February 2021 - tor-commits - lists.torproject.org

[tor/release-0.4.5] exit: Deny re-entry into the network
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit 93ac6ec4d3d19aaff7fed2ea97b0a30528da3767 Author: Roger Dingledine <arma(a)torproject.org> Date: Wed Jan 27 23:48:57 2021 -0500 exit: Deny re-entry into the network Exit relays now reject exit attempts to known relay addresses + ORPort and also to authorities on the ORPort and DirPort. Closes #2667 Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- changes/ticket2667 | 4 ++++ src/core/or/connection_edge.c | 25 ++++++++… [View More]+++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/changes/ticket2667 b/changes/ticket2667 new file mode 100644 index 0000000000..cc42286ef9 --- /dev/null +++ b/changes/ticket2667 @@ -0,0 +1,4 @@ + o Major feature (exit): + - Re-entry into the network is now denied at the Exit level to all relays' + ORPort and authorities' ORPort+DirPort. This is to help mitigate a series + of attacks. See ticket for more information. Closes ticket 2667. diff --git a/src/core/or/connection_edge.c b/src/core/or/connection_edge.c index 67a772be08..f9a9bbdb73 100644 --- a/src/core/or/connection_edge.c +++ b/src/core/or/connection_edge.c @@ -4035,6 +4035,31 @@ connection_exit_connect(edge_connection_t *edge_conn) return; } + /* Next, check for attempts to connect back into the Tor network. We don't + * want to allow these for the same reason we don't want to allow + * infinite-length circuits (see "A Practical Congestion Attack on Tor Using + * Long Paths", Usenix Security 2009). See also ticket 2667. + * + * The TORPROTOCOL reason is used instead of EXITPOLICY so client do NOT + * attempt to retry connecting onto another circuit that will also fail + * bringing considerable more load on the network if so. + * + * Since the address+port set here is a bloomfilter, in very rare cases, the + * check will create a false positive meaning that the destination could + * actually be legit and thus being denied exit. However, sending back a + * reason that makes the client retry results in much worst consequences in + * case of an attack so this is a small price to pay. */ + if (!connection_edge_is_rendezvous_stream(edge_conn) && + nodelist_reentry_probably_contains(&conn->addr, conn->port)) { + log_info(LD_EXIT, "%s:%d tried to connect back to a known relay address. " + "Closing.", escaped_safe_str_client(conn->address), + conn->port); + connection_edge_end(edge_conn, END_STREAM_REASON_TORPROTOCOL); + circuit_detach_stream(circuit_get_by_edge_conn(edge_conn), edge_conn); + connection_free(conn); + return; + } + #ifdef HAVE_SYS_UN_H if (conn->socket_family != AF_UNIX) { #else [View Less]

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[tor/release-0.4.5] Merge branch 'tor-gitlab/mr/285' into ticket2667_044_01
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit b2434d30d2c1071f01d9331752fc7d357169332f Merge: ea38016202 705fd37875 Author: David Goulet <dgoulet(a)torproject.org> Date: Fri Jan 29 14:54:21 2021 -0500 Merge branch 'tor-gitlab/mr/285' into ticket2667_044_01 changes/ticket2667 | 4 ++ src/core/or/address_set.c | 74 +++++++++++++++++++++++++++++++++++ src/core/or/address_set.h | 18 ++++++++- src/core/or/connection_edge.c | 25 ++++++++++++ src/feature/nodelist/dirlist.c | 11 ++++-- src/… [View More]

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[tor/release-0.4.5] Merge branch 'maint-0.4.3' into maint-0.4.4
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit 903bfc4eca6a02c56db66c708f3f102129a470df Merge: 36b51a1c71 e50648582b Author: David Goulet <dgoulet(a)torproject.org> Date: Wed Feb 3 08:54:40 2021 -0500 Merge branch 'maint-0.4.3' into maint-0.4.4 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(-)

