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add some crypto/util functions from karsten, as the first

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step of integrating his new hidden service stuff


svn:r11489
This commit is contained in:
Roger Dingledine 2007-09-18 17:07:56 +00:00
parent 5985135ed6
commit f15a4c8bd7
3 changed files with 339 additions and 0 deletions
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222
src/common/crypto.c
View File

@ -1144,6 +1144,170 @@ crypto_cipher_decrypt(crypto_cipher_env_t *env, char *to,
return 0;
}
#define AES_CIPHER_BLOCK_SIZE (16)
#define AES_IV_SIZE (16)
/** Encrypt <b>fromlen</b> bytes (at least 1) from <b>from</b> with the
* symmetric key <b>key</b> of 16 bytes length to <b>to</b> of length
* <b>tolen</b> which needs to be <b>fromlen</b>, padded to the next 16
* bytes, plus exactly 16 bytes for the initialization vector. On success,
* return the number of bytes written, on failure, return -1.
*/
int
crypto_cipher_encrypt_cbc(const char *key, char *to, size_t tolen,
const char *from, size_t fromlen)
{
EVP_CIPHER_CTX ctx_msg, ctx_iv; /* cipher contexts for message and IV */
unsigned char iv[AES_IV_SIZE]; /* initialization vector */
int outlen, tmplen; /* length of encrypted strings (w/ and wo/ final data) */
tor_assert(key);
tor_assert(to);
tor_assert(tolen >= fromlen + AES_IV_SIZE +
(AES_CIPHER_BLOCK_SIZE - fromlen % AES_CIPHER_BLOCK_SIZE));
tor_assert(from);
tor_assert(fromlen > 0);
/* generate random initialization vector */
crypto_rand((char *)iv, AES_IV_SIZE);
/* initialize cipher context for the initialization vector */
EVP_CIPHER_CTX_init(&ctx_iv);
/* disable padding for encryption of initialization vector */
EVP_CIPHER_CTX_set_padding(&ctx_iv, 0);
/* set up cipher context for the initialization vector for encryption with
* cipher type AES-128 in ECB mode, default implementation, given key, and
* no initialization vector */
EVP_EncryptInit_ex(&ctx_iv, EVP_aes_128_ecb(), NULL, (unsigned char *)key,
NULL);
/* encrypt initialization vector (no padding necessary) and write it to the
* first 16 bytes of the result */
if (!EVP_EncryptUpdate(&ctx_iv, (unsigned char *)to, &outlen, iv,
AES_IV_SIZE)) {
crypto_log_errors(LOG_WARN, "encrypting initialization vector");
return -1;
}
/* clear all information from cipher context for the initialization vector
* and free up any allocated memory associate with it */
EVP_CIPHER_CTX_cleanup(&ctx_iv);
/* initialize cipher context for the message */
EVP_CIPHER_CTX_init(&ctx_msg);
/* set up cipher context for encryption with cipher type AES-128 in CBC mode,
* default implementation, given key, and initialization vector */
EVP_EncryptInit_ex(&ctx_msg, EVP_aes_128_cbc(), NULL, (unsigned char *)key,
iv);
/* encrypt fromlen bytes from buffer from and write the encrypted version to
* buffer to */
if (!EVP_EncryptUpdate(&ctx_msg,
((unsigned char *)to) + AES_IV_SIZE, &outlen,
(const unsigned char *)from, (int)fromlen)) {
crypto_log_errors(LOG_WARN, "encrypting");
return -1;
}
/* encrypt the final data */
if (!EVP_EncryptFinal_ex(&ctx_msg,
((unsigned char *)to) + AES_IV_SIZE + outlen,
&tmplen)) {
crypto_log_errors(LOG_WARN, "encrypting the final data");
return -1;
}
outlen += tmplen;
/* clear all information from cipher context and free up any allocated memory
* associate with it */
EVP_CIPHER_CTX_cleanup(&ctx_msg);
/* return number of written bytes */
return outlen + AES_IV_SIZE;
}
/** Decrypt <b>fromlen</b> bytes (at least 1) from <b>from</b> with the
* symmetric key <b>key</b> of 16 bytes length to <b>to</b> of length
* <b>tolen</b> which may be <b>fromlen</b> minus 16 for the initialization
* vector (the size of padding cannot be determined in advance). On success,
* return the number of bytes written, on failure (NOT including providing
* the wrong key, which occasionally returns the correct length!), return -1.
*/
int
crypto_cipher_decrypt_cbc(const char *key, char *to, size_t tolen,
const char *from, size_t fromlen)
{
