Adding upstream version 2.2.40.upstream/2.2.40upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 589 insertions, 0 deletions

diff --git a/sm/encrypt.c b/sm/encrypt.c
new file mode 100644
index 0000000..587b568
--- /dev/null
+++ b/sm/encrypt.c
@@ -0,0 +1,589 @@
+/* encrypt.c - Encrypt a message
+ * Copyright (C) 2001, 2003, 2004, 2007, 2008,
+ *               2010 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 <https://www.gnu.org/licenses/>.
+ */
+
+#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 "../common/i18n.h"
+#include "../common/compliance.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;
+
+
+/* Callback parameters for the encryption.  */
+struct encrypt_cb_parm_s
+{
+  estream_t fp;
+  DEK dek;
+  int eof_seen;
+  int ready;
+  int readerror;
+  int bufsize;
+  unsigned char *buffer;
+  int buflen;
+};
+
+
+
+
+
+/* Initialize the data encryption key (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);
+    }
+
+  /* Extra check for algorithms we consider to be too weak for
+     encryption, although we support them for decryption.  Note that
+     there is another check below discriminating on the key length. */
+  switch (dek->algo)
+    {
+    case GCRY_CIPHER_DES:
+    case GCRY_CIPHER_RFC2268_40:
+      log_error ("cipher algorithm '%s' not allowed: too weak\n",
+                 gnupg_cipher_algo_name (dek->algo));
+      return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
+    default:
+      break;
+    }
+
+  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);
+
+  /* Make sure we don't use weak keys. */
+  if (dek->keylen < 100/8)
+    {
+      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_create_nonce (dek->iv, dek->ivlen);
+  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;
+}
+
+
+static int
+encode_session_key (DEK dek, gcry_sexp_t * r_data)
+{
+  gcry_sexp_t data;
+  char *p;
+  int rc;
+
+  p = xtrymalloc (64 + 2 * dek->keylen);
+  if (!p)
+    return gpg_error_from_syserror ();
+  strcpy (p, "(data\n (flags pkcs1)\n (value #");
+  bin2hex (dek->key, dek->keylen, p + strlen (p));
+  strcat (p, "#))\n");
+  rc = gcry_sexp_sscan (&data, NULL, p, strlen (p));
+  xfree (p);
+  *r_data = data;
+  return rc;
+}
+
+
+/* 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, ksba_cert_t cert, unsigned char **encval)
+{
+  gcry_sexp_t s_ciph, s_data, s_pkey;
+  int rc;
+  ksba_sexp_t 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, (char*)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. */
+  s_data = NULL; /* (avoid compiler warning) */
+  rc = encode_session_key (dek, &s_data);
+  if (rc)
+    {
+      gcry_sexp_release (s_pkey);
+      log_error ("encode_session_key failed: %s\n", gpg_strerror (rc));
+      return rc;
+    }
+
+  /* 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. */
+  if (!rc)
+    {
+      rc = make_canon_sexp (s_ciph, encval, NULL);
+      gcry_sexp_release (s_ciph);
+    }
+  return rc;
+}
+
+
+
+/* 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 = es_getc (parm->fp);
+          if (c == EOF)
+            {
+              if (es_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_t ctrl, certlist_t recplist, int data_fd, estream_t out_fp)
+{
+  int rc = 0;
+  gnupg_ksba_io_t b64writer = NULL;
+  gpg_error_t err;
+  ksba_writer_t writer;
+  ksba_reader_t reader = NULL;
+  ksba_cms_t cms = NULL;
+  ksba_stop_reason_t stopreason;
+  KEYDB_HANDLE kh = NULL;
+  struct encrypt_cb_parm_s encparm;
+  DEK dek = NULL;
+  int recpno;
+  estream_t data_fp = NULL;
+  certlist_t cl;
+  int count;
+  int compliant;
+
+  memset (&encparm, 0, sizeof encparm);
+
+  audit_set_type (ctrl->audit, AUDIT_TYPE_ENCRYPT);
+
+  /* Check that the certificate list is not empty and that at least
+     one certificate is not flagged as encrypt_to; i.e. is a real
+     recipient. */
+  for (cl = recplist; cl; cl = cl->next)
+    if (!cl->is_encrypt_to)
+      break;
+  if (!cl)
+    {
+      log_error(_("no valid recipients given\n"));
+      gpgsm_status (ctrl, STATUS_NO_RECP, "0");
+      audit_log_i (ctrl->audit, AUDIT_GOT_RECIPIENTS, 0);
+      rc = gpg_error (GPG_ERR_NO_PUBKEY);
+      goto leave;
+    }
+
+  for (count = 0, cl = recplist; cl; cl = cl->next)
+    count++;
+  audit_log_i (ctrl->audit, AUDIT_GOT_RECIPIENTS, count);
+
+  kh = keydb_new ();
+  if (!kh)
+    {
+      log_error (_("failed to allocate keyDB handle\n"));
+      rc = gpg_error (GPG_ERR_GENERAL);
+      goto leave;
+    }
+
+  /* Fixme:  We should use the unlocked version of the es functions.  */
+  data_fp = es_fdopen_nc (data_fd, "rb");
+  if (!data_fp)
+    {
+      rc = gpg_error_from_syserror ();
+      log_error ("fdopen() failed: %s\n", strerror (errno));
+      goto leave;
+    }
+
+  err = ksba_reader_new (&reader);
+  if (err)
+      rc = err;
+  if (!rc)
+    rc = ksba_reader_set_cb (reader, encrypt_cb, &encparm);
+  if (rc)
+      goto leave;
+
+  encparm.fp = data_fp;
+
+  ctrl->pem_name = "ENCRYPTED MESSAGE";
+  rc = gnupg_ksba_create_writer
