Commit 21d5dbd4 authored by Arlo Breault's avatar Arlo Breault Committed by Nick Mathewson
Browse files

Refactor initiate_descriptor_downloads() to be safer 

(It's smarter to use asprintf and join than character pointers and a
long buffer.)
parent 29f15a97

src/or/routerlist.c

+23 −23
Original line number Diff line number Diff line
@@ -4289,18 +4289,13 @@ list_pending_fpsk_downloads(fp_pair_map_t *result) 
 * range.)  If <b>source</b> is given, download from <b>source</b>;

 * otherwise, download from an appropriate random directory server.

 */

static void

initiate_descriptor_downloads(const routerstatus_t *source,

                              int purpose,

                              smartlist_t *digests,

                              int lo, int hi, int pds_flags)

MOCK_IMPL(STATIC void, initiate_descriptor_downloads,

          (const routerstatus_t *source, int purpose, smartlist_t *digests,

           int lo, int hi, int pds_flags))

{

  int i, n = hi-lo;

  char *resource, *cp;

  size_t r_len;



  int digest_len = DIGEST_LEN, enc_digest_len = HEX_DIGEST_LEN;

  char sep = '+';

  char *sep = "+";

  int b64_256 = 0;



  if (purpose == DIR_PURPOSE_FETCH_MICRODESC) {
@@ -4308,32 +4303,37 @@ initiate_descriptor_downloads(const routerstatus_t *source, 
     * 256-bit digests. */

    digest_len = DIGEST256_LEN;

    enc_digest_len = BASE64_DIGEST256_LEN;

    sep = '-';

    sep = "-";

    b64_256 = 1;

  }



  if (n <= 0)

    return;

  if (lo < 0)

    lo = 0;

  if (hi > smartlist_len(digests))

    hi = smartlist_len(digests);



  r_len = 8 + (enc_digest_len+1)*n;

  cp = resource = tor_malloc(r_len);

  memcpy(cp, "d/", 2);

  cp += 2;

  for (i = lo; i < hi; ++i) {

  if (hi-lo <= 0)

    return;



  digest_len += 1;  // for the NULL

  smartlist_t *tmp = smartlist_new();



  for (; lo < hi; ++lo) {

    cp = tor_malloc(enc_digest_len);

    if (b64_256) {

      digest256_to_base64(cp, smartlist_get(digests, i));

      digest256_to_base64(cp, smartlist_get(digests, lo));

    } else {

      base16_encode(cp, r_len-(cp-resource),

                    smartlist_get(digests,i), digest_len);

      base16_encode(cp, enc_digest_len, smartlist_get(digests, lo), digest_len);

    }

    cp += enc_digest_len;

    *cp++ = sep;

    smartlist_add(tmp, cp);

  }

  memcpy(cp-1, ".z", 3);



  cp = smartlist_join_strings(tmp, sep, 0, NULL);

  tor_asprintf(&resource, "d/%s.z", cp);



  SMARTLIST_FOREACH(tmp, char *, cp1, tor_free(cp1));

  smartlist_free(tmp);

  tor_free(cp);



  if (source) {

    /* We know which authority we want. */

src/or/routerlist.h

+4 −0
Original line number Diff line number Diff line
@@ -211,6 +211,10 @@ STATIC int choose_array_element_by_weight(const u64_dbl_t *entries, 
                                          int n_entries);

STATIC void scale_array_elements_to_u64(u64_dbl_t *entries, int n_entries,

                                        uint64_t *total_out);

MOCK_DECL(STATIC void, initiate_descriptor_downloads,

          (const routerstatus_t *source, int purpose, smartlist_t *digests,

           int lo, int hi, int pds_flags));



#endif



#endif