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Commit 0c61bc37 authored by Nick Mathewson's avatar Nick Mathewson :game_die:
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Remove the notion of "onion ciphers"; make packing and unpacking separate fns 

svn:r236
parent 54af75b1
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doc/TODO
+ 2
− 2
View file @ 0c61bc37
......@@ -12,8 +12,8 @@ ARMA - arma claims
X Abandoned
- Use a stronger cipher
NICK - 3des for now
. Use a stronger cipher
o 3des for now
- aes when we everybody has openssl 0.9.7
. Topics / circuits
o Implement topics
......
doc/tor-spec.txt
+ 2
− 5
View file @ 0c61bc37
......@@ -273,13 +273,11 @@ which reveals the downstream node.
in a circuit. Each (unencrypted) layer has the following fields:
Version [1 byte]
Back cipher [4 bits]
Forward cipher [4 bits]
Port [2 bytes]
Address [4 bytes]
Expiration time [4 bytes]
Key seed material [16 bytes]
[Total: 28 bytes]
[Total: 27 bytes]
The value of Version is currently 2.
......@@ -287,7 +285,7 @@ which reveals the downstream node.
0: Identity
1: Single DES in OFB
2: RC4
3: Triple DES in OFB
3: Triple DES (encrypt-decrypt-encrypt) in OFB
The port and address field denote the IPV4 address and port of
the next onion router in the circuit, or are set to 0 for the
......@@ -305,7 +303,6 @@ which reveals the downstream node.
2. For I=N downto 1:
A. Create an onion layer L, setting Version=2,
BackCipher=DES/OFB(1), ForwardCipher=DES/OFB(2),
ExpirationTime=now + 1 day, and Seed=16 random bytes.
If I=N, set Port=Address=0. Else, set Port and Address to
......
src/or/circuit.c
+ 9
− 17
View file @ 0c61bc37
......@@ -140,7 +140,7 @@ try_again:
return test_aci;
}
int circuit_init(circuit_t *circ, int aci_type) {
int circuit_init(circuit_t *circ, int aci_type, onion_layer_t *layer) {
unsigned char iv[16];
unsigned char digest1[20];
unsigned char digest2[20];
......@@ -150,19 +150,13 @@ int circuit_init(circuit_t *circ, int aci_type) {
assert(circ && circ->onion);
log(LOG_DEBUG,"circuit_init(): starting");
circ->n_port = ntohs(*(uint16_t *)(circ->onion+2));
circ->n_port = layer->port;
log(LOG_DEBUG,"circuit_init(): Set port to %u.",circ->n_port);
circ->n_addr = ntohl(*(uint32_t *)(circ->onion+4));
circ->p_f = *(circ->onion+1) >> 4; /* backf */
log(LOG_DEBUG,"circuit_init(): Set BACKF to %u.",circ->p_f);
circ->n_f = *(circ->onion+1) & 0x0f; /* forwf */
log(LOG_DEBUG,"circuit_init(): Set FORWF to %u.",circ->n_f);
circ->n_addr = layer->addr;
circ->state = CIRCUIT_STATE_OPEN;
log(LOG_DEBUG,"circuit_init(): aci_type = %u.",aci_type);
gettimeofday(&start,NULL);
circ->n_aci = get_unique_aci_by_addr_port(circ->n_addr, circ->n_port, aci_type);
......@@ -188,24 +182,26 @@ int circuit_init(circuit_t *circ, int aci_type) {
/* keys */
memset(iv, 0, 16);
crypto_SHA_digest(circ->onion+12,16,digest1);
crypto_SHA_digest(layer->keyseed,16,digest1);
crypto_SHA_digest(digest1,20,digest2);
crypto_SHA_digest(digest2,20,digest1);
log(LOG_DEBUG,"circuit_init(): Computed keys.");
if (!(circ->p_crypto = create_onion_cipher(circ->p_f,digest2,iv,1))) {
if (!(circ->p_crypto =
crypto_create_init_cipher(DEFAULT_CIPHER,digest2,iv,1))) {
log(LOG_ERR,"Cipher initialization failed (ACI %u).",circ->n_aci);
return -1;
}
if (!(circ->n_crypto = create_onion_cipher(circ->n_f, digest1, iv, 0))) {
if (!(circ->n_crypto =
