This commit was manufactured by cvs2svn to create branch

'GNUPG-1-9-BRANCH'.

1 files changed, 550 insertions, 0 deletions

diff --git a/sm/encrypt.c b/sm/encrypt.c
new file mode 100644
index 000000000..725a81b70
--- /dev/null
+++ b/sm/encrypt.c
@@ -0,0 +1,550 @@
+/* encrypt.c - Encrypt a message
+ *	Copyright (C) 2001, 2003 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 2 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h> 
+#include <time.h>
+#include <assert.h>
+
+#include "gpgsm.h"
+#include <gcrypt.h>
+#include <ksba.h>
+
+#include "keydb.h"
+#include "i18n.h"
+
+
+struct dek_s {
+  const char *algoid;
+  int algo;
+  gcry_cipher_hd_t chd;
+  char key[32];
+  int keylen;
+  char iv[32];
+  int ivlen;
+};
+typedef struct dek_s *DEK;
+
+struct encrypt_cb_parm_s {
+  FILE *fp;
+  DEK dek;
+  int eof_seen;
+  int ready;
+  int readerror;
+  int bufsize;
+  unsigned char *buffer;
+  int buflen;
+};
+
+
+
+
+
+/* initialize the data encryptionkey (session key) */
+static int
+init_dek (DEK dek)
+{
+  int rc=0, mode, i;
+
+  dek->algo = gcry_cipher_map_name (dek->algoid);
+  mode = gcry_cipher_mode_from_oid (dek->algoid);
+  if (!dek->algo || !mode)
+    {
+      log_error ("unsupported algorithm `%s'\n", dek->algoid);
+      return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
+    }
+
+  dek->keylen = gcry_cipher_get_algo_keylen (dek->algo);
+  if (!dek->keylen || dek->keylen > sizeof (dek->key))
+    return gpg_error (GPG_ERR_BUG);
+
+  dek->ivlen = gcry_cipher_get_algo_blklen (dek->algo);
+  if (!dek->ivlen || dek->ivlen > sizeof (dek->iv))
+    return gpg_error (GPG_ERR_BUG);
+
+  if (dek->keylen < 100/8)
+    { /* make sure we don't use weak keys */
+      log_error ("key length of `%s' too small\n", dek->algoid);
+      return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
+    }
+  
+  rc = gcry_cipher_open (&dek->chd, dek->algo, mode, GCRY_CIPHER_SECURE);
+  if (rc)
+    {
+      log_error ("failed to create cipher context: %s\n", gpg_strerror (rc));
+      return rc;
+    }
+  
+  for (i=0; i < 8; i++)
+    {
+      gcry_randomize (dek->key, dek->keylen, GCRY_STRONG_RANDOM );
+      rc = gcry_cipher_setkey (dek->chd, dek->key, dek->keylen);
+      if (gpg_err_code (rc) != GPG_ERR_WEAK_KEY)
+        break;
+      log_info(_("weak key created - retrying\n") );
+    }
+  if (rc)
+    {
+      log_error ("failed to set the key: %s\n", gpg_strerror (rc));
+      gcry_cipher_close (dek->chd);
+      dek->chd = NULL;
+      return rc;
+    }
+
+  gcry_randomize (dek->iv, dek->ivlen, GCRY_STRONG_RANDOM);
+  rc = gcry_cipher_setiv (dek->chd, dek->iv, dek->ivlen);
+  if (rc)
+    {
+      log_error ("failed to set the IV: %s\n", gpg_strerror (rc));
+      gcry_cipher_close (dek->chd);
+      dek->chd = NULL;
+      return rc;
+    }
+  
+  return 0;
+}
+
+
+/* Encode the session key. NBITS is the number of bits which should be
+   used for packing the session key.  returns: An mpi with the session
+   key (caller must free) */
+static gcry_mpi_t
+encode_session_key (DEK dek, unsigned int nbits)
+{
+  int nframe = (nbits+7) / 8;
+  byte *p;
+  byte *frame;
+  int i,n;
+  gcry_mpi_t a;
+
+  if (dek->keylen + 7 > nframe || !nframe)
+    log_bug ("can't encode a %d bit key in a %d bits frame\n",
+             dek->keylen*8, nbits );
+
+  /* We encode the session key in this way:
+   *
+   *	   0  2  RND(n bytes)  0  KEY(k bytes)
+   *
+   * (But how can we store the leading 0 - the external representaion
+   *	of MPIs doesn't allow leading zeroes =:-)
+   *
+   * RND are non-zero random bytes.
