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[GNUnet-SVN] r24365 - gnunet/src/util
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From: |
gnunet |
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Subject: |
[GNUnet-SVN] r24365 - gnunet/src/util |
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Date: |
Wed, 17 Oct 2012 17:37:12 +0200 |
Author: grothoff
Date: 2012-10-17 17:37:12 +0200 (Wed, 17 Oct 2012)
New Revision: 24365
Added:
gnunet/src/util/crypto_ecc.c
Modified:
gnunet/src/util/Makefile.am
Log:
-ecc draft code
Modified: gnunet/src/util/Makefile.am
===================================================================
--- gnunet/src/util/Makefile.am 2012-10-17 15:26:13 UTC (rev 24364)
+++ gnunet/src/util/Makefile.am 2012-10-17 15:37:12 UTC (rev 24365)
@@ -74,6 +74,7 @@
container_slist.c \
crypto_aes.c \
crypto_crc.c \
+ crypto_ecc.c \
crypto_hash.c \
crypto_hkdf.c \
crypto_kdf.c \
Added: gnunet/src/util/crypto_ecc.c
===================================================================
--- gnunet/src/util/crypto_ecc.c (rev 0)
+++ gnunet/src/util/crypto_ecc.c 2012-10-17 15:37:12 UTC (rev 24365)
@@ -0,0 +1,1319 @@
+/*
+ This file is part of GNUnet.
+ (C) 2001, 2002, 2003, 2004, 2005, 2006, 2009, 2012 Christian Grothoff
(and other contributing authors)
+
+ GNUnet 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, or (at your
+ option) any later version.
+
+ GNUnet 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 GNUnet; see the file COPYING. If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file util/crypto_ecc.c
+ * @brief public key cryptography (ECC) with libgcrypt
+ * @author Christian Grothoff
+ *
+ * This is just a first, completely untested, draft hack for future ECC
support.
+ * TODO:
+ * - declare public API in gnunet_crypto_lib (move some structs, etc.)
+ * - implement gnunet-ecc binary
+ * - convert existing RSA testcases
+ * - adjust encoding length and other parameters
+ * - actually test it!
+ */
+#include "platform.h"
+#include <gcrypt.h>
+#include "gnunet_common.h"
+#include "gnunet_util_lib.h"
+
+#define EXTRA_CHECKS ALLOW_EXTRA_CHECKS
+
+#define CURVE "NIST P-521"
+
+#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
+
+#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util",
syscall)
+
+#define LOG_STRERROR_FILE(kind,syscall,filename) GNUNET_log_from_strerror_file
(kind, "util", syscall, filename)
+
+
+/**
+ * FIXME: what is an acceptable value here?
+ */
+#define GNUNET_CRYPTO_ECC_DATA_ENCODING_LENGTH 64
+
+/**
+ * Length of the q-point (Q = dP) in the public key.
+ * FIXME: double-check that this is right.
+ */
+#define GNUNET_CRYPTO_ECC_PUBLIC_KEY_LENGTH 64
+
+
+/**
+ * @brief an ECC signature
+ */
+struct GNUNET_CRYPTO_EccSignature
+{
+ unsigned char sig[GNUNET_CRYPTO_ECC_DATA_ENCODING_LENGTH];
+};
+
+
+GNUNET_NETWORK_STRUCT_BEGIN
+
+/**
+ * @brief header of what an ECC signature signs
+ * this must be followed by "size - 8" bytes of
+ * the actual signed data
+ */
+struct GNUNET_CRYPTO_EccSignaturePurpose
+{
+ /**
+ * How many bytes does this signature sign?
+ * (including this purpose header); in network
+ * byte order (!).
+ */
+ uint32_t size GNUNET_PACKED;
+
+ /**
+ * What does this signature vouch for? This
+ * must contain a GNUNET_SIGNATURE_PURPOSE_XXX
+ * constant (from gnunet_signatures.h). In
+ * network byte order!
+ */
+ uint32_t purpose GNUNET_PACKED;
+
+};
+
+
+/**
+ * Public ECC key (always for NIST P-521) encoded in a format suitable
+ * for network transmission.
+ */
+struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded
+{
+ /**
+ * Size of the encoding, in network byte order.
+ */
+ uint16_t size;
+
+ /**
+ * Actual length of the q-point binary encoding.
+ */
+ uint16_t len;
+
+ /**
+ * 0-padded q-point in binary encoding (GCRYPT_MPI_FMT_USG).
+ */
+ unsigned char key[GNUNET_CRYPTO_ECC_PUBLIC_KEY_LENGTH];
+};
+
+
+struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded
+{
+ /**
+ * Overall size of the private key.
+ */
+ uint16_t size;
+
+ /**
+ * Size of the q and d components of the private key.
+ * Note that the other parameters are from NIST P-521.
+ */
+ uint16_t sizes[2];
+};
+
+
+/**
+ * ECC Encrypted data.
+ */
+struct GNUNET_CRYPTO_EccEncryptedData
+{
+ unsigned char encoding[GNUNET_CRYPTO_ECC_DATA_ENCODING_LENGTH];
+};
+
+GNUNET_NETWORK_STRUCT_END
+
+
+
+/**
+ * The private information of an ECC private key.
+ */
+struct GNUNET_CRYPTO_EccPrivateKey
+{
+
+ /**
+ * Libgcrypt S-expression for the ECC key.
+ */
+ gcry_sexp_t sexp;
+};
+
+
+/**
+ * Function called upon completion of 'GNUNET_CRYPTO_ecc_key_create_async'.
+ *
+ * @param cls closure
+ * @param pk NULL on error, otherwise the private key (which must be free'd by
the callee)
+ * @param emsg NULL on success, otherwise an error message
+ */
+typedef void (*GNUNET_CRYPTO_EccKeyCallback)(void *cls,
+ struct GNUNET_CRYPTO_EccPrivateKey
*pk,
+ const char *emsg);
+
+
+
+/**
+ * Log an error message at log-level 'level' that indicates
+ * a failure of the command 'cmd' with the message given
+ * by gcry_strerror(rc).
