mirror of
git://git.gnupg.org/gnupg.git
synced 2025-07-02 22:46:30 +02:00
--encrypt does now work for a hardwired key.
This commit is contained in:
Werner Koch
parent
79956a08e0
commit
f312047a67
3 changed files with 423 additions and 105 deletions
522
sm/encrypt.c
522
sm/encrypt.c
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@ -35,13 +35,336 @@
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#include "i18n.h"
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KsbaCert
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struct dek_s {
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const char *algoid;
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int algo;
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GCRY_CIPHER_HD chd;
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char key[32];
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int keylen;
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char iv[32];
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int ivlen;
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};
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typedef struct dek_s *DEK;
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struct encrypt_cb_parm_s {
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FILE *fp;
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DEK dek;
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int eof_seen;
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int ready;
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int readerror;
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int bufsize;
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unsigned char *buffer;
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int buflen;
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};
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static KsbaCert
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get_default_recipient (void)
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{
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return NULL;
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const char key[] =
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"CN=test cert 1,OU=Aegypten Project,O=g10 Code GmbH,L=#44FC7373656C646F7266#,C=DE";
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KsbaCert cert = NULL;
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KEYDB_HANDLE kh = NULL;
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int rc;
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kh = keydb_new (0);
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if (!kh)
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return NULL;
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rc = keydb_search_subject (kh, key);
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if (rc)
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{
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log_debug ("failed to find default certificate: rc=%d\n", rc);
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}
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else
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{
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rc = keydb_get_cert (kh, &cert);
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if (rc)
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{
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log_debug ("failed to get cert: rc=%d\n", rc);
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}
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}
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keydb_release (kh);
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return cert;
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}
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/* initialize the data encryptionkey (session key) */
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static int
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init_dek (DEK dek)
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{
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int rc=0, i;
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dek->algo = gcry_cipher_map_name (dek->algoid);
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if (!dek->algo)
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{
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log_error ("unsupported algorithm `%s'\n", dek->algoid);
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return GNUPG_Unsupported_Algorithm;
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}
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dek->keylen = gcry_cipher_get_algo_keylen (dek->algo);
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if (!dek->keylen || dek->keylen > sizeof (dek->key))
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return GNUPG_Bug;
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dek->ivlen = gcry_cipher_get_algo_blklen (dek->algo);
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if (!dek->ivlen || dek->ivlen > sizeof (dek->iv))
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return GNUPG_Bug;
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if (dek->keylen < 100/8)
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{ /* make sure we don't use weak keys */
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log_error ("key length of `%s' too small\n", dek->algoid);
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return GNUPG_Unsupported_Algorithm;
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}
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dek->chd = gcry_cipher_open (dek->algo,
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GCRY_CIPHER_MODE_CBC,
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GCRY_CIPHER_SECURE);
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if (!dek->chd)
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{
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log_error ("failed to create cipher context: %s\n", gcry_strerror (-1));
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return GNUPG_General_Error;
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}
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for (i=0; i < 8; i++)
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{
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gcry_randomize (dek->key, dek->keylen, GCRY_STRONG_RANDOM );
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rc = gcry_cipher_setkey (dek->chd, dek->key, dek->keylen);
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if (rc != GCRYERR_WEAK_KEY)
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break;
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log_info(_("weak key created - retrying\n") );
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}
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if (rc)
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{
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log_error ("failed to set the key: %s\n", gcry_strerror (rc));
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gcry_cipher_close (dek->chd);
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dek->chd = NULL;
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return map_gcry_err (rc);
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}
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gcry_randomize (dek->iv, dek->ivlen, GCRY_STRONG_RANDOM);
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rc = gcry_cipher_setiv (dek->chd, dek->iv, dek->ivlen);
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if (rc)
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{
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log_error ("failed to set the IV: %s\n", gcry_strerror (rc));
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gcry_cipher_close (dek->chd);
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dek->chd = NULL;
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return map_gcry_err (rc);
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}
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return 0;
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}
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/* Encode the session key. NBITS is the number of bits which should be
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used for packing the session key. returns: An mpi with the session
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key (caller must free) */
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static GCRY_MPI
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encode_session_key (DEK dek, unsigned int nbits)
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{
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int nframe = (nbits+7) / 8;
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byte *p;
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byte *frame;
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int i,n;
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MPI a;
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if (dek->keylen + 7 > nframe || !nframe)
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log_bug ("can't encode a %d bit key in a %d bits frame\n",
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dek->keylen*8, nbits );
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/* We encode the session key in this way:
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*
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* 0 2 RND(n bytes) 0 KEY(k bytes)
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*
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* (But how can we store the leading 0 - the external representaion
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* of MPIs doesn't allow leading zeroes =:-)
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*
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* RND are non-zero random bytes.