+   * KEY is the encryption key (session key) 
+   */
+
+  frame = gcry_xmalloc_secure (nframe);
+  n = 0;
+  frame[n++] = 0;
+  frame[n++] = 2;
+  i = nframe - 3 - dek->keylen;
+  assert (i > 0);
+  p = gcry_random_bytes_secure (i, GCRY_STRONG_RANDOM);
+  /* replace zero bytes by new values */
+  for (;;)
+    {
+      int j, k;
+      byte *pp;
+
+      /* count the zero bytes */
+      for(j=k=0; j < i; j++ )
+        {
+          if( !p[j] )
+            k++;
+        }
+      if( !k )
+        break; /* okay: no zero bytes */
+
+      k += k/128; /* better get some more */
+      pp = gcry_random_bytes_secure (k, GCRY_STRONG_RANDOM);
+      for (j=0; j < i && k; j++)
+        {
+          if( !p[j] )
+            p[j] = pp[--k];
+        }
+      xfree (pp);
+    }
+  memcpy (frame+n, p, i);
+  xfree (p);
+
+  n += i;
+  frame[n++] = 0;
+  memcpy (frame+n, dek->key, dek->keylen);
+  n += dek->keylen;
+  assert (n == nframe);
+  if (gcry_mpi_scan (&a, GCRYMPI_FMT_USG, frame, n, &nframe) )
+    BUG ();
+  gcry_free(frame);
+
+  return a;
+}
+
+
+
+/* encrypt the DEK under the key contained in CERT and return it as a
+   canonical S-Exp in encval */
+static int
+encrypt_dek (const DEK dek, KsbaCert cert, char **encval)
+{
+  gcry_sexp_t s_ciph, s_data, s_pkey;
+  int rc;
+  KsbaSexp buf;
+  size_t len;
+
+  *encval = NULL;
+
+  /* get the key from the cert */
+  buf = ksba_cert_get_public_key (cert);
+  if (!buf)
+    {
+      log_error ("no public key for recipient\n");
+      return gpg_error (GPG_ERR_NO_PUBKEY);
+    }
+  len = gcry_sexp_canon_len (buf, 0, NULL, NULL);
+  if (!len)
+    {
+      log_error ("libksba did not return a proper S-Exp\n");
+      return gpg_error (GPG_ERR_BUG);
+    }
+  rc = gcry_sexp_sscan (&s_pkey, NULL, buf, len);
+  xfree (buf); buf = NULL;
+  if (rc)
+    {
+      log_error ("gcry_sexp_scan failed: %s\n", gpg_strerror (rc));
+      return rc;
+    }
+
+  /* put the encoded cleartext into a simple list */
+  {
+    /* fixme: actually the pkcs-1 encoding should go into libgcrypt */
+    gcry_mpi_t data = encode_session_key (dek, gcry_pk_get_nbits (s_pkey));
+    if (!data)
+      {
+        gcry_mpi_release (data);
+        return gpg_error (GPG_ERR_GENERAL);
+      }
+    if (gcry_sexp_build (&s_data, NULL, "%m", data))
+      BUG ();
+    gcry_mpi_release (data);
+  }
+
+  /* pass it to libgcrypt */
+  rc = gcry_pk_encrypt (&s_ciph, s_data, s_pkey);
+  gcry_sexp_release (s_data);
+  gcry_sexp_release (s_pkey);
+  
+  /* reformat it */
+  len = gcry_sexp_sprint (s_ciph, GCRYSEXP_FMT_CANON, NULL, 0);
+  assert (len); 
+  buf = xtrymalloc (len);
+  if (!buf)
+    {
+      gpg_error_t tmperr = OUT_OF_CORE (errno);
+      gcry_sexp_release (s_ciph);
+      return tmperr;
+    }
+  len = gcry_sexp_sprint (s_ciph, GCRYSEXP_FMT_CANON, buf, len);
+  assert (len);
+
+  *encval = buf;
+  return 0;
+}
+
+
+
+/* do the actual encryption */
+static int
+encrypt_cb (void *cb_value, char *buffer, size_t count, size_t *nread)
+{
+  struct encrypt_cb_parm_s *parm = cb_value;
+  int blklen = parm->dek->ivlen;
+  unsigned char *p;
+  size_t n;
+
+  *nread = 0;
+  if (!buffer)
+    return -1; /* not supported */
+
+  if (parm->ready)
+    return -1;
+
+  if (count < blklen)
+    BUG ();
+     
+  if (!parm->eof_seen)
+    { /* fillup the buffer */
+      p = parm->buffer;