+ */
+#define LOG_GCRY(level, cmd, rc) do { LOG(level, _("`%s' failed at %s:%d with
error: %s\n"), cmd, __FILE__, __LINE__, gcry_strerror(rc)); } while(0);
+
+
+/**
+ * If target != size, move target bytes to the
+ * end of the size-sized buffer and zero out the
+ * first target-size bytes.
+ *
+ * @param buf original buffer
+ * @param size number of bytes in the buffer
+ * @param target target size of the buffer
+ */
+static void
+adjust (unsigned char *buf, size_t size, size_t target)
+{
+ if (size < target)
+ {
+ memmove (&buf[target - size], buf, size);
+ memset (buf, 0, target - size);
+ }
+}
+
+
+/**
+ * Free memory occupied by hostkey
+ * @param privatekey pointer to the memory to free
+ */
+void
+GNUNET_CRYPTO_ecc_key_free (struct GNUNET_CRYPTO_EccPrivateKey *privatekey)
+{
+ gcry_sexp_release (privatekey->sexp);
+ GNUNET_free (privatekey);
+}
+
+
+/**
+ * Extract values from an S-expression.
+ *
+ * @param array where to store the result(s)
+ * @param sexp S-expression to parse
+ * @param topname top-level name in the S-expression that is of interest
+ * @param elems names of the elements to extract
+ * @return 0 on success
+ */
+static int
+key_from_sexp (gcry_mpi_t * array, gcry_sexp_t sexp, const char *topname,
+ const char *elems)
+{
+ gcry_sexp_t list;
+ gcry_sexp_t l2;
+ const char *s;
+ unsigned int i;
+ unsigned int idx;
+
+ list = gcry_sexp_find_token (sexp, topname, 0);
+ if (! list)
+ return 1;
+ l2 = gcry_sexp_cadr (list);
+ gcry_sexp_release (list);
+ list = l2;
+ if (! list)
+ return 2;
+
+ idx = 0;
+ for (s = elems; *s; s++, idx++)
+ {
+ l2 = gcry_sexp_find_token (list, s, 1);
+ if (! l2)
+ {
+ for (i = 0; i < idx; i++)
+ {
+ gcry_free (array[i]);
+ array[i] = NULL;
+ }
+ gcry_sexp_release (list);
+ return 3; /* required parameter not found */
+ }
+ array[idx] = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
+ gcry_sexp_release (l2);
+ if (! array[idx])
+ {
+ for (i = 0; i < idx; i++)
+ {
+ gcry_free (array[i]);
+ array[i] = NULL;
+ }
+ gcry_sexp_release (list);
+ return 4; /* required parameter is invalid */
+ }
+ }
+ gcry_sexp_release (list);
+ return 0;
+}
+
+
+/**
+ * Extract the public key for the given private key.
+ *
+ * @param priv the private key
+ * @param pub where to write the public key
+ */
+void
+GNUNET_CRYPTO_ecc_key_get_public (const struct GNUNET_CRYPTO_EccPrivateKey
*priv,
+ struct
GNUNET_CRYPTO_EccPublicKeyBinaryEncoded *pub)
+{
+ gcry_mpi_t skey;
+ size_t size;
+ int rc;
+
+ rc = key_from_sexp (&skey, priv->sexp, "public-key", "q");
+ if (rc)
+ rc = key_from_sexp (&skey, priv->sexp, "private-key", "q");
+ if (rc)
+ rc = key_from_sexp (&skey, priv->sexp, "ecc", "q");
+ GNUNET_assert (0 == rc);
+ pub->size = htons (sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded));
+ size = GNUNET_CRYPTO_ECC_DATA_ENCODING_LENGTH;
+ GNUNET_assert (0 ==
+ gcry_mpi_print (GCRYMPI_FMT_USG, pub->key, size, &size,
+ skey));
+ pub->len = htons (size);
+ adjust (&pub->key[0], size, GNUNET_CRYPTO_ECC_DATA_ENCODING_LENGTH);
+ gcry_mpi_release (skey);
+}
+
+
+/**
+ * Convert a public key to a string.
+ *
+ * @param pub key to convert
+ * @return string representing 'pub'
+ */
+char *
+GNUNET_CRYPTO_ecc_public_key_to_string (struct
GNUNET_CRYPTO_EccPublicKeyBinaryEncoded *pub)
+{
+ char *pubkeybuf;
+ size_t keylen = (sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded)) *
8;
+ char *end;
+
+ if (keylen % 5 > 0)
+ keylen += 5 - keylen % 5;
+ keylen /= 5;
+ pubkeybuf = GNUNET_malloc (keylen + 1);
+ end = GNUNET_STRINGS_data_to_string ((unsigned char *) pub,
+ sizeof (struct
GNUNET_CRYPTO_EccPublicKeyBinaryEncoded),
+ pubkeybuf,
+ keylen);
+ if (NULL == end)
+ {
+ GNUNET_free (pubkeybuf);
+ return NULL;
+ }
+ *end = '\0';
+ return pubkeybuf;
+}
+
+
+/**
+ * Convert a string representing a public key to a public key.
+ *
+ * @param enc encoded public key
+ * @param enclen number of bytes in enc (without 0-terminator)
+ * @param pub where to store the public key
+ * @return GNUNET_OK on success
+ */
+int
+GNUNET_CRYPTO_ecc_public_key_from_string (const char *enc,
+ size_t enclen,
+ struct
GNUNET_CRYPTO_EccPublicKeyBinaryEncoded *pub)
+{
+ size_t keylen = (sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded)) *
8;
+
+ if (keylen % 5 > 0)
+ keylen += 5 - keylen % 5;
+ keylen /= 5;
+ if (enclen != keylen)
+ return GNUNET_SYSERR;
+
+ if (GNUNET_OK != GNUNET_STRINGS_string_to_data (enc, enclen,
+ (unsigned char*) pub,
+ sizeof (struct
GNUNET_CRYPTO_EccPublicKeyBinaryEncoded)))
+ return GNUNET_SYSERR;
+ if ( (ntohs (pub->size) != sizeof (struct
GNUNET_CRYPTO_EccPublicKeyBinaryEncoded)) ||
+ (ntohs (pub->len) > GNUNET_CRYPTO_ECC_DATA_ENCODING_LENGTH) )
+ return GNUNET_SYSERR;
+ return GNUNET_OK;
+}
+
+
+/**
+ * Convert the given public key from the network format to the
+ * S-expression that can be used by libgcrypt.