crypto_create_init_cipher(DEFAULT_CIPHER,digest1,iv,0))) {
log(LOG_ERR,"Cipher initialization failed (ACI %u).",circ->n_aci);
return -1;
}
log(LOG_DEBUG,"circuit_init(): Cipher initialization complete.");
circ->expire = ntohl(*(uint32_t *)(circ->onion+8));
circ->expire = layer->expire;
return 0;
}
......@@ -678,7 +674,6 @@ retry_circuit:
}
int circuit_create_onion(void) {
int i;
int routelen; /* length of the route */
unsigned int *route; /* hops in the route as an array of indexes into rarray */
unsigned char *onion; /* holds the onion */
......@@ -711,9 +706,6 @@ int circuit_create_onion(void) {
}
log(LOG_DEBUG,"circuit_create_onion(): Created an onion of size %u bytes.",onionlen);
log(LOG_DEBUG,"circuit_create_onion(): Crypt path :");
for (i=0;i<routelen;i++) {
log(LOG_DEBUG,"circuit_create_onion() : %u/%u",(cpath[i])->forwf, (cpath[i])->backf);
}
return circuit_establish_circuit(route, routelen, onion, onionlen, cpath);
}
......
src/or/onion.c
+ 57
− 57
View file @ 0c61bc37
......@@ -217,28 +217,29 @@ static int onion_process(circuit_t *circ) {
int retval;
aci_t aci_type;
struct sockaddr_in me; /* my router identity */
onion_layer_t layer;
if(learn_my_address(&me) < 0)
return -1;
/* decrypt it in-place */
if(decrypt_onion(circ->onion,circ->onionlen,getprivatekey()) < 0) {
if(decrypt_onion(circ->onion,circ->onionlen,getprivatekey(),&layer) < 0) {
log(LOG_DEBUG,"command_process_create_cell(): decrypt_onion() failed, closing circuit.");
return -1;
}
log(LOG_DEBUG,"command_process_create_cell(): Onion decrypted.");
/* check freshness */
if (ntohl(*(uint32_t *)(circ->onion+8)) < (uint32_t)time(NULL)) /* expired onion */
if (layer.expire < (uint32_t)time(NULL)) /* expired onion */ /*XXXX*/
{
log(LOG_NOTICE,"I have just received an expired onion. This could be a replay attack.");
return -1;
}
aci_type = decide_aci_type(ntohl(me.sin_addr.s_addr), ntohs(me.sin_port),
ntohl(*(uint32_t *)(circ->onion+4)),ntohs(*(uint16_t *)(circ->onion+2)));
layer.addr, layer.port);
if(circuit_init(circ, aci_type) < 0) {
if(circuit_init(circ, aci_type, &layer) < 0) {
log(LOG_ERR,"process_onion(): init_circuit() failed.");
return -1;
}
......@@ -335,7 +336,7 @@ int chooselen(double cw)
*/
unsigned int *new_route(double cw, routerinfo_t **rarray, int rarray_len, int *routelen)
{
int i, j;
int i;
int num_acceptable_routers;
unsigned int *route;
unsigned int oldchoice, choice;
......@@ -431,40 +432,17 @@ static int count_acceptable_routers(routerinfo_t **rarray, int rarray_len) {
return num;
}
crypto_cipher_env_t *
create_onion_cipher(int cipher_type, char *key, char *iv, int encrypt_mode)
{
switch (cipher_type) {
case ONION_CIPHER_DES:
cipher_type = CRYPTO_CIPHER_DES;
break;
case ONION_CIPHER_3DES:
cipher_type = CRYPTO_CIPHER_3DES;
break;
case ONION_CIPHER_RC4 :
cipher_type = CRYPTO_CIPHER_RC4;
break;
case ONION_CIPHER_IDENTITY :
cipher_type = CRYPTO_CIPHER_IDENTITY;
break;
default:
log(LOG_ERR, "Unknown cipher type %d", cipher_type);
return NULL;
}
return crypto_create_init_cipher(cipher_type, key, iv, encrypt_mode);
}
/* creates a new onion from route, stores it and its length into buf and len respectively */
unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int *route, int routelen, int *len, crypt_path_t **cpath)
{
int i,j;
char *layer;
char *layerp;
crypt_path_t *hop = NULL;
unsigned char *buf;
routerinfo_t *router;
unsigned char iv[16];
