Commit 785f5cda authored by Nick Mathewson's avatar Nick Mathewson 🦞
Browse files

Make crypto_pseudo_rand* never fail. 


svn:r797
parent 99a6d48f

src/common/crypto.c

+15 −2
Original line number Diff line number Diff line
@@ -999,10 +999,23 @@ int crypto_rand(unsigned int n, unsigned char *to) 
  return (RAND_bytes(to, n) != 1);

}



int crypto_pseudo_rand(unsigned int n, unsigned char *to)

void crypto_pseudo_rand(unsigned int n, unsigned char *to)

{

  assert(to);

  return (RAND_pseudo_bytes(to, n) == -1);

  if (RAND_pseudo_bytes(to, n) == -1) {

    log_fn(LOG_ERR, "RAND_pseudo_bytes failed unexpectedly.");

    exit(1);

  }

}



int crypto_pseudo_rand_int(int max) {

  unsigned int val;

  crypto_pseudo_rand(sizeof(val), (unsigned char*) &val);

  /* Bug: Low values are _slightly_ favored over high values because

   * ((unsigned)-1)%max != max-1 .  This shouldn't matter if max is

   * significantly smaller than ((unsigned)-1).

   **/

  return val % max;

}



/* errors */

src/common/crypto.h

+2 −3
Original line number Diff line number Diff line
@@ -100,9 +100,8 @@ int crypto_SHA_digest(unsigned char *m, int len, unsigned char *digest); 
/* random numbers */

int crypto_seed_rng();

int crypto_rand(unsigned int n, unsigned char *to);

int crypto_pseudo_rand(unsigned int n, unsigned char *to);



#define CRYPTO_PSEUDO_RAND_INT(v) crypto_pseudo_rand(sizeof(v),(char*)&(v))

void crypto_pseudo_rand(unsigned int n, unsigned char *to);

int crypto_pseudo_rand_int(int max);



/* errors */

char *crypto_perror();

src/or/connection_edge.c

+2 −5
Original line number Diff line number Diff line
@@ -608,11 +608,8 @@ static int connection_ap_handshake_send_begin(connection_t *ap_conn, circuit_t * 
  assert(ap_conn->socks_request);

  assert(ap_conn->socks_request->addr);



  if(crypto_pseudo_rand(STREAM_ID_SIZE, ap_conn->stream_id) < 0) {

    /* XXX can we just make this call abort if it fails? then this func could be a void. */

  crypto_pseudo_rand(STREAM_ID_SIZE, ap_conn->stream_id);

  /* FIXME check for collisions */

    return -1;

  }



  memcpy(payload, ap_conn->stream_id, STREAM_ID_SIZE);

  payload_len = STREAM_ID_SIZE + 1 +

src/or/onion.c

+2 −9
Original line number Diff line number Diff line
@@ -160,17 +160,13 @@ int onionskin_answer(circuit_t *circ, unsigned char *payload, unsigned char *key 
/* uses a weighted coin with weight cw to choose a route length */

static int chooselen(double cw) {

  int len = 2;

  uint8_t coin;

  

  if ((cw < 0) || (cw >= 1)) /* invalid parameter */

    return -1;

  

  while(1)

  {

    if (CRYPTO_PSEUDO_RAND_INT(coin))

      return -1;

    

    if (coin > cw*255) /* don't extend */

    if (crypto_pseudo_rand_int(255) > cw*255) /* don't extend */

      break;

    else

      len++;
@@ -279,10 +275,7 @@ int onion_extend_cpath(crypt_path_t **head_ptr, int path_len, routerinfo_t **rou 
  log_fn(LOG_DEBUG, "Path is %d long; we want %d", cur_len, path_len);



 again:

  if (CRYPTO_PSEUDO_RAND_INT(choice)) {

    return -1;

  }

  choice %= rarray_len;

  choice = crypto_pseudo_rand_int(rarray_len);

  log_fn(LOG_DEBUG,"Contemplating router %s for hop %d",

         rarray[choice]->nickname, cur_len);

  for (i = 0, cpath = *head_ptr; i < cur_len; ++i, cpath=cpath->next) {