/*
- * Copyright (C) 2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2011 Andre Noll <maan@tuebingen.mpg.de>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
/** \file gcrypt.c Libgrcypt-based encryption/decryption routines. */
#include <regex.h>
-#include <stdbool.h>
#include <gcrypt.h>
#include "para.h"
//#define GCRYPT_DEBUG 1
+static bool libgcrypt_has_oaep;
+static const char *rsa_decrypt_sexp;
+
#ifdef GCRYPT_DEBUG
static void dump_buffer(const char *msg, unsigned char *buf, int len)
{
int i;
- fprintf(stderr, "%s (%u bytes): ", msg, len);
+ fprintf(stderr, "%s (%d bytes): ", msg, len);
for (i = 0; i < len; i++)
fprintf(stderr, "%02x ", buf[i]);
fprintf(stderr, "\n");
}
/*
- * This is called at the beginning of every program that uses libgcrypt. We
- * don't have to initialize any random seed here, but the call to gcry_control
- * is necessary to avoid warnings of the form "missing initialization - please
- * fix the application".
+ * This is called at the beginning of every program that uses libgcrypt. We
+ * don't have to initialize any random seed here, but we must initialize the
+ * gcrypt library. This task is performed by gcry_check_version() which can
+ * also check that the gcrypt library version is at least the minimal required
+ * version. This function also tells us whether we have to use our own OAEP
+ * padding code.
*/
void init_random_seed_or_die(void)
{
- gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
+ const char *ver, *req_ver;
+
+ ver = gcry_check_version(NULL);
+ req_ver = "1.4.0";
+ if (!gcry_check_version(req_ver)) {
+ PARA_EMERG_LOG("fatal: need at least libgcrypt-%s, have: %s\n",
+ req_ver, ver);
+ exit(EXIT_FAILURE);
+ }
+ req_ver = "1.5.0";
+ if (gcry_check_version(req_ver)) {
+ libgcrypt_has_oaep = true;
+ rsa_decrypt_sexp = "(enc-val(flags oaep)(rsa(a %m)))";
+ } else {
+ libgcrypt_has_oaep = false;
+ rsa_decrypt_sexp = "(enc-val(rsa(a %m)))";
+ }
}
/** S-expression for the public part of an RSA key. */
-#define RSA_PUBKEY_SEXP "(public-key (rsa (n %m) (e %m)))"
+#define RSA_PUBKEY_SEXP "(public-key (rsa (n %m) (e %m)))"
/** S-expression for a private RSA key. */
#define RSA_PRIVKEY_SEXP "(private-key (rsa (n %m) (e %m) (d %m) (p %m) (q %m) (u %m)))"
{
gcry_error_t gret;
gcry_md_hd_t handle;
- size_t n;;
+ size_t n;
unsigned char *md;
unsigned char octet_string[4], *rp = result, *end = rp + result_len;
/* rfc 3447, section 7.1.2 */
static int unpad_oaep(unsigned char *in, size_t in_len, unsigned char *out,
size_t *out_len)
-{ int ret;
+{
unsigned char *masked_seed = in + 1;
unsigned char *db = in + 1 + HASH_SIZE;
unsigned char seed[HASH_SIZE], seed_mask[HASH_SIZE];
p++;
*out_len = in + in_len - p;
memcpy(out, p, *out_len);
- return ret;
+ return 1;
}
struct asymmetric_key {
key[j++] = begin[i];
}
key[j] = '\0';
- //PARA_CRIT_LOG("key: %s\n", key);
blob_size = key_size * 2;
blob = para_malloc(blob_size);
ret = base64_decode(key, blob, blob_size);
/* bit 6 has value 0 */
static inline bool is_primitive(unsigned char c)
{
- return ((c & (1<<6)) == 0);
+ return (c & (1<<6)) == 0;
}
static inline bool is_primitive_integer(unsigned char c)
{
if (!is_primitive(c))
return false;
- return ((c & 0x1f) == ASN1_TYPE_INTEGER);
+ return (c & 0x1f) == ASN1_TYPE_INTEGER;
}
/* Bit 8 is zero (and bits 7-1 give the length) */
{
const unsigned char *p = data, *end = data + len;
- /* the whole thing istarts with one sequence */
+ /* the whole thing starts with one sequence */
if (*p != ASN1_TYPE_SEQUENCE)
return -E_ASN1_PARSE;
p++;
if (p >= end)
return -E_ASN1_PARSE;
- /* Skip next integer */
+ /* skip next integer */
if (*p != ASN1_TYPE_INTEGER)
return -E_ASN1_PARSE;
p++;
ret = read_bignum(cp, end, &u, NULL);
if (ret < 0)
goto release_q;
- cp += ret;
/*
* OpenSSL uses slightly different parameters than gcrypt. To use these
* parameters we need to swap the values of p and q and recompute u.