struct in_addr netaddr;
onion_layer_t layer;
assert(rarray && route && len && routelen);
......@@ -491,7 +469,7 @@ unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int
crypto_pk_keysize((rarray[route[i]])->pkey));
}
layer = buf + *len - ONION_LAYER_SIZE - ONION_PADDING_SIZE; /* pointer to innermost layer */
layerp = buf + *len - ONION_LAYER_SIZE - ONION_PADDING_SIZE; /* pointer to innermost layer */
/* create the onion layer by layer, starting with the innermost */
for (i=0;i<routelen;i++) {
router = rarray[route[i]];
......@@ -500,32 +478,31 @@ unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int
// log(LOG_DEBUG,"create_onion() : This router is %s:%u",inet_ntoa(*((struct in_addr *)&router->addr)),router->or_port);
// log(LOG_DEBUG,"create_onion() : Key pointer = %u.",router->pkey);
// log(LOG_DEBUG,"create_onion() : Key size = %u.",crypto_pk_keysize(router->pkey));
*layer = OR_VERSION;
/* Back F + Forw F both use DES OFB*/
*(layer+1) = (ONION_DEFAULT_CIPHER << 4) /* for backf */ +
ONION_DEFAULT_CIPHER; /* for forwf */
/* Dest Port */
layer.version = OR_VERSION;
if (i) /* not last hop */
*(uint16_t *)(layer+2) = htons(rarray[route[i-1]]->or_port);
layer.port = rarray[route[i-1]]->or_port;
else
*(uint16_t *)(layer+2) = htons(0);
layer.port = 0;
/* Dest Addr */
if (i) /* not last hop */
*(uint32_t *)(layer+4) = htonl(rarray[route[i-1]]->addr);
layer.addr = rarray[route[i-1]]->addr;
else
*(uint32_t *)(layer+4) = htonl(0);
layer.addr = 0;
/* Expiration Time */
*(uint32_t *)(layer+8) = htonl((uint32_t)(time(NULL) + 86400)); /* NOW + 1 day */
layer.expire = (uint32_t)(time(NULL) + 86400); /* NOW + 1 day */
/* Key Seed Material */
if(crypto_rand(16, layer+12)) { /* error */
if(crypto_rand(16, layer.keyseed)) { /* error */
log(LOG_ERR,"Error generating random data.");
goto error;
}
onion_pack(layerp, &layer);
// log(LOG_DEBUG,"create_onion() : Onion layer %u built : %u, %u, %u, %s, %u.",i+1,layer->zero,layer->backf,layer->forwf,inet_ntoa(*((struct in_addr *)&layer->addr)),layer->port);
/* build up the crypt_path */
......@@ -538,12 +515,9 @@ unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int
log(LOG_DEBUG,"create_onion() : Building hop %u of crypt path.",i+1);
hop = cpath[i];
/* set crypto functions */
hop->backf = *(layer+1) >> 4;
hop->forwf = *(layer+1) & 0x0f;
/* calculate keys */
crypto_SHA_digest(layer+12,16,hop->digest3);
crypto_SHA_digest(layer.keyseed,16,hop->digest3);
log(LOG_DEBUG,"create_onion() : First SHA pass performed.");
crypto_SHA_digest(hop->digest3,20,hop->digest2);
log(LOG_DEBUG,"create_onion() : Second SHA pass performed.");
......@@ -554,13 +528,15 @@ unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int
memset((void *)iv,0,16);
/* initialize cipher engines */
if (! (hop->f_crypto = create_onion_cipher(hop->forwf, hop->digest3, iv, 1))) {
if (! (hop->f_crypto =
crypto_create_init_cipher(DEFAULT_CIPHER, hop->digest3, iv, 1))) {
/* cipher initialization failed */
log(LOG_ERR,"Could not create a crypto environment.");
goto error;
}
if (! (hop->b_crypto = create_onion_cipher(hop->backf, hop->digest2, iv, 0))) {
if (! (hop->b_crypto =
crypto_create_init_cipher(DEFAULT_CIPHER, hop->digest2, iv, 0))) {
/* cipher initialization failed */
log(LOG_ERR,"Could not create a crypto environment.");
goto error;
......@@ -571,7 +547,7 @@ unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int