+ *
+ * @param publicKey public key to decode
+ * @return NULL on error
+ */
+static gcry_sexp_t
+decode_public_key (const struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded
*publicKey)
+{
+ gcry_sexp_t result;
+ gcry_mpi_t q;
+ size_t size;
+ size_t erroff;
+ int rc;
+
+ if (ntohs (publicKey->len) > GNUNET_CRYPTO_ECC_DATA_ENCODING_LENGTH)
+ {
+ GNUNET_break (0);
+ return NULL;
+ }
+ size = ntohs (publicKey->size);
+ if (0 != (rc = gcry_mpi_scan (&q, GCRYMPI_FMT_USG, publicKey->key, size,
&size)))
+ {
+ LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
+ return NULL;
+ }
+ rc = gcry_sexp_build (&result, &erroff, "(public-key(ecc((curve \"" CURVE
"\")(q %m)))", q);
+ gcry_mpi_release (q);
+ if (0 != rc)
+ {
+ LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc); /* erroff
gives more info */
+ return NULL;
+ }
+ return result;
+}
+
+
+/**
+ * Encode the private key in a format suitable for
+ * storing it into a file.
+ *
+ * @returns encoding of the private key.
+ * The first 4 bytes give the size of the array, as usual.
+ */
+struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded *
+GNUNET_CRYPTO_ecc_encode_key (const struct GNUNET_CRYPTO_EccPrivateKey
*hostkey)
+{
+ struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded *retval;
+ gcry_mpi_t pkv[2];
+ void *pbu[2];
+ size_t sizes[2];
+ size_t off;
+ int rc;
+ unsigned int i;
+ size_t size;
+
+#if EXTRA_CHECKS
+ if (gcry_pk_testkey (hostkey->sexp))
+ {
+ GNUNET_break (0);
+ return NULL;
+ }
+#endif
+
+ memset (pkv, 0, sizeof (gcry_mpi_t) * 2);
+ rc = key_from_sexp (pkv, hostkey->sexp, "private-key", "qd");
+ if (rc)
+ rc = key_from_sexp (pkv, hostkey->sexp, "ecc", "qd");
+ GNUNET_assert (0 == rc);
+ size = sizeof (struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded);
+ for (i=0;i<2;i++)
+ {
+ if (NULL != pkv[i])
+ {
+ GNUNET_assert (0 ==
+ gcry_mpi_aprint (GCRYMPI_FMT_USG,
+ (unsigned char **) &pbu[i], &sizes[i],
+ pkv[i]));
+ size += sizes[i];
+ }
+ else
+ {
+ pbu[i] = NULL;
+ sizes[i] = 0;
+ }
+ }
+ GNUNET_assert (size < 65536);
+ retval = GNUNET_malloc (size);
+ retval->size = htons (size);
+ off = 0;
+ for (i=0;i<2;i++)
+ {
+ retval->sizes[i] = htons (sizes[0]);
+ memcpy (&((char *) (&retval[1]))[off], pbu[i], sizes[i]);
+ off += sizes[i];
+ if (NULL != pkv[i])
+ gcry_mpi_release (pkv[i]);
+ if (NULL != pbu[i])
+ free (pbu[i]);
+ }
+ return retval;
+}
+
+
+/**
+ * Decode the private key from the file-format back
+ * to the "normal", internal format.
+ *
+ * @param buf the buffer where the private key data is stored
+ * @param len the length of the data in 'buffer'
+ * @return NULL on error
+ */
+struct GNUNET_CRYPTO_EccPrivateKey *
+GNUNET_CRYPTO_ecc_decode_key (const char *buf, uint16_t len)
+{
+ struct GNUNET_CRYPTO_EccPrivateKey *ret;
+ const struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded *encoding =
+ (const struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded *) buf;
+ gcry_sexp_t res;
+ gcry_mpi_t q;
+ gcry_mpi_t d;
+ int rc;
+ size_t size;
+ size_t pos;
+ uint16_t enc_len;
+ size_t erroff;
+
+ enc_len = ntohs (encoding->size);
+ if (len != enc_len)
+ return NULL;
+ pos = 0;
+ size = ntohs (encoding->sizes[0]);
+ rc = gcry_mpi_scan (&q, GCRYMPI_FMT_USG,
+ &((const unsigned char *) (&encoding[1]))[pos], size,
+ &size);
+ pos += ntohs (encoding->sizes[0]);
+ if (0 != rc)
+ {
+ LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
+ return NULL;
+ }
+ size = ntohs (encoding->sizes[1]);
+ rc = gcry_mpi_scan (&d, GCRYMPI_FMT_USG,
+ &((const unsigned char *) (&encoding[1]))[pos], size,
+ &size);
+ pos += ntohs (encoding->sizes[1]);
+ if (0 != rc)
+ {
+ LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
+ gcry_mpi_release (d);
+ return NULL;
+ }
+ rc = gcry_sexp_build (&res, &erroff,
+ "(private-key(ecc(q %m)(d %m)(curve \"" CURVE "\")))",
+ q, d);
+ gcry_mpi_release (q);
+ gcry_mpi_release (d);
+ if (0 != rc)
+ LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
+#if EXTRA_CHECKS
+ if (0 != (rc = gcry_pk_testkey (res)))
+ {
+ LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
+ return NULL;
+ }
+#endif
+ ret = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_EccPrivateKey));
+ ret->sexp = res;
+ return ret;
+}
+
+
+/**
+ * Create a new private key. Caller must free return value.
