--- /dev/null
+/* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
+
+/** \file openssl.c Openssl-based encryption/decryption routines. */
+
+#include <regex.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <openssl/rand.h>
+#include <openssl/err.h>
+#include <openssl/pem.h>
+#include <openssl/sha.h>
+#include <openssl/bn.h>
+#include <openssl/aes.h>
+
+#include "para.h"
+#include "error.h"
+#include "string.h"
+#include "crypt.h"
+#include "fd.h"
+#include "crypt_backend.h"
+#include "base64.h"
+#include "portable_io.h"
+
+struct asymmetric_key {
+ RSA *rsa;
+};
+
+void get_random_bytes_or_die(unsigned char *buf, int num)
+{
+ unsigned long err;
+
+ /* RAND_bytes() returns 1 on success, 0 otherwise. */
+ if (RAND_bytes(buf, num) == 1)
+ return;
+ err = ERR_get_error();
+ PARA_EMERG_LOG("%s\n", ERR_reason_error_string(err));
+ exit(EXIT_FAILURE);
+}
+
+/*
+ * Read 64 bytes from /dev/urandom and add them to the SSL PRNG. Seed the PRNG
+ * used by random(3) with a random seed obtained from SSL. If /dev/urandom is
+ * not readable, the function calls exit().
+ *
+ * \sa RAND_load_file(3), \ref get_random_bytes_or_die(), srandom(3),
+ * random(3), \ref para_random().
+ */
+void init_random_seed_or_die(void)
+{
+ int seed, ret = RAND_load_file("/dev/urandom", 64);
+
+ if (ret != 64) {
+ PARA_EMERG_LOG("could not seed PRNG (ret = %d)\n", ret);
+ exit(EXIT_FAILURE);
+ }
+ get_random_bytes_or_die((unsigned char *)&seed, sizeof(seed));
+ srandom(seed);
+}
+
+static int get_private_key(const char *path, RSA **rsa)
+{
+ EVP_PKEY *pkey;
+ BIO *bio = BIO_new(BIO_s_file());
+
+ *rsa = NULL;
+ if (!bio)
+ return -E_PRIVATE_KEY;
+ if (BIO_read_filename(bio, path) <= 0)
+ goto bio_free;
+ pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
+ if (!pkey)
+ goto bio_free;
+ *rsa = EVP_PKEY_get1_RSA(pkey);
+ EVP_PKEY_free(pkey);
+bio_free:
+ BIO_free(bio);
+ return *rsa? RSA_size(*rsa) : -E_PRIVATE_KEY;
+}
+
+/*
+ * The public key loading functions below were inspired by corresponding code
+ * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
+ * Finland. However, not much of the original code remains.
+ */
+
+static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
+{
+ const unsigned char *p = buf, *end = buf + len;
+ uint32_t bnsize;
+ BIGNUM *bn;
+
+ if (p + 4 < p)
+ return -E_BIGNUM;
+ if (p + 4 > end)
+ return -E_BIGNUM;
+ bnsize = read_u32_be(p);
+ PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
+ p += 4;
+ if (p + bnsize < p)
+ return -E_BIGNUM;
+ if (p + bnsize > end)
+ return -E_BIGNUM;
+ if (bnsize > 8192)
+ return -E_BIGNUM;
+ bn = BN_bin2bn(p, bnsize, NULL);
+ if (!bn)
+ return -E_BIGNUM;
+ *result = bn;
+ return bnsize + 4;
+}
+
+static int read_rsa_bignums(const unsigned char *blob, int blen, RSA **result)
+{
+ int ret;
+ RSA *rsa;
+ BIGNUM *n, *e;
+ const unsigned char *p = blob, *end = blob + blen;
+
+ rsa = RSA_new();
+ if (!rsa)
+ return -E_BIGNUM;
+ ret = read_bignum(p, end - p, &e);
+ if (ret < 0)
+ goto fail;
+ p += ret;
+ ret = read_bignum(p, end - p, &n);
+ if (ret < 0)
+ goto fail;
+#ifdef HAVE_RSA_SET0_KEY
+ RSA_set0_key(rsa, n, e, NULL);
+#else
+ rsa->n = n;
+ rsa->e = e;
+#endif
+ *result = rsa;
+ return 1;
+fail:
+ RSA_free(rsa);
+ return ret;
+}
+
+int get_public_key(const char *key_file, struct asymmetric_key **result)
+{
+ struct asymmetric_key *key = NULL;
+ void *map = NULL;
+ unsigned char *blob = NULL;
+ size_t map_size, encoded_size, decoded_size;
+ int ret, ret2;
+ char *cp;
