/** \file gcrypt.c Libgrcypt-based encryption/decryption routines. */
#include <regex.h>
-#include <sys/types.h>
-#include <sys/socket.h>
+#include <stdbool.h>
+#include <gcrypt.h>
#include "para.h"
#include "error.h"
#include "string.h"
#include "crypt.h"
+#include "crypt_backend.h"
#include "fd.h"
-struct asymmetric_key {
- int x;
-};
+//#define GCRYPT_DEBUG 1
+
+#ifdef GCRYPT_DEBUG
+static void dump_buffer(const char *msg, unsigned char *buf, int len)
+{
+ int i;
+
+ fprintf(stderr, "%s (%u bytes): ", msg, len);
+ for (i = 0; i < len; i++)
+ fprintf(stderr, "%02x ", buf[i]);
+ fprintf(stderr, "\n");
+}
+#else
+/** Empty. Define GCRYPT_DEBUG to dump buffers. */
+#define dump_buffer(a, b, c)
+#endif
+
+void hash_function(const char *data, unsigned long len, unsigned char *hash)
+{
+ gcry_error_t gret;
+ gcry_md_hd_t handle;
+ unsigned char *md;
+
+ gret = gcry_md_open(&handle, GCRY_MD_SHA1, 0);
+ assert(gret == 0);
+ gcry_md_write(handle, data, (size_t)len);
+ gcry_md_final(handle);
+ md = gcry_md_read(handle, GCRY_MD_SHA1);
+ assert(md);
+ memcpy(hash, md, HASH_SIZE);
+ gcry_md_close(handle);
+}
void get_random_bytes_or_die(unsigned char *buf, int num)
{
+ gcry_randomize(buf, (size_t)num, GCRY_STRONG_RANDOM);
}
+/*
+ * 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".
+ */
void init_random_seed_or_die(void)
{
+ gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
+}
+
+/** S-expression for the public part of an RSA key. */
+#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)
+{ int ret;
+ 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 ret;
+}
+
+struct asymmetric_key {
+ gcry_sexp_t sexp;
+ int num_bytes;
+};
+
+static const char *gcrypt_strerror(gcry_error_t gret)
+{
+ return gcry_strerror(gcry_err_code(gret));
+}
+
+static int decode_key(const char *key_file, const char *header_str,
+ const char *footer_str, unsigned char **result)
+{
+ int ret, ret2, i, j;
+ void *map;
+ size_t map_size, key_size, blob_size;
+ unsigned char *blob = NULL;
+ char *begin, *footer, *key;
+
+ ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
+ if (ret < 0)
+ return ret;
+ ret = -E_KEY_MARKER;
+ if (strncmp(map, header_str, strlen(header_str)))
+ goto unmap;
+ footer = strstr(map, footer_str);
+ ret = -E_KEY_MARKER;
+ if (!footer)
+ goto unmap;
+ begin = map + strlen(header_str);
+ /* skip whitespace at the beginning */
+ for (; begin < footer; begin++) {
+ if (para_isspace(*begin))
+ continue;
+ break;
+ }
+ ret = -E_KEY_MARKER;
+ if (begin >= footer)
+ goto unmap;
+
+ key_size = footer - begin;
+ key = para_malloc(key_size + 1);
+ for (i = 0, j = 0; begin + i < footer; i++) {
+ if (para_isspace(begin[i]))
+ continue;
+ 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);
+ free(key);
+ if (ret < 0)
+ goto free_unmap;
+ goto unmap;
+free_unmap:
+ free(blob);
+ blob = NULL;
+unmap:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+ if (ret < 0) {
+ free(blob);
+ blob = NULL;
+ }
+ *result = blob;
+ return ret;
+}
+
+/** ASN Types and their code. */
+enum asn1_types {
+ /** The next object is an integer. */
+ ASN1_TYPE_INTEGER = 0x2,
+ /** Bit string object. */
+ ASN1_TYPE_BIT_STRING = 0x03,
+ /** Keys start with one big type sequence. */
+ ASN1_TYPE_SEQUENCE = 0x30,
+};
+
+/* bit 6 has value 0 */
+static inline bool is_primitive(unsigned char c)
+{
+ 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);
+}
+
+/* Bit 8 is zero (and bits 7-1 give the length) */
+static inline bool is_short_form(unsigned char c)
+{
+ return (c & 0x80) == 0;
+}
+
+static inline int get_short_form_length(unsigned char c)
+{
+ return c & 0x7f;
+}
+
+static inline int get_long_form_num_length_bytes(unsigned char c)
+{
+ 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
+ * zero is not considered as an additional byte for bn_bytes.