ret = read_bignum(cp, end, &e, NULL);
if (ret < 0)
goto release_n;
- cp += ret;
gret = gcry_sexp_build(&sexp, &erroff, RSA_PUBKEY_SEXP, n, e);
if (gret) {
}
key = para_malloc(sizeof(*key));
key->sexp = sexp;
+ key->num_bytes = n_size;
*result = key;
- ret = n_size * 8;
+ ret = n_size;
PARA_INFO_LOG("successfully read %u bit asn public key\n", n_size * 8);
release_e:
size_t nr_scanned, erroff, decoded_size;
gcry_mpi_t e = NULL, n = NULL;
- PARA_DEBUG_LOG("decoding %d byte public rsa-ssh key\n", size);
+ PARA_DEBUG_LOG("decoding %d byte public rsa-ssh key\n", size);
if (size > INT_MAX / 4)
return -ERRNO_TO_PARA_ERROR(EOVERFLOW);
blob = para_malloc(2 * size);
key->num_bytes = ret;
key->sexp = sexp;
*result = key;
- ret = key->num_bytes;
unmap:
ret2 = para_munmap(map, map_size);
if (ret >= 0 && ret2 < 0)
free(key);
}
+static int decode_rsa(gcry_sexp_t sexp, int key_size, unsigned char *outbuf,
+ size_t *nbytes)
+{
+ int ret;
+ gcry_error_t gret;
+ unsigned char oaep_buf[512];
+ gcry_mpi_t out_mpi;
+
+ if (libgcrypt_has_oaep) {
+ const char *p = gcry_sexp_nth_data(sexp, 1, nbytes);
+
+ if (!p) {
+ PARA_ERROR_LOG("could not get data from list\n");
+ return -E_OEAP;
+ }
+ memcpy(outbuf, p, *nbytes);
+ return 1;
+ }
+ out_mpi = gcry_sexp_nth_mpi(sexp, 0, GCRYMPI_FMT_USG);
+ if (!out_mpi)
+ return -E_SEXP_FIND;
+ gret = gcry_mpi_print(GCRYMPI_FMT_USG, oaep_buf, sizeof(oaep_buf),
+ nbytes, out_mpi);
+ if (gret) {
+ PARA_ERROR_LOG("mpi_print: %s\n", gcrypt_strerror(gret));
+ ret = -E_MPI_PRINT;
+ goto out_mpi_release;
+ }
+ /*
+ * An oaep-encoded buffer always starts with at least one zero byte.
+ * However, leading zeroes in an mpi are omitted in the output of
+ * gcry_mpi_print() when using the GCRYMPI_FMT_USG format. The
+ * alternative, GCRYMPI_FMT_STD, does not work either because here the
+ * leading zero(es) might also be omitted, depending on the value of
+ * the second byte.
+ *
+ * To circumvent this, we shift the oaep buffer to the right. But first
+ * we check that the buffer actually started with a zero byte, i.e. that
+ * nbytes < key_size. Otherwise a decoding error occurred.
