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Hello,

I found that the following code {{{ int crypto_expand_key_material_TAP(const uint8_t *key_in, size_t key_in_len, uint8_t *key_out, size_t key_out_len) { int i; uint8_t *cp, *tmp = tor_malloc(key_in_len+1); uint8_t digest[DIGEST_LEN];

/* If we try to get more than this amount of key data, we'll repeat blocks./ tor_assert(key_out_len <= DIGEST_LEN256);

memcpy(tmp, key_in, key_in_len); for (cp = key_out, i=0; cp < key_out+key_out_len; ++i, cp += DIGEST_LEN) { tmp[key_in_len] = i; if (crypto_digest((char*)digest, (const char *)tmp, key_in_len+1)) goto err; memcpy(cp, digest, MIN(DIGEST_LEN, key_out_len-(cp-key_out))); } memwipe(tmp, 0, key_in_len+1); tor_free(tmp); memwipe(digest, 0, sizeof(digest)); return 0;

err: memwipe(tmp, 0, key_in_len+1); tor_free(tmp); memwipe(digest, 0, sizeof(digest)); return -1; } }}}

contains twice this code

  memwipe(tmp, 0, key_in_len+1);
  tor_free(tmp);
  memwipe(digest, 0, sizeof(digest));

then I think it will be ok to modify like this

int crypto_expand_key_material_TAP(const uint8_t *key_in, size_t key_in_len,
                               uint8_t *key_out, size_t key_out_len)
{
  int i, r = -1;
  uint8_t *cp, *tmp = tor_malloc(key_in_len+1);
  uint8_t digest[DIGEST_LEN];

  /* If we try to get more than this amount of key data, we'll repeat blocks.*/
  tor_assert(key_out_len <= DIGEST_LEN*256);

  memcpy(tmp, key_in, key_in_len);
  for (cp = key_out, i=0; cp < key_out+key_out_len;
       ++i, cp += DIGEST_LEN) {
    tmp[key_in_len] = i;
    if (crypto_digest((char*)digest, (const char *)tmp, key_in_len+1))
      goto exit;
    memcpy(cp, digest, MIN(DIGEST_LEN, key_out_len-(cp-key_out)));
  }
  
  r = 0;
 exit:
  memwipe(tmp, 0, key_in_len+1);
  tor_free(tmp);
  memwipe(digest, 0, sizeof(digest));
  return r;
}

Trac:
Username: pfrankw