commit bd4a3f64a1f6802c97a7976ff9f80495ef3ba57d Author: David Goulet dgoulet@torproject.org Date: Mon Feb 1 12:20:39 2021 -0500

node: Move reentry set to use a digestmap_t

Any lookup now will be certain and not probabilistic as the bloomfilter.

Closes #40269

Signed-off-by: David Goulet dgoulet@torproject.org --- src/core/or/connection_edge.c | 2 +- src/feature/nodelist/nodelist.c | 63 ++++++++++++++++++++++++++++++++--------- src/feature/nodelist/nodelist.h | 3 +- src/test/test_address_set.c | 12 ++++---- 4 files changed, 57 insertions(+), 23 deletions(-)

diff --git a/src/core/or/connection_edge.c b/src/core/or/connection_edge.c index da5431c47e..27a616fa24 100644 --- a/src/core/or/connection_edge.c +++ b/src/core/or/connection_edge.c @@ -4290,7 +4290,7 @@ connection_exit_connect(edge_connection_t *edge_conn) * case of an attack so this is a small price to pay. */ if (!connection_edge_is_rendezvous_stream(edge_conn) && !network_reentry_is_allowed() && - nodelist_reentry_probably_contains(&conn->addr, conn->port)) { + nodelist_reentry_contains(&conn->addr, conn->port)) { log_info(LD_EXIT, "%s tried to connect back to a known relay address. " "Closing.", connection_describe(conn)); connection_edge_end(edge_conn, END_STREAM_REASON_TORPROTOCOL); diff --git a/src/feature/nodelist/nodelist.c b/src/feature/nodelist/nodelist.c index 6a6f277849..03b158e68d 100644 --- a/src/feature/nodelist/nodelist.c +++ b/src/feature/nodelist/nodelist.c @@ -137,7 +137,7 @@ typedef struct nodelist_t {

/* Set of addresses + port that belong to nodes we know and that we don't * allow network re-entry towards them. */ - addr_port_set_t *reentry_set; + digestmap_t *reentry_set;

/* The valid-after time of the last live consensus that initialized the * nodelist. We use this to detect outdated nodelists that need to be @@ -485,6 +485,42 @@ node_add_to_address_set(const node_t *node) } }

+/** Build a construction for the reentry set consisting of an address and port + * pair. + * + * If the given address is _not_ AF_INET or AF_INET6, then the item is an + * array of 0s. + * + * Return a pointer to a static buffer containing the item. Next call to this + * function invalidates its previous content. */ +static char * +build_addr_port_item(const tor_addr_t *addr, const uint16_t port) +{ + /* At most 16 bytes are put in this (IPv6) and then 2 bytes for the port + * which is within the maximum of 20 bytes (DIGEST_LEN). */ + static char data[DIGEST_LEN]; + + memset(data, 0, sizeof(data)); + switch (tor_addr_family(addr)) { + case AF_INET: + memcpy(data, &addr->addr.in_addr.s_addr, 4); + break; + case AF_INET6: + memcpy(data, &addr->addr.in6_addr.s6_addr, 16); + break; + case AF_UNSPEC: + /* Leave the 0. */ + break; + default: + /* LCOV_EXCL_START */ + tor_fragile_assert(); + /* LCOV_EXCL_STOP */ + } + + memcpy(data + 16, &port, sizeof(port)); + return data; +} + /** Add the given address into the nodelist address set. */ void nodelist_add_addr_to_address_set(const tor_addr_t *addr, @@ -498,10 +534,12 @@ nodelist_add_addr_to_address_set(const tor_addr_t *addr, } address_set_add(the_nodelist->node_addrs, addr); if (or_port != 0) { - addr_port_set_add(the_nodelist->reentry_set, addr, or_port); + digestmap_set(the_nodelist->reentry_set, + build_addr_port_item(addr, or_port), (void*) 1); } if (dir_port != 0) { - addr_port_set_add(the_nodelist->reentry_set, addr, dir_port); + digestmap_set(the_nodelist->reentry_set, + build_addr_port_item(addr, dir_port), (void*) 1); } }

@@ -522,7 +560,7 @@ nodelist_probably_contains_address(const tor_addr_t *addr) /** Return true if <b>addr</b> is the address of some node in the nodelist and * corresponds also to the given port. If not, probably return false. */ bool -nodelist_reentry_probably_contains(const tor_addr_t *addr, uint16_t port) +nodelist_reentry_contains(const tor_addr_t *addr, uint16_t port) { if (BUG(!addr) || BUG(!port)) return false; @@ -530,8 +568,8 @@ nodelist_reentry_probably_contains(const tor_addr_t *addr, uint16_t port) if (!the_nodelist || !the_nodelist->reentry_set) return false;