+ */
+ ret = -E_SEXP_DECRYPT;
+ if (*nbytes >= key_size)
+ goto out_mpi_release;
+ memmove(oaep_buf + key_size - *nbytes, oaep_buf, *nbytes);
+ memset(oaep_buf, 0, key_size - *nbytes);
+
+ PARA_DEBUG_LOG("decrypted buffer before unpad (%d bytes):\n",
+ key_size);
+ dump_buffer("non-unpadded decrypted buffer", oaep_buf, key_size);
+ ret = unpad_oaep(oaep_buf, key_size, outbuf, nbytes);
+ if (ret < 0)
+ goto out_mpi_release;
+ PARA_DEBUG_LOG("decrypted buffer after unpad (%zu bytes):\n",
+ *nbytes);
+ dump_buffer("unpadded decrypted buffer", outbuf, *nbytes);
+ ret = 1;
+out_mpi_release:
+ gcry_mpi_release(out_mpi);
+ return ret;
+}
+
int priv_decrypt(const char *key_file, unsigned char *outbuf,
unsigned char *inbuf, int inlen)
{
gcry_error_t gret;
int ret, key_size;
struct asymmetric_key *priv;
- gcry_mpi_t in_mpi = NULL, out_mpi = NULL;
+ gcry_mpi_t in_mpi = NULL;
gcry_sexp_t in, out, priv_key;
size_t nbytes;
- unsigned char oaep_buf[512];
PARA_INFO_LOG("decrypting %d byte input\n", inlen);
/* key_file -> asymmetric key priv */
ret = -E_MPI_SCAN;
goto key_release;
}
-
/* in_mpi -> in sexp */
- gret = gcry_sexp_build(&in, NULL, "(enc-val(rsa(a %m)))", in_mpi);
+ gret = gcry_sexp_build(&in, NULL, rsa_decrypt_sexp, in_mpi);
if (gret) {
PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
ret = -E_SEXP_BUILD;
ret = -E_SEXP_DECRYPT;
goto in_release;
}
- out_mpi = gcry_sexp_nth_mpi(out, 0, GCRYMPI_FMT_USG);
- if (!out_mpi) {
- ret = -E_SEXP_FIND;
+ ret = decode_rsa(out, key_size, outbuf, &nbytes);
+ if (ret < 0)
goto out_release;
- }
- gret = gcry_mpi_print(GCRYMPI_FMT_USG, oaep_buf, sizeof(oaep_buf),
- &nbytes, out_mpi);
- if (gret) {
- PARA_ERROR_LOG("mpi_print: %s\n", gcrypt_strerror(gret));
- ret = -E_MPI_PRINT;
- goto out_mpi_release;
- }
- /*
- * An oaep-encoded buffer always starts with at least one zero byte.
- * However, leading zeroes in an mpi are omitted in the output of
- * gcry_mpi_print() when using the GCRYMPI_FMT_USG format. The
- * alternative, GCRYMPI_FMT_STD, does not work either because here the
- * leading zero(es) might also be omitted, depending on the value of
- * the second byte.
- *
- * To circumvent this, we shift the oaep buffer to the right. But first
- * we check that the buffer actually started with a zero byte, i.e. that
- * nbytes < key_size. Otherwise a decoding error occurred.
