt is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of
+   the License, or (at your option) any later version.
+  
+   Libgcrypt 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 Lesser General Public License for more details.
+  
+   You should have received a copy of the GNU Lesser General Public
+   License along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Input data format:
+
+=======
+# A hash denotes a comment line
+e861b700e17e8afe68[...]f1
+f7a7ca5367c661f8e6[...]61
+10001
+
+# After an empty line another input block may follow. 
+7861b700e17e8afe68[...]f3
+e7a7ca5367c661f8e6[...]71
+3
+=========
+
+*/
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <errno.h>
+#include <ctype.h>
+#ifdef HAVE_W32_SYSTEM
+# include <fcntl.h> /* We need setmode().  */
+#else
+# include <signal.h>
+#endif
+#include <assert.h>
+#include <unistd.h>
+
+#ifdef _GCRYPT_IN_LIBGCRYPT
+# include "../src/gcrypt.h"
+#else
+# include <gcrypt.h>
+# define PACKAGE_BUGREPORT "devnull@example.org"
+# define PACKAGE_VERSION "[build on " __DATE__ " " __TIME__ "]"
+#endif
+
+
+#define PGM "rsacvt"
+
+#define my_isascii(c) (!((c) & 0x80))
+#define digitp(p)   (*(p) >= '0' && *(p) <= '9')
+#define hexdigitp(a) (digitp (a)                     \
+                      || (*(a) >= 'A' && *(a) <= 'F')  \
+                      || (*(a) >= 'a' && *(a) <= 'f'))
+#define xtoi_1(p)   (*(p) <= '9'? (*(p)- '0'): \
+                     *(p) <= 'F'? (*(p)-'A'+10):(*(p)-'a'+10))
+#define xtoi_2(p)   ((xtoi_1(p) * 16) + xtoi_1((p)+1))
+#define DIM(v)               (sizeof(v)/sizeof((v)[0]))
+#define DIMof(type,member)   DIM(((type *)0)->member)
+
+
+/* Verbose mode flag.  */
+static int verbose;
+
+/* Prefix output with labels.  */
+static int with_labels;
+
+/* Do not suppress leading zeroes.  */
+static int keep_lz; 
+
+
+/* Print a error message and exit the process with an error code.  */
+static void
+die (const char *format, ...)
+{
+  va_list arg_ptr;
+
+  va_start (arg_ptr, format);
+  fputs (PGM ": ", stderr);
+  vfprintf (stderr, format, arg_ptr);
+  va_end (arg_ptr);
+  exit (1);
+}
+
+
+static char *
+read_textline (FILE *fp)
+{
+  char line[4096];
+  char *p;
+  int any = 0;
+
+  /* Read line but skip over initial empty lines.  */
+  do
+    {
+      do 
+        {
+          if (!fgets (line, sizeof line, fp))
+            {
+              if (feof (fp))
+                return NULL;
+              die ("error reading input line: %s\n", strerror (errno));
+            }
+          p = strchr (line, '\n');
+          if (p)
+            *p = 0;
+          p = line + (*line? (strlen (line)-1):0);
+          for ( ;p > line; p--)
+            if (my_isascii (*p) && isspace (*p))
+              *p = 0;
+        }
+      while (!any && !*line);
+      any = 1;
+    }
+  while (*line == '#');  /* Always skip comment lines.  */
+  if (verbose > 1)
+    fprintf (stderr, PGM ": received line: %s\n", line);
+  return gcry_xstrdup (line);
+}
+
+
+static gcry_mpi_t
+read_hexmpi_line (FILE *fp, int *got_eof)
+{
+  gpg_error_t err;
+  gcry_mpi_t a;
+  char *line;
+
+  *got_eof = 0;
+  line = read_textline (fp);
+  if (!line)
+    {
+      *got_eof = 1;
+      return NULL;
