X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=crypt.c;h=8116fb6eeacdbeaa0f1f22d14cfcc3726ee3bbbf;hp=8e1814dd3d82e5fd1d50301402faea6b0d9a9934;hb=dda88dcb390a44e1f1f68f6248ed513c75dce4bf;hpb=a24d175e6d093d6d9f6e583c3026e45924bad621 diff --git a/crypt.c b/crypt.c index 8e1814dd..8116fb6e 100644 --- a/crypt.c +++ b/crypt.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2005-2011 Andre Noll + * Copyright (C) 2005 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -14,28 +14,21 @@ #include #include #include +#include +#include #include "para.h" #include "error.h" #include "string.h" #include "crypt.h" #include "fd.h" +#include "crypt_backend.h" +#include "base64.h" struct asymmetric_key { RSA *rsa; }; -/** - * Fill a buffer with random content. - * - * \param buf The buffer to fill. - * \param num The size of \a buf in bytes. - * - * This function puts \a num cryptographically strong pseudo-random bytes into - * buf. If libssl can not guarantee an unpredictable byte sequence (for example - * because the PRNG has not been seeded with enough randomness) the function - * logs an error message and calls exit(). - */ void get_random_bytes_or_die(unsigned char *buf, int num) { unsigned long err; @@ -48,13 +41,10 @@ void get_random_bytes_or_die(unsigned char *buf, int num) exit(EXIT_FAILURE); } -/** - * Seed pseudo random number generators. - * - * This function reads 64 bytes from /dev/urandom and adds them to the SSL - * PRNG. It also seeds the PRNG used by random() with a random seed obtained - * from SSL. If /dev/random could not be read, an error message is logged and - * the function calls exit(). +/* + * 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(). @@ -71,19 +61,6 @@ void init_random_seed_or_die(void) srandom(seed); } -static int check_key_file(const char *file, int private) -{ - struct stat st; - - if (stat(file, &st) != 0) - return -ERRNO_TO_PARA_ERROR(errno); - if (private != LOAD_PRIVATE_KEY) - return 0; - if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) - return -E_KEY_PERM; - return 1; -} - static EVP_PKEY *load_key(const char *file, int private) { BIO *key; @@ -107,44 +84,137 @@ static EVP_PKEY *load_key(const char *file, int private) return pkey; } -/** - * Read an asymmetric key from a file. - * - * \param key_file The file containing the key. - * \param private if non-zero, read the private key, otherwise the public key. - * \param result The key structure is returned here. - * - * \return The size of the key on success, negative on errors. - * - * \sa openssl(1), rsa(1). - */ -int get_asymmetric_key(const char *key_file, int private, - struct asymmetric_key **result) +static int get_openssl_key(const char *key_file, RSA **rsa, int private) { - struct asymmetric_key *key; - RSA *rsa; - EVP_PKEY *pkey = load_key(key_file, private); + EVP_PKEY *key = load_key(key_file, private); - if (!pkey) + if (!key) return (private == LOAD_PRIVATE_KEY)? -E_PRIVATE_KEY : -E_PUBLIC_KEY; - rsa = EVP_PKEY_get1_RSA(pkey); - EVP_PKEY_free(pkey); - if (!rsa) + *rsa = EVP_PKEY_get1_RSA(key); + EVP_PKEY_free(key); + if (!*rsa) return -E_RSA; - key = para_malloc(sizeof(*key)); - key->rsa = rsa; - *result = key; - return RSA_size(rsa); + return RSA_size(*rsa); } -/** - * Deallocate an asymmetric key structure. - * - * \param key Pointer to the key structure to free. - * - * This must be called for any key obtained by get_asymmetric_key(). +/* + * The public key loading functions below were inspired by corresponding code + * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen , 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; + 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_asymmetric_key(const char *key_file, int private, + 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)); + if (private) { + ret = get_openssl_key(key_file, &key->rsa, LOAD_PRIVATE_KEY); + goto 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; + 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_asymmetric_key(struct asymmetric_key *key) { if (!key) @@ -153,20 +223,6 @@ void free_asymmetric_key(struct asymmetric_key *key) free(key); } -/** - * Decrypt a buffer using a private key. - * - * \param key_file Full path of the key. - * \param outbuf The output buffer. - * \param inbuf The encrypted input buffer. - * \param inlen The length of \a inbuf in bytes. - * - * 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 priv_decrypt(const char *key_file, unsigned char *outbuf, unsigned char *inbuf, int inlen) { @@ -195,18 +251,6 @@ out: return ret; } -/** - * Encrypt a buffer using an RSA key - * - * \param pub: The public 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 pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf, unsigned len, unsigned char *outbuf) { @@ -220,31 +264,35 @@ int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf, } struct stream_cipher { - RC4_KEY key; + bool use_aes; + union { + RC4_KEY