- */
- ret = -E_SEXP_DECRYPT;
- if (nbytes >= key_size)
- goto out_mpi_release;
- memmove(oaep_buf + key_size - nbytes, oaep_buf, nbytes);
- memset(oaep_buf, 0, key_size - nbytes);
-
- PARA_DEBUG_LOG("decrypted buffer before unpad (%d bytes):\n",
- key_size);
- dump_buffer("non-unpadded decrypted buffer", oaep_buf, key_size);;
- unpad_oaep(oaep_buf, key_size, outbuf, &nbytes);
- PARA_DEBUG_LOG("decrypted buffer after unpad (%zu bytes):\n",
- nbytes);
- dump_buffer("unpadded decrypted buffer", outbuf, nbytes);;
+ PARA_INFO_LOG("successfully decrypted %zu byte message\n", nbytes);
ret = nbytes;
- PARA_INFO_LOG("successfully decrypted %u byte message\n", ret);
-out_mpi_release:
- gcry_mpi_release(out_mpi);
out_release:
gcry_sexp_release(out);
in_release:
unsigned len, unsigned char *outbuf)
{
gcry_error_t gret;
- const size_t pad_size = 256;
gcry_sexp_t pub_key, in, out, out_a;
gcry_mpi_t out_mpi = NULL;
size_t nbytes;
int ret;
- unsigned char padded_input[256];
PARA_INFO_LOG("encrypting %u byte input with %d-byte key\n", len, pub->num_bytes);
pub_key = gcry_sexp_find_token(pub->sexp, "public-key", 0);
if (!pub_key)
return -E_SEXP_FIND;
-
- /* inbuf -> padded inbuf */
- pad_oaep(inbuf, len, padded_input, pad_size);
-
- /* padded inbuf -> in sexp */
- gret = gcry_sexp_build(&in, NULL, "(data(flags raw)(value %b))",
- pad_size, padded_input);
+ if (libgcrypt_has_oaep) {
+ gret = gcry_sexp_build(&in, NULL,
+ "(data(flags oaep)(value %b))", len, inbuf);
+ } else {
+ unsigned char padded_input[256];
+ const size_t pad_size = 256;
+ /* inbuf -> padded inbuf */
+ pad_oaep(inbuf, len, padded_input, pad_size);
+ /* padded inbuf -> in sexp */
+ gret = gcry_sexp_build(&in, NULL,
+ "(data(flags raw)(value %b))", pad_size, padded_input);
+ }
if (gret) {
PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
ret = -E_SEXP_BUILD;
gcry_cipher_hd_t handle;
};
-struct stream_cipher *sc_new(const unsigned char *data, int len)
+struct stream_cipher *sc_new(const unsigned char *data, int len,
+ bool use_aes)
{
gcry_error_t gret;
-
struct stream_cipher *sc = para_malloc(sizeof(*sc));
+
+ if (use_aes) {
+ assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
+ gret = gcry_cipher_open(&sc->handle, GCRY_CIPHER_AES128,
+ GCRY_CIPHER_MODE_CTR, 0);
+ assert(gret == 0);
+ gret = gcry_cipher_setkey(sc->handle, data,
+ AES_CRT128_BLOCK_SIZE);
+ assert(gret == 0);
+ gret = gcry_cipher_setctr(sc->handle,
+ data + AES_CRT128_BLOCK_SIZE, AES_CRT128_BLOCK_SIZE);
+ assert(gret == 0);
+ return sc;
+ }
gret = gcry_cipher_open(&sc->handle, GCRY_CIPHER_ARCFOUR,
GCRY_CIPHER_MODE_STREAM, 0);
if (gret) {
free(sc);
}
-int sc_send_bin_buffer(struct stream_cipher_context *scc, char *buf,
- size_t size)
-{
- gcry_error_t gret;
- int ret;
- unsigned char *tmp = para_malloc(size);
-
- assert(size);
- gret = gcry_cipher_encrypt(scc->send->handle, tmp, size,
- (unsigned char *)buf, size);
- assert(gret == 0);
- ret = write_all(scc->fd, (char *)tmp, &size);
- free(tmp);
- return ret;
-}
-
-int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf,
- size_t size)
+void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
{
+ gcry_cipher_hd_t handle = sc->handle;
gcry_error_t gret;
- ssize_t ret = recv(scc->fd, buf, size, 0);
- if (ret < 0)
- ret = -ERRNO_TO_PARA_ERROR(errno);
- if (ret <= 0)
- return ret;
/* perform in-place encryption */
- gret = gcry_cipher_encrypt(scc->recv->handle, (unsigned char *)buf, ret,
+ *dst = *src;
+ gret = gcry_cipher_encrypt(handle, src->iov_base, src->iov_len,
NULL, 0);
assert(gret == 0);
- return ret;
}
projects / paraslash.git / blobdiff