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* KEY is the encryption key (session key)
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*/
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frame = gcry_xmalloc_secure (nframe);
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n = 0;
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frame[n++] = 0;
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frame[n++] = 2;
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i = nframe - 3 - dek->keylen;
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assert (i > 0);
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p = gcry_random_bytes_secure (i, GCRY_STRONG_RANDOM);
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/* replace zero bytes by new values */
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for (;;)
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{
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int j, k;
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byte *pp;
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/* count the zero bytes */
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for(j=k=0; j < i; j++ )
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{
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if( !p[j] )
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k++;
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}
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if( !k )
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break; /* okay: no zero bytes */
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k += k/128; /* better get some more */
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pp = gcry_random_bytes_secure (k, GCRY_STRONG_RANDOM);
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for (j=0; j < i && k; j++)
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{
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if( !p[j] )
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p[j] = pp[--k];
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}
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xfree (pp);
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}
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memcpy (frame+n, p, i);
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xfree (p);
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n += i;
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frame[n++] = 0;
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memcpy (frame+n, dek->key, dek->keylen);
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n += dek->keylen;
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assert (n == nframe);
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if (gcry_mpi_scan (&a, GCRYMPI_FMT_USG, frame, &nframe) )
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BUG ();
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gcry_free(frame);
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return a;
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}
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/* encrypt the DEK under the key contained in CERT and return it as a
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canonical S-Exp in encval */
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static int
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encrypt_dek (const DEK dek, KsbaCert cert, char **encval)
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{
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GCRY_SEXP s_ciph, s_data, s_pkey;
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int rc;
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char *buf;
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size_t len;
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*encval = NULL;
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/* get the key from the cert */
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buf = ksba_cert_get_public_key (cert);
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if (!buf)
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{
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log_error ("no public key for recipient\n");
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return GNUPG_No_Public_Key;
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}
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rc = gcry_sexp_sscan (&s_pkey, NULL, buf, strlen(buf));
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xfree (buf); buf = NULL;
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if (rc)
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{
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log_error ("gcry_sexp_scan failed: %s\n", gcry_strerror (rc));
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return map_gcry_err (rc);
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}
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/* put the encoded cleartext into a simple list */
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{
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/* fixme: actually the pkcs-1 encoding should go into libgcrypt */
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GCRY_MPI data = encode_session_key (dek, gcry_pk_get_nbits (s_pkey));
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if (!data)
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{
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gcry_mpi_release (data);
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return GNUPG_General_Error;
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}
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if (gcry_sexp_build (&s_data, NULL, "%m", data))
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BUG ();
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gcry_mpi_release (data);
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}
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/* pass it to libgcrypt */
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rc = gcry_pk_encrypt (&s_ciph, s_data, s_pkey);
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gcry_sexp_release (s_data);
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gcry_sexp_release (s_pkey);
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/* reformat it */
