-/*
- * Copyright (C) 2011-2012 Andre Noll <maan@systemlinux.org>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 2011 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
/** \file gcrypt.c Libgrcypt-based encryption/decryption routines. */
#include "crypt.h"
#include "crypt_backend.h"
#include "fd.h"
+#include "base64.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 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.
+ * This is called at the beginning of every program that uses libgcrypt. The
+ * call to gcry_check_version() initializes the gcrypt library and checks that
+ * we have at least the minimal required version.
*/
void init_random_seed_or_die(void)
{
- const char *ver, *req_ver;
+ const char *req_ver = "1.5.0";
+ int seed;
- 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);
+ req_ver, gcry_check_version(NULL));
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)))";
- }
+ get_random_bytes_or_die((unsigned char *)&seed, sizeof(seed));
+ srandom(seed);
}
/** 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)))"
-
-/* rfc 3447, appendix B.2 */
-static void mgf1(unsigned char *seed, size_t seed_len, unsigned result_len,
- unsigned char *result)
-{
- gcry_error_t gret;
- gcry_md_hd_t handle;
- size_t n;;
- unsigned char *md;
- unsigned char octet_string[4], *rp = result, *end = rp + result_len;
-
- assert(result_len / HASH_SIZE < 1ULL << 31);
- gret = gcry_md_open(&handle, GCRY_MD_SHA1, 0);
- assert(gret == 0);
- for (n = 0; rp < end; n++) {
- gcry_md_write(handle, seed, seed_len);
- octet_string[0] = (unsigned char)((n >> 24) & 255);
- octet_string[1] = (unsigned char)((n >> 16) & 255);
- octet_string[2] = (unsigned char)((n >> 8)) & 255;
- octet_string[3] = (unsigned char)(n & 255);
- gcry_md_write(handle, octet_string, 4);
- gcry_md_final(handle);
- md = gcry_md_read(handle, GCRY_MD_SHA1);
- memcpy(rp, md, PARA_MIN(HASH_SIZE, (int)(end - rp)));
- rp += HASH_SIZE;
- gcry_md_reset(handle);
- }
- gcry_md_close(handle);
-}
-
-/** The sha1 hash of an empty file. */
-static const unsigned char empty_hash[HASH_SIZE] =
- "\xda" "\x39" "\xa3" "\xee" "\x5e"
- "\x6b" "\x4b" "\x0d" "\x32" "\x55"
- "\xbf" "\xef" "\x95" "\x60" "\x18"
- "\x90" "\xaf" "\xd8" "\x07" "\x09";
-
-/* rfc3447, section 7.1.1 */
-static void pad_oaep(unsigned char *in, size_t in_len, unsigned char *out,
- size_t out_len)
-{
- size_t ps_len = out_len - in_len - 2 * HASH_SIZE - 2;
- size_t n, mask_len = out_len - HASH_SIZE - 1;
- unsigned char *seed = out + 1, *db = seed + HASH_SIZE,
- *ps = db + HASH_SIZE, *one = ps + ps_len;
- unsigned char *db_mask, seed_mask[HASH_SIZE];
-
- assert(in_len <= out_len - 2 - 2 * HASH_SIZE);
- assert(out_len > 2 * HASH_SIZE + 2);
- PARA_DEBUG_LOG("padding %zu byte input -> %zu byte output\n",
- in_len, out_len);
- dump_buffer("unpadded buffer", in, in_len);
-
- out[0] = '\0';
- get_random_bytes_or_die(seed, HASH_SIZE);
- memcpy(db, empty_hash, HASH_SIZE);
- memset(ps, 0, ps_len);
- *one = 0x01;
- memcpy(one + 1, in, in_len);
- db_mask = para_malloc(mask_len);
- mgf1(seed, HASH_SIZE, mask_len, db_mask);
- for (n = 0; n < mask_len; n++)
- db[n] ^= db_mask[n];
- mgf1(db, mask_len, HASH_SIZE, seed_mask);
- for (n = 0; n < HASH_SIZE; n++)
- seed[n] ^= seed_mask[n];
- free(db_mask);
- dump_buffer("padded buffer", out, out_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)
-{
- unsigned char *masked_seed = in + 1;
- unsigned char *db = in + 1 + HASH_SIZE;
- unsigned char seed[HASH_SIZE], seed_mask[HASH_SIZE];
- unsigned char *db_mask, *p;