+      for (n=parm->buflen; n < parm->bufsize; n++)
+        {
+          int c = getc (parm->fp);
+          if (c == EOF)
+            {
+              if (ferror (parm->fp))
+                {
+                  parm->readerror = errno;
+                  return -1;
+                }
+              parm->eof_seen = 1;
+              break; 
+            }
+          p[n] = c;
+        }
+      parm->buflen = n;
+    }
+  
+  n = parm->buflen < count? parm->buflen : count;
+  n = n/blklen * blklen;
+  if (n)
+    { /* encrypt the stuff */
+      gcry_cipher_encrypt (parm->dek->chd, buffer, n, parm->buffer, n);
+      *nread = n;
+      /* Who cares about cycles, take the easy way and shift the buffer */
+      parm->buflen -= n;
+      memmove (parm->buffer, parm->buffer+n, parm->buflen);
+    }
+  else if (parm->eof_seen)
+    { /* no complete block but eof: add padding */
+      /* fixme: we should try to do this also in the above code path */
+      int i, npad = blklen - (parm->buflen % blklen);
+      p = parm->buffer;
+      for (n=parm->buflen, i=0; n < parm->bufsize && i < npad; n++, i++)
+        p[n] = npad;
+      gcry_cipher_encrypt (parm->dek->chd, buffer, n, parm->buffer, n);
+      *nread = n;
+      parm->ready = 1;
+    }
+
+  return 0;
+}
+
+
+
+
+/* Perform an encrypt operation.  
+
+   Encrypt the data received on DATA-FD and write it to OUT_FP.  The
+   recipients are take from the certificate given in recplist; if this
+   is NULL it will be encrypted for a default recipient */
+int
+gpgsm_encrypt (CTRL ctrl, CERTLIST recplist, int data_fd, FILE *out_fp)
+{
+  int rc = 0;
+  Base64Context b64writer = NULL;
+  KsbaError err;
+  KsbaWriter writer;
+  KsbaReader reader = NULL;
+  KsbaCMS cms = NULL;
+  KsbaStopReason stopreason;
+  KEYDB_HANDLE kh = NULL;
+  struct encrypt_cb_parm_s encparm;
+  DEK dek = NULL;
+  int recpno;
+  FILE *data_fp = NULL;
+  CERTLIST cl;
+
+  memset (&encparm, 0, sizeof encparm);
+
+  if (!recplist)
+    {
+      log_error(_("no valid recipients given\n"));
+      gpgsm_status (ctrl, STATUS_NO_RECP, "0");
+      rc = gpg_error (GPG_ERR_NO_PUBKEY);
+      goto leave;
+    }
+
+  kh = keydb_new (0);
+  if (!kh)
+    {
+      log_error (_("failed to allocated keyDB handle\n"));
+      rc = gpg_error (GPG_ERR_GENERAL);
+      goto leave;
+    }
+
+  data_fp = fdopen ( dup (data_fd), "rb");
+  if (!data_fp)
+    {
+      rc = gpg_error (gpg_err_code_from_errno (errno));
+      log_error ("fdopen() failed: %s\n", strerror (errno));
+      goto leave;
+    }
+
+  reader = ksba_reader_new ();
+  if (!reader)
+      rc = KSBA_Out_Of_Core;
+  if (!rc)
+    rc = ksba_reader_set_cb (reader, encrypt_cb, &encparm);
+  if (rc)
+    {
+      rc = map_ksba_err (rc);
+      goto leave;
+    }
+  encparm.fp = data_fp;
+
+  ctrl->pem_name = "ENCRYPTED MESSAGE";
+  rc = gpgsm_create_writer (&b64writer, ctrl, out_fp, &writer);
+  if (rc)
+    {
+      log_error ("can't create writer: %s\n", gpg_strerror (rc));
+      goto leave;
+    }
+
+  cms = ksba_cms_new ();
+  if (!cms)
+    {
+      rc = gpg_error (GPG_ERR_ENOMEM);
+      goto leave;
+    }
+
+  err = ksba_cms_set_reader_writer (cms, reader, writer);
+  if (err)
+    {
+      log_debug ("ksba_cms_set_reader_writer failed: %s\n",
+                 ksba_strerror (err));
+      rc = map_ksba_err (err);
