-/*
- * Copyright (C) 2011 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 <regex.h>
-#include <sys/types.h>
-#include <sys/socket.h>
+#include <gcrypt.h>
#include "para.h"
#include "error.h"
#include "string.h"
#include "crypt.h"
+#include "crypt_backend.h"
#include "fd.h"
+#include "base64.h"
+
+//#define GCRYPT_DEBUG 1
+
+#ifdef GCRYPT_DEBUG
+static void dump_buffer(const char *msg, unsigned char *buf, int len)
+{
+ int i;
+
+ fprintf(stderr, "%s (%d 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. The
+ * call to gcry_check_version() initializes the gcrypt library and checks that
+ * we have at least the minimal required version.
+ */
+void crypt_init(void)
+{
+ const char *req_ver = "1.5.0";
+ int seed;
+
+ if (!gcry_check_version(req_ver)) {
+ PARA_EMERG_LOG("fatal: need at least libgcrypt-%s, have: %s\n",
+ req_ver, gcry_check_version(NULL));
+ exit(EXIT_FAILURE);
+ }
+
+ /*
+ * Allocate a pool of secure memory. This also drops privileges where
+ * needed.
+ */
+ gcry_control(GCRYCTL_INIT_SECMEM, 65536, 0);
+
+ /* Tell Libgcrypt that initialization has completed. */
+ gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
+
+ get_random_bytes_or_die((unsigned char *)&seed, sizeof(seed));
+ srandom(seed);
+}
+
+void crypt_shutdown(void)
+{
+ /*
+ * WK does not see a way to apply a patch for the sake of Valgrind, so
+ * as of 2018 libgrypt has no deinitialization routine to free the
+ * resources on exit.
+ */
+}
+
+/** 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)))"
+/** S-expression for decryption. */
+#define RSA_DECRYPT_SEXP "(enc-val(flags oaep)(rsa(a %m)))"
struct asymmetric_key {
- int x;
+ gcry_sexp_t sexp;
+ int num_bytes;
};
-void get_random_bytes_or_die(unsigned char *buf, int num)
+static const char *gcrypt_strerror(gcry_error_t gret)
{
+ return gcry_strerror(gcry_err_code(gret));
}
-void init_random_seed_or_die(void)
+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)
+ goto out;
+ 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';
+ 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);
+ blob = NULL;
+unmap:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+ if (ret < 0) {
+ free(blob);
+ blob = NULL;
+ }
+out:
+ *result = blob;
+ return ret;
}
-int get_asymmetric_key(const char *key_file, int private,
- struct asymmetric_key **result)
+/** 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 0;
+ return (c & (1<<6)) == 0;
}
-void free_asymmetric_key(struct asymmetric_key *key)
+static inline bool is_primitive_integer(unsigned char c)
{
+ if (!is_primitive(c))
+ return false;
+ return (c & 0x1f) == ASN1_TYPE_INTEGER;
}
-int priv_decrypt(const char *key_file, unsigned char *outbuf,
- unsigned char *inbuf, int inlen)
+/* Bit 8 is zero (and bits 7-1 give the length) */
+static inline bool is_short_form(unsigned char c)
{
- return 0;
+ return (c & 0x80) == 0;
}
-int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
- unsigned len, unsigned char *outbuf)
+static inline int get_short_form_length(unsigned char c)
{
- return 0;
+ return c & 0x7f;
}
-struct stream_cipher {
- int x;
-};
+static inline int get_long_form_num_length_bytes(unsigned char c)
+{
+ return c & 0x7f;
+}
-struct stream_cipher *sc_new(const unsigned char *data, int len)
+/*
+ * 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)
{
- return NULL;
+ 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, (unsigned)bn_size);
+ gret = gcry_mpi_scan(bn, GCRYMPI_FMT_STD, cp, bn_size, NULL);
+ if (gret) {
+ PARA_ERROR_LOG("gcry_mpi_scan: %s\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;
}
-void sc_free(struct stream_cipher *sc)
+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;