+ *
+ * @return fresh private key
+ */
+static struct GNUNET_CRYPTO_EccPrivateKey *
+ecc_key_create ()
+{
+ struct GNUNET_CRYPTO_EccPrivateKey *ret;
+ gcry_sexp_t s_key;
+ gcry_sexp_t s_keyparam;
+
+ GNUNET_assert (0 ==
+ gcry_sexp_build (&s_keyparam, NULL,
+ "(genkey(ecc(curve \"" CURVE "\")))"));
+ GNUNET_assert (0 == gcry_pk_genkey (&s_key, s_keyparam));
+ gcry_sexp_release (s_keyparam);
+#if EXTRA_CHECKS
+ GNUNET_assert (0 == gcry_pk_testkey (s_key));
+#endif
+ ret = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_EccPrivateKey));
+ ret->sexp = s_key;
+ return ret;
+}
+
+
+/**
+ * Try to read the private key from the given file.
+ *
+ * @param filename file to read the key from
+ * @return NULL on error
+ */
+static struct GNUNET_CRYPTO_EccPrivateKey *
+try_read_key (const char *filename)
+{
+ struct GNUNET_CRYPTO_EccPrivateKey *ret;
+ struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded *enc;
+ struct GNUNET_DISK_FileHandle *fd;
+ OFF_T fs;
+ uint16_t len;
+
+ if (GNUNET_YES != GNUNET_DISK_file_test (filename))
+ return NULL;
+
+ /* hostkey file exists already, read it! */
+ if (NULL == (fd = GNUNET_DISK_file_open (filename, GNUNET_DISK_OPEN_READ,
+ GNUNET_DISK_PERM_NONE)))
+ {
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "open", filename);
+ return NULL;
+ }
+ if (GNUNET_OK != (GNUNET_DISK_file_handle_size (fd, &fs)))
+ {
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "stat", filename);
+ (void) GNUNET_DISK_file_close (fd);
+ return NULL;
+ }
+ if (0 == fs)
+ {
+ GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fd));
+ return NULL;
+ }
+ if (fs > UINT16_MAX)
+ {
+ LOG (GNUNET_ERROR_TYPE_ERROR,
+ _("File `%s' does not contain a valid private key (too long, %llu
bytes). Deleting it.\n"),
+ filename,
+ (unsigned long long) fs);
+ GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fd));
+ if (0 != UNLINK (filename))
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "unlink", filename);
+ return NULL;
+ }
+
+ enc = GNUNET_malloc (fs);
+ GNUNET_break (fs == GNUNET_DISK_file_read (fd, enc, fs));
+ len = ntohs (enc->size);
+ ret = NULL;
+ if ((len != fs) ||
+ (NULL == (ret = GNUNET_CRYPTO_ecc_decode_key ((char *) enc, len))))
+ {
+ LOG (GNUNET_ERROR_TYPE_ERROR,
+ _("File `%s' does not contain a valid private key (failed decode,
%llu bytes). Deleting it.\n"),
+ filename,
+ (unsigned long long) fs);
+ GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fd));
+ if (0 != UNLINK (filename))
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "unlink", filename);
+ GNUNET_free (enc);
+ return NULL;
+ }
+ GNUNET_free (enc);
+
+ GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fd));
+ return ret;
+}
+
+
+/**
+ * Wait for a short time (we're trying to lock a file or want
+ * to give another process a shot at finishing a disk write, etc.).
+ * Sleeps for 100ms (as that should be long enough for virtually all
+ * modern systems to context switch and allow another process to do
+ * some 'real' work).
+ */
+static void
+short_wait ()
+{
+ struct GNUNET_TIME_Relative timeout;
+
+ timeout = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 100);
+ (void) GNUNET_NETWORK_socket_select (NULL, NULL, NULL, timeout);
+}
+
+
+/**
+ * Create a new private key by reading it from a file. If the
+ * files does not exist, create a new key and write it to the
+ * file. Caller must free return value. Note that this function
+ * can not guarantee that another process might not be trying
+ * the same operation on the same file at the same time.
+ * If the contents of the file
+ * are invalid the old file is deleted and a fresh key is
+ * created.
+ *
+ * @return new private key, NULL on error (for example,
+ * permission denied)
+ */
+struct GNUNET_CRYPTO_EccPrivateKey *
+GNUNET_CRYPTO_ecc_key_create_from_file (const char *filename)
+{
+ struct GNUNET_CRYPTO_EccPrivateKey *ret;
+ struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded *enc;
+ uint16_t len;
+ struct GNUNET_DISK_FileHandle *fd;
+ unsigned int cnt;
+ int ec;
+ uint64_t fs;
+ struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded pub;
+ struct GNUNET_PeerIdentity pid;
+
+ if (GNUNET_SYSERR == GNUNET_DISK_directory_create_for_file (filename))
+ return NULL;
+ while (GNUNET_YES != GNUNET_DISK_file_test (filename))
+ {
+ fd = GNUNET_DISK_file_open (filename,
+ GNUNET_DISK_OPEN_WRITE |
GNUNET_DISK_OPEN_CREATE
+ | GNUNET_DISK_OPEN_FAILIFEXISTS,
+ GNUNET_DISK_PERM_USER_READ |
+ GNUNET_DISK_PERM_USER_WRITE);
+ if (NULL == fd)
+ {
+ if (errno == EEXIST)
+ {
+ if (GNUNET_YES != GNUNET_DISK_file_test (filename))
+ {
+ /* must exist but not be accessible, fail for good! */
+ if (0 != ACCESS (filename, R_OK))
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "access", filename);
+ else
+ GNUNET_break (0); /* what is going on!? */
+ return NULL;
+ }
+ continue;
+ }
