Commit 00f74e03 authored by Nick Mathewson's avatar Nick Mathewson 🤹
Browse files

Improve API of routerinfo_incompatible_with_extrainfo() 

This API change makes it so that routerinfo_incompatible...() no
longer takes a routerinfo_t, so that it's obvious that it should
only look at fields from the signed_descriptor_t.

This change should prevent a recurrence of #17150.
parent 49ff09ae

src/or/dirserv.c

+6 −3
Original line number Diff line number Diff line
@@ -691,12 +691,14 @@ dirserv_add_descriptor(routerinfo_t *ri, const char **msg, const char *source) 
static was_router_added_t

dirserv_add_extrainfo(extrainfo_t *ei, const char **msg)

{

  const routerinfo_t *ri;

  routerinfo_t *ri;

  int r;

  tor_assert(msg);

  *msg = NULL;



  ri = router_get_by_id_digest(ei->cache_info.identity_digest);

  /* Needs to be mutable so routerinfo_incompatible_with_extrainfo

   * can mess with some of the flags in ri->cache_info. */

  ri = router_get_mutable_by_digest(ei->cache_info.identity_digest);

  if (!ri) {

    *msg = "No corresponding router descriptor for extra-info descriptor";

    extrainfo_free(ei);
@@ -716,7 +718,8 @@ dirserv_add_extrainfo(extrainfo_t *ei, const char **msg) 
    return ROUTER_BAD_EI;

  }



  if ((r = routerinfo_incompatible_with_extrainfo(ri, ei, NULL, msg))) {

  if ((r = routerinfo_incompatible_with_extrainfo(ri->identity_pkey, ei,

                                                  &ri->cache_info, msg))) {

    extrainfo_free(ei);

    return r < 0 ? ROUTER_IS_ALREADY_KNOWN : ROUTER_BAD_EI;

  }

src/or/router.c

+2 −1
Original line number Diff line number Diff line
@@ -2072,7 +2072,8 @@ router_build_fresh_descriptor(routerinfo_t **r, extrainfo_t **e) 
                         ri->cache_info.signed_descriptor_digest);



  if (ei) {

    tor_assert(! routerinfo_incompatible_with_extrainfo(ri, ei, NULL, NULL));

    tor_assert(! routerinfo_incompatible_with_extrainfo(ri->identity_pkey, ei,

                                                        &ri->cache_info, NULL));

  }



  *r = ri;

src/or/routerlist.c

+10 −11
Original line number Diff line number Diff line
@@ -2900,7 +2900,7 @@ extrainfo_insert,(routerlist_t *rl, extrainfo_t *ei, int warn_if_incompatible)) 
                     "Mismatch in digest in extrainfo map.");

    goto done;

  }

  if (routerinfo_incompatible_with_extrainfo(ri, ei, sd,

  if (routerinfo_incompatible_with_extrainfo(ri->identity_pkey, ei, sd,

                                             &compatibility_error_msg)) {

    char d1[HEX_DIGEST_LEN+1], d2[HEX_DIGEST_LEN+1];

    r = (ri->cache_info.extrainfo_is_bogus) ?
@@ -4901,9 +4901,9 @@ router_differences_are_cosmetic(const routerinfo_t *r1, const routerinfo_t *r2) 
/** Check whether <b>sd</b> describes a router descriptor compatible with the

 * extrainfo document <b>ei</b>.

 *

 * <b>ri</b> (which must also be provided) is the full routerinfo corresponding

 * to the same router -- but note that it might not refer to the same specific

 * descriptor as sd.

 * <b>identity_pkey</b> (which must also be provided) is RSA1024 identity key

 * for the router. We use it to check the signature of the extrainfo document,

 * if it has not already been checked.

 *

 * If no router is compatible with <b>ei</b>, <b>ei</b> should be

 * dropped.  Return 0 for "compatible", return 1 for "reject, and inform
@@ -4915,16 +4915,15 @@ router_differences_are_cosmetic(const routerinfo_t *r1, const routerinfo_t *r2) 
 * but the extrainfo was nonetheless incompatible.

 **/

int

routerinfo_incompatible_with_extrainfo(const routerinfo_t *ri,

routerinfo_incompatible_with_extrainfo(const crypto_pk_t *identity_pkey,

                                       extrainfo_t *ei,

                                       signed_descriptor_t *sd,

                                       const char **msg)

{

  int digest_matches, digest256_matches, r=1;

  tor_assert(ri);

  tor_assert(identity_pkey);

  tor_assert(sd);

  tor_assert(ei);

  if (!sd)

    sd = (signed_descriptor_t*)&ri->cache_info;



  if (ei->bad_sig) {

    if (msg) *msg = "Extrainfo signature was bad, or signed with wrong key.";
@@ -4942,7 +4941,7 @@ routerinfo_incompatible_with_extrainfo(const routerinfo_t *ri, 


  /* The identity must match exactly to have been generated at the same time

   * by the same router. */

  if (tor_memneq(ri->cache_info.identity_digest,

  if (tor_memneq(sd->identity_digest,

                 ei->cache_info.identity_digest,

                 DIGEST_LEN)) {

    if (msg) *msg = "Extrainfo nickname or identity did not match routerinfo";
@@ -4956,7 +4955,7 @@ routerinfo_incompatible_with_extrainfo(const routerinfo_t *ri, 


  if (ei->pending_sig) {

    char signed_digest[128];

    if (crypto_pk_public_checksig(ri->identity_pkey,

    if (crypto_pk_public_checksig(identity_pkey,

                       signed_digest, sizeof(signed_digest),

                       ei->pending_sig, ei->pending_sig_len) != DIGEST_LEN ||

        tor_memneq(signed_digest, ei->cache_info.signed_descriptor_digest,
@@ -4967,7 +4966,7 @@ routerinfo_incompatible_with_extrainfo(const routerinfo_t *ri, 
      goto err; /* Bad signature, or no match. */

    }



    ei->cache_info.send_unencrypted = ri->cache_info.send_unencrypted;

    ei->cache_info.send_unencrypted = sd->send_unencrypted;

    tor_free(ei->pending_sig);

  }

src/or/routerlist.h

+1 −1
Original line number Diff line number Diff line
@@ -187,7 +187,7 @@ void update_extrainfo_downloads(time_t now); 
void router_reset_descriptor_download_failures(void);

int router_differences_are_cosmetic(const routerinfo_t *r1,

                                    const routerinfo_t *r2);

int routerinfo_incompatible_with_extrainfo(const routerinfo_t *ri,

int routerinfo_incompatible_with_extrainfo(const crypto_pk_t *ri,

                                           extrainfo_t *ei,

                                           signed_descriptor_t *sd,

                                           const char **msg);