EVP_CIPHER_CTX ctx_msg, ctx_iv; /* cipher contexts for message and IV */
unsigned char iv[AES_IV_SIZE]; /* initialization vector */
int outlen, tmplen; /* length of decrypted strings (w/ and wo/ final data) */
tor_assert(key);
tor_assert(to);
tor_assert(tolen >= fromlen - AES_IV_SIZE);
tor_assert(from);
tor_assert(fromlen > 0);
/* initialize cipher context for the initialization vector */
EVP_CIPHER_CTX_init(&ctx_iv);
/* disable padding for decryption of initialization vector */
EVP_CIPHER_CTX_set_padding(&ctx_iv, 0);
/* set up cipher context for the initialization vector for decryption with
* cipher type AES-128 in ECB mode, default implementation, given key, and
* no initialization vector */
EVP_DecryptInit_ex(&ctx_iv, EVP_aes_128_ecb(), NULL, (unsigned char *)key,
NULL);
/* decrypt initialization vector (is not padded) */
if (!EVP_DecryptUpdate(&ctx_iv, iv, &outlen, (const unsigned char *)from,
AES_IV_SIZE)) {
crypto_log_errors(LOG_WARN, "decrypting initialization vector");
return -1;
}
/* clear all information from cipher context for the initialization vector
* and free up any allocated memory associate with it */
EVP_CIPHER_CTX_cleanup(&ctx_iv);
/* initialize cipher context for the message */
EVP_CIPHER_CTX_init(&ctx_msg);
/* set up cipher context for decryption with cipher type AES-128 in CBC mode,
* default implementation, given key, and initialization vector */
EVP_DecryptInit_ex(&ctx_msg, EVP_aes_128_cbc(), NULL, (unsigned char *)key,
iv);
/* decrypt fromlen-16 bytes from buffer from and write the decrypted version
* to buffer to */
if (!EVP_DecryptUpdate(&ctx_msg, (unsigned char *)to, &outlen,
((const unsigned char *)from) + AES_IV_SIZE,
(int)fromlen - AES_IV_SIZE)) {
crypto_log_errors(LOG_INFO, "decrypting");
return -1;
}
/* decrypt the final data */
if (!EVP_DecryptFinal_ex(&ctx_msg, ((unsigned char *)to) + outlen,
&tmplen)) {
crypto_log_errors(LOG_INFO, "decrypting the final data");
return -1;
}
outlen += tmplen;
/* clear all information from cipher context and free up any allocated memory
* associate with it */
EVP_CIPHER_CTX_cleanup(&ctx_msg);
/* return number of written bytes */
return outlen;
}
/* SHA-1 */
/** Compute the SHA1 digest of <b>len</b> bytes in data stored in
@ -1803,6 +1967,64 @@ base32_encode(char *dest, size_t destlen, const char *src, size_t srclen)
dest[i] = '\0';
}
/** Implements base32 decoding as in rfc3548. Limitation: Requires
* that srclen*5 is a multiple of 8. Returns 0 if successful, -1 otherwise.
*/
int
base32_decode(char *dest, size_t destlen, const char *src, size_t srclen)
{
unsigned int nbits, i, j, bit;
char *tmp;
nbits = srclen * 5;
tor_assert((nbits%8) == 0); /* We need an even multiple of 8 bits. */
tor_assert((nbits/8) <= destlen); /* We need enough space. */
tor_assert(destlen < SIZE_T_CEILING);
/* Convert base32 encoded chars to the 5-bit values that they represent. */
tmp = tor_malloc_zero(srclen);
for (j = 0; j < srclen; ++j) {
if (src[j] > 0x60 && src[j] < 0x7B) tmp[j] = src[j] - 0x61;
else if (src[j] > 0x31 && src[j] < 0x38) tmp[j] = src[j] - 0x18;
else {
log_warn(LD_BUG, "illegal character in base32 encoded string");
return -1;
}
}
/* Assemble result byte-wise by applying five possible cases. */
for (i = 0, bit = 0; bit < nbits; ++i, bit += 8) {
switch (bit % 40) {
case 0:
dest[i] = (((uint8_t)tmp[(bit/5)]) << 3) +
(((uint8_t)tmp[(bit/5)+1]) >> 2);
break;
case 8:
dest[i] = (((uint8_t)tmp[(bit/5)]) << 6) +
(((uint8_t)tmp[(bit/5)+1]) << 1) +
(((uint8_t)tmp[(bit/5)+2]) >> 4);
break;
case 16:
dest[i] = (((uint8_t)tmp[(bit/5)]) << 4) +
(((uint8_t)tmp[(bit/5)+1]) >> 1);
break;
case 24:
dest[i] = (((uint8_t)tmp[(bit/5)]) << 7) +
(((uint8_t)tmp[(bit/5)+1]) << 2) +
(((uint8_t)tmp[(bit/5)+2]) >> 3);
break;
case 32:
dest[i] = (((uint8_t)tmp[(bit/5)]) << 5) +
((uint8_t)tmp[(bit/5)+1]);
break;
}
}
tor_free(tmp);
tmp = NULL;
return 0;
}
/** Implement RFC2440-style iterated-salted S2K conversion: convert the
* <b>secret_len</b>-byte <b>secret</b> into a <b>key_out_len</b> byte
* <b>key_out</b>. As in RFC2440, the first 8 bytes of s2k_specifier