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "open", filename);
+ return NULL;
+ }
+ cnt = 0;
+
+ while (GNUNET_YES !=
+ GNUNET_DISK_file_lock (fd, 0,
+ sizeof (struct
GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded),
+ GNUNET_YES))
+ {
+ short_wait ();
+ if (0 == ++cnt % 10)
+ {
+ ec = errno;
+ LOG (GNUNET_ERROR_TYPE_ERROR,
+ _("Could not acquire lock on file `%s': %s...\n"), filename,
+ STRERROR (ec));
+ }
+ }
+ LOG (GNUNET_ERROR_TYPE_INFO,
+ _("Creating a new private key. This may take a while.\n"));
+ ret = ecc_key_create ();
+ GNUNET_assert (ret != NULL);
+ enc = GNUNET_CRYPTO_ecc_encode_key (ret);
+ GNUNET_assert (enc != NULL);
+ GNUNET_assert (ntohs (enc->size) ==
+ GNUNET_DISK_file_write (fd, enc, ntohs (enc->size)));
+ GNUNET_free (enc);
+
+ GNUNET_DISK_file_sync (fd);
+ if (GNUNET_YES !=
+ GNUNET_DISK_file_unlock (fd, 0,
+ sizeof (struct
GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded)))
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "fcntl", filename);
+ GNUNET_assert (GNUNET_YES == GNUNET_DISK_file_close (fd));
+ GNUNET_CRYPTO_ecc_key_get_public (ret, &pub);
+ GNUNET_CRYPTO_hash (&pub, sizeof (pub), &pid.hashPubKey);
+ LOG (GNUNET_ERROR_TYPE_INFO,
+ _("I am host `%s'. Stored new private key in `%s'.\n"),
+ GNUNET_i2s (&pid), filename);
+ return ret;
+ }
+ /* hostkey file exists already, read it! */
+ fd = GNUNET_DISK_file_open (filename, GNUNET_DISK_OPEN_READ,
+ GNUNET_DISK_PERM_NONE);
+ if (NULL == fd)
+ {
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "open", filename);
+ return NULL;
+ }
+ cnt = 0;
+ while (1)
+ {
+ if (GNUNET_YES !=
+ GNUNET_DISK_file_lock (fd, 0,
+ sizeof (struct
GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded),
+ GNUNET_NO))
+ {
+ if (0 == ++cnt % 60)
+ {
+ ec = errno;
+ LOG (GNUNET_ERROR_TYPE_ERROR,
+ _("Could not acquire lock on file `%s': %s...\n"), filename,
+ STRERROR (ec));
+ LOG (GNUNET_ERROR_TYPE_ERROR,
+ _
+ ("This may be ok if someone is currently generating a
hostkey.\n"));
+ }
+ short_wait ();
+ continue;
+ }
+ if (GNUNET_YES != GNUNET_DISK_file_test (filename))
+ {
+ /* eh, what!? File we opened is now gone!? */
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "stat", filename);
+ if (GNUNET_YES !=
+ GNUNET_DISK_file_unlock (fd, 0,
+ sizeof (struct
GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded)))
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "fcntl", filename);
+ GNUNET_assert (GNUNET_OK == GNUNET_DISK_file_close (fd));
+
+ return NULL;
+ }
+ if (GNUNET_OK != GNUNET_DISK_file_size (filename, &fs, GNUNET_YES,
GNUNET_YES))
+ fs = 0;
+ if (fs < sizeof (struct GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded))
+ {
+ /* maybe we got the read lock before the hostkey generating
+ * process had a chance to get the write lock; give it up! */
+ if (GNUNET_YES !=
+ GNUNET_DISK_file_unlock (fd, 0,
+ sizeof (struct
GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded)))
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "fcntl", filename);
+ if (0 == ++cnt % 10)
+ {
+ LOG (GNUNET_ERROR_TYPE_ERROR,
+ _
+ ("When trying to read hostkey file `%s' I found %u bytes but I
need at least %u.\n"),
+ filename, (unsigned int) fs,
+ (unsigned int) sizeof (struct
GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded));
+ LOG (GNUNET_ERROR_TYPE_ERROR,
+ _
+ ("This may be ok if someone is currently generating a
hostkey.\n"));
+ }
+ short_wait (); /* wait a bit longer! */
+ continue;
+ }
+ break;
+ }
+ enc = GNUNET_malloc (fs);
+ GNUNET_assert (fs == GNUNET_DISK_file_read (fd, enc, fs));
+ len = ntohs (enc->size);
+ ret = NULL;
+ if ((len != fs) ||
+ (NULL == (ret = GNUNET_CRYPTO_ecc_decode_key ((char *) enc, len))))
+ {
+ LOG (GNUNET_ERROR_TYPE_ERROR,
+ _("File `%s' does not contain a valid private key. Deleting it.\n"),
+ filename);
+ if (0 != UNLINK (filename))
+ {
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "unlink", filename);
+ }
+ }
+ GNUNET_free (enc);
+ if (GNUNET_YES !=
+ GNUNET_DISK_file_unlock (fd, 0,
+ sizeof (struct
GNUNET_CRYPTO_EccPrivateKeyBinaryEncoded)))
+ LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "fcntl", filename);
+ GNUNET_assert (GNUNET_YES == GNUNET_DISK_file_close (fd));
+ if (ret != NULL)
+ {
+ GNUNET_CRYPTO_ecc_key_get_public (ret, &pub);
+ GNUNET_CRYPTO_hash (&pub, sizeof (pub), &pid.hashPubKey);
+ LOG (GNUNET_ERROR_TYPE_INFO,
+ _("I am host `%s'. Read private key from `%s'.\n"), GNUNET_i2s
(&pid),
+ filename);
+ }
+ return ret;
+}
+
+
+/**
+ * Handle to cancel private key generation and state for the
+ * key generation operation.
+ */
+struct GNUNET_CRYPTO_EccKeyGenerationContext
+{
+
+ /**
+ * Continuation to call upon completion.
+ */
+ GNUNET_CRYPTO_EccKeyCallback cont;
+
+ /**
+ * Closure for 'cont'.
+ */
+ void *cont_cls;
+
+ /**
+ * Name of the file.
+ */
+ char *filename;
+
+ /**
+ * Handle to the helper process which does the key generation.