- size_t n, mask_len = in_len - HASH_SIZE - 1;
-
- mgf1(db, mask_len, HASH_SIZE, seed_mask);
- for (n = 0; n < HASH_SIZE; n++)
- seed[n] = masked_seed[n] ^ seed_mask[n];
- db_mask = para_malloc(mask_len);
- mgf1(seed, HASH_SIZE, mask_len, db_mask);
- for (n = 0; n < mask_len; n++)
- db[n] ^= db_mask[n];
- free(db_mask);
- if (memcmp(db, empty_hash, HASH_SIZE))
- return -E_OEAP;
- for (p = db + HASH_SIZE; p < in + in_len - 1; p++)
- if (*p != '\0')
- break;
- if (p >= in + in_len - 1)
- return -E_OEAP;
- p++;
- *out_len = in + in_len - p;
- memcpy(out, p, *out_len);
- return 1;
-}
+/** S-expression for decryption. */
+#define RSA_DECRYPT_SEXP "(enc-val(flags oaep)(rsa(a %m)))"
struct asymmetric_key {
gcry_sexp_t sexp;
ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
if (ret < 0)
- return ret;
+ goto out;
ret = -E_KEY_MARKER;
if (strncmp(map, header_str, strlen(header_str)))
goto unmap;
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);
+ ret = base64_decode(key, j, (char **)&blob, &blob_size);
free(key);
if (ret < 0)
goto free_unmap;
+ ret = blob_size;
goto unmap;
free_unmap:
free(blob);
free(blob);
blob = NULL;
}
+out:
*result = blob;
return ret;
}
/* 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) */
return c & 0x7f;
}
-static int find_pubkey_bignum_offset(const unsigned char *data, int len)
-{
- const unsigned char *p = data, *end = data + len;
-
- /* the whole thing istarts with one sequence */
- if (*p != ASN1_TYPE_SEQUENCE)
- return -E_ASN1_PARSE;
- p++;
- if (p >= end)
- return -E_ASN1_PARSE;
- if (is_short_form(*p))
- p++;
- else
- p += 1 + get_long_form_num_length_bytes(*p);
- if (p >= end)
- return -E_ASN1_PARSE;
- /* another sequence containing the object id, skip it */
- if (*p != ASN1_TYPE_SEQUENCE)
- return -E_ASN1_PARSE;
- p++;
- if (p >= end)
- return -E_ASN1_PARSE;
- if (!is_short_form(*p))
- return -E_ASN1_PARSE;
- p += 1 + get_short_form_length(*p);
- if (p >= end)
- return -E_ASN1_PARSE;
- /* all numbers are wrapped in a bit string object that follows */
- if (*p != ASN1_TYPE_BIT_STRING)
- return -E_ASN1_PARSE;
- p++;
- if (p >= end)
- return -E_ASN1_PARSE;
- if (is_short_form(*p))
- p++;
- else
- p += 1 + get_long_form_num_length_bytes(*p);
- p++; /* skip number of unused bits in the bit string */
- if (p >= end)
- return -E_ASN1_PARSE;
-
- /* next, we have a sequence of two integers (n and e) */
- if (*p != ASN1_TYPE_SEQUENCE)
- return -E_ASN1_PARSE;
- p++;
- if (p >= end)
- return -E_ASN1_PARSE;
- if (is_short_form(*p))
- p++;
- else
- p += 1 + get_long_form_num_length_bytes(*p);
- if (p >= end)
- return -E_ASN1_PARSE;
- if (*p != ASN1_TYPE_INTEGER)
- return -E_ASN1_PARSE;
- return p - data;
-}
-
/*
* Returns: Number of bytes scanned. This may differ from the value returned via
* bn_bytes because the latter does not include the ASN.1 prefix and a leading
for (i = 0; i < num_bytes; i++, cp++)
bn_size = (bn_size << 8) + *cp;
}
- PARA_DEBUG_LOG("bn_size %d (0x%x)\n", bn_size, bn_size);
+ PARA_DEBUG_LOG("bn_size %d (0x%x)\n", bn_size, (unsigned)bn_size);
gret = gcry_mpi_scan(bn, GCRYMPI_FMT_STD, cp, bn_size, NULL);
if (gret) {
PARA_ERROR_LOG("%s while scanning n\n",
if (p >= end)
return -E_ASN1_PARSE;
- /* Skip next integer */
+ /* skip next integer */
if (*p != ASN1_TYPE_INTEGER)
return -E_ASN1_PARSE;
p++;
gcry_sexp_t sexp;
struct asymmetric_key *key;
+ *result = NULL;
ret = decode_key(key_file, PRIVATE_KEY_HEADER, PRIVATE_KEY_FOOTER,
&blob);
if (ret < 0)
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.