+      goto leave;
+    }
+
+  /* We are going to create enveloped data with uninterpreted data as
+     inner content */
+  err = ksba_cms_set_content_type (cms, 0, KSBA_CT_ENVELOPED_DATA);
+  if (!err)
+    err = ksba_cms_set_content_type (cms, 1, KSBA_CT_DATA);
+  if (err)
+    {
+      log_debug ("ksba_cms_set_content_type failed: %s\n",
+                 ksba_strerror (err));
+      rc = map_ksba_err (err);
+      goto leave;
+    }
+
+  /* create a session key */
+  dek = xtrycalloc (1, sizeof *dek); /* hmmm: should we put it into secmem?*/
+  if (!dek)
+    rc = OUT_OF_CORE (errno);
+  else
+  {
+    dek->algoid = opt.def_cipher_algoid;
+    rc = init_dek (dek);
+  }
+  if (rc)
+    {
+      log_error ("failed to create the session key: %s\n",
+                 gpg_strerror (rc));
+      goto leave;
+    }
+
+  err = ksba_cms_set_content_enc_algo (cms, dek->algoid, dek->iv, dek->ivlen);
+  if (err)
+    {
+      log_error ("ksba_cms_set_content_enc_algo failed: %s\n",
+                 ksba_strerror (err));
+      rc = map_ksba_err (err);
+      goto leave;
+    }
+
+  encparm.dek = dek;
+  /* Use a ~8k (AES) or ~4k (3DES) buffer */
+  encparm.bufsize = 500 * dek->ivlen;
+  encparm.buffer = xtrymalloc (encparm.bufsize);
+  if (!encparm.buffer)
+    {
+      rc = OUT_OF_CORE (errno);
+      goto leave;
+    }
+
+  /* gather certificates of recipients, encrypt the session key for
+     each and store them in the CMS object */
+  for (recpno = 0, cl = recplist; cl; recpno++, cl = cl->next)
+    {
+      char *encval;
+      
+      rc = encrypt_dek (dek, cl->cert, &encval);
+      if (rc)
+        {
+          log_error ("encryption failed for recipient no. %d: %s\n",
+                     recpno, gpg_strerror (rc));
+          goto leave;
+        }
+      
+      err = ksba_cms_add_recipient (cms, cl->cert);
+      if (err)
+        {
+          log_error ("ksba_cms_add_recipient failed: %s\n",
+                     ksba_strerror (err));
+          rc = map_ksba_err (err);
+          xfree (encval);
+          goto leave;
+        }
+      
+      err = ksba_cms_set_enc_val (cms, recpno, encval);
+      xfree (encval);
+      if (err)
+        {
+          log_error ("ksba_cms_set_enc_val failed: %s\n",
+                     ksba_strerror (err));
+          rc = map_ksba_err (err);
+          goto leave;
+        }
+  }
+
+  /* main control loop for encryption */
+  recpno = 0;
+  do 
+    {
+      err = ksba_cms_build (cms, &stopreason);
+      if (err)
+        {
+          log_debug ("ksba_cms_build failed: %s\n", ksba_strerror (err));
+          rc = map_ksba_err (err);
+          goto leave;
+        }
+    }
+  while (stopreason != KSBA_SR_READY);   
+
+  if (encparm.readerror)
+    {
+      log_error ("error reading input: %s\n", strerror (encparm.readerror));
+      rc = gpg_error (gpg_err_code_from_errno (encparm.readerror));
+      goto leave;
+    }
+
+
+  rc = gpgsm_finish_writer (b64writer);
+  if (rc) 
+    {
+      log_error ("write failed: %s\n", gpg_strerror (rc));
+      goto leave;
+    }
+  log_info ("encrypted data created\n");
+
+ leave:
+  ksba_cms_release (cms);
+  gpgsm_destroy_writer (b64writer);
+  ksba_reader_release (reader);
+  keydb_release (kh); 
+  xfree (dek);
+  if (data_fp)
+    fclose (data_fp);
+  xfree (encparm.buffer);
+  return rc;
+}