+    }
+  err = gcry_mpi_scan (&a, GCRYMPI_FMT_HEX, line, 0, NULL);
+  gcry_free (line);
+  if (err)
+    a = NULL;
+  return a;
+}
+
+
+static int
+skip_to_empty_line (FILE *fp)
+{
+  char line[256];
+  char *p;
+
+  do
+    {
+      if (!fgets (line, sizeof line, fp))
+        {
+          if (feof (fp))
+            return -1;
+          die ("error reading input line: %s\n", strerror (errno));
+        }
+      p = strchr (line, '\n');
+      if (p)
+        *p =0;
+    }
+  while (*line);
+  return 0;
+}
+
+
+/* Print an MPI on a line.  */
+static void
+print_mpi_line (const char *label, gcry_mpi_t a)
+{
+  unsigned char *buf, *p;
+  gcry_error_t err;
+  int writerr = 0;
+
+  if (with_labels && label)
+    printf ("%s = ", label);
+
+  err = gcry_mpi_aprint (GCRYMPI_FMT_HEX, &buf, NULL, a);
+  if (err)
+    die ("gcry_mpi_aprint failed: %s\n", gpg_strerror (err));
+
+  p = buf;
+  if (!keep_lz && p[0] == '0' && p[1] == '0' && p[2])
+    p += 2;
+    
+  printf ("%s\n", p);
+  if (ferror (stdout))
+    writerr++;
+  if (!writerr && fflush (stdout) == EOF)
+    writerr++;
+  if (writerr)
+    die ("writing output failed: %s\n", strerror (errno));
+  gcry_free (buf);
+}
+
+
+/* Compute and print missing RSA parameters.  */
+static void
+compute_missing (gcry_mpi_t rsa_p, gcry_mpi_t rsa_q, gcry_mpi_t rsa_e)
+{
+  gcry_mpi_t rsa_n, rsa_d, rsa_pm1, rsa_qm1, rsa_u;
+  gcry_mpi_t phi, tmp_g, tmp_f;
+
+  rsa_n = gcry_mpi_new (0);
+  rsa_d = gcry_mpi_new (0);
+  rsa_pm1 = gcry_mpi_new (0);
+  rsa_qm1 = gcry_mpi_new (0);
+  rsa_u = gcry_mpi_new (0);
+
+  phi = gcry_mpi_new (0);
+  tmp_f = gcry_mpi_new (0);
+  tmp_g = gcry_mpi_new (0);
+
+  /* Check that p < q; if not swap p and q.  */ 
+  if (gcry_mpi_cmp (rsa_p, rsa_q) > 0)
+    {
+      fprintf (stderr, PGM ": swapping p and q\n");
+      gcry_mpi_swap (rsa_p, rsa_q);
+    }
+
+  gcry_mpi_mul (rsa_n, rsa_p, rsa_q);
+  
+
+  /* Compute the Euler totient:  phi = (p-1)(q-1)  */
+  gcry_mpi_sub_ui (rsa_pm1, rsa_p, 1);
+  gcry_mpi_sub_ui (rsa_qm1, rsa_q, 1);
+  gcry_mpi_mul (phi, rsa_pm1, rsa_qm1);
+
+  if (!gcry_mpi_gcd (tmp_g, rsa_e, phi))
+    die ("parameter 'e' does match 'p' and 'q'\n");
+
+  /* Compute: f = lcm(p-1,q-1) = phi / gcd(p-1,q-1) */
+  gcry_mpi_gcd (tmp_g, rsa_pm1, rsa_qm1);
+  gcry_mpi_div (tmp_f, NULL, phi, tmp_g, -1);
+
+  /* Compute the secret key:  d = e^{-1} mod lcm(p-1,q-1) */
+  gcry_mpi_invm (rsa_d, rsa_e, tmp_f);
+
+  /* Compute the CRT helpers: d mod (p-1), d mod (q-1)   */
+  gcry_mpi_mod (rsa_pm1, rsa_d, rsa_pm1);
+  gcry_mpi_mod (rsa_qm1, rsa_d, rsa_pm1);
+
+  /* Compute the CRT value: u = p^{-1} mod q  */
+  gcry_mpi_invm (rsa_u, rsa_p, rsa_q);
+
+  gcry_mpi_release (phi);
+  gcry_mpi_release (tmp_f);
+  gcry_mpi_release (tmp_g);
+
+  /* Print everything.  */
+  print_mpi_line ("n", rsa_n);
+  print_mpi_line ("e", rsa_e);
+  print_mpi_line ("d", rsa_d);
+  print_mpi_line ("p", rsa_p);
+  print_mpi_line ("q", rsa_q);
+  print_mpi_line ("dmp1", rsa_pm1);
+  print_mpi_line ("dmq1", rsa_qm1);
+  print_mpi_line ("u", rsa_u);
+
+  gcry_mpi_release (rsa_n);
+  gcry_mpi_release (rsa_d);
+  gcry_mpi_release (rsa_pm1);
+  gcry_mpi_release (rsa_qm1);
+  gcry_mpi_release (rsa_u);
+}
+
+
+