- return addr_port_set_probably_contains(the_nodelist->reentry_set, - addr, port); + return digestmap_get(the_nodelist->reentry_set, + build_addr_port_item(addr, port)) != NULL; }

/** Add <b>ri</b> to an appropriate node in the nodelist. If we replace an @@ -667,15 +705,12 @@ nodelist_set_consensus(const networkstatus_t *ns) get_estimated_address_per_node(); estimated_addresses += (get_n_authorities(V3_DIRINFO | BRIDGE_DIRINFO) * get_estimated_address_per_node()); + /* Clear our sets because we will repopulate them with what this new + * consensus contains. */ address_set_free(the_nodelist->node_addrs); - addr_port_set_free(the_nodelist->reentry_set); the_nodelist->node_addrs = address_set_new(estimated_addresses); - /* Times two here is for both the ORPort and DirPort. We double it again in - * order to minimize as much as possible the false positive when looking up - * this set. Reason is that Exit streams that are legitimate but end up a - * false positive against this set will thus be considered reentry and be - * rejected which means a bad UX. */ - the_nodelist->reentry_set = addr_port_set_new(estimated_addresses * 2 * 2); + digestmap_free(the_nodelist->reentry_set, NULL); + the_nodelist->reentry_set = digestmap_new();

SMARTLIST_FOREACH_BEGIN(ns->routerstatus_list, routerstatus_t *, rs) { node_t *node = node_get_or_create(rs->identity_digest); @@ -902,7 +937,7 @@ nodelist_free_all(void)

address_set_free(the_nodelist->node_addrs); the_nodelist->node_addrs = NULL; - addr_port_set_free(the_nodelist->reentry_set); + digestmap_free(the_nodelist->reentry_set, NULL); the_nodelist->reentry_set = NULL;

tor_free(the_nodelist); diff --git a/src/feature/nodelist/nodelist.h b/src/feature/nodelist/nodelist.h index ada0a640a1..44b8918b06 100644 --- a/src/feature/nodelist/nodelist.h +++ b/src/feature/nodelist/nodelist.h @@ -35,8 +35,7 @@ node_t *nodelist_add_microdesc(microdesc_t *md); void nodelist_set_consensus(const networkstatus_t *ns); void nodelist_ensure_freshness(const networkstatus_t *ns); int nodelist_probably_contains_address(const tor_addr_t *addr); -bool nodelist_reentry_probably_contains(const tor_addr_t *addr, - uint16_t port); +bool nodelist_reentry_contains(const tor_addr_t *addr, uint16_t port); void nodelist_add_addr_to_address_set(const tor_addr_t *addr, uint16_t or_port, uint16_t dir_port);

diff --git a/src/test/test_address_set.c b/src/test/test_address_set.c index 55a0b106d2..a73fbab76a 100644 --- a/src/test/test_address_set.c +++ b/src/test/test_address_set.c @@ -215,8 +215,8 @@ test_exit_no_reentry(void *arg) nodelist_set_consensus(dummy_ns);

/* The address set is empty. Try it anyway */ - tt_assert(!nodelist_reentry_probably_contains(&addr_v4, 244)); - tt_assert(!nodelist_reentry_probably_contains(&addr_v6, 244)); + tt_assert(!nodelist_reentry_contains(&addr_v4, 244)); + tt_assert(!nodelist_reentry_contains(&addr_v6, 244));

/* Now let's populate the network */ md = tor_malloc_zero(sizeof(*md)); @@ -243,12 +243,12 @@ test_exit_no_reentry(void *arg)

/* First let's try an address that is on the no-reentry list, but with a different port */ - tt_assert(!nodelist_reentry_probably_contains(&addr_v4, 666)); - tt_assert(!nodelist_reentry_probably_contains(&addr_v6, 444)); + tt_assert(!nodelist_reentry_contains(&addr_v4, 666)); + tt_assert(!nodelist_reentry_contains(&addr_v6, 444));

/* OK now let's try with the right address and right port */ - tt_assert(nodelist_reentry_probably_contains(&addr_v4, 444)); - tt_assert(nodelist_reentry_probably_contains(&addr_v6, 666)); + tt_assert(nodelist_reentry_contains(&addr_v4, 444)); + tt_assert(nodelist_reentry_contains(&addr_v6, 666));

done: routerstatus_free(rs); routerinfo_free(ri); microdesc_free(md);