+ */
+ struct GNUNET_OS_Process *gnunet_ecc;
+
+ /**
+ * Handle to 'stdout' of gnunet-ecc. We 'read' on stdout to detect
+ * process termination (instead of messing with SIGCHLD).
+ */
+ struct GNUNET_DISK_PipeHandle *gnunet_ecc_out;
+
+ /**
+ * Location where we store the private key if it already existed.
+ * (if this is used, 'filename', 'gnunet_ecc' and 'gnunet_ecc_out' will
+ * not be used).
+ */
+ struct GNUNET_CRYPTO_EccPrivateKey *pk;
+
+ /**
+ * Task reading from 'gnunet_ecc_out' to wait for process termination.
+ */
+ GNUNET_SCHEDULER_TaskIdentifier read_task;
+
+};
+
+
+/**
+ * Abort ECC key generation.
+ *
+ * @param gc key generation context to abort
+ */
+void
+GNUNET_CRYPTO_ecc_key_create_stop (struct
GNUNET_CRYPTO_EccKeyGenerationContext *gc)
+{
+ if (GNUNET_SCHEDULER_NO_TASK != gc->read_task)
+ {
+ GNUNET_SCHEDULER_cancel (gc->read_task);
+ gc->read_task = GNUNET_SCHEDULER_NO_TASK;
+ }
+ if (NULL != gc->gnunet_ecc)
+ {
+ (void) GNUNET_OS_process_kill (gc->gnunet_ecc, SIGKILL);
+ GNUNET_break (GNUNET_OK ==
+ GNUNET_OS_process_wait (gc->gnunet_ecc));
+ GNUNET_OS_process_destroy (gc->gnunet_ecc);
+ GNUNET_DISK_pipe_close (gc->gnunet_ecc_out);
+ }
+
+ if (NULL != gc->filename)
+ {
+ if (0 != UNLINK (gc->filename))
+ GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink",
gc->filename);
+ GNUNET_free (gc->filename);
+ }
+ if (NULL != gc->pk)
+ GNUNET_CRYPTO_ecc_key_free (gc->pk);
+ GNUNET_free (gc);
+}
+
+
+/**
+ * Task called upon shutdown or process termination of 'gnunet-ecc' during
+ * ECC key generation. Check where we are and perform the appropriate
+ * action.
+ *
+ * @param cls the 'struct GNUNET_CRYPTO_EccKeyGenerationContext'
+ * @param tc scheduler context
+ */
+static void
+check_key_generation_completion (void *cls,
+ const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+ struct GNUNET_CRYPTO_EccKeyGenerationContext *gc = cls;
+ struct GNUNET_CRYPTO_EccPrivateKey *pk;
+
+ gc->read_task = GNUNET_SCHEDULER_NO_TASK;
+ if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
+ {
+ gc->cont (gc->cont_cls, NULL, _("interrupted by shutdown"));
+ GNUNET_CRYPTO_ecc_key_create_stop (gc);
+ return;
+ }
+ GNUNET_assert (GNUNET_OK ==
+ GNUNET_OS_process_wait (gc->gnunet_ecc));
+ GNUNET_OS_process_destroy (gc->gnunet_ecc);
+ gc->gnunet_ecc = NULL;
+ if (NULL == (pk = try_read_key (gc->filename)))
+ {
+ GNUNET_break (0);
+ gc->cont (gc->cont_cls, NULL, _("gnunet-ecc failed"));
+ GNUNET_CRYPTO_ecc_key_create_stop (gc);
+ return;
+ }
+ gc->cont (gc->cont_cls, pk, NULL);
+ GNUNET_DISK_pipe_close (gc->gnunet_ecc_out);
+ GNUNET_free (gc->filename);
+ GNUNET_free (gc);
+}
+
+
+/**
+ * Return the private ECC key which already existed on disk
+ * (asynchronously) to the caller.
+ *
+ * @param cls the 'struct GNUNET_CRYPTO_EccKeyGenerationContext'
+ * @param tc scheduler context (unused)
+ */
+static void
+async_return_key (void *cls,
+ const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+ struct GNUNET_CRYPTO_EccKeyGenerationContext *gc = cls;
+
+ gc->cont (gc->cont_cls,
+ gc->pk,
+ NULL);
+ GNUNET_free (gc);
+}
+
+
+/**
+ * Create a new private key by reading it from a file. If the files
+ * does not exist, create a new key and write it to the file. If the
+ * contents of the file are invalid the old file is deleted and a
+ * fresh key is created.
+ *
+ * @param filename name of file to use for storage
+ * @param cont function to call when done (or on errors)
+ * @param cont_cls closure for 'cont'
+ * @return handle to abort operation, NULL on fatal errors (cont will not be
called if NULL is returned)
+ */
+struct GNUNET_CRYPTO_EccKeyGenerationContext *
+GNUNET_CRYPTO_ecc_key_create_start (const char *filename,
+ GNUNET_CRYPTO_EccKeyCallback cont,
+ void *cont_cls)
+{
+ struct GNUNET_CRYPTO_EccKeyGenerationContext *gc;
+ struct GNUNET_CRYPTO_EccPrivateKey *pk;
+ const char *weak_random;
+
+ if (NULL != (pk = try_read_key (filename)))
+ {
+ /* quick happy ending: key already exists! */
+ gc = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_EccKeyGenerationContext));
+ gc->pk = pk;
+ gc->cont = cont;
+ gc->cont_cls = cont_cls;
+ gc->read_task = GNUNET_SCHEDULER_add_now (&async_return_key,
+ gc);
+ return gc;
+ }
+ gc = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_EccKeyGenerationContext));
+ gc->filename = GNUNET_strdup (filename);
+ gc->cont = cont;
+ gc->cont_cls = cont_cls;
+ gc->gnunet_ecc_out = GNUNET_DISK_pipe (GNUNET_NO,
+ GNUNET_NO,
+ GNUNET_NO,
+ GNUNET_YES);
+ if (NULL == gc->gnunet_ecc_out)
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "pipe");
+ GNUNET_free (gc->filename);
+ GNUNET_free (gc);
+ return NULL;
+ }
+ weak_random = NULL;
+ if (GNUNET_YES ==
+ GNUNET_CRYPTO_random_is_weak ())
+ weak_random = "-w";
+ gc->gnunet_ecc = GNUNET_OS_start_process (GNUNET_NO,
+ GNUNET_OS_INHERIT_STD_ERR,
+ NULL,
+ gc->gnunet_ecc_out,
+ "gnunet-ecc",
+ "gnunet-ecc",
+ gc->filename,
+ weak_random,
+ NULL);
+ if (NULL == gc->gnunet_ecc)
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "fork");
+ GNUNET_DISK_pipe_close (gc->gnunet_ecc_out);
+ GNUNET_free (gc->filename);
+ GNUNET_free (gc);
+ return NULL;
+ }
+ GNUNET_assert (GNUNET_OK ==
+ GNUNET_DISK_pipe_close_end (gc->gnunet_ecc_out,
+ GNUNET_DISK_PIPE_END_WRITE));
+ gc->read_task = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL,
+ GNUNET_DISK_pipe_handle
(gc->gnunet_ecc_out,
+
GNUNET_DISK_PIPE_END_READ),
+
&check_key_generation_completion,
+ gc);
+ return gc;
+}
+
+
+/**
+ * Setup a hostkey file for a peer given the name of the
+ * configuration file (!). This function is used so that
+ * at a later point code can be certain that reading a
+ * hostkey is fast (for example in time-dependent testcases).
