/*
- * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
+ * Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file crypt.c openssl-based RSA encryption/decryption routines */
+/** \file crypt.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/rc4.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"
+
+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 adds them to the SSL PRNG. Seed the PRNG
+ * used by random() with a random seed obtained from SSL. If /dev/random 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 EVP_PKEY *load_key(const char *file, int private)
{
BIO *key;
EVP_PKEY *pkey = NULL;
+ int ret = check_key_file(file, private);
+ if (ret < 0) {
+ PARA_ERROR_LOG("%s\n", para_strerror(-ret));
+ return NULL;
+ }
key = BIO_new(BIO_s_file());
if (!key)
return NULL;
return pkey;
}
-
-int get_rsa_key(char *key_file, RSA **rsa, int private)
+static int get_openssl_key(const char *key_file, RSA **rsa, int private)
{
EVP_PKEY *key = load_key(key_file, private);
if (!key)
- return (private == LOAD_PRIVATE_KEY)? -E_PRIVATE_KEY : -E_PUBLIC_KEY;
+ return (private == LOAD_PRIVATE_KEY)? -E_PRIVATE_KEY
+ : -E_PUBLIC_KEY;
*rsa = EVP_PKEY_get1_RSA(key);
EVP_PKEY_free(key);
if (!*rsa)
return RSA_size(*rsa);
}
-/**
- * decrypt a buffer using an RSA key
- *
- * \param key_file full path of the rsa key
- * \param outbuf the output buffer
- * \param inbuf the encrypted input buffer
- * \param rsa_inlen the length of \a inbuf
- *
- * The \a outbuf must be large enough to hold at least \a rsa_inlen bytes.
- *
- * \return The size of the recovered plaintext on success, negative on errors.
- *
- * \sa RSA_private_decrypt(3)
- **/
-int para_decrypt_buffer(char *key_file, unsigned char *outbuf, unsigned char *inbuf,
- int rsa_inlen)
+/*
+ * 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_ssh_u32(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;
- int ret = get_rsa_key(key_file, &rsa, LOAD_PRIVATE_KEY);
+ const unsigned char *p = blob, *end = blob + blen;
+ rsa = RSA_new();
+ if (!rsa)
+ return -E_BIGNUM;
+ ret = read_bignum(p, end - p, &rsa->e);
if (ret < 0)
- return ret;
- ret = RSA_private_decrypt(rsa_inlen, inbuf, outbuf, rsa, RSA_PKCS1_PADDING);
- return (ret > 0)? ret : -E_DECRYPT;
+ goto fail;
+ p += ret;
+ ret = read_bignum(p, end - p, &rsa->n);
+ if (ret < 0)
+ goto fail;
+ *result = rsa;
+ return 1;
+fail:
+ RSA_free(rsa);
+ return ret;
}
-/**
- * decrypt the challenge number sent by para_server
- *
- * \param key_file full path of the rsa key
- * \param challenge_nr result is stored here
- * \param inbuf the input buffer
- * \param rsa_inlen the length of \a inbuf
- *
- * \return positive on success, negative on errors
- *
- * \sa para_decrypt_buffer()
- */
-int para_decrypt_challenge(char *key_file, long unsigned *challenge_nr,
- unsigned char *inbuf, int rsa_inlen)
+int get_asymmetric_key(const char *key_file, int private,
+ struct asymmetric_key **result)
{
- unsigned char *rsa_out = OPENSSL_malloc(rsa_inlen + 1);
- int ret = para_decrypt_buffer(key_file, rsa_out, inbuf, rsa_inlen);
+ struct asymmetric_key *key = NULL;
+ void *map = NULL;
+ unsigned char *blob = NULL;
+ size_t map_size, blob_size, decoded_size;
+ int ret, ret2;
+ char *cp;
- if (ret >= 0) {
- rsa_out[ret] = '\0';
- ret = sscanf((char *)rsa_out, "%lu", challenge_nr) == 1?