rc4_key; + EVP_CIPHER_CTX *aes; + } context; }; -/** - * Allocate and initialize a stream cipher structure. - * - * \param data The key. - * \param len The size of the key. - * - * \return A new stream cipher structure. - */ -struct stream_cipher *sc_new(const unsigned char *data, int len) +struct stream_cipher *sc_new(const unsigned char *data, int len, + bool use_aes) { struct stream_cipher *sc = para_malloc(sizeof(*sc)); - RC4_set_key(&sc->key, len, data); + + 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); + sc->context.aes = EVP_CIPHER_CTX_new(); + EVP_EncryptInit_ex(sc->context.aes, EVP_aes_128_ctr(), NULL, data, + data + AES_CRT128_BLOCK_SIZE); return sc; } -/** - * Deallocate a stream cipher structure. - * - * \param sc A stream cipher previously obtained by sc_new(). - */ void sc_free(struct stream_cipher *sc) { + if (!sc) + return; + EVP_CIPHER_CTX_free(sc->context.aes); free(sc); } @@ -255,133 +303,55 @@ void sc_free(struct stream_cipher *sc) */ #define RC4_ALIGN 8 -/** - * Encrypt and send a buffer. - * - * \param scc The context. - * \param buf The buffer to send. - * \param len The size of \a buf in bytes. - * - * \return The return value of the underyling call to write_all(). - * - * \sa \ref write_all(), RC4(3). - */ -int sc_send_bin_buffer(struct stream_cipher_context *scc, const char *buf, - size_t len) +static void rc4_crypt(RC4_KEY *key, struct iovec *src, struct iovec *dst) { - int ret; - unsigned char *tmp; - static unsigned char remainder[RC4_ALIGN]; - size_t l1 = ROUND_DOWN(len, RC4_ALIGN), l2 = ROUND_UP(len, RC4_ALIGN); - - assert(len); - tmp = para_malloc(l2); - RC4(&scc->send->key, l1, (const unsigned char *)buf, tmp); + 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) { - memcpy(remainder, buf + l1, len - l1); - RC4(&scc->send->key, len - l1, remainder, tmp + l1); + unsigned char remainder[RC4_ALIGN] = ""; + memcpy(remainder, src->iov_base + l1, len - l1); + RC4(key, len - l1, remainder, dst->iov_base + l1); } - ret = write_all(scc->fd, (char *)tmp, &len); - free(tmp); - return ret; -} - -/** - * Encrypt and send a \p NULL-terminated buffer. - * - * \param scc The context. - * \param buf The buffer to send. - * - * \return The return value of the underyling call to sc_send_bin_buffer(). - */ -int sc_send_buffer(struct stream_cipher_context *scc, const char *buf) -{ - return sc_send_bin_buffer(scc, buf, strlen(buf)); -} - -/** - * Format, encrypt and send a buffer. - * - * \param scc The context. - * \param fmt A format string. - * - * \return The return value of the underyling call to sc_send_buffer(). - */ -__printf_2_3 int sc_send_va_buffer(struct stream_cipher_context *scc, - const char *fmt, ...) -{ - char *msg; - int ret; - - PARA_VSPRINTF(fmt, msg); - ret = sc_send_buffer(scc, msg); - free(msg); - return ret; + ((char *)dst->iov_base)[len] = '\0'; } -/** - * Receive a buffer and decrypt it. - * - * \param scc The context. - * \param buf The buffer to write the decrypted data to. - * \param size The size of \a buf. - * - * \return The number of bytes received on success, negative on errors, zero if - * the peer has performed an orderly shutdown. - * - * \sa recv(2), RC4(3). - */ -int sc_recv_bin_buffer(struct stream_cipher_context *scc, char *buf, - size_t size) +static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src, + struct iovec *dst) { - unsigned char *tmp = para_malloc(size); - ssize_t ret = recv(scc->fd, tmp, size, 0); - - if (ret > 0) - RC4(&scc->recv->key, ret, tmp, (unsigned char *)buf); - else if (ret < 0) - ret = -ERRNO_TO_PARA_ERROR(errno); - free(tmp); - return ret; + 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; } -/** - * Receive a buffer, decrypt it and write terminating NULL byte. - * - * \param scc The context. - * \param buf The buffer to write the decrypted data to. - * \param size The size of \a buf. - * - * Read at most \a size - 1 bytes from file descriptor given by \a scc, decrypt - * the received data and write a NULL byte at the end of the decrypted data. - * - * \return The return value of the underlying call to \ref - * sc_recv_bin_buffer(). - */ -int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size) +void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst) { - int n; - - assert(size); - n = sc_recv_bin_buffer(scc, buf, size - 1); - if (n >= 0) - buf[n] = '\0'; - else - *buf = '\0'; - return n; + if (sc->use_aes) + return aes_ctr128_crypt(sc->context.aes, src, dst); + return rc4_crypt(&sc->context.rc4_key, src, dst); } -/** - * Compute the hash of the given input data. - * - * \param data Pointer to the data to compute the hash value from. - * \param len The length of \a data in bytes. - * \param hash Result pointer. - * - * \a hash must point to an area at least \p HASH_SIZE bytes large. - * - * \sa sha(3), openssl(1). - * */ void hash_function(const char *data, unsigned long len, unsigned char *hash) { SHA_CTX c;