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[tor/release-0.4.5] Merge branch 'tor-gitlab/mr/284' into ticket2667_043_01
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit 705fd37875c4acd61037da6a2680678ae128e4a4 Merge: 79cb47cfc2 9eba65bd8b Author: David Goulet <dgoulet(a)torproject.org> Date: Fri Jan 29 14:51:38 2021 -0500 Merge branch 'tor-gitlab/mr/284' into ticket2667_043_01 changes/ticket2667 | 4 ++ src/core/or/address_set.c | 74 +++++++++++++++++++++++++++++++++++ src/core/or/address_set.h | 18 ++++++++- src/core/or/connection_edge.c | 25 ++++++++++++ src/feature/nodelist/dirlist.c | 11 ++++-- src/… [View More]feature/nodelist/nodelist.c | 87 +++++++++++++++++++++++++++++------------ src/feature/nodelist/nodelist.h | 6 ++- src/test/test_address_set.c | 80 +++++++++++++++++++++++++++++++++++++ 8 files changed, 274 insertions(+), 31 deletions(-) diff --cc src/feature/nodelist/nodelist.c index 6c7fd6d0f9,9d553ce1f5..5df8e63073 --- a/src/feature/nodelist/nodelist.c +++ b/src/feature/nodelist/nodelist.c @@@ -633,14 -664,16 +665,17 @@@ nodelist_set_consensus(networkstatus_t SMARTLIST_FOREACH(the_nodelist->nodes, node_t *, node, node->rs = NULL); - /* Conservatively estimate that every node will have 2 addresses. */ + /* Conservatively estimate that every node will have 2 addresses (v4 and + * v6). Then we add the number of configured trusted authorities we have. */ int estimated_addresses = smartlist_len(ns->routerstatus_list) * get_estimated_address_per_node(); - estimated_addresses += (get_n_authorities(V3_DIRINFO & BRIDGE_DIRINFO) * + estimated_addresses += (get_n_authorities(V3_DIRINFO | BRIDGE_DIRINFO) * get_estimated_address_per_node()); 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. */ + the_nodelist->reentry_set = addr_port_set_new(estimated_addresses * 2); SMARTLIST_FOREACH_BEGIN(ns->routerstatus_list, routerstatus_t *, rs) { node_t *node = node_get_or_create(rs->identity_digest); diff --cc src/test/test_address_set.c index 829ecd79e8,6d9fab67ab..4c99008ae3 --- a/src/test/test_address_set.c +++ b/src/test/test_address_set.c @@@ -179,9 -174,87 +179,88 @@@ test_nodelist(void *arg UNMOCK(networkstatus_get_latest_consensus); UNMOCK(networkstatus_get_latest_consensus_by_flavor); UNMOCK(get_estimated_address_per_node); + UNMOCK(dirlist_add_trusted_dir_addresses); } + /** Test that the no-reentry exit filter works as intended */ + static void + test_exit_no_reentry(void *arg) + { + routerstatus_t *rs = NULL; microdesc_t *md = NULL; routerinfo_t *ri = NULL; + (void) arg; + + MOCK(networkstatus_get_latest_consensus, + mock_networkstatus_get_latest_consensus); + MOCK(networkstatus_get_latest_consensus_by_flavor, + mock_networkstatus_get_latest_consensus_by_flavor); + MOCK(get_estimated_address_per_node, + mock_get_estimated_address_per_node); + MOCK(dirlist_add_trusted_dir_addresses, + mock_dirlist_add_trusted_dir_addresses); + + dummy_ns = tor_malloc_zero(sizeof(*dummy_ns)); + dummy_ns->flavor = FLAV_MICRODESC; + dummy_ns->routerstatus_list = smartlist_new(); + + tor_addr_t addr_v4, addr_v6, dummy_addr; + tor_addr_parse(&addr_v4, "42.42.42.42"); + tor_addr_parse(&addr_v6, "1:2:3:4::"); + memset(&dummy_addr, 'A', sizeof(dummy_addr)); + + /* This will make the nodelist bloom filter very large + * (the_nodelist->node_addrs) so we will fail the contain test rarely. */ + addr_per_node = 1024; + + /* After this point the nodelist is populated with the directory authorities + * address and ports */ + 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)); + + /* Now let's populate the network */ + md = tor_malloc_zero(sizeof(*md)); + ri = tor_malloc_zero(sizeof(*ri)); + rs = tor_malloc_zero(sizeof(*rs)); + crypto_rand(rs->identity_digest, sizeof(rs->identity_digest)); + crypto_rand(md->digest, sizeof(md->digest)); + memcpy(rs->descriptor_digest, md->digest, DIGEST256_LEN); + + /* Setup the rs, ri and md addresses. */ + rs->addr = tor_addr_to_ipv4h(&addr_v4); + rs->or_port = 444; + tor_addr_parse(&rs->ipv6_addr, "1:2:3:4::"); + rs->ipv6_orport = 666; + ri->addr = tor_addr_to_ipv4h(&addr_v4); + tor_addr_parse(&ri->ipv6_addr, "1:2:3:4::"); + tor_addr_parse(&md->ipv6_addr, "1:2:3:4::"); + + /* Add the rs to the consensus becoming a node_t. */ + smartlist_add(dummy_ns->routerstatus_list, rs); + nodelist_set_consensus(dummy_ns); + + /* Now that the nodelist is populated let's do some retry attempts */ + + /* 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)); + + /* 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)); + + done: + routerstatus_free(rs); routerinfo_free(ri); microdesc_free(md); + smartlist_clear(dummy_ns->routerstatus_list); + networkstatus_vote_free(dummy_ns); + UNMOCK(networkstatus_get_latest_consensus); + UNMOCK(networkstatus_get_latest_consensus_by_flavor); + UNMOCK(get_estimated_address_per_node); + UNMOCK(dirlist_add_trusted_dir_addresses); + } + struct testcase_t address_set_tests[] = { { "contains", test_contains, TT_FORK, NULL, NULL }, [View Less]