- 1 : -E_CHALLENGE;
+ key = para_malloc(sizeof(*key));
+ if (private) {
+ ret = get_openssl_key(key_file, &key->rsa, LOAD_PRIVATE_KEY);
+ goto out;
}
- OPENSSL_free(rsa_out);
+ 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 = para_munmap(map, map_size);
+ map = NULL;
+ if (ret < 0)
+ goto out;
+ ret = get_openssl_key(key_file, &key->rsa, LOAD_PUBLIC_KEY);
+ goto out;
+ }
+ cp = map + ret;
+ PARA_INFO_LOG("decoding public rsa-ssh key %s\n", key_file);
+ ret = -ERRNO_TO_PARA_ERROR(EOVERFLOW);
+ if (map_size > INT_MAX / 4)
+ goto out_unmap;
+ blob_size = 2 * map_size;
+ blob = para_malloc(blob_size);
+ ret = uudecode(cp, blob, blob_size);
+ if (ret < 0)
+ goto out_unmap;
+ decoded_size = ret;
+ 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;
}
-/**
- * encrypt a buffer using an RSA key
- *
- * \param rsa: public rsa key
- * \param inbuf the input buffer
- * \param len the length of \a inbuf
- * \param outbuf the output buffer
- *
- * \return The size of the encrypted data on success, negative on errors
- *
- * \sa RSA_public_encrypt(3)
- */
-int para_encrypt_buffer(RSA *rsa, unsigned char *inbuf,
- const unsigned len, unsigned char *outbuf)
+void free_asymmetric_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;
+
+ if (inlen < 0)
+ return -E_RSA;
+ ret = get_asymmetric_key(key_file, LOAD_PRIVATE_KEY, &priv);
+ if (ret < 0)
+ 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:
+ free_asymmetric_key(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 aes_ctr_128_context {
+ AES_KEY key;
+ unsigned char ivec[AES_CRT128_BLOCK_SIZE];
+ unsigned char ecount[AES_CRT128_BLOCK_SIZE];
+ unsigned int num;
+};
+
+struct stream_cipher {
+ bool use_aes;
+ union {
+ RC4_KEY rc4_key;
+ struct aes_ctr_128_context aes;
+ } context;
+};
+
+struct stream_cipher *sc_new(const unsigned char *data, int len,
+ bool use_aes)
+{
+ int ret;
+ struct stream_cipher *sc = para_malloc(sizeof(*sc));
+ struct aes_ctr_128_context *aes;
+
+ sc->use_aes = use_aes;
+ if (!use_aes) {
+ RC4_set_key(&sc->context.rc4_key, len, data);
+ return sc;
+ }
+ assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
+ aes = &sc->context.aes;
+ ret = AES_set_encrypt_key(data, AES_CRT128_BLOCK_SIZE * 8 /* bits */,
+ &aes->key);
+ assert(ret == 0);
+ memcpy(aes->ivec, data + AES_CRT128_BLOCK_SIZE, AES_CRT128_BLOCK_SIZE);
+ aes->num = 0;
+ return sc;
+}
+
+void sc_free(struct stream_cipher *sc)
{
- int ret = RSA_public_encrypt(len, inbuf, outbuf, rsa,
- RSA_PKCS1_PADDING);
- return ret < 0? -E_ENCRYPT : ret;
+ free(sc);
}
/**
- * encrypt the given challenge number
- *
- * \param rsa: public rsa key
- * \param challenge_nr the number to be encrypted
- * \param outbuf the output buffer
- *
- * \a outbuf must be at least 64 bytes long
- *
- * \return The size of the encrypted data on success, negative on errors
- *
- * \sa para_encrypt_buffer()
- *
+ * The RC4() implementation of openssl apparently reads and writes data in
+ * blocks of 8 bytes. So we have to make sure our buffer sizes are a multiple
+ * of this.
*/
-int para_encrypt_challenge(RSA* rsa, long unsigned challenge_nr,
- unsigned char *outbuf)
+#define RC4_ALIGN 8
+
+static void rc4_crypt(RC4_KEY *key, struct iovec *src, struct iovec *dst)
{
- unsigned char *inbuf = (unsigned char*) make_message("%lu", challenge_nr);
- int ret = para_encrypt_buffer(rsa, inbuf, strlen((char *)inbuf), outbuf);
- free(inbuf);
- return ret;
+ size_t len = src->iov_len, l1, l2;
+
+ assert(len > 0);
+ assert(len < ((typeof(src->iov_len))-1) / 2);
+ l1 = ROUND_DOWN(len, RC4_ALIGN);
+ l2 = ROUND_UP(len, RC4_ALIGN);
+
+ *dst = (typeof(*dst)) {
+ /* Add one for the terminating zero byte. */
+ .iov_base = para_malloc(l2 + 1),
+ .iov_len = len
+ };
+ RC4(key, l1, src->iov_base, dst->iov_base);
+ if (len > l1) {
+ unsigned char remainder[RC4_ALIGN] = "";
+ memcpy(remainder, src->iov_base + l1, len - l1);
+ RC4(key, len - l1, remainder, dst->iov_base + l1);
+ }
+ ((char *)dst->iov_base)[len] = '\0';
+}
+
+static void aes_ctr128_crypt(struct aes_ctr_128_context *aes, struct iovec *src,
+ struct iovec *dst)
+{
+ size_t len = src->iov_len;
+
+ *dst = (typeof(*dst)) {
+ /* Add one for the terminating zero byte. */
+ .iov_base = para_malloc(len + 1),
+ .iov_len = len
+ };
+ AES_ctr128_encrypt(src->iov_base, dst->iov_base, len,
+ &aes->key, aes->ivec, aes->ecount, &aes->num);
+ ((char *)dst->iov_base)[len] = '\0';
}
+void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
+{
+ if (sc->use_aes)
+ return aes_ctr128_crypt(&sc->context.aes, src, dst);
+ return rc4_crypt(&sc->context.rc4_key, 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