+    (&b64writer, ((ctrl->create_pem? GNUPG_KSBA_IO_PEM : 0)
+                  | (ctrl->create_base64? GNUPG_KSBA_IO_BASE64 : 0)),
+     ctrl->pem_name, out_fp, &writer);
+  if (rc)
+    {
+      log_error ("can't create writer: %s\n", gpg_strerror (rc));
+      goto leave;
+    }
+
+  err = ksba_cms_new (&cms);
+  if (err)
+    {
+      rc = err;
+      goto leave;
+    }
+
+  err = ksba_cms_set_reader_writer (cms, reader, writer);
+  if (err)
+    {
+      log_debug ("ksba_cms_set_reader_writer failed: %s\n",
+                 gpg_strerror (err));
+      rc = err;
+      goto leave;
+    }
+
+  audit_log (ctrl->audit, AUDIT_GOT_DATA);
+
+  /* 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",
+                 gpg_strerror (err));
+      rc = err;
+      goto leave;
+    }
+
+  /* Check compliance.  */
+  if (!gnupg_cipher_is_allowed
+      (opt.compliance, 1, gcry_cipher_map_name (opt.def_cipher_algoid),
+       gcry_cipher_mode_from_oid (opt.def_cipher_algoid)))
+    {
+      log_error (_("cipher algorithm '%s' may not be used in %s mode\n"),
+		 opt.def_cipher_algoid,
+		 gnupg_compliance_option_string (opt.compliance));
+      rc = gpg_error (GPG_ERR_CIPHER_ALGO);
+      goto leave;
+    }
+
+  if (!gnupg_rng_is_compliant (opt.compliance))
+    {
+      rc = gpg_error (GPG_ERR_FORBIDDEN);
+      log_error (_("%s is not compliant with %s mode\n"),
+                 "RNG",
+                 gnupg_compliance_option_string (opt.compliance));
+      gpgsm_status_with_error (ctrl, STATUS_ERROR,
+                               "random-compliance", rc);
+      goto leave;
+    }
+
+  /* Create a session key */
+  dek = xtrycalloc_secure (1, sizeof *dek);
+  if (!dek)
+    rc = out_of_core ();
+  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",
+                 gpg_strerror (err));
+      rc = 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 ();
+      goto leave;
+    }
+
+  audit_log_s (ctrl->audit, AUDIT_SESSION_KEY, dek->algoid);
+
+  compliant = gnupg_cipher_is_compliant (CO_DE_VS, dek->algo,
+                                         GCRY_CIPHER_MODE_CBC);
+
+  /* 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)
+    {
+      unsigned char *encval;
+      unsigned int nbits;
+      int pk_algo;
+
+      /* Check compliance.  */
+      pk_algo = gpgsm_get_key_algo_info (cl->cert, &nbits);
+      if (!gnupg_pk_is_compliant (opt.compliance, pk_algo, 0,
+                                  NULL, nbits, NULL))
+        {
+          char  kidstr[10+1];
+
+          snprintf (kidstr, sizeof kidstr, "0x%08lX",
+                    gpgsm_get_short_fingerprint (cl->cert, NULL));
+          log_info (_("WARNING: key %s is not suitable for encryption"
+                      " in %s mode\n"),
+                    kidstr,
+                    gnupg_compliance_option_string (opt.compliance));
+        }
+
+      /* Fixme: When adding ECC we need to provide the curvename and
+       * the key to gnupg_pk_is_compliant.  */
+      if (compliant
+          && !gnupg_pk_is_compliant (CO_DE_VS, pk_algo, 0, NULL, nbits, NULL))
+        compliant = 0;
+
+      rc = encrypt_dek (dek, cl->cert, &encval);
+      if (rc)
+        {
+          audit_log_cert (ctrl->audit, AUDIT_ENCRYPTED_TO, cl->cert, 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)
+        {
+          audit_log_cert (ctrl->audit, AUDIT_ENCRYPTED_TO, cl->cert, err);
+          log_error ("ksba_cms_add_recipient failed: %s\n",
+                     gpg_strerror (err));
+          rc = err;
+          xfree (encval);
+          goto leave;
+        }
+
+      err = ksba_cms_set_enc_val (cms, recpno, encval);
+      xfree (encval);
+      audit_log_cert (ctrl->audit, AUDIT_ENCRYPTED_TO, cl->cert, err);
+      if (err)
+        {
+          log_error ("ksba_cms_set_enc_val failed: %s\n",
+                     gpg_strerror (err));
+          rc = err;
+          goto leave;
+        }
+    }
+
+  if (compliant && gnupg_gcrypt_is_compliant (CO_DE_VS))
+    gpgsm_status (ctrl, STATUS_ENCRYPTION_COMPLIANCE_MODE,
+                  gnupg_status_compliance_flag (CO_DE_VS));
+  else if (opt.require_compliance
+           && opt.compliance == CO_DE_VS)
+    {
+      log_error (_("operation forced to fail due to"
+                   " unfulfilled compliance rules\n"));
+      gpgsm_errors_seen = 1;
+      rc = gpg_error (GPG_ERR_FORBIDDEN);
+      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", gpg_strerror (err));
+          rc = 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 = gnupg_ksba_finish_writer (b64writer);
+  if (rc)
+    {
+      log_error ("write failed: %s\n", gpg_strerror (rc));
+      goto leave;
+    }
+  audit_log (ctrl->audit, AUDIT_ENCRYPTION_DONE);
+  if (!opt.quiet)
+    log_info ("encrypted data created\n");
+
+ leave:
+  ksba_cms_release (cms);
+  gnupg_ksba_destroy_writer (b64writer);
+  ksba_reader_release (reader);
+  keydb_release (kh);
+  xfree (dek);
+  es_fclose (data_fp);
+  xfree (encparm.buffer);
+  return rc;
+}