/* padding if this is the innermost layer */
if (!i) {
if (crypto_pseudo_rand(ONION_PADDING_SIZE, layer + ONION_LAYER_SIZE)) { /* error */
if (crypto_pseudo_rand(ONION_PADDING_SIZE, layerp + ONION_LAYER_SIZE)) { /* error */
log(LOG_ERR,"Error generating pseudo-random data.");
goto error;
}
......@@ -580,14 +556,14 @@ unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int
/* encrypt */
if(encrypt_onion(layer,ONION_PADDING_SIZE+(i+1)*ONION_LAYER_SIZE,router->pkey) < 0) {
if(encrypt_onion(layerp,ONION_PADDING_SIZE+(i+1)*ONION_LAYER_SIZE,router->pkey,layer.keyseed) < 0) {
log(LOG_ERR,"Error encrypting onion layer.");
goto error;
}
log(LOG_DEBUG,"create_onion() : Encrypted layer.");
/* calculate pointer to next layer */
layer = buf + (routelen-i-2)*ONION_LAYER_SIZE;
layerp = buf + (routelen-i-2)*ONION_LAYER_SIZE;
}
return buf;
......@@ -609,7 +585,7 @@ unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int
/* encrypts 128 bytes of the onion with the specified public key, the rest with
* DES OFB with the key as defined in the outter layer */
int encrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *pkey) {
int encrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *pkey, char* keyseed) {
unsigned char *tmpbuf = NULL; /* temporary buffer for crypto operations */
unsigned char digest[20]; /* stores SHA1 output - 160 bits */
unsigned char iv[8];
......@@ -631,7 +607,7 @@ int encrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *pkey
log(LOG_DEBUG,"encrypt_onion() : allocated %u bytes of memory for the encrypted onion (at %u).",onionlen,tmpbuf);
/* get key1 = SHA1(KeySeed) */
if (crypto_SHA_digest(onion+12,16,digest)) {
if (crypto_SHA_digest(keyseed,16,digest)) {
log(LOG_ERR,"Error computing SHA1 digest.");
goto error;
}
......@@ -675,7 +651,7 @@ int encrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *pkey
}
/* decrypts the first 128 bytes using RSA and prkey, decrypts the rest with DES OFB with key1 */
int decrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *prkey) {
int decrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *prkey, onion_layer_t *layer) {
void *tmpbuf = NULL; /* temporary buffer for crypto operations */
unsigned char digest[20]; /* stores SHA1 output - 160 bits */
unsigned char iv[8];
......@@ -702,8 +678,10 @@ int decrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *prke
}
log(LOG_DEBUG,"decrypt_onion() : RSA decryption complete.");
onion_unpack(layer, onion);
/* get key1 = SHA1(KeySeed) */
if (crypto_SHA_digest(tmpbuf+12,16,digest)) {
if (crypto_SHA_digest(layer->keyseed,16,digest)) {
log(LOG_ERR,"Error computing SHA1 digest.");
goto error;
}
......@@ -828,6 +806,28 @@ static int find_tracked_onion(unsigned char *onion, uint32_t onionlen) {
return 0;
}
void
onion_pack(char *dest, onion_layer_t *src)
{
assert((src->version & 0x80) == 0);
*(uint8_t*)dest = src->version;
*(uint16_t*)(dest+1) = htons(src->port);
*(uint32_t*)(dest+3) = htonl(src->addr);
*(uint32_t*)(dest+7) = htonl(src->expire);
memcpy(dest+11, src->keyseed, ONION_KEYSEED_LEN);
}
void
onion_unpack(onion_layer_t *dest, char *src)
{
dest->version = *(uint8_t*)src;
dest->port = ntohs(*(uint16_t*)(src+1));
dest->addr = ntohl(*(uint32_t*)(src+3));
dest->expire = ntohl(*(uint32_t*)(src+7));
memcpy(dest->keyseed, src+11, ONION_KEYSEED_LEN);
}
/*
Local Variables:
mode:c
......