return ret;
}
-/** Public keys start with this header. */
-#define PUBLIC_KEY_HEADER "-----BEGIN PUBLIC KEY-----"
-/** Public keys end with this footer. */
-#define PUBLIC_KEY_FOOTER "-----END PUBLIC KEY-----"
-
-static int get_asn_public_key(const char *key_file, struct asymmetric_key **result)
-{
- gcry_mpi_t n = NULL, e = NULL;
- unsigned char *blob, *cp, *end;
- int blob_size, ret, n_size;
- gcry_error_t gret;
- size_t erroff;
- gcry_sexp_t sexp;
- struct asymmetric_key *key;
-
- ret = decode_key(key_file, PUBLIC_KEY_HEADER, PUBLIC_KEY_FOOTER,
- &blob);
- if (ret < 0)
- return ret;
- blob_size = ret;
- end = blob + blob_size;
- ret = find_pubkey_bignum_offset(blob, blob_size);
- if (ret < 0)
- goto free_blob;
- PARA_DEBUG_LOG("decoding public RSA params at offset %d\n", ret);
- cp = blob + ret;
-
- ret = read_bignum(cp, end, &n, &n_size);
- if (ret < 0)
- goto free_blob;
- cp += ret;
-
- 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) {
- PARA_ERROR_LOG("offset %zu: %s\n", erroff,
- gcry_strerror(gcry_err_code(gret)));
- ret = -E_SEXP_BUILD;
- goto release_e;
- }
- key = para_malloc(sizeof(*key));
- key->sexp = sexp;
- *result = key;
- ret = n_size;
- PARA_INFO_LOG("successfully read %u bit asn public key\n", n_size * 8);
-
-release_e:
- gcry_mpi_release(e);
-release_n:
- gcry_mpi_release(n);
-free_blob:
- free(blob);
- return ret;
-}
-
static int get_ssh_public_key(unsigned char *data, int size, gcry_sexp_t *result)
{
int ret;
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);
- if (size > INT_MAX / 4)
- return -ERRNO_TO_PARA_ERROR(EOVERFLOW);
- blob = para_malloc(2 * size);
- ret = uudecode((char *)data, blob, 2 * size);
+ PARA_DEBUG_LOG("decoding %d byte public rsa-ssh key\n", size);
+ ret = uudecode((char *)data, size, (char **)&blob, &decoded_size);
if (ret < 0)
goto free_blob;
- decoded_size = ret;
end = blob + decoded_size;
dump_buffer("decoded key", blob, decoded_size);
ret = check_ssh_key_header(blob, decoded_size);
goto release_n;
}
ret = nr_scanned / 32 * 32;
- PARA_INFO_LOG("successfully read %u bit ssh public key\n", ret * 8);
+ PARA_INFO_LOG("successfully read %d bit ssh public key\n", ret * 8);
release_n:
gcry_mpi_release(n);
release_e:
return ret;
}
-int get_asymmetric_key(const char *key_file, int private,
- struct asymmetric_key **result)
+int get_public_key(const char *key_file, struct asymmetric_key **result)
{
int ret, ret2;
void *map;
gcry_sexp_t sexp;
struct asymmetric_key *key;
- if (private)
- return get_private_key(key_file, result);
ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
if (ret < 0)
return ret;
ret = is_ssh_rsa_key(map, map_size);
if (!ret) {
- ret = para_munmap(map, map_size);
- if (ret < 0)
- return ret;
- return get_asn_public_key(key_file, result);
+ para_munmap(map, map_size);
+ return -E_SSH_PARSE;
}
start = map + ret;