+static void
+usage (int show_help)
+{
+  if (!show_help)
+    {
+      fputs ("usage: " PGM 
+             " [OPTION] [FILE] (try --help for more information)\n", stderr);
+      exit (2);
+    }
+  fputs
+    ("Usage: " PGM " [OPTIONS] [FILE]\n"
+     "Take RSA parameters p, n, e and compute missing parameters.\n"
+     "OPTIONS:\n"
+     "  --version        Print version information\n"
+     "  --verbose        Print additional information\n"
+     "  --labels         Prefix output with labels\n"
+     "  --keep-lz        Keep all leading zeroes in the output\n"
+     "  --help           Print this text\n"
+     "With no FILE, or if FILE is -, read standard input.\n"
+     "Report bugs to " PACKAGE_BUGREPORT ".\n" , stdout);
+  exit (0);
+}
+
+
+int
+main (int argc, char **argv)
+{
+  int last_argc = -1;
+  FILE *input;
+  gcry_mpi_t  rsa_p, rsa_q, rsa_e;
+  int got_eof;
+  int any = 0;
+
+  if (argc)
+    { argc--; argv++; }
+
+  while (argc && last_argc != argc )
+    {
+      last_argc = argc;
+      if (!strcmp (*argv, "--"))
+        {
+          argc--; argv++;
+          break;
+        }
+      else if (!strcmp (*argv, "--help"))
+        {
+          usage (1);
+        }
+      else if (!strcmp (*argv, "--version"))
+        {
+          fputs (PGM " (Libgcrypt) " PACKAGE_VERSION "\n", stdout);
+          printf ("libgcrypt %s\n", gcry_check_version (NULL));
+          exit (0);
+        }
+      else if (!strcmp (*argv, "--verbose"))
+        {
+          verbose++;
+          argc--; argv++;
+        }
+      else if (!strcmp (*argv, "--labels"))
+        {
+          with_labels = 1;
+          argc--; argv++;
+        }
+      else if (!strcmp (*argv, "--keep-lz"))
+        {
+          keep_lz = 1;
+          argc--; argv++;
+        }
+    }          
+
+  if (argc > 1)
+    usage (0);
+
+#if !defined (HAVE_W32_SYSTEM) && !defined (_WIN32)
+  signal (SIGPIPE, SIG_IGN);
+#endif
+
+  if (argc == 1 && strcmp (argv[0], "-"))
+    {
+      input = fopen (argv[0], "r");
+      if (!input)
+        die ("can't open `%s': %s\n", argv[0], strerror (errno));
+    }
+  else
+    input = stdin;
+
+  gcry_control (GCRYCTL_SET_VERBOSITY, (int)verbose);
+  if (!gcry_check_version ("1.4.0"))
+    die ("Libgcrypt is not sufficient enough\n");
+  gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
+  gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
+
+  do
+    {
+      rsa_p = read_hexmpi_line (input, &got_eof);
+      if (!rsa_p && got_eof)
+        break;
+      if (!rsa_p)
+        die ("RSA parameter 'p' missing or not properly hex encoded\n");
+      rsa_q = read_hexmpi_line (input, &got_eof);
+      if (!rsa_q)
+        die ("RSA parameter 'q' missing or not properly hex encoded\n");
+      rsa_e = read_hexmpi_line (input, &got_eof);
+      if (!rsa_e)
+        die ("RSA parameter 'e' missing or not properly hex encoded\n");
+      got_eof = skip_to_empty_line (input);
+      
+      if (any)
+        putchar ('\n');
+
+      compute_missing (rsa_p, rsa_q, rsa_e);
+      
+      gcry_mpi_release (rsa_p);
+      gcry_mpi_release (rsa_q);
+      gcry_mpi_release (rsa_e);
+
+      any = 1;
+    }
+  while (!got_eof);
+  
+  return 0;
+}
+