+ */
+static int read_bignum(unsigned char *start, unsigned char *end, gcry_mpi_t *bn,
+ int *bn_bytes)
+{
+ int i, bn_size;
+ gcry_error_t gret;
+ unsigned char *cp = start;
+
+ if (!is_primitive_integer(*cp))
+ return -E_BAD_PRIVATE_KEY;
+ cp++;
+ if (is_short_form(*cp)) {
+ bn_size = get_short_form_length(*cp);
+ cp++;
+ } else {
+ int num_bytes = get_long_form_num_length_bytes(*cp);
+ if (cp + num_bytes > end)
+ return -E_BAD_PRIVATE_KEY;
+ if (num_bytes > 4) /* nobody has such a large modulus */
+ return -E_BAD_PRIVATE_KEY;
+ cp++;
+ bn_size = 0;
+ 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);
+ gret = gcry_mpi_scan(bn, GCRYMPI_FMT_STD, cp, bn_size, NULL);
+ if (gret) {
+ PARA_ERROR_LOG("%s while scanning n\n",
+ gcry_strerror(gcry_err_code(gret)));
+ return-E_MPI_SCAN;
+ }
+ /*
+ * Don't take the first leading zero into account for the size of the
+ * bignum.
+ */
+ if (*cp == '\0') {
+ cp++;
+ bn_size--;
+ }
+ if (bn_bytes)
+ *bn_bytes = bn_size;
+ cp += bn_size;
+// unsigned char *buf;
+// gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, *bn);
+// PARA_CRIT_LOG("bn: %s\n", buf);
+ return cp - start;
+}
+
+static int find_privkey_bignum_offset(const unsigned char *data, int len)
+{
+ const unsigned char *p = data, *end = data + len;
+
+ /* like the public key, the whole thing is contained in a 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;
+
+ /* Skip next integer */
+ if (*p != ASN1_TYPE_INTEGER)
+ return -E_ASN1_PARSE;
+ p++;
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ if (is_short_form(*p))
+ p += 1 + get_short_form_length(*p);
+ else
+ p += 1 + get_long_form_num_length_bytes(*p);
+ if (p >= end)
+ return -E_ASN1_PARSE;
+ return p - data;
+}
+
+/** Private keys start with this header. */
+#define PRIVATE_KEY_HEADER "-----BEGIN RSA PRIVATE KEY-----"
+/** Private keys end with this footer. */
+#define PRIVATE_KEY_FOOTER "-----END RSA PRIVATE KEY-----"
+
+static int get_private_key(const char *key_file, struct asymmetric_key **result)
+{
+ gcry_mpi_t n = NULL, e = NULL, d = NULL, p = NULL, q = NULL,
+ u = 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, PRIVATE_KEY_HEADER, PRIVATE_KEY_FOOTER,
+ &blob);
+ if (ret < 0)
+ return ret;
+ blob_size = ret;
+ end = blob + blob_size;
+ ret = find_privkey_bignum_offset(blob, blob_size);
+ if (ret < 0)
+ goto free_blob;
+ PARA_INFO_LOG("reading 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;
+
+ ret = read_bignum(cp, end, &d, NULL);
+ if (ret < 0)
+ goto release_e;
+ cp += ret;
+
+ ret = read_bignum(cp, end, &p, NULL);
+ if (ret < 0)
+ goto release_d;
+ cp += ret;
+
+ ret = read_bignum(cp, end, &q, NULL);
+ if (ret < 0)
+ goto release_p;
+ cp += ret;
+ 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.
