diff options
| -rw-r--r-- | src/util/crypto_ecc.c | 84 |
1 files changed, 72 insertions, 12 deletions
diff --git a/src/util/crypto_ecc.c b/src/util/crypto_ecc.c index 7f88c3e5fa..97ba2a3b65 100644 --- a/src/util/crypto_ecc.c +++ b/src/util/crypto_ecc.c @@ -170,7 +170,7 @@ GNUNET_CRYPTO_ecc_key_get_public (const struct GNUNET_CRYPTO_EccPrivateKey *priv * @return string representing 'pub' */ char * -GNUNET_CRYPTO_ecc_public_key_to_string (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded *pub) +GNUNET_CRYPTO_ecc_public_key_to_string (const struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded *pub) { char *pubkeybuf; size_t keylen = (sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded)) * 8; @@ -340,8 +340,9 @@ GNUNET_CRYPTO_ecc_decode_key (const char *buf, if (len < sizeof (uint16_t)) return NULL; memcpy (&be, buf, sizeof (be)); - if (len != ntohs (be)) + if (len < ntohs (be)) return NULL; + len = ntohs (be); if (0 != (rc = gcry_sexp_sscan (&sexp, &erroff, &buf[2], @@ -644,7 +645,7 @@ GNUNET_CRYPTO_ecc_key_create_from_file (const char *filename) GNUNET_assert (fs == GNUNET_DISK_file_read (fd, enc, fs)); len = ntohs (enc->size); ret = NULL; - if ((len != fs) || + if ((len > fs) || (NULL == (ret = GNUNET_CRYPTO_ecc_decode_key ((char *) enc, len)))) { LOG (GNUNET_ERROR_TYPE_ERROR, @@ -936,7 +937,6 @@ data_to_pkcs1 (const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose) GNUNET_CRYPTO_short_hash (purpose, ntohl (purpose->size), &hc); #define FORMATSTRING "(4:data(5:flags3:raw)(5:value32:01234567890123456789012345678901))" -#define FORMATSTRING2 "(4:data(4:hash6:sha25632:01234567890123456789012345678901))" bufSize = strlen (FORMATSTRING) + 1; { char buff[bufSize]; @@ -1065,16 +1065,76 @@ GNUNET_CRYPTO_ecc_ecdh (const struct GNUNET_CRYPTO_EccPrivateKey *key, const struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded *pub, struct GNUNET_HashCode *key_material) { - gcry_sexp_t psexp; + size_t size; + size_t slen; + int rc; + gcry_sexp_t data; + unsigned char sdata_buf[2048]; /* big enough to print 'sdata' and 'r_sig' */ - if (! (psexp = decode_public_key (pub))) - return GNUNET_SYSERR; - + /* first, extract the q value from the public key */ + { + gcry_sexp_t psexp; + gcry_mpi_t sdata; + + if (! (psexp = decode_public_key (pub))) + return GNUNET_SYSERR; + rc = key_from_sexp (&sdata, psexp, "public-key", "q"); + if (rc) + rc = key_from_sexp (&sdata, psexp, "ecc", "q"); + GNUNET_assert (0 == rc); + gcry_sexp_release (psexp); + size = sizeof (sdata_buf); + GNUNET_assert (0 == + gcry_mpi_print (GCRYMPI_FMT_USG, sdata_buf, size, &size, + sdata)); + gcry_mpi_release (sdata); + } + /* convert q value into an S-expression -- whatever format libgcrypt wants, + re-using format from sign operation for now... */ + { + char *sexp_string; + +#define FORMATPREFIX "(4:data(5:flags3:raw)(5:value%u:" +#define FORMATPOSTFIX "))" + sexp_string = GNUNET_malloc (strlen (FORMATPREFIX) + size + 12 + + strlen (FORMATPOSTFIX) + 1); + GNUNET_snprintf (sexp_string, + strlen (FORMATPREFIX) + 12, + FORMATPREFIX, + size); + slen = strlen (sexp_string); + memcpy (&sexp_string[slen], + sdata_buf, + size); + memcpy (&sexp_string[slen + size], + FORMATPOSTFIX, + strlen (FORMATPOSTFIX) + 1); + GNUNET_assert (0 == gcry_sexp_new (&data, + sexp_string, + slen + size + strlen (FORMATPOSTFIX), + 0)); + GNUNET_free (sexp_string); + } + /* then call the 'multiply' function, hoping it simply multiplies the points; + here we need essentially a WRAPPER around _gcry_mpi_ex_mul_point! - FIXME-WK!*/ +#if WK + { + gcry_sexp_t result; + + rc = gcry_ecc_mul_point (&result, data /* scalar */, key->sexp /* point and ctx */); + GNUNET_assert (0 == rc); + slen = gcry_sexp_sprint (result, GCRYSEXP_FMT_DEFAULT, sdata_buf, sizeof (sdata_buf)); + GNUNET_assert (0 != slen); + } +#else + /* use broken version, insecure! */ + GNUNET_break (0); + slen = sprintf ((char*) sdata_buf, "FIXME-this is not key material"); +#endif + gcry_sexp_release (data); - gcry_sexp_release (psexp); - GNUNET_break (0); // not implemented - /* FIXME: this totally breaks security ... */ - memset (key_material, 42, sizeof (struct GNUNET_HashCode)); + /* finally, get a string of the resulting S-expression and hash it to generate the key material */ + GNUNET_CRYPTO_hash (sdata_buf, slen, key_material); return GNUNET_OK; } |