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len = gcry_sexp_sprint (s_ciph, GCRYSEXP_FMT_CANON, NULL, 0);
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assert (len);
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buf = xtrymalloc (len);
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if (!buf)
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{
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gcry_sexp_release (s_ciph);
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return GNUPG_Out_Of_Core;
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}
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len = gcry_sexp_sprint (s_ciph, GCRYSEXP_FMT_CANON, buf, len);
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assert (len);
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*encval = buf;
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return 0;
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}
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/* do the actual encryption */
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static int
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encrypt_cb (void *cb_value, char *buffer, size_t count, size_t *nread)
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{
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struct encrypt_cb_parm_s *parm = cb_value;
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int blklen = parm->dek->ivlen;
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unsigned char *p;
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size_t n;
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*nread = 0;
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if (!buffer)
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return -1; /* not supported */
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if (parm->ready)
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return -1;
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if (count < blklen)
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BUG ();
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if (!parm->eof_seen)
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{ /* fillup the buffer */
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p = parm->buffer;
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for (n=parm->buflen; n < parm->bufsize; n++)
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{
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int c = getc (parm->fp);
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if (c == EOF)
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{
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if (ferror (parm->fp))
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{
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parm->readerror = errno;
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return -1;
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}
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parm->eof_seen = 1;
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break;
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}
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p[n] = c;
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}
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parm->buflen = n;
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}
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n = parm->buflen < count? parm->buflen : count;
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n = n/blklen * blklen;
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if (n)
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{ /* encrypt the stuff */
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gcry_cipher_encrypt (parm->dek->chd, buffer, n, parm->buffer, n);
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*nread = n;
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/* Who cares about cycles, take the easy way and shift the buffer */
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parm->buflen -= n;
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memmove (parm->buffer, parm->buffer+n, parm->buflen);
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}
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else if (parm->eof_seen)
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{ /* no complete block but eof: add padding */
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/* fixme: we should try to do this also in the above code path */
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int i, npad = blklen - (parm->buflen % blklen);
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p = parm->buffer;
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for (n=parm->buflen, i=0; n < parm->bufsize && i < npad; n++, i++)
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p[n] = npad;
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gcry_cipher_encrypt (parm->dek->chd, buffer, n, parm->buffer, n);
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*nread = n;
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parm->ready = 1;
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}
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return 0;
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}
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/* Perform an encrypt operation.
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@ -50,23 +373,21 @@ get_default_recipient (void)
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int
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gpgsm_encrypt (CTRL ctrl, int data_fd, FILE *out_fp)
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{
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int i, rc;
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Base64Context b64reader = NULL;
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int rc = 0;
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Base64Context b64writer = NULL;
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KsbaError err;
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KsbaWriter writer;
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KsbaReader reader;
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KsbaReader reader = NULL;
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KsbaCMS cms = NULL;