+ *
+ * @param cfg_name name of the configuration file to use
+ */
+void
+GNUNET_CRYPTO_ecc_setup_hostkey (const char *cfg_name)
+{
+ struct GNUNET_CONFIGURATION_Handle *cfg;
+ struct GNUNET_CRYPTO_EccPrivateKey *pk;
+ char *fn;
+
+ cfg = GNUNET_CONFIGURATION_create ();
+ (void) GNUNET_CONFIGURATION_load (cfg, cfg_name);
+ if (GNUNET_OK ==
+ GNUNET_CONFIGURATION_get_value_filename (cfg, "GNUNETD", "HOSTKEY", &fn))
+ {
+ pk = GNUNET_CRYPTO_ecc_key_create_from_file (fn);
+ if (NULL != pk)
+ GNUNET_CRYPTO_ecc_key_free (pk);
+ GNUNET_free (fn);
+ }
+ GNUNET_CONFIGURATION_destroy (cfg);
+}
+
+
+/**
+ * Encrypt a block with the public key of another host that uses the
+ * same cipher.
+ *
+ * @param block the block to encrypt
+ * @param size the size of block
+ * @param publicKey the encoded public key used to encrypt
+ * @param target where to store the encrypted block
+ * @returns GNUNET_SYSERR on error, GNUNET_OK if ok
+ */
+int
+GNUNET_CRYPTO_ecc_encrypt (const void *block, size_t size,
+ const struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded
+ *publicKey,
+ struct GNUNET_CRYPTO_EccEncryptedData *target)
+{
+ gcry_sexp_t result;
+ gcry_sexp_t data;
+ gcry_sexp_t psexp;
+ gcry_mpi_t val;
+ gcry_mpi_t rval;
+ size_t isize;
+ size_t erroff;
+
+ GNUNET_assert (size <= sizeof (struct GNUNET_HashCode));
+ if (! (psexp = decode_public_key (publicKey)))
+ return GNUNET_SYSERR;
+ isize = size;
+ GNUNET_assert (0 ==
+ gcry_mpi_scan (&val, GCRYMPI_FMT_USG, block, isize, &isize));
+ GNUNET_assert (0 ==
+ gcry_sexp_build (&data, &erroff,
+ "(data (flags pkcs1)(value %m))", val));
+ gcry_mpi_release (val);
+ GNUNET_assert (0 == gcry_pk_encrypt (&result, data, psexp));
+ gcry_sexp_release (data);
+ gcry_sexp_release (psexp);
+
+ GNUNET_assert (0 == key_from_sexp (&rval, result, "ecc", "a"));
+ gcry_sexp_release (result);
+ isize = sizeof (struct GNUNET_CRYPTO_EccEncryptedData);
+ GNUNET_assert (0 ==
+ gcry_mpi_print (GCRYMPI_FMT_USG, (unsigned char *) target,
+ isize, &isize, rval));
+ gcry_mpi_release (rval);
+ adjust (&target->encoding[0], isize,
+ sizeof (struct GNUNET_CRYPTO_EccEncryptedData));
+ return GNUNET_OK;
+}
+
+
+/**
+ * Decrypt a given block with the hostkey.
+ *
+ * @param key the key with which to decrypt this block
+ * @param block the data to decrypt, encoded as returned by encrypt
+ * @param result pointer to a location where the result can be stored
+ * @param max the maximum number of bits to store for the result, if
+ * the decrypted block is bigger, an error is returned
+ * @return the size of the decrypted block, -1 on error
+ */
+ssize_t
+GNUNET_CRYPTO_ecc_decrypt (const struct GNUNET_CRYPTO_EccPrivateKey * key,
+ const struct GNUNET_CRYPTO_EccEncryptedData * block,
+ void *result, size_t max)
+{
+ gcry_sexp_t resultsexp;
+ gcry_sexp_t data;
+ size_t erroff;
+ size_t size;
+ gcry_mpi_t val;
+ unsigned char *endp;
+ unsigned char *tmp;
+
+#if EXTRA_CHECKS
+ GNUNET_assert (0 == gcry_pk_testkey (key->sexp));
+#endif
+ size = sizeof (struct GNUNET_CRYPTO_EccEncryptedData);
+ GNUNET_assert (0 ==
+ gcry_mpi_scan (&val, GCRYMPI_FMT_USG, &block->encoding[0],
+ size, &size));
+ GNUNET_assert (0 ==
+ gcry_sexp_build (&data, &erroff, "(enc-val(flags)(ecc(a
%m)))",
+ val));
+ gcry_mpi_release (val);
+ GNUNET_assert (0 == gcry_pk_decrypt (&resultsexp, data, key->sexp));
+ gcry_sexp_release (data);
+ /* resultsexp has format "(value %m)" */
+ GNUNET_assert (NULL !=
+ (val = gcry_sexp_nth_mpi (resultsexp, 1, GCRYMPI_FMT_USG)));
+ gcry_sexp_release (resultsexp);
+ size = max + GNUNET_CRYPTO_ECC_DATA_ENCODING_LENGTH * 2;
+ tmp = GNUNET_malloc (size);
+ GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG, tmp, size, &size, val));
+ gcry_mpi_release (val);
+ endp = tmp;
+ endp += (size - max);
+ size = max;
+ memcpy (result, endp, size);
+ GNUNET_free (tmp);
+ return size;
+}
+
+
+/**
+ * Sign a given block.