6
src/common/crypto.h
View File

@ -124,6 +124,11 @@ int crypto_cipher_encrypt(crypto_cipher_env_t *env, char *to,
int crypto_cipher_decrypt(crypto_cipher_env_t *env, char *to,
const char *from, size_t fromlen);
int crypto_cipher_encrypt_cbc(const char *key, char *to, size_t tolen,
const char *from, size_t fromlen);
int crypto_cipher_decrypt_cbc(const char *key, char *to, size_t tolen,
const char *from, size_t fromlen);
/* SHA-1 */
int crypto_digest(char *digest, const char *m, size_t len);
crypto_digest_env_t *crypto_new_digest_env(void);
@ -164,6 +169,7 @@ int base64_decode(char *dest, size_t destlen, const char *src, size_t srclen);
/** Characters that can appear (case-insensitively) in a base-32 encoding. */
#define BASE32_CHARS "abcdefghijklmnopqrstuvwxyz234567"
void base32_encode(char *dest, size_t destlen, const char *src, size_t srclen);
int base32_decode(char *dest, size_t destlen, const char *src, size_t srclen);
int digest_to_base64(char *d64, const char *digest);
int digest_from_base64(char *digest, const char *d64);

111
src/or/test.c
View File

@ -3084,6 +3084,115 @@ test_util_mempool(void)
smartlist_free(allocated);
}
/* Test AES-CBC encryption and decryption. */
static void
test_crypto_aes_cbc(void)
{
char *plain, *encrypted1, *encrypted2, *decrypted1, *decrypted2;
char plain_1[1], plain_15[15], plain_16[16], plain_17[17];
char key1[16], key2[16];
size_t encrypted_size, decrypted_size;
plain = tor_malloc(4095);
encrypted1 = tor_malloc(4095 + 1 + 16);
encrypted2 = tor_malloc(4095 + 1 + 16);
decrypted1 = tor_malloc(4095 + 1);
decrypted2 = tor_malloc(4095 + 1);
crypto_rand(plain, 4095);
crypto_rand(key1, 16);
crypto_rand(key2, 16);
crypto_rand(plain_1, 1);
crypto_rand(plain_15, 15);
crypto_rand(plain_16, 16);
crypto_rand(plain_17, 17);
key1[0] = key2[0] + 128; /* Make sure that contents are different. */
/* Encrypt and decrypt with the same key. */
encrypted_size = crypto_cipher_encrypt_cbc(key1, encrypted1, 4095 + 1 + 16,
plain, 4095);
test_eq(encrypted_size, 4095 + 1 + 16);
decrypted_size = crypto_cipher_decrypt_cbc(key1, decrypted1, 4095 + 1,
encrypted1, encrypted_size);
test_eq(decrypted_size, 4095);
test_memeq(plain, decrypted1, 4095);
/* Encrypt a second time (with a new random initialization vector). */
encrypted_size = crypto_cipher_encrypt_cbc(key1, encrypted2, 4095 + 1 + 16,
plain, 4095);
test_eq(encrypted_size, 4095 + 1 + 16);
decrypted_size = crypto_cipher_decrypt_cbc(key1, decrypted2, 4095 + 1,
encrypted2, encrypted_size);
test_eq(decrypted_size, 4095);
test_memeq(plain, decrypted2, 4095);