end = map + map_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)
return ret;
}
-void free_asymmetric_key(struct asymmetric_key *key)
+void free_public_key(struct asymmetric_key *key)
{
if (!key)
return;
free(key);
}
-static int decode_rsa(gcry_sexp_t sexp, int key_size, unsigned char *outbuf,
- size_t *nbytes)
+static int decode_rsa(gcry_sexp_t sexp, 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);
+ const char *p = gcry_sexp_nth_data(sexp, 1, 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;
+ if (!p)
+ return -E_RSA_DECODE;
+ memcpy(outbuf, p, *nbytes);
+ return 1;
}
int priv_decrypt(const char *key_file, unsigned char *outbuf,
unsigned char *inbuf, int inlen)
{
gcry_error_t gret;
- int ret, key_size;
+ int ret;
struct asymmetric_key *priv;
gcry_mpi_t in_mpi = NULL;
gcry_sexp_t in, out, priv_key;
size_t nbytes;
+ ret = check_private_key_file(key_file);
+ if (ret < 0)
+ return ret;
PARA_INFO_LOG("decrypting %d byte input\n", inlen);
/* key_file -> asymmetric key priv */
ret = get_private_key(key_file, &priv);
if (ret < 0)
return ret;
- key_size = ret / 8;
/* asymmetric key priv -> sexp priv_key */
ret = -E_SEXP_FIND;
goto key_release;
}
/* in_mpi -> in sexp */
- gret = gcry_sexp_build(&in, NULL, rsa_decrypt_sexp, 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;
}
- ret = decode_rsa(out, key_size, outbuf, &nbytes);
+ ret = decode_rsa(out, outbuf, &nbytes);
if (ret < 0)
goto out_release;
PARA_INFO_LOG("successfully decrypted %zu byte message\n", nbytes);
key_release:
gcry_sexp_release(priv_key);
free_key:
- free_asymmetric_key(priv);
+ gcry_sexp_release(priv->sexp);
+ free(priv);
return ret;
}
pub_key = gcry_sexp_find_token(pub->sexp, "public-key", 0);
if (!pub_key)
return -E_SEXP_FIND;
- 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);
- }
+ gret = gcry_sexp_build(&in, NULL, "(data(flags oaep)(value %b))", len, inbuf);
if (gret) {
PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
ret = -E_SEXP_BUILD;
struct stream_cipher *sc_new(const unsigned char *data, int len)
{
gcry_error_t gret;
-
struct stream_cipher *sc = para_malloc(sizeof(*sc));
- gret = gcry_cipher_open(&sc->handle, GCRY_CIPHER_ARCFOUR,
- GCRY_CIPHER_MODE_STREAM, 0);
- if (gret) {
- PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
- free(sc);
- return NULL;
- }
- gret = gcry_cipher_setkey(sc->handle, data, (size_t)len);
+
+ 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;
}
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 = xwrite(scc->fd, (char *)tmp, size);
- free(tmp);
- return ret;
-}
-
-int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf,
- size_t size)
-{
- 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,
- NULL, 0);
- assert(gret == 0);
- return ret;
-}
-
void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
{
gcry_cipher_hd_t handle = sc->handle;
projects / paraslash.git / blobdiff