commit 77ed99b1a79e61146d9e3b9f51aac4fd1c2f5b03 Author: teor teor2345@gmail.com Date: Thu Oct 26 16:30:24 2017 +1100

Remove buggy IPv6 and ed25519 handling from get_lspecs_from_extend_info()

The previous version of this function had the following issues: * it didn't check if the extend_info contained an IPv6 address, * it didn't check if the ed25519 identity key was valid. But we can't add IPv6 support in a bugfix release.

Instead, BUG() if the address is an IPv6 address, so we always put IPv4 addresses in link specifiers. And ignore missing ed25519 identifiers, rather than generating an all-zero link specifier.

This supports v3 hidden services on IPv4, dual-stack, and IPv6, and v3 single onion services on IPv4 only.

Part of 23820, bugfix on 0.3.2.1-alpha. --- src/or/hs_circuit.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/src/or/hs_circuit.c b/src/or/hs_circuit.c index e1e513c5f..c8c9b4e56 100644 --- a/src/or/hs_circuit.c +++ b/src/or/hs_circuit.c @@ -533,7 +533,10 @@ retry_service_rendezvous_point(const origin_circuit_t *circ) }

/* Using an extend info object ei, set all possible link specifiers in lspecs. - * IPv4, legacy ID and ed25519 ID are mandatory thus MUST be present in ei. */ + * legacy ID is mandatory thus MUST be present in ei. If IPv4 is not present, + * logs a BUG() warning, and returns an empty smartlist. Clients never make + * direct connections to rendezvous points, so they should always have an + * IPv4 address in ei. */ static void get_lspecs_from_extend_info(const extend_info_t *ei, smartlist_t *lspecs) { @@ -542,7 +545,11 @@ get_lspecs_from_extend_info(const extend_info_t *ei, smartlist_t *lspecs) tor_assert(ei); tor_assert(lspecs);

- /* IPv4 is mandatory. */ + /* We require IPv4, we will add IPv6 support in a later tor version */ + if (BUG(!tor_addr_is_v4(&ei->addr))) { + return; + } + ls = link_specifier_new(); link_specifier_set_ls_type(ls, LS_IPV4); link_specifier_set_un_ipv4_addr(ls, tor_addr_to_ipv4h(&ei->addr)); @@ -560,15 +567,15 @@ get_lspecs_from_extend_info(const extend_info_t *ei, smartlist_t *lspecs) link_specifier_set_ls_len(ls, link_specifier_getlen_un_legacy_id(ls)); smartlist_add(lspecs, ls);

- /* ed25519 ID is mandatory. */ - ls = link_specifier_new(); - link_specifier_set_ls_type(ls, LS_ED25519_ID); - memcpy(link_specifier_getarray_un_ed25519_id(ls), &ei->ed_identity, - link_specifier_getlen_un_ed25519_id(ls)); - link_specifier_set_ls_len(ls, link_specifier_getlen_un_ed25519_id(ls)); - smartlist_add(lspecs, ls); - - /* XXX: IPv6 is not clearly a thing in extend_info_t? */ + /* ed25519 ID is only included if the node has it. */ + if (!ed25519_public_key_is_zero(&ei->ed_identity)) { + ls = link_specifier_new(); + link_specifier_set_ls_type(ls, LS_ED25519_ID); + memcpy(link_specifier_getarray_un_ed25519_id(ls), &ei->ed_identity, + link_specifier_getlen_un_ed25519_id(ls)); + link_specifier_set_ls_len(ls, link_specifier_getlen_un_ed25519_id(ls)); + smartlist_add(lspecs, ls); + } }

/* Using the given descriptor intro point ip, the extend information of the @@ -1053,6 +1060,14 @@ hs_circ_send_introduce1(origin_circuit_t *intro_circ, * object which is used to build the content of the cell. */ setup_introduce1_data(ip, rend_circ->build_state->chosen_exit, subcredential, &intro1_data); + /* If we didn't get any link specifiers, it's because our extend info was + * bad. */ + if (BUG(!intro1_data.link_specifiers) || + !smartlist_len(intro1_data.link_specifiers)) { + log_warn(LD_REND, "Unable to get link specifiers for INTRODUCE1 cell on " + "circuit %u.", TO_CIRCUIT(intro_circ)->n_circ_id); + goto done; + }

/* Final step before we encode a cell, we setup the circuit identifier which * will generate both the rendezvous cookie and client keypair for this