test_memneq(encrypted1, encrypted2, encrypted_size);
/* Decrypt with the wrong key. */
decrypted_size = crypto_cipher_decrypt_cbc(key2, decrypted2, 4095 + 1,
encrypted1, encrypted_size);
test_memneq(plain, decrypted2, encrypted_size);
/* Alter the initialization vector. */
encrypted1[0] += 42;
decrypted_size = crypto_cipher_decrypt_cbc(key1, decrypted1, 4095 + 1,
encrypted1, encrypted_size);
test_memneq(plain, decrypted2, 4095);
/* Special length case: 1. */
encrypted_size = crypto_cipher_encrypt_cbc(key1, encrypted1, 32,
plain_1, 1);
test_eq(encrypted_size, 32);
decrypted_size = crypto_cipher_decrypt_cbc(key1, decrypted1, 16,
encrypted1, 32);
test_eq(decrypted_size, 1);
test_memeq(plain_1, decrypted1, 1);
/* Special length case: 15. */
encrypted_size = crypto_cipher_encrypt_cbc(key1, encrypted1, 32,
plain_15, 15);
test_eq(encrypted_size, 32);
decrypted_size = crypto_cipher_decrypt_cbc(key1, decrypted1, 16,
encrypted1, 32);
test_eq(decrypted_size, 15);
test_memeq(plain_15, decrypted1, 15);
/* Special length case: 16. */
encrypted_size = crypto_cipher_encrypt_cbc(key1, encrypted1, 48,
plain_16, 16);
test_eq(encrypted_size, 48);
decrypted_size = crypto_cipher_decrypt_cbc(key1, decrypted1, 32,
encrypted1, 48);
test_eq(decrypted_size, 16);
test_memeq(plain_16, decrypted1, 16);
/* Special length case: 17. */
encrypted_size = crypto_cipher_encrypt_cbc(key1, encrypted1, 48,
plain_17, 17);
test_eq(encrypted_size, 48);
decrypted_size = crypto_cipher_decrypt_cbc(key1, decrypted1, 32,
encrypted1, 48);
test_eq(decrypted_size, 17);
test_memeq(plain_17, decrypted1, 17);
/* Free memory. */
tor_free(plain);
tor_free(encrypted1);
tor_free(encrypted2);
tor_free(decrypted1);
tor_free(decrypted2);
}
/* Test base32 decoding. */
static void
test_crypto_base32_decode(void)
{
char plain[60], encoded[96 + 1], decoded[60];
int res;
crypto_rand(plain, 60);
/* Encode and decode a random string. */
base32_encode(encoded, 96 + 1, plain, 60);
res = base32_decode(decoded, 60, encoded, 96);
test_eq(res, 0);
test_memeq(plain, decoded, 60);
/* Change encoded string and decode. */
if (encoded[0] == 'a')
encoded[0] = 'b';
else
encoded[0] = 'a';
res = base32_decode(decoded, 60, encoded, 96);
test_eq(res, 0);
test_memneq(plain, decoded, 60);
}
#define ENT(x) { #x, test_ ## x, 0, 0 }
#define SUBENT(x,y) { #x "/" #y, test_ ## x ## _ ## y, 1, 0 }
@ -3097,6 +3206,8 @@ static struct {
ENT(crypto),
SUBENT(crypto, dh),
SUBENT(crypto, s2k),
SUBENT(crypto, aes_cbc),
SUBENT(crypto, base32_decode),
ENT(util),
SUBENT(util, ip6_helpers),
SUBENT(util, gzip),