}
-int sc_send_bin_buffer(struct stream_cipher_context *scc, const char *buf,
- size_t len)
+/** 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)
{
- return 0;
+ 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;
+
+ *result = NULL;
+ 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;
}
-int sc_send_buffer(struct stream_cipher_context *scc, const char *buf)
+int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
{
- return 0;
+ unsigned char *blob, *p, *end;
+ int ret;
+ gcry_error_t gret;
+ size_t nr_scanned, erroff, decoded_size;
+ gcry_mpi_t e, n;
+ gcry_sexp_t sexp;
+ struct asymmetric_key *key;
+
+ ret = decode_ssh_key(key_file, &blob, &decoded_size);
+ if (ret < 0)
+ return ret;
+ p = blob + ret;
+ end = blob + decoded_size;
+ 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);
+ 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);
+ 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_n;
+ }
+ ret = ROUND_DOWN(nr_scanned, 32);
+ PARA_INFO_LOG("successfully read %d bit ssh public key\n", ret * 8);
+ key = para_malloc(sizeof(*key));
+ key->num_bytes = ret;
+ key->sexp = sexp;
+ *result = key;
+release_n:
+ gcry_mpi_release(n);
+release_e:
+ gcry_mpi_release(e);
+free_blob:
+ free(blob);
+ return ret;
}
-__printf_2_3 int sc_send_va_buffer(struct stream_cipher_context *scc,
- const char *fmt, ...)
+void apc_free_pubkey(struct asymmetric_key *key)
{
- return 0;
+ if (!key)
+ return;
+ gcry_sexp_release(key->sexp);
+ free(key);
}
-int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf,
- size_t size)
+static int decode_rsa(gcry_sexp_t sexp, unsigned char *outbuf, size_t *nbytes)
{
- return 0;
+ const char *p = gcry_sexp_nth_data(sexp, 1, nbytes);
+
+ if (!p)
+ return -E_RSA_DECODE;
+ memcpy(outbuf, p, *nbytes);
+ return 1;
}
-int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size)
+int apc_priv_decrypt(const char *key_file, unsigned char *outbuf,
+ unsigned char *inbuf, int inlen)
{
- return 0;
+ gcry_error_t gret;
+ 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;
+
+ /* 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, RSA_DECRYPT_SEXP, 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;
+ }
+ ret = decode_rsa(out, outbuf, &nbytes);
+ if (ret < 0)
+ goto out_release;
+ PARA_INFO_LOG("successfully decrypted %zu byte message\n", nbytes);
+ ret = nbytes;
+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:
+ gcry_sexp_release(priv->sexp);
+ free(priv);
+ return ret;
}
-void hash_function(const char *data, unsigned long len, unsigned char *hash)
+int apc_pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
+ unsigned len, unsigned char *outbuf)
+{
+ gcry_error_t gret;
+ gcry_sexp_t pub_key, in, out, out_a;
+ gcry_mpi_t out_mpi = NULL;
+ size_t nbytes;
+ int ret;
+
+ 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;
+ 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;
+ 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_USG);
+ 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 {
+ gcry_cipher_hd_t handle;
+};
+
+struct stream_cipher *sc_new(const unsigned char *data, int len)
+{
+ gcry_error_t gret;
+ struct stream_cipher *sc = para_malloc(sizeof(*sc));
+
+ 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;
+}
+
+void sc_free(struct stream_cipher *sc)
{
+ if (!sc)
+ return;
+ gcry_cipher_close(sc->handle);
+ free(sc);
+}
+
+void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
+{
+ gcry_cipher_hd_t handle = sc->handle;
+ gcry_error_t gret;
+
+ /* perform in-place encryption */
+ *dst = *src;
+ gret = gcry_cipher_encrypt(handle, src->iov_base, src->iov_len,
+ NULL, 0);
+ assert(gret == 0);
}
projects / paraslash.git / blobdiff