+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;
+ /*
+ * 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;
+
+ 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;
+ key->num_bytes = n_size;
+ *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;
+ 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)
+{
+ 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;
+unmap:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+ return ret;
+}
+
+void free_asymmetric_key(struct asymmetric_key *key)