src/or/or.h
+ 25
− 13
View file @ 0c61bc37
......@@ -132,13 +132,18 @@
#define TOPIC_STATE_RESOLVING
/* available cipher functions */
#if 0
#define ONION_CIPHER_IDENTITY 0
#define ONION_CIPHER_DES 1
#define ONION_CIPHER_RC4 2
#define ONION_CIPHER_3DES 3
#endif
/* default cipher function */
#if 0
#define ONION_DEFAULT_CIPHER ONION_CIPHER_3DES
#endif
#define DEFAULT_CIPHER CRYPTO_CIPHER_3DES
#define CELL_DIRECTION_IN 1
#define CELL_DIRECTION_OUT 2
......@@ -325,8 +330,6 @@ typedef struct {
} routerinfo_t;
typedef struct {
unsigned int forwf;
unsigned int backf;
char digest2[20]; /* second SHA output for onion_layer_t.keyseed */
char digest3[20]; /* third SHA output for onion_layer_t.keyseed */
......@@ -355,9 +358,6 @@ typedef struct {
struct data_queue_t *data_queue; /* for queueing cells at the edges */
unsigned char p_f; /* crypto functions */
unsigned char n_f;
crypto_cipher_env_t *p_crypto; /* crypto environments */
crypto_cipher_env_t *n_crypto;
......@@ -383,7 +383,19 @@ struct onion_queue_t {
struct onion_queue_t *next;
};
#define ONION_LAYER_SIZE 28
#define ONION_KEYSEED_LEN 16
typedef struct {
uint8_t version;
uint16_t port;
uint32_t addr;
uint32_t expire;
unsigned char keyseed[ONION_KEYSEED_LEN];
} onion_layer_t;
/* ugly hack XXXX */
#define ONION_KEYSEED_OFFSET 11
#define ONION_LAYER_SIZE 27
#define ONION_PADDING_SIZE (128-ONION_LAYER_SIZE)
typedef struct {
......@@ -490,7 +502,7 @@ void circuit_resume_edge_reading(circuit_t *circ, int edge_type);
int circuit_consider_stop_edge_reading(circuit_t *circ, int edge_type);
int circuit_consider_sending_sendme(circuit_t *circ, int edge_type);
int circuit_init(circuit_t *circ, int aci_type);
int circuit_init(circuit_t *circ, int aci_type, onion_layer_t *layer);
void circuit_free(circuit_t *circ);
void circuit_free_cpath(crypt_path_t **cpath, int cpathlen);
......@@ -737,24 +749,24 @@ int chooselen(double cw);
*/
unsigned int *new_route(double cw, routerinfo_t **rarray, int rarray_len, int *routelen);
/* create a cipher by onion cipher type. */
crypto_cipher_env_t *create_onion_cipher(int cipher_type, char *key, char *iv, int encrypt_mode);
/* creates a new onion from route, stores it and its length into bufp and lenp respectively */
unsigned char *create_onion(routerinfo_t **rarray, int rarray_len, unsigned int *route, int routelen, int *len, crypt_path_t **cpath);
/* encrypts 128 bytes of the onion with the specified public key, the rest with
* DES OFB with the key as defined in the outter layer */
int encrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *pkey);
int encrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *pkey, char *keyseed);
/* decrypts the first 128 bytes using RSA and prkey, decrypts the rest with DES OFB with key1 */
int decrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *prkey);
/* decrypts the first 128 bytes using RSA and prkey, decrypts the rest with DES OFB with key1. Writes the first layer into 'layer' */
int decrypt_onion(unsigned char *onion, uint32_t onionlen, crypto_pk_env_t *prkey, onion_layer_t *layer);
/* delete first n bytes of the onion and pads the end with n bytes of random data */
void pad_onion(unsigned char *onion, uint32_t onionlen, int n);
void init_tracked_tree(void);
void onion_pack(char *dest, onion_layer_t *src);
void onion_unpack(onion_layer_t *dest, char *src);
/********************************* routers.c ***************************/
int learn_my_address(struct sockaddr_in *me);
......
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