+ *
+ * @param key private key to use for the signing
+ * @param purpose what to sign (size, purpose)
+ * @param sig where to write the signature
+ * @return GNUNET_SYSERR on error, GNUNET_OK on success
+ */
+int
+GNUNET_CRYPTO_ecc_sign (const struct GNUNET_CRYPTO_EccPrivateKey *key,
+ const struct GNUNET_CRYPTO_EccSignaturePurpose
*purpose,
+ struct GNUNET_CRYPTO_EccSignature *sig)
+{
+ gcry_sexp_t result;
+ gcry_sexp_t data;
+ size_t ssize;
+ gcry_mpi_t rval;
+ struct GNUNET_HashCode hc;
+ char *buff;
+ int bufSize;
+
+ GNUNET_CRYPTO_hash (purpose, ntohl (purpose->size), &hc);
+#define FORMATSTRING
"(4:data(5:flags5:pkcs1)(4:hash6:sha51264:0123456789012345678901234567890123456789012345678901234567890123))"
+ bufSize = strlen (FORMATSTRING) + 1;
+ buff = GNUNET_malloc (bufSize);
+ memcpy (buff, FORMATSTRING, bufSize);
+ memcpy (&buff
+ [bufSize -
+ strlen
+
("0123456789012345678901234567890123456789012345678901234567890123))")
+ - 1], &hc, sizeof (struct GNUNET_HashCode));
+ GNUNET_assert (0 == gcry_sexp_new (&data, buff, bufSize, 0));
+ GNUNET_free (buff);
+ GNUNET_assert (0 == gcry_pk_sign (&result, data, key->sexp));
+ gcry_sexp_release (data);
+ GNUNET_assert (0 == key_from_sexp (&rval, result, "ecc", "s"));
+ gcry_sexp_release (result);
+ ssize = sizeof (struct GNUNET_CRYPTO_EccSignature);
+ GNUNET_assert (0 ==
+ gcry_mpi_print (GCRYMPI_FMT_USG, (unsigned char *) sig, ssize,
+ &ssize, rval));
+ gcry_mpi_release (rval);
+ adjust (sig->sig, ssize, sizeof (struct GNUNET_CRYPTO_EccSignature));
+ return GNUNET_OK;
+}
+
+
+/**
+ * Verify signature.
+ *
+ * @param purpose what is the purpose that the signature should have?
+ * @param validate block to validate (size, purpose, data)
+ * @param sig signature that is being validated
+ * @param publicKey public key of the signer
+ * @returns GNUNET_OK if ok, GNUNET_SYSERR if invalid
+ */
+int
+GNUNET_CRYPTO_ecc_verify (uint32_t purpose,
+ const struct GNUNET_CRYPTO_EccSignaturePurpose
+ *validate,
+ const struct GNUNET_CRYPTO_EccSignature *sig,
+ const struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded
+ *publicKey)
+{
+ gcry_sexp_t data;
+ gcry_sexp_t sigdata;
+ size_t size;
+ gcry_mpi_t val;
+ gcry_sexp_t psexp;
+ struct GNUNET_HashCode hc;
+ char *buff;
+ int bufSize;
+ size_t erroff;
+ int rc;
+
+ if (purpose != ntohl (validate->purpose))
+ return GNUNET_SYSERR; /* purpose mismatch */
+ GNUNET_CRYPTO_hash (validate, ntohl (validate->size), &hc);
+ size = sizeof (struct GNUNET_CRYPTO_EccSignature);
+ GNUNET_assert (0 ==
+ gcry_mpi_scan (&val, GCRYMPI_FMT_USG,
+ (const unsigned char *) sig, size, &size));
+ GNUNET_assert (0 ==
+ gcry_sexp_build (&sigdata, &erroff, "(sig-val(ecc(s %m)))",
+ val));
+ gcry_mpi_release (val);
+ bufSize = strlen (FORMATSTRING) + 1;
+ buff = GNUNET_malloc (bufSize);
+ memcpy (buff, FORMATSTRING, bufSize);
+ memcpy (&buff
+ [strlen (FORMATSTRING) -
+ strlen
+
("0123456789012345678901234567890123456789012345678901234567890123))")],
+ &hc, sizeof (struct GNUNET_HashCode));
+ GNUNET_assert (0 == gcry_sexp_new (&data, buff, bufSize, 0));
+ GNUNET_free (buff);
+ if (! (psexp = decode_public_key (publicKey)))
+ {
+ gcry_sexp_release (data);
+ gcry_sexp_release (sigdata);
+ return GNUNET_SYSERR;
+ }
+ rc = gcry_pk_verify (sigdata, data, psexp);
+ gcry_sexp_release (psexp);
+ gcry_sexp_release (data);
+ gcry_sexp_release (sigdata);
+ if (rc)
+ {
+ LOG (GNUNET_ERROR_TYPE_WARNING,
+ _("ECC signature verification failed at %s:%d: %s\n"), __FILE__,
+ __LINE__, gcry_strerror (rc));
+ return GNUNET_SYSERR;
+ }
+ return GNUNET_OK;
+}
+
+
+/* end of crypto_ecc.c */
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