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[tor/release-0.4.5] Merge branch 'maint-0.3.5' into maint-0.4.3
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit e50648582b6e0bc7bb37edc08e7a4d67b50f2c53 Merge: 0f8195406e c2cee6c780 Author: David Goulet <dgoulet(a)torproject.org> Date: Wed Feb 3 08:54:40 2021 -0500 Merge branch 'maint-0.3.5' into maint-0.4.3 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(-)

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[tor/release-0.4.5] node: Move reentry set to use a digestmap_t
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit c2cee6c780a1329a6906e91dc6f7854635727691 Author: David Goulet <dgoulet(a)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(a)torproject.org> --- src/core/or/connection_edge.c | 2 +- src/feature/nodelist/nodelist.c | 63 ++++++++++++++++++++++++++++++++--------- src/… [View More]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 b40fa3e567..4727a0ad66 100644 --- a/src/core/or/connection_edge.c +++ b/src/core/or/connection_edge.c @@ -4062,7 +4062,7 @@ 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:%d tried to connect back to a known relay address. " "Closing.", escaped_safe_str_client(conn->address), conn->port); diff --git a/src/feature/nodelist/nodelist.c b/src/feature/nodelist/nodelist.c index 22b93762e7..9d56f2c3aa 100644 --- a/src/feature/nodelist/nodelist.c +++ b/src/feature/nodelist/nodelist.c @@ -136,7 +136,7 @@ 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 @@ -488,6 +488,42 @@ 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, @@ -501,10 +537,12 @@ 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); } } @@ -525,7 +563,7 @@ 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; @@ -533,8 +571,8 @@ 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 @@ -669,15 +707,12 @@ nodelist_set_consensus(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); @@ -904,7 +939,7 @@ 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 4c4ee6fe83..bc09731ce2 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(networkstatus_t *ns); void nodelist_ensure_freshness(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 6d9fab67ab..4e55d71ff4 100644 --- a/src/test/test_address_set.c +++ b/src/test/test_address_set.c @@ -210,8 +210,8 @@ 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)); @@ -238,12 +238,12 @@ 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); [View Less]

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[tor/release-0.4.5] Merge branch 'maint-0.3.5' into maint-0.4.3
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit 0f8195406e0a2a97a3167d4bb40484f4bd091289 Merge: 705fd37875 98590621bb Author: David Goulet <dgoulet(a)torproject.org> Date: Wed Feb 3 08:51:36 2021 -0500 Merge branch 'maint-0.3.5' into maint-0.4.3 src/core/or/connection_edge.c | 12 ++++++++++++ src/feature/nodelist/nodelist.c | 8 ++++++-- 2 files changed, 18 insertions(+), 2 deletions(-)

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[tor/release-0.4.5] Merge branch 'maint-0.4.3' into maint-0.4.4
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit eda81ea27ee72682d5533ee072cdf1061becfdc9 Merge: 903bfc4eca cc5d5a5d1e Author: David Goulet <dgoulet(a)torproject.org> Date: Wed Feb 3 08:56:38 2021 -0500 Merge branch 'maint-0.4.3' into maint-0.4.4 src/core/or/connection_edge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

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[tor/release-0.4.5] Merge branch 'maint-0.3.5' into maint-0.4.3
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit cc5d5a5d1ebf8d42d77713eab11d200770d869e8 Merge: e50648582b a3cef41fc3 Author: David Goulet <dgoulet(a)torproject.org> Date: Wed Feb 3 08:56:38 2021 -0500 Merge branch 'maint-0.3.5' into maint-0.4.3 src/core/or/connection_edge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

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[tor/release-0.4.5] Merge branch 'maint-0.4.4' into maint-0.4.5
by dgoulet＠torproject.org 03 Feb '21

03 Feb '21

commit a0b3e9116d1eb0cfa6a73b17d275c54516291b9b Merge: 40eeb63b5e eda81ea27e Author: David Goulet <dgoulet(a)torproject.org> Date: Wed Feb 3 08:58:02 2021 -0500 Merge branch 'maint-0.4.4' into maint-0.4.5 src/core/or/address_set.c | 74 ++++++++++++++++++++++++++++++++++++++++++ src/core/or/address_set.h | 15 +++++++++ src/feature/nodelist/dirlist.c | 2 ++ 3 files changed, 91 insertions(+)

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