commit 4e977cce40ed95f4f25f8511eb8791072d691c93 Author: Nick Mathewson nickm@torproject.org Date: Tue Feb 23 14:09:03 2021 -0500

Add support for knowing multiple HTTP DirPorts for an authority.

(These aren't yet set or used.) --- src/feature/dirclient/dir_server_st.h | 6 ++ src/feature/nodelist/dirlist.c | 110 +++++++++++++++++++++++++++++++++- src/feature/nodelist/dirlist.h | 29 +++++++++ 3 files changed, 144 insertions(+), 1 deletion(-)

diff --git a/src/feature/dirclient/dir_server_st.h b/src/feature/dirclient/dir_server_st.h index 57530a571b..d1ecbcf515 100644 --- a/src/feature/dirclient/dir_server_st.h +++ b/src/feature/dirclient/dir_server_st.h @@ -16,6 +16,8 @@ #include "core/or/or.h" #include "feature/nodelist/routerstatus_st.h"

+struct smartlist_t; + /** Represents information about a single trusted or fallback directory * server. */ struct dir_server_t { @@ -48,6 +50,10 @@ struct dir_server_t { time_t addr_current_at; /**< When was the document that we derived the * address information from published? */

+ /** Authority only. Can be null. If present, a list of auth_dirport_t + * representing HTTP dirports for this authority. */ + struct smartlist_t *auth_dirports; + routerstatus_t fake_status; /**< Used when we need to pass this trusted * dir_server_t to * directory_request_set_routerstatus. diff --git a/src/feature/nodelist/dirlist.c b/src/feature/nodelist/dirlist.c index 423c4106e2..c9d0a991e5 100644 --- a/src/feature/nodelist/dirlist.c +++ b/src/feature/nodelist/dirlist.c @@ -43,6 +43,14 @@ #include "feature/dirclient/dir_server_st.h" #include "feature/nodelist/node_st.h"

+/** Information about an (HTTP) dirport for a directory authority. */ +struct auth_dirport_t { + /** What is the intended usage for this dirport? One of AUTH_USAGE_* */ + auth_dirport_usage_t usage; + /** What is the correct address/port ? */ + tor_addr_port_t dirport; +}; + /** Global list of a dir_server_t object for each directory * authority. */ static smartlist_t *trusted_dir_servers = NULL; @@ -66,6 +74,11 @@ add_trusted_dir_to_nodelist_addr_set(const dir_server_t *dir) /* IPv6 DirPort is not a thing yet for authorities. */ nodelist_add_addr_to_address_set(&dir->ipv6_addr, dir->ipv6_orport, 0); } + if (dir->auth_dirports) { + SMARTLIST_FOREACH_BEGIN(dir->auth_dirports, const auth_dirport_t *, p) { + nodelist_add_addr_to_address_set(&p->dirport.addr, 0, p->dirport.port); + } SMARTLIST_FOREACH_END(p); + } }

/** Go over the trusted directory server list and add their address(es) to the @@ -256,7 +269,10 @@ MOCK_IMPL(int, router_digest_is_trusted_dir_type, /** Return true iff the given address matches a trusted directory that matches * at least one bit of type. * - * If type is NO_DIRINFO or ALL_DIRINFO, any authority is matched. */ + * If type is NO_DIRINFO or ALL_DIRINFO, any authority is matched. + * + * Only ORPorts' addresses are considered. + */ bool router_addr_is_trusted_dir_type(const tor_addr_t *addr, dirinfo_type_t type) { @@ -404,10 +420,98 @@ trusted_dir_server_new(const char *nickname, const char *address, ipv6_addrport, digest, v3_auth_digest, type, weight); + + if (ipv4_dirport) { + tor_addr_port_t p; + memset(&p, 0, sizeof(p)); + tor_addr_copy(&p.addr, &ipv4_addr); + p.port = ipv4_dirport; + trusted_dir_server_add_dirport(result, AUTH_USAGE_LEGACY, &p); + } tor_free(hostname); return result; }