+ */
+ if (gcry_mpi_cmp(p, q) > 0) {
+ gcry_mpi_swap(p, q);
+ gcry_mpi_invm(u, p, q);
+ }
+ gret = gcry_sexp_build(&sexp, &erroff, RSA_PRIVKEY_SEXP,
+ n, e, d, p, q, u);
+
+ if (gret) {
+ PARA_ERROR_LOG("offset %zu: %s\n", erroff,
+ gcry_strerror(gcry_err_code(gret)));
+ ret = -E_SEXP_BUILD;
+ goto release_u;
+ }
+ key = para_malloc(sizeof(*key));
+ key->sexp = sexp;
+ *result = key;
+ ret = n_size * 8;
+ PARA_INFO_LOG("succesfully read %d bit private key\n", ret);
+release_u:
+ gcry_mpi_release(u);
+release_q:
+ gcry_mpi_release(q);
+release_p:
+ gcry_mpi_release(p);
+release_d:
+ gcry_mpi_release(d);
+release_e:
+ gcry_mpi_release(e);
+release_n:
+ gcry_mpi_release(n);
+free_blob:
+ free(blob);
+ 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 * 8;
+ 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;
+ gcry_error_t gret;
+ unsigned char *blob = NULL, *p, *end;
+ 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);
+ 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);
+ if (ret < 0)
+ goto free_blob;
+ p = blob + ret;
+ ret = -E_SSH_PARSE;
+ if (p >= end)
+ goto free_blob;
+ PARA_DEBUG_LOG("scanning modulus and public exponent\n");
+ gret = gcry_mpi_scan(&e, GCRYMPI_FMT_SSH, p, end - p, &nr_scanned);
+ if (gret) {
+ ret = -E_MPI_SCAN;
+ PARA_CRIT_LOG("%s\n", gcry_strerror(gcry_err_code(gret)));
+ goto free_blob;
+ }
+ PARA_DEBUG_LOG("scanned e (%zu bytes)\n", nr_scanned);
+// gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, rsa_e);
+// PARA_CRIT_LOG("e: %s\n", buf);
+ p += nr_scanned;
+ if (p >= end)
+ goto release_e;
+ gret = gcry_mpi_scan(&n, GCRYMPI_FMT_SSH, p, end - p, &nr_scanned);
+ if (gret) {
+ ret = -E_MPI_SCAN;
+ PARA_ERROR_LOG("%s\n", gcry_strerror(gcry_err_code(gret)));
+ goto release_e;
+ }
+ PARA_DEBUG_LOG("scanned n (%zu bytes)\n", nr_scanned);
+// gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, rsa_n);
+// PARA_CRIT_LOG("n: %s\n", buf);
+ gret = gcry_sexp_build(result, &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_n;
+ }
+ ret = nr_scanned / 32 * 32;
+ PARA_INFO_LOG("successfully read %u bit ssh public key\n", ret * 8);
+release_n:
+ gcry_mpi_release(n);
+release_e:
+ gcry_mpi_release(e);
+free_blob:
+ free(blob);
+ return ret;
}
int get_asymmetric_key(const char *key_file, int private,
struct asymmetric_key **result)
{
- return 0;
+ int ret, ret2;
+ void *map;
+ size_t map_size;
+ unsigned char *start, *end;
+ 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);
+ }
+ start = map + ret;
+ end = map + map_size;
+ ret = -E_SSH_PARSE;
+ if (start >= end)
+ goto unmap;
+ ret = get_ssh_public_key(start, end - start, &sexp);
+ if (ret < 0)
+ goto unmap;
+ key = para_malloc(sizeof(*key));
+ 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)
+ ret = ret2;
+ return ret;
}
void free_asymmetric_key(struct asymmetric_key *key)
{
+ if (!key)
+ return;
+ gcry_sexp_release(key->sexp);
+ free(key);
}
int priv_decrypt(const char *key_file, unsigned char *outbuf,
unsigned char *inbuf, int inlen)
{
- return 0;
+ gcry_error_t gret;
+ int ret, key_size;
+ struct asymmetric_key *priv;
+ gcry_mpi_t in_mpi = NULL, out_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 = 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;
+ priv_key = gcry_sexp_find_token(priv->sexp, "private-key", 0);
+ if (!priv_key)
+ goto free_key;
+
+ /* inbuf -> in_mpi */
+ gret = gcry_mpi_scan(&in_mpi, GCRYMPI_FMT_USG, inbuf,