+
+ key = para_malloc(sizeof(*key));
+ ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
+ if (ret < 0)
+ goto out;
+ ret = is_ssh_rsa_key(map, map_size);
+ if (!ret) {
+ ret = -E_SSH_PARSE;
+ goto out_unmap;
+ }
+ cp = map + ret;
+ encoded_size = map_size - ret;
+ PARA_INFO_LOG("decoding public rsa-ssh key %s\n", key_file);
+ ret = uudecode(cp, encoded_size, (char **)&blob, &decoded_size);
+ if (ret < 0)
+ goto out_unmap;
+ ret = check_ssh_key_header(blob, decoded_size);
+ if (ret < 0)
+ goto out_unmap;
+ ret = read_rsa_bignums(blob + ret, decoded_size - ret, &key->rsa);
+ if (ret < 0)
+ goto out_unmap;
+ ret = RSA_size(key->rsa);
+out_unmap:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+out:
+ if (ret < 0) {
+ free(key);
+ *result = NULL;
+ PARA_ERROR_LOG("key %s: %s\n", key_file, para_strerror(-ret));
+ } else
+ *result = key;
+ free(blob);
+ return ret;
+}
+
+void free_public_key(struct asymmetric_key *key)
+{
+ if (!key)
+ return;
+ RSA_free(key->rsa);
+ free(key);
+}
+
+int priv_decrypt(const char *key_file, unsigned char *outbuf,
+ unsigned char *inbuf, int inlen)
+{
+ struct asymmetric_key *priv;
+ int ret;
+
+ ret = check_private_key_file(key_file);
+ if (ret < 0)
+ return ret;
+ if (inlen < 0)
+ return -E_RSA;
+ priv = para_malloc(sizeof(*priv));
+ ret = get_private_key(key_file, &priv->rsa);
+ if (ret < 0) {
+ free(priv);
+ return ret;
+ }
+ /*
+ * RSA is vulnerable to timing attacks. Generate a random blinding
+ * factor to protect against this kind of attack.
+ */
+ ret = -E_BLINDING;
+ if (RSA_blinding_on(priv->rsa, NULL) == 0)
+ goto out;
+ ret = RSA_private_decrypt(inlen, inbuf, outbuf, priv->rsa,
+ RSA_PKCS1_OAEP_PADDING);
+ RSA_blinding_off(priv->rsa);
+ if (ret <= 0)
+ ret = -E_DECRYPT;
+out:
+ RSA_free(priv->rsa);
+ free(priv);
+ return ret;
+}
+
+int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
+ unsigned len, unsigned char *outbuf)
+{
+ int ret, flen = len; /* RSA_public_encrypt expects a signed int */
+
+ if (flen < 0)
+ return -E_ENCRYPT;
+ ret = RSA_public_encrypt(flen, inbuf, outbuf, pub->rsa,
+ RSA_PKCS1_OAEP_PADDING);
+ return ret < 0? -E_ENCRYPT : ret;
+}
+
+struct stream_cipher {
+ EVP_CIPHER_CTX *aes;
+};
+
+struct stream_cipher *sc_new(const unsigned char *data, int len)
+{
+ struct stream_cipher *sc = para_malloc(sizeof(*sc));
+
+ assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
+ sc->aes = EVP_CIPHER_CTX_new();
+ EVP_EncryptInit_ex(sc->aes, EVP_aes_128_ctr(), NULL, data,
+ data + AES_CRT128_BLOCK_SIZE);
+ return sc;
+}
+
+void sc_free(struct stream_cipher *sc)
+{
+ if (!sc)
+ return;
+ EVP_CIPHER_CTX_free(sc->aes);
+ free(sc);
+}
+
+static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
+ struct iovec *dst)
+{
+ int ret, inlen = src->iov_len, outlen, tmplen;
+
+ *dst = (typeof(*dst)) {
+ /* Add one for the terminating zero byte. */
+ .iov_base = para_malloc(inlen + 1),
+ .iov_len = inlen
+ };
+ ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
+ assert(ret != 0);
+ ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
+ assert(ret != 0);
+ outlen += tmplen;
+ ((char *)dst->iov_base)[outlen] = '\0';
+ dst->iov_len = outlen;
+}
+
+void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
+{
+ return aes_ctr128_crypt(sc->aes, src, dst);
+}
+
+void hash_function(const char *data, unsigned long len, unsigned char *hash)
+{
+ SHA_CTX c;
+ SHA1_Init(&c);
+ SHA1_Update(&c, data, len);
+ SHA1_Final(hash, &c);
+}
projects / paraslash.git / blobdiff