+/** + * Add @a dirport as an HTTP DirPort contact point for the directory authority + * @a ds, for use when contacting that authority for the given @a usage. + * + * Multiple ports of the same usage are allowed; if present, then only + * the first one of each address family is currently used. + */ +void +trusted_dir_server_add_dirport(dir_server_t *ds, + auth_dirport_usage_t usage, + const tor_addr_port_t *dirport) +{ + tor_assert(ds); + tor_assert(dirport); + + if (BUG(! ds->is_authority)) { + return; + } + + if (ds->auth_dirports == NULL) { + ds->auth_dirports = smartlist_new(); + } + + auth_dirport_t *port = tor_malloc_zero(sizeof(auth_dirport_t)); + port->usage = usage; + tor_addr_port_copy(&port->dirport, dirport); + smartlist_add(ds->auth_dirports, port); +} + +/** + * Helper for trusted_dir_server_get_dirport: only return the exact requested + * usage type. + */ +static const tor_addr_port_t * +trusted_dir_server_get_dirport_exact(const dir_server_t *ds, + auth_dirport_usage_t usage, + int addr_family) +{ + tor_assert(ds); + tor_assert_nonfatal(addr_family == AF_INET || addr_family == AF_INET6); + if (ds->auth_dirports == NULL) + return NULL; + + SMARTLIST_FOREACH_BEGIN(ds->auth_dirports, const auth_dirport_t *, port) { + if (port->usage == usage && + tor_addr_family(&port->dirport.addr) == addr_family) { + return &port->dirport; + } + } SMARTLIST_FOREACH_END(port); + + return NULL; +} + +/** + * Return the DirPort of the authority @a ds for with the usage type + * @a usage and address family @a addr_family. If none is found, try + * again with an AUTH_USAGE_LEGACY dirport, if there is one. Return NULL + * if no port can be found. + */ +const tor_addr_port_t * +trusted_dir_server_get_dirport(const dir_server_t *ds, + auth_dirport_usage_t usage, + int addr_family) +{ + const tor_addr_port_t *port; + + while (1) { + port = trusted_dir_server_get_dirport_exact(ds, usage, addr_family); + if (port) + return port; + + // If we tried LEGACY, there is no fallback from this point. + if (usage == AUTH_USAGE_LEGACY) + return NULL; + + // Try again with LEGACY. + usage = AUTH_USAGE_LEGACY; + } +} + /** Return a new dir_server_t for a fallback directory server at * <b>addr</b>:<b>or_port</b>/<b>dir_port</b>, with identity key digest * <b>id_digest</b> */ @@ -447,6 +551,10 @@ dir_server_free_(dir_server_t *ds) if (!ds) return;

+ if (ds->auth_dirports) { + SMARTLIST_FOREACH(ds->auth_dirports, auth_dirport_t *, p, tor_free(p)); + smartlist_free(ds->auth_dirports); + } tor_free(ds->nickname); tor_free(ds->description); tor_free(ds->address); diff --git a/src/feature/nodelist/dirlist.h b/src/feature/nodelist/dirlist.h index ae3debf4e5..70bbb780d1 100644 --- a/src/feature/nodelist/dirlist.h +++ b/src/feature/nodelist/dirlist.h @@ -11,6 +11,28 @@ #ifndef TOR_DIRLIST_H #define TOR_DIRLIST_H

+typedef struct auth_dirport_t auth_dirport_t; +/** + * Different usages for an authority's HTTP directory port. + * + * Historically, only legacy ports existed; proposal 330 added multiple types + * of dirport to better enable authorities to offload work and resist DoS + * attacks. + **/ +typedef enum auth_dirport_usage_t { + /** Flag for an authority's dirport that is intended for misc/legacy + * usage. May be used when no other dirport is available. */ + AUTH_USAGE_LEGACY, + /** Flag for an authority's dirport that is intended for descriptor uploads + * only. */ + AUTH_USAGE_UPLOAD, + /** Flag for an authority's dirport that is intended for voting only */ + AUTH_USAGE_VOTING, + /** Flag for an authority's dirport that is intended for relay downloads + * only. */ + AUTH_USAGE_DOWNLOAD, +} auth_dirport_usage_t; + int get_n_authorities(dirinfo_type_t type); const smartlist_t *router_get_trusted_dir_servers(void); const smartlist_t *router_get_fallback_dir_servers(void); @@ -28,6 +50,10 @@ MOCK_DECL(dir_server_t *, trusteddirserver_get_by_v3_auth_digest, MOCK_DECL(int, router_digest_is_trusted_dir_type, (const char *digest, dirinfo_type_t type));

+const tor_addr_port_t *trusted_dir_server_get_dirport(const dir_server_t *ds, + auth_dirport_usage_t usage, + int addr_family); + bool router_addr_is_trusted_dir_type(const tor_addr_t *addr, dirinfo_type_t type); #define router_addr_is_trusted_dir(d) \ @@ -41,6 +67,9 @@ dir_server_t *trusted_dir_server_new(const char *nickname, const char *address, const tor_addr_port_t *addrport_ipv6, const char *digest, const char *v3_auth_digest, dirinfo_type_t type, double weight); +void trusted_dir_server_add_dirport(dir_server_t *ds, + auth_dirport_usage_t usage, + const tor_addr_port_t *dirport); dir_server_t *fallback_dir_server_new(const tor_addr_t *addr, uint16_t dir_port, uint16_t or_port, const tor_addr_port_t *addrport_ipv6,