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KsbaStopReason stopreason;
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KsbaCert cert;
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KEYDB_HANDLE kh = NULL;
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GCRY_MD_HD data_md = NULL;
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int signer;
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const char *algoid;
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struct encrypt_cb_parm_s encparm;
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DEK dek = NULL;
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int recpno;
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FILE *data_fp = NULL;
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int algo;
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memset (&encparm, 0, sizeof encparm);
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kh = keydb_new (0);
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if (!kh)
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{
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@ -83,12 +404,17 @@ gpgsm_encrypt (CTRL ctrl, int data_fd, FILE *out_fp)
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goto leave;
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}
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rc = gpgsm_create_reader (&b64reader, ctrl, data_fp, &reader);
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reader = ksba_reader_new ();
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if (!reader)
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rc = KSBA_Out_Of_Core;
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if (!rc)
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rc = ksba_reader_set_cb (reader, encrypt_cb, &encparm);
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if (rc)
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{
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log_error ("can't create reader: %s\n", gnupg_strerror (rc));
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rc = map_ksba_err (rc);
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goto leave;
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}
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encparm.fp = data_fp;
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rc = gpgsm_create_writer (&b64writer, ctrl, out_fp, &writer);
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if (rc)
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@ -113,10 +439,11 @@ gpgsm_encrypt (CTRL ctrl, int data_fd, FILE *out_fp)
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goto leave;
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}
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/* We are going to create signed data with data as encap. content */
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/* We are going to create enveloped data with uninterpreted data as
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inner content */
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err = ksba_cms_set_content_type (cms, 0, KSBA_CT_ENVELOPED_DATA);
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if (!err)
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err = ksba_cms_set_content_type (cms, 1, KSBA_CT_ENCRYPTED_DATA);
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err = ksba_cms_set_content_type (cms, 1, KSBA_CT_DATA);
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if (err)
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{
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log_debug ("ksba_cms_set_content_type failed: %s\n",
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@ -125,54 +452,92 @@ gpgsm_encrypt (CTRL ctrl, int data_fd, FILE *out_fp)
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goto leave;
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}
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/* gather certificates of recipients and store them in the CMS object */
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cert = get_default_recipient ();
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if (!cert)
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/* create a session key */
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dek = xtrycalloc (1, sizeof *dek); /* hmmm: should we put it into secmem?*/
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if (!dek)
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rc = GNUPG_Out_Of_Core;
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else
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{
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dek->algoid = "1.2.840.113549.3.7"; /*des-EDE3-CBC*/
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rc = init_dek (dek);
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}
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if (rc)
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{
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log_error ("no default recipient found\n");
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rc = seterr (General_Error);
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log_error ("failed to create the session key: %s\n",
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gnupg_strerror (rc));
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goto leave;
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}
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/* err = ksba_cms_add_signer (cms, cert); */
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/* if (err) */
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/* { */
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/* log_debug ("ksba_cms_add_signer failed: %s\n", ksba_strerror (err)); */
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/* rc = map_ksba_err (err); */
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/* goto leave; */
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/* } */
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cert = NULL; /* cms does now own the certificate */
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/* Set the hash algorithm we are going to use */
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err = ksba_cms_add_digest_algo (cms, "1.3.14.3.2.26" /*SHA-1*/);