+ inlen, NULL);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_MPI_SCAN;
+ goto key_release;
+ }
+
+ /* in_mpi -> in sexp */
+ gret = gcry_sexp_build(&in, NULL, "(enc-val(rsa(a %m)))", in_mpi);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_BUILD;
+ goto in_mpi_release;
+ }
+
+ /* rsa decryption: in sexp -> out sexp */
+ gret = gcry_pk_decrypt(&out, in, priv_key);
+ if (gret) {
+ PARA_ERROR_LOG("decrypt: %s\n", gcrypt_strerror(gret));
+ 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;
+ 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);;
+ 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:
+ gcry_sexp_release(in);
+in_mpi_release:
+ gcry_mpi_release(in_mpi);
+key_release:
+ gcry_sexp_release(priv_key);
+free_key:
+ free_asymmetric_key(priv);
+ return ret;
}
int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
unsigned len, unsigned char *outbuf)
{
- return 0;
+ 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);
+
+ /* get pub key */
+ 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 (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_BUILD;
+ goto key_release;
+ }
+ /* rsa sexp encryption: in -> out */
+ gret = gcry_pk_encrypt(&out, in, pub_key);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_ENCRYPT;
+ goto in_release;
+ }
+ /* extract a, an MPI with the result of the RSA operation */
+ ret = -E_SEXP_FIND;
+ out_a = gcry_sexp_find_token(out, "a", 0);
+ if (!out_a)
+ goto out_release;
+ /* convert sexp out_a -> out_mpi */
+ out_mpi = gcry_sexp_nth_mpi(out_a, 1, GCRYMPI_FMT_STD);
+ if (!out_mpi) {
+ ret = -E_SEXP_FIND;
+ goto out_a_release;
+ }
+ gret = gcry_mpi_print(GCRYMPI_FMT_USG, outbuf, 512 /* FIXME */, &nbytes, out_mpi);
+ if (gret) {
+ PARA_ERROR_LOG("%s\n", gcrypt_strerror(gret));
+ ret = -E_SEXP_ENCRYPT;
+ goto out_mpi_release;
+ }
+ PARA_INFO_LOG("encrypted buffer is %zu bytes\n", nbytes);
+ dump_buffer("enc buf", outbuf, nbytes);
+ ret = nbytes;
+
+out_mpi_release:
+ gcry_mpi_release(out_mpi);
+out_a_release:
+ gcry_sexp_release(out_a);
+out_release:
+ gcry_sexp_release(out);
+in_release:
+ gcry_sexp_release(in);
+key_release:
+ gcry_sexp_release(pub_key);
+ return ret;
}
struct stream_cipher {
- int x;
+ gcry_cipher_hd_t handle;
};
struct stream_cipher *sc_new(const unsigned char *data, int len)
{
- return NULL;
+ 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(gret == 0);
+ return sc;
}
void sc_free(struct stream_cipher *sc)
{
+ if (!sc)
+ return;
+ gcry_cipher_close(sc->handle);
+ free(sc);
}
-int sc_send_bin_buffer(struct stream_cipher_context *scc, const char *buf,
- size_t len)
+int sc_send_bin_buffer(struct stream_cipher_context *scc, char *buf,
+ size_t size)
{
- return 0;
-}
+ gcry_error_t gret;
+ int ret;
+ unsigned char *tmp = para_malloc(size);
-int sc_send_buffer(struct stream_cipher_context *scc, const char *buf)
-{
- return 0;
-}
-
-__printf_2_3 int sc_send_va_buffer(struct stream_cipher_context *scc,
- const char *fmt, ...)
-{
- return 0;
+ 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)
{
- return 0;
-}
+ gcry_error_t gret;
+ ssize_t ret = recv(scc->fd, buf, size, 0);
-int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size)
-{
- return 0;
-}
-
-void hash_function(const char *data, unsigned long len, unsigned char *hash)
-{
+ 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;
}
projects / paraslash.git / commitdiff