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err = ksba_cms_set_content_enc_algo (cms, dek->algoid, dek->iv, dek->ivlen);
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if (err)
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{
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log_debug ("ksba_cms_add_digest_algo failed: %s\n", ksba_strerror (err));
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log_error ("ksba_cms_set_content_enc_algo failed: %s\n",
|
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ksba_strerror (err));
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rc = map_ksba_err (err);
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goto leave;
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}
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/* Prepare hashing (actually we are figuring out what we have set above)*/
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data_md = gcry_md_open (0, 0);
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if (!data_md)
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encparm.dek = dek;
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/* fixme: we should use a larger buffer - the small one is better
|
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for testing */
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encparm.bufsize = 10 * dek->ivlen;
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encparm.buffer = xtrymalloc (encparm.bufsize);
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if (!encparm.buffer)
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{
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rc = map_gcry_err (gcry_errno());
|
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log_error ("md_open failed: %s\n", gcry_strerror (-1));
|
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rc = seterr (Out_Of_Core);
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goto leave;
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}
|
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for (i=0; (algoid=ksba_cms_get_digest_algo_list (cms, i)); i++)
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|
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/* gather certificates of recipients, encrypt the session key for
|
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each and store them in the CMS object */
|
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for (recpno = 0; recpno < 1; recpno++)
|
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{
|
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algo = gcry_md_map_name (algoid);
|
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if (!algo)
|
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KsbaCert cert;
|
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char *encval;
|
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|
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/* fixme: get the recipients out of the arguments passed to us */
|
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cert = get_default_recipient ();
|
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if (!cert)
|
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{
|
||||
log_error ("unknown hash algorithm `%s'\n", algoid? algoid:"?");
|
||||
rc = GNUPG_Bug;
|
||||
log_error ("no default recipient found\n");
|
||||
rc = seterr (General_Error);
|
||||
goto leave;
|
||||
}
|
||||
gcry_md_enable (data_md, algo);
|
||||
}
|
||||
|
||||
rc = encrypt_dek (dek, cert, &encval);
|
||||
if (rc)
|
||||
{
|
||||
log_error ("encryption failed for recipient no. %d: %s\n",
|
||||
recpno, gnupg_strerror (rc));
|
||||
ksba_cert_release (cert);
|
||||
goto leave;
|
||||
}
|
||||
|
||||
err = ksba_cms_add_recipient (cms, cert);
|
||||
if (err)
|
||||
{
|
||||
log_error ("ksba_cms_add_recipient failed: %s\n",
|
||||
ksba_strerror (err));
|
||||
rc = map_ksba_err (err);
|
||||
xfree (encval);
|
||||
ksba_cert_release (cert);
|
||||
goto leave;
|
||||
}
|
||||
cert = NULL; /* cms does now own the certificate */
|
||||
|
||||
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;
|
||||
}
|
||||
}
|
||||
|
||||
signer = 0;
|
||||
/* main control loop for encryption */
|
||||
recpno = 0;
|
||||
do
|
||||
{
|
||||
err = ksba_cms_build (cms, &stopreason);
|
||||
|
|
@ -183,65 +548,17 @@ gpgsm_encrypt (CTRL ctrl, int data_fd, FILE *out_fp)
|
|||
goto leave;
|
||||
}
|
||||
log_debug ("ksba_cms_build - stop reason %d\n", stopreason);
|
||||
|
||||
if (stopreason == KSBA_SR_BEGIN_DATA)
|
||||
{
|
||||
}
|
||||
else if (stopreason == KSBA_SR_NEED_SIG)
|
||||
{ /* calculate the signature for all signers */
|
||||
GCRY_MD_HD md;
|
||||
|
||||
algo = GCRY_MD_SHA1;
|
||||
signer = 0;
|
||||
md = gcry_md_open (algo, 0);
|
||||
if (!md)
|
||||
{
|
||||
log_error ("md_open failed: %s\n", gcry_strerror (-1));
|
||||
goto leave;
|
||||
}
|
||||
ksba_cms_set_hash_function (cms, HASH_FNC, md);
|
||||
rc = ksba_cms_hash_signed_attrs (cms, signer);
|
||||
if (rc)
|
||||
{
|
||||
log_debug ("hashing signed attrs failed: %s\n",
|
||||
ksba_strerror (rc));
|
||||
gcry_md_close (md);
|
||||
goto leave;
|
||||
}
|
||||
|
||||
{ /* This is all an temporary hack */
|
||||
char *sigval;
|
||||
|
||||
cert = NULL;
|
||||
if (!cert)
|
||||
{
|
||||
log_error ("oops - failed to get cert again\n");
|
||||
rc = seterr (General_Error);
|
||||
goto leave;
|
||||
}
|
||||
|
||||
sigval = NULL;
|
||||
rc = gpgsm_create_cms_signature (cert, md, algo, &sigval);
|
||||
if (rc)
|
||||
{
|
||||
ksba_cert_release (cert);
|
||||
goto leave;
|
||||
}
|
||||
|
||||
err = ksba_cms_set_sig_val (cms, signer, sigval);
|
||||
xfree (sigval);
|
||||
if (err)
|
||||
{
|
||||
log_error ("failed to store the signature: %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 = seterr (Read_Error);
|
||||
goto leave;
|
||||
}
|
||||
|
||||
|
||||
rc = gpgsm_finish_writer (b64writer);
|
||||
if (rc)
|
||||
{
|
||||
|
|
@ -253,10 +570,11 @@ gpgsm_encrypt (CTRL ctrl, int data_fd, FILE *out_fp)
|
|||
leave:
|
||||
ksba_cms_release (cms);
|
||||
gpgsm_destroy_writer (b64writer);
|
||||
gpgsm_destroy_reader (b64reader);
|
||||
ksba_reader_release (reader);
|
||||
keydb_release (kh);
|
||||
gcry_md_close (data_md);
|
||||
xfree (dek);
|
||||
if (data_fp)
|
||||
fclose (data_fp);
|
||||
xfree (encparm.buffer);
|
||||
return rc;
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue