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Diffstat (limited to 'src/feature/client/addressmap.c')
| -rw-r--r-- | src/feature/client/addressmap.c | 1156 |
1 files changed, 1156 insertions, 0 deletions
diff --git a/src/feature/client/addressmap.c b/src/feature/client/addressmap.c new file mode 100644 index 0000000000..bbe786a6a2 --- /dev/null +++ b/src/feature/client/addressmap.c @@ -0,0 +1,1156 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file addressmap.c + * + * \brief The addressmap module manages the processes by which we rewrite + * addresses in client requess. It handles the MapAddress controller and + * torrc commands, and the TrackHostExits feature, and the client-side DNS + * cache (deprecated). + */ + +#define ADDRESSMAP_PRIVATE + +#include "lib/crypt_ops/crypto_rand.h" + +#include "core/or/or.h" +#include "feature/client/addressmap.h" +#include "core/or/circuituse.h" +#include "app/config/config.h" +#include "core/or/connection_edge.h" +#include "feature/control/control.h" +#include "feature/relay/dns.h" +#include "feature/nodelist/nodelist.h" +#include "feature/nodelist/routerset.h" + +#include "core/or/entry_connection_st.h" + +/** A client-side struct to remember requests to rewrite addresses + * to new addresses. These structs are stored in the hash table + * "addressmap" below. + * + * There are 5 ways to set an address mapping: + * - A MapAddress command from the controller [permanent] + * - An AddressMap directive in the torrc [permanent] + * - When a TrackHostExits torrc directive is triggered [temporary] + * - When a DNS resolve succeeds [temporary] + * - When a DNS resolve fails [temporary] + * + * When an addressmap request is made but one is already registered, + * the new one is replaced only if the currently registered one has + * no "new_address" (that is, it's in the process of DNS resolve), + * or if the new one is permanent (expires==0 or 1). + * + * (We overload the 'expires' field, using "0" for mappings set via + * the configuration file, "1" for mappings set from the control + * interface, and other values for DNS and TrackHostExit mappings that can + * expire.) + * + * A mapping may be 'wildcarded'. If "src_wildcard" is true, then + * any address that ends with a . followed by the key for this entry will + * get remapped by it. If "dst_wildcard" is also true, then only the + * matching suffix of such addresses will get replaced by new_address. + */ +typedef struct { + char *new_address; + time_t expires; + addressmap_entry_source_bitfield_t source:3; + unsigned src_wildcard:1; + unsigned dst_wildcard:1; + short num_resolve_failures; +} addressmap_entry_t; + +/** Entry for mapping addresses to which virtual address we mapped them to. */ +typedef struct { + char *ipv4_address; + char *ipv6_address; + char *hostname_address; +} virtaddress_entry_t; + +/** A hash table to store client-side address rewrite instructions. */ +static strmap_t *addressmap=NULL; + +/** + * Table mapping addresses to which virtual address, if any, we + * assigned them to. + * + * We maintain the following invariant: if [A,B] is in + * virtaddress_reversemap, then B must be a virtual address, and [A,B] + * must be in addressmap. We do not require that the converse hold: + * if it fails, then we could end up mapping two virtual addresses to + * the same address, which is no disaster. + **/ +static strmap_t *virtaddress_reversemap=NULL; + +/** Initialize addressmap. */ +void +addressmap_init(void) +{ + addressmap = strmap_new(); + virtaddress_reversemap = strmap_new(); +} + +#define addressmap_ent_free(ent) \ + FREE_AND_NULL(addressmap_entry_t, addressmap_ent_free_, (ent)) + +/** Free the memory associated with the addressmap entry <b>_ent</b>. */ +static void +addressmap_ent_free_(addressmap_entry_t *ent) +{ + if (!ent) + return; + + tor_free(ent->new_address); + tor_free(ent); +} + +static void +addressmap_ent_free_void(void *ent) +{ + addressmap_ent_free_(ent); +} + +#define addressmap_virtaddress_ent_free(ent) \ + FREE_AND_NULL(virtaddress_entry_t, addressmap_virtaddress_ent_free_, (ent)) + +/** Free storage held by a virtaddress_entry_t* entry in <b>_ent</b>. */ +static void +addressmap_virtaddress_ent_free_(virtaddress_entry_t *ent) +{ + if (!ent) + return; + tor_free(ent->ipv4_address); + tor_free(ent->ipv6_address); + tor_free(ent->hostname_address); + tor_free(ent); +} + +static void +addressmap_virtaddress_ent_free_void(void *ent) +{ + addressmap_virtaddress_ent_free_(ent); +} + +/** Remove <b>address</b> (which must map to <b>ent</b>) from the + * virtual address map. */ +static void +addressmap_virtaddress_remove(const char *address, addressmap_entry_t *ent) +{ + if (ent && ent->new_address && + address_is_in_virtual_range(ent->new_address)) { + virtaddress_entry_t *ve = + strmap_get(virtaddress_reversemap, ent->new_address); + /*log_fn(LOG_NOTICE,"remove reverse mapping for %s",ent->new_address);*/ + if (ve) { + if (!strcmp(address, ve->ipv4_address)) + tor_free(ve->ipv4_address); + if (!strcmp(address, ve->ipv6_address)) + tor_free(ve->ipv6_address); + if (!strcmp(address, ve->hostname_address)) + tor_free(ve->hostname_address); + if (!ve->ipv4_address && !ve->ipv6_address && !ve->hostname_address) { + tor_free(ve); + strmap_remove(virtaddress_reversemap, ent->new_address); + } + } + } +} + +/** Remove <b>ent</b> (which must be mapped to by <b>address</b>) from the + * client address maps, and then free it. */ +static void +addressmap_ent_remove(const char *address, addressmap_entry_t *ent) +{ + addressmap_virtaddress_remove(address, ent); + addressmap_ent_free(ent); +} + +/** Unregister all TrackHostExits mappings from any address to + * *.exitname.exit. */ +void +clear_trackexithost_mappings(const char *exitname) +{ + char *suffix = NULL; + if (!addressmap || !exitname) + return; + tor_asprintf(&suffix, ".%s.exit", exitname); + tor_strlower(suffix); + + STRMAP_FOREACH_MODIFY(addressmap, address, addressmap_entry_t *, ent) { + if (ent->source == ADDRMAPSRC_TRACKEXIT && + !strcmpend(ent->new_address, suffix)) { + addressmap_ent_remove(address, ent); + MAP_DEL_CURRENT(address); + } + } STRMAP_FOREACH_END; + + tor_free(suffix); +} + +/** Remove all TRACKEXIT mappings from the addressmap for which the target + * host is unknown or no longer allowed, or for which the source address + * is no longer in trackexithosts. */ +void +addressmap_clear_excluded_trackexithosts(const or_options_t *options) +{ + const routerset_t *allow_nodes = options->ExitNodes; + const routerset_t *exclude_nodes = options->ExcludeExitNodesUnion_; + + if (!addressmap) + return; + if (routerset_is_empty(allow_nodes)) + allow_nodes = NULL; + if (allow_nodes == NULL && routerset_is_empty(exclude_nodes)) + return; + + STRMAP_FOREACH_MODIFY(addressmap, address, addressmap_entry_t *, ent) { + size_t len; + const char *target = ent->new_address, *dot; + char *nodename; + const node_t *node; + + if (!target) { + /* DNS resolving in progress */ + continue; + } else if (strcmpend(target, ".exit")) { + /* Not a .exit mapping */ + continue; + } else if (ent->source != ADDRMAPSRC_TRACKEXIT) { + /* Not a trackexit mapping. */ + continue; + } + len = strlen(target); + if (len < 6) + continue; /* malformed. */ + dot = target + len - 6; /* dot now points to just before .exit */ + while (dot > target && *dot != '.') + dot--; + if (*dot == '.') dot++; + nodename = tor_strndup(dot, len-5-(dot-target)); + node = node_get_by_nickname(nodename, NNF_NO_WARN_UNNAMED); + tor_free(nodename); + if (!node || + (allow_nodes && !routerset_contains_node(allow_nodes, node)) || + routerset_contains_node(exclude_nodes, node) || + !hostname_in_track_host_exits(options, address)) { + /* We don't know this one, or we want to be rid of it. */ + addressmap_ent_remove(address, ent); + MAP_DEL_CURRENT(address); + } + } STRMAP_FOREACH_END; +} + +/** Return true iff <b>address</b> is one that we are configured to + * automap on resolve according to <b>options</b>. */ +int +addressmap_address_should_automap(const char *address, + const or_options_t *options) +{ + const smartlist_t *suffix_list = options->AutomapHostsSuffixes; + + if (!suffix_list) + return 0; + + SMARTLIST_FOREACH_BEGIN(suffix_list, const char *, suffix) { + if (!strcmp(suffix, ".")) + return 1; + if (!strcasecmpend(address, suffix)) + return 1; + } SMARTLIST_FOREACH_END(suffix); + return 0; +} + +/** Remove all AUTOMAP mappings from the addressmap for which the + * source address no longer matches AutomapHostsSuffixes, which is + * no longer allowed by AutomapHostsOnResolve, or for which the + * target address is no longer in the virtual network. */ +void +addressmap_clear_invalid_automaps(const or_options_t *options) +{ + int clear_all = !options->AutomapHostsOnResolve; + const smartlist_t *suffixes = options->AutomapHostsSuffixes; + + if (!addressmap) + return; + + if (!suffixes) + clear_all = 1; /* This should be impossible, but let's be sure. */ + + STRMAP_FOREACH_MODIFY(addressmap, src_address, addressmap_entry_t *, ent) { + int remove_this = clear_all; + if (ent->source != ADDRMAPSRC_AUTOMAP) + continue; /* not an automap mapping. */ + + if (!remove_this) { + remove_this = ! addressmap_address_should_automap(src_address, options); + } + + if (!remove_this && ! address_is_in_virtual_range(ent->new_address)) + remove_this = 1; + + if (remove_this) { + addressmap_ent_remove(src_address, ent); + MAP_DEL_CURRENT(src_address); + } + } STRMAP_FOREACH_END; +} + +/** Remove all entries from the addressmap that were set via the + * configuration file or the command line. */ +void +addressmap_clear_configured(void) +{ + addressmap_get_mappings(NULL, 0, 0, 0); +} + +/** Remove all entries from the addressmap that are set to expire, ever. */ +void +addressmap_clear_transient(void) +{ + addressmap_get_mappings(NULL, 2, TIME_MAX, 0); +} + +/** Clean out entries from the addressmap cache that were + * added long enough ago that they are no longer valid. + */ +void +addressmap_clean(time_t now) +{ + addressmap_get_mappings(NULL, 2, now, 0); +} + +/** Free all the elements in the addressmap, and free the addressmap + * itself. */ +void +addressmap_free_all(void) +{ + strmap_free(addressmap, addressmap_ent_free_void); + addressmap = NULL; + + strmap_free(virtaddress_reversemap, addressmap_virtaddress_ent_free_void); + virtaddress_reversemap = NULL; +} + +/** Try to find a match for AddressMap expressions that use + * wildcard notation such as '*.c.d *.e.f' (so 'a.c.d' will map to 'a.e.f') or + * '*.c.d a.b.c' (so 'a.c.d' will map to a.b.c). + * Return the matching entry in AddressMap or NULL if no match is found. + * For expressions such as '*.c.d *.e.f', truncate <b>address</b> 'a.c.d' + * to 'a' before we return the matching AddressMap entry. + * + * This function does not handle the case where a pattern of the form "*.c.d" + * matches the address c.d -- that's done by the main addressmap_rewrite + * function. + */ +static addressmap_entry_t * +addressmap_match_superdomains(char *address) +{ + addressmap_entry_t *val; + char *cp; + + cp = address; + while ((cp = strchr(cp, '.'))) { + /* cp now points to a suffix of address that begins with a . */ + val = strmap_get_lc(addressmap, cp+1); + if (val && val->src_wildcard) { + if (val->dst_wildcard) + *cp = '\0'; + return val; + } + ++cp; + } + return NULL; +} + +/** Look at address, and rewrite it until it doesn't want any + * more rewrites; but don't get into an infinite loop. + * Don't write more than maxlen chars into address. Return true if the + * address changed; false otherwise. Set *<b>expires_out</b> to the + * expiry time of the result, or to <b>time_max</b> if the result does + * not expire. + * + * If <b>exit_source_out</b> is non-null, we set it as follows. If we the + * address starts out as a non-exit address, and we remap it to an .exit + * address at any point, then set *<b>exit_source_out</b> to the + * address_entry_source_t of the first such rule. Set *<b>exit_source_out</b> + * to ADDRMAPSRC_NONE if there is no such rewrite, or if the original address + * was a .exit. + */ +int +addressmap_rewrite(char *address, size_t maxlen, + unsigned flags, + time_t *expires_out, + addressmap_entry_source_t *exit_source_out) +{ + addressmap_entry_t *ent; + int rewrites; + time_t expires = TIME_MAX; + addressmap_entry_source_t exit_source = ADDRMAPSRC_NONE; + char *addr_orig = tor_strdup(address); + char *log_addr_orig = NULL; + + /* We use a loop here to limit the total number of rewrites we do, + * so that we can't hit an infinite loop. */ + for (rewrites = 0; rewrites < 16; rewrites++) { + int exact_match = 0; + log_addr_orig = tor_strdup(escaped_safe_str_client(address)); + + /* First check to see if there's an exact match for this address */ + ent = strmap_get(addressmap, address); + + if (!ent || !ent->new_address) { + /* And if we don't have an exact match, try to check whether + * we have a pattern-based match. + */ + ent = addressmap_match_superdomains(address); + } else { + if (ent->src_wildcard && !ent->dst_wildcard && + !strcasecmp(address, ent->new_address)) { + /* This is a rule like "rewrite *.example.com to example.com", and we + * just got "example.com". Instead of calling it an infinite loop, + * call it complete. */ + goto done; + } + exact_match = 1; + } + + if (!ent || !ent->new_address) { + /* We still have no match at all. We're done! */ + goto done; + } + + /* Check wither the flags we were passed tell us not to use this + * mapping. */ + switch (ent->source) { + case ADDRMAPSRC_DNS: + { + sa_family_t f; + tor_addr_t tmp; + f = tor_addr_parse(&tmp, ent->new_address); + if (f == AF_INET && !(flags & AMR_FLAG_USE_IPV4_DNS)) + goto done; + else if (f == AF_INET6 && !(flags & AMR_FLAG_USE_IPV6_DNS)) + goto done; + } + break; + case ADDRMAPSRC_CONTROLLER: + case ADDRMAPSRC_TORRC: + if (!(flags & AMR_FLAG_USE_MAPADDRESS)) + goto done; + break; + case ADDRMAPSRC_AUTOMAP: + if (!(flags & AMR_FLAG_USE_AUTOMAP)) + goto done; + break; + case ADDRMAPSRC_TRACKEXIT: + if (!(flags & AMR_FLAG_USE_TRACKEXIT)) + goto done; + break; + case ADDRMAPSRC_NONE: + default: + log_warn(LD_BUG, "Unknown addrmap source value %d. Ignoring it.", + (int) ent->source); + goto done; + } + + /* Now fill in the address with the new address. That might be via + * appending some new stuff to the end, or via just replacing it. */ + if (ent->dst_wildcard && !exact_match) { + strlcat(address, ".", maxlen); + strlcat(address, ent->new_address, maxlen); + } else { + strlcpy(address, ent->new_address, maxlen); + } + + /* Is this now a .exit address? If so, remember where we got it.*/ + if (!strcmpend(address, ".exit") && + strcmpend(addr_orig, ".exit") && + exit_source == ADDRMAPSRC_NONE) { + exit_source = ent->source; + } + + log_info(LD_APP, "Addressmap: rewriting %s to %s", + log_addr_orig, escaped_safe_str_client(address)); + if (ent->expires > 1 && ent->expires < expires) + expires = ent->expires; + + tor_free(log_addr_orig); + } + log_warn(LD_CONFIG, + "Loop detected: we've rewritten %s 16 times! Using it as-is.", + escaped_safe_str_client(address)); + /* it's fine to rewrite a rewrite, but don't loop forever */ + + done: + tor_free(addr_orig); + tor_free(log_addr_orig); + if (exit_source_out) + *exit_source_out = exit_source; + if (expires_out) + *expires_out = expires; + return (rewrites > 0); +} + +/** If we have a cached reverse DNS entry for the address stored in the + * <b>maxlen</b>-byte buffer <b>address</b> (typically, a dotted quad) then + * rewrite to the cached value and return 1. Otherwise return 0. Set + * *<b>expires_out</b> to the expiry time of the result, or to <b>time_max</b> + * if the result does not expire. */ +int +addressmap_rewrite_reverse(char *address, size_t maxlen, unsigned flags, + time_t *expires_out) +{ + char *s, *cp; + addressmap_entry_t *ent; + int r = 0; + { + sa_family_t f; + tor_addr_t tmp; + f = tor_addr_parse(&tmp, address); + if (f == AF_INET && !(flags & AMR_FLAG_USE_IPV4_DNS)) + return 0; + else if (f == AF_INET6 && !(flags & AMR_FLAG_USE_IPV6_DNS)) + return 0; + /* FFFF we should reverse-map virtual addresses even if we haven't + * enabled DNS cacheing. */ + } + + tor_asprintf(&s, "REVERSE[%s]", address); + ent = strmap_get(addressmap, s); + if (ent) { + cp = tor_strdup(escaped_safe_str_client(ent->new_address)); + log_info(LD_APP, "Rewrote reverse lookup %s -> %s", + escaped_safe_str_client(s), cp); + tor_free(cp); + strlcpy(address, ent->new_address, maxlen); + r = 1; + } + + if (expires_out) + *expires_out = (ent && ent->expires > 1) ? ent->expires : TIME_MAX; + + tor_free(s); + return r; +} + +/** Return 1 if <b>address</b> is already registered, else return 0. If address + * is already registered, and <b>update_expires</b> is non-zero, then update + * the expiry time on the mapping with update_expires if it is a + * mapping created by TrackHostExits. */ +int +addressmap_have_mapping(const char *address, int update_expiry) +{ + addressmap_entry_t *ent; + if (!(ent=strmap_get_lc(addressmap, address))) + return 0; + if (update_expiry && ent->source==ADDRMAPSRC_TRACKEXIT) + ent->expires=time(NULL) + update_expiry; + return 1; +} + +/** Register a request to map <b>address</b> to <b>new_address</b>, + * which will expire on <b>expires</b> (or 0 if never expires from + * config file, 1 if never expires from controller, 2 if never expires + * (virtual address mapping) from the controller.) + * + * <b>new_address</b> should be a newly dup'ed string, which we'll use or + * free as appropriate. We will leave <b>address</b> alone. + * + * If <b>wildcard_addr</b> is true, then the mapping will match any address + * equal to <b>address</b>, or any address ending with a period followed by + * <b>address</b>. If <b>wildcard_addr</b> and <b>wildcard_new_addr</b> are + * both true, the mapping will rewrite addresses that end with + * ".<b>address</b>" into ones that end with ".<b>new_address</b>". + * + * If <b>new_address</b> is NULL, or <b>new_address</b> is equal to + * <b>address</b> and <b>wildcard_addr</b> is equal to + * <b>wildcard_new_addr</b>, remove any mappings that exist from + * <b>address</b>. + * + * It is an error to set <b>wildcard_new_addr</b> if <b>wildcard_addr</b> is + * not set. */ +void +addressmap_register(const char *address, char *new_address, time_t expires, + addressmap_entry_source_t source, + const int wildcard_addr, + const int wildcard_new_addr) +{ + addressmap_entry_t *ent; + + if (wildcard_new_addr) + tor_assert(wildcard_addr); + + ent = strmap_get(addressmap, address); + if (!new_address || (!strcasecmp(address,new_address) && + wildcard_addr == wildcard_new_addr)) { + /* Remove the mapping, if any. */ + tor_free(new_address); + if (ent) { + addressmap_ent_remove(address,ent); + strmap_remove(addressmap, address); + } + return; + } + if (!ent) { /* make a new one and register it */ + ent = tor_malloc_zero(sizeof(addressmap_entry_t)); + strmap_set(addressmap, address, ent); + } else if (ent->new_address) { /* we need to clean up the old mapping. */ + if (expires > 1) { + log_info(LD_APP,"Temporary addressmap ('%s' to '%s') not performed, " + "since it's already mapped to '%s'", + safe_str_client(address), + safe_str_client(new_address), + safe_str_client(ent->new_address)); + tor_free(new_address); + return; + } + if (address_is_in_virtual_range(ent->new_address) && + expires != 2) { + /* XXX This isn't the perfect test; we want to avoid removing + * mappings set from the control interface _as virtual mapping */ + addressmap_virtaddress_remove(address, ent); + } + tor_free(ent->new_address); + } /* else { we have an in-progress resolve with no mapping. } */ + + ent->new_address = new_address; + ent->expires = expires==2 ? 1 : expires; + ent->num_resolve_failures = 0; + ent->source = source; + ent->src_wildcard = wildcard_addr ? 1 : 0; + ent->dst_wildcard = wildcard_new_addr ? 1 : 0; + + log_info(LD_CONFIG, "Addressmap: (re)mapped '%s' to '%s'", + safe_str_client(address), + safe_str_client(ent->new_address)); + control_event_address_mapped(address, ent->new_address, expires, NULL, 1); +} + +/** An attempt to resolve <b>address</b> failed at some OR. + * Increment the number of resolve failures we have on record + * for it, and then return that number. + */ +int +client_dns_incr_failures(const char *address) +{ + addressmap_entry_t *ent = strmap_get(addressmap, address); + if (!ent) { + ent = tor_malloc_zero(sizeof(addressmap_entry_t)); + ent->expires = time(NULL) + MAX_DNS_ENTRY_AGE; + strmap_set(addressmap,address,ent); + } + if (ent->num_resolve_failures < SHRT_MAX) + ++ent->num_resolve_failures; /* don't overflow */ + log_info(LD_APP, "Address %s now has %d resolve failures.", + safe_str_client(address), + ent->num_resolve_failures); + return ent->num_resolve_failures; +} + +/** If <b>address</b> is in the client DNS addressmap, reset + * the number of resolve failures we have on record for it. + * This is used when we fail a stream because it won't resolve: + * otherwise future attempts on that address will only try once. + */ +void +client_dns_clear_failures(const char *address) +{ + addressmap_entry_t *ent = strmap_get(addressmap, address); + if (ent) + ent->num_resolve_failures = 0; +} + +/** Record the fact that <b>address</b> resolved to <b>name</b>. + * We can now use this in subsequent streams via addressmap_rewrite() + * so we can more correctly choose an exit that will allow <b>address</b>. + * + * If <b>exitname</b> is defined, then append the addresses with + * ".exitname.exit" before registering the mapping. + * + * If <b>ttl</b> is nonnegative, the mapping will be valid for + * <b>ttl</b>seconds; otherwise, we use the default. + */ +static void +client_dns_set_addressmap_impl(entry_connection_t *for_conn, + const char *address, const char *name, + const char *exitname, + int ttl) +{ + char *extendedaddress=NULL, *extendedval=NULL; + (void)for_conn; + + tor_assert(address); + tor_assert(name); + + if (ttl<0) + ttl = DEFAULT_DNS_TTL; + else + ttl = dns_clip_ttl(ttl); + + if (exitname) { + /* XXXX fails to ever get attempts to get an exit address of + * google.com.digest[=~]nickname.exit; we need a syntax for this that + * won't make strict RFC952-compliant applications (like us) barf. */ + tor_asprintf(&extendedaddress, + "%s.%s.exit", address, exitname); + tor_asprintf(&extendedval, + "%s.%s.exit", name, exitname); + } else { + tor_asprintf(&extendedaddress, + "%s", address); + tor_asprintf(&extendedval, + "%s", name); + } + addressmap_register(extendedaddress, extendedval, + time(NULL) + ttl, ADDRMAPSRC_DNS, 0, 0); + tor_free(extendedaddress); +} + +/** Record the fact that <b>address</b> resolved to <b>val</b>. + * We can now use this in subsequent streams via addressmap_rewrite() + * so we can more correctly choose an exit that will allow <b>address</b>. + * + * If <b>exitname</b> is defined, then append the addresses with + * ".exitname.exit" before registering the mapping. + * + * If <b>ttl</b> is nonnegative, the mapping will be valid for + * <b>ttl</b>seconds; otherwise, we use the default. + */ +void +client_dns_set_addressmap(entry_connection_t *for_conn, + const char *address, + const tor_addr_t *val, + const char *exitname, + int ttl) +{ + tor_addr_t addr_tmp; + char valbuf[TOR_ADDR_BUF_LEN]; + + tor_assert(address); + tor_assert(val); + + if (tor_addr_parse(&addr_tmp, address) >= 0) + return; /* If address was an IP address already, don't add a mapping. */ + + if (tor_addr_family(val) == AF_INET) { + if (! for_conn->entry_cfg.cache_ipv4_answers) + return; + } else if (tor_addr_family(val) == AF_INET6) { + if (! for_conn->entry_cfg.cache_ipv6_answers) + return; + } + + if (! tor_addr_to_str(valbuf, val, sizeof(valbuf), 1)) + return; + + client_dns_set_addressmap_impl(for_conn, address, valbuf, exitname, ttl); +} + +/** Add a cache entry noting that <b>address</b> (ordinarily a dotted quad) + * resolved via a RESOLVE_PTR request to the hostname <b>v</b>. + * + * If <b>exitname</b> is defined, then append the addresses with + * ".exitname.exit" before registering the mapping. + * + * If <b>ttl</b> is nonnegative, the mapping will be valid for + * <b>ttl</b>seconds; otherwise, we use the default. + */ +void +client_dns_set_reverse_addressmap(entry_connection_t *for_conn, + const char *address, const char *v, + const char *exitname, + int ttl) +{ + char *s = NULL; + { + tor_addr_t tmp_addr; + sa_family_t f = tor_addr_parse(&tmp_addr, address); + if ((f == AF_INET && ! for_conn->entry_cfg.cache_ipv4_answers) || + (f == AF_INET6 && ! for_conn->entry_cfg.cache_ipv6_answers)) + return; + } + tor_asprintf(&s, "REVERSE[%s]", address); + client_dns_set_addressmap_impl(for_conn, s, v, exitname, ttl); + tor_free(s); +} + +/* By default, we hand out 127.192.0.1 through 127.254.254.254. + * These addresses should map to localhost, so even if the + * application accidentally tried to connect to them directly (not + * via Tor), it wouldn't get too far astray. + * + * These options are configured by parse_virtual_addr_network(). + */ + +static virtual_addr_conf_t virtaddr_conf_ipv4; +static virtual_addr_conf_t virtaddr_conf_ipv6; + +/** Read a netmask of the form 127.192.0.0/10 from "val", and check whether + * it's a valid set of virtual addresses to hand out in response to MAPADDRESS + * requests. Return 0 on success; set *msg (if provided) to a newly allocated + * string and return -1 on failure. If validate_only is false, sets the + * actual virtual address range to the parsed value. */ +int +parse_virtual_addr_network(const char *val, sa_family_t family, + int validate_only, + char **msg) +{ + const int ipv6 = (family == AF_INET6); + tor_addr_t addr; + maskbits_t bits; + const int max_prefix_bits = ipv6 ? 104 : 16; + virtual_addr_conf_t *conf = ipv6 ? &virtaddr_conf_ipv6 : &virtaddr_conf_ipv4; + + if (!val || val[0] == '\0') { + if (msg) + tor_asprintf(msg, "Value not present (%s) after VirtualAddressNetwork%s", + val?"Empty":"NULL", ipv6?"IPv6":""); + return -1; + } + if (tor_addr_parse_mask_ports(val, 0, &addr, &bits, NULL, NULL) < 0) { + if (msg) + tor_asprintf(msg, "Error parsing VirtualAddressNetwork%s %s", + ipv6?"IPv6":"", val); + return -1; + } + if (tor_addr_family(&addr) != family) { + if (msg) + tor_asprintf(msg, "Incorrect address type for VirtualAddressNetwork%s", + ipv6?"IPv6":""); + return -1; + } +#if 0 + if (port_min != 1 || port_max != 65535) { + if (msg) + tor_asprintf(msg, "Can't specify ports on VirtualAddressNetwork%s", + ipv6?"IPv6":""); + return -1; + } +#endif /* 0 */ + + if (bits > max_prefix_bits) { + if (msg) + tor_asprintf(msg, "VirtualAddressNetwork%s expects a /%d " + "network or larger",ipv6?"IPv6":"", max_prefix_bits); + return -1; + } + + if (validate_only) + return 0; + + tor_addr_copy(&conf->addr, &addr); + conf->bits = bits; + + return 0; +} + +/** + * Return true iff <b>addr</b> is likely to have been returned by + * client_dns_get_unused_address. + **/ +int +address_is_in_virtual_range(const char *address) +{ + tor_addr_t addr; + tor_assert(address); + if (!strcasecmpend(address, ".virtual")) { + return 1; + } else if (tor_addr_parse(&addr, address) >= 0) { + const virtual_addr_conf_t *conf = (tor_addr_family(&addr) == AF_INET6) ? + &virtaddr_conf_ipv6 : &virtaddr_conf_ipv4; + if (tor_addr_compare_masked(&addr, &conf->addr, conf->bits, CMP_EXACT)==0) + return 1; + } + return 0; +} + +/** Return a random address conforming to the virtual address configuration + * in <b>conf</b>. + */ +STATIC void +get_random_virtual_addr(const virtual_addr_conf_t *conf, tor_addr_t *addr_out) +{ + uint8_t tmp[4]; + const uint8_t *addr_bytes; + uint8_t bytes[16]; + const int ipv6 = tor_addr_family(&conf->addr) == AF_INET6; + const int total_bytes = ipv6 ? 16 : 4; + + tor_assert(conf->bits <= total_bytes * 8); + + /* Set addr_bytes to the bytes of the virtual network, in host order */ + if (ipv6) { + addr_bytes = tor_addr_to_in6_addr8(&conf->addr); + } else { + set_uint32(tmp, tor_addr_to_ipv4n(&conf->addr)); + addr_bytes = tmp; + } + + /* Get an appropriate number of random bytes. */ + crypto_rand((char*)bytes, total_bytes); + + /* Now replace the first "conf->bits" bits of 'bytes' with addr_bytes*/ + if (conf->bits >= 8) + memcpy(bytes, addr_bytes, conf->bits / 8); + if (conf->bits & 7) { + uint8_t mask = 0xff >> (conf->bits & 7); + bytes[conf->bits/8] &= mask; + bytes[conf->bits/8] |= addr_bytes[conf->bits/8] & ~mask; + } + + if (ipv6) + tor_addr_from_ipv6_bytes(addr_out, (char*) bytes); + else + tor_addr_from_ipv4n(addr_out, get_uint32(bytes)); + + tor_assert(tor_addr_compare_masked(addr_out, &conf->addr, + conf->bits, CMP_EXACT)==0); +} + +/** Return a newly allocated string holding an address of <b>type</b> + * (one of RESOLVED_TYPE_{IPV4|IPV6|HOSTNAME}) that has not yet been + * mapped, and that is very unlikely to be the address of any real host. + * + * May return NULL if we have run out of virtual addresses. + */ +static char * +addressmap_get_virtual_address(int type) +{ + char buf[64]; + tor_assert(addressmap); + + if (type == RESOLVED_TYPE_HOSTNAME) { + char rand_bytes[10]; + do { + crypto_rand(rand_bytes, sizeof(rand_bytes)); + base32_encode(buf,sizeof(buf),rand_bytes,sizeof(rand_bytes)); + strlcat(buf, ".virtual", sizeof(buf)); + } while (strmap_get(addressmap, buf)); + return tor_strdup(buf); + } else if (type == RESOLVED_TYPE_IPV4 || type == RESOLVED_TYPE_IPV6) { + const int ipv6 = (type == RESOLVED_TYPE_IPV6); + const virtual_addr_conf_t *conf = ipv6 ? + &virtaddr_conf_ipv6 : &virtaddr_conf_ipv4; + + /* Don't try more than 1000 times. This gives us P < 1e-9 for + * failing to get a good address so long as the address space is + * less than ~97.95% full. That's always going to be true under + * sensible circumstances for an IPv6 /10, and it's going to be + * true for an IPv4 /10 as long as we've handed out less than + * 4.08 million addresses. */ + uint32_t attempts = 1000; + + tor_addr_t addr; + + while (attempts--) { + get_random_virtual_addr(conf, &addr); + + if (!ipv6) { + /* Don't hand out any .0 or .255 address. */ + const uint32_t a = tor_addr_to_ipv4h(&addr); + if ((a & 0xff) == 0 || (a & 0xff) == 0xff) + continue; + } + + tor_addr_to_str(buf, &addr, sizeof(buf), 1); + if (!strmap_get(addressmap, buf)) { + /* XXXX This code is to make sure I didn't add an undecorated version + * by mistake. I hope it's needless. */ + char tmp[TOR_ADDR_BUF_LEN]; + tor_addr_to_str(tmp, &addr, sizeof(tmp), 0); + if (strmap_get(addressmap, tmp)) { + // LCOV_EXCL_START + log_warn(LD_BUG, "%s wasn't in the addressmap, but %s was.", + buf, tmp); + continue; + // LCOV_EXCL_STOP + } + + return tor_strdup(buf); + } + } + log_warn(LD_CONFIG, "Ran out of virtual addresses!"); + return NULL; + } else { + // LCOV_EXCL_START + log_warn(LD_BUG, "Called with unsupported address type (%d)", type); + return NULL; + // LCOV_EXCL_STOP + } +} + +/** A controller has requested that we map some address of type + * <b>type</b> to the address <b>new_address</b>. Choose an address + * that is unlikely to be used, and map it, and return it in a newly + * allocated string. If another address of the same type is already + * mapped to <b>new_address</b>, try to return a copy of that address. + * + * The string in <b>new_address</b> may be freed or inserted into a map + * as appropriate. May return NULL if are out of virtual addresses. + **/ +const char * +addressmap_register_virtual_address(int type, char *new_address) +{ + char **addrp; + virtaddress_entry_t *vent; + int vent_needs_to_be_added = 0; + + tor_assert(new_address); + tor_assert(addressmap); + tor_assert(virtaddress_reversemap); + + vent = strmap_get(virtaddress_reversemap, new_address); + if (!vent) { + vent = tor_malloc_zero(sizeof(virtaddress_entry_t)); + vent_needs_to_be_added = 1; + } + + if (type == RESOLVED_TYPE_IPV4) + addrp = &vent->ipv4_address; + else if (type == RESOLVED_TYPE_IPV6) + addrp = &vent->ipv6_address; + else + addrp = &vent->hostname_address; + + if (*addrp) { + addressmap_entry_t *ent = strmap_get(addressmap, *addrp); + if (ent && ent->new_address && + !strcasecmp(new_address, ent->new_address)) { + tor_free(new_address); + tor_assert(!vent_needs_to_be_added); + return *addrp; + } else { + log_warn(LD_BUG, + "Internal confusion: I thought that '%s' was mapped to by " + "'%s', but '%s' really maps to '%s'. This is a harmless bug.", + safe_str_client(new_address), + safe_str_client(*addrp), + safe_str_client(*addrp), + ent?safe_str_client(ent->new_address):"(nothing)"); + } + } + + tor_free(*addrp); + *addrp = addressmap_get_virtual_address(type); + if (!*addrp) { + tor_free(vent); + tor_free(new_address); + return NULL; + } + log_info(LD_APP, "Registering map from %s to %s", *addrp, new_address); + if (vent_needs_to_be_added) + strmap_set(virtaddress_reversemap, new_address, vent); + addressmap_register(*addrp, new_address, 2, ADDRMAPSRC_AUTOMAP, 0, 0); + + /* FFFF register corresponding reverse mapping. */ + +#if 0 + { + /* Try to catch possible bugs */ + addressmap_entry_t *ent; + ent = strmap_get(addressmap, *addrp); + tor_assert(ent); + tor_assert(!strcasecmp(ent->new_address,new_address)); + vent = strmap_get(virtaddress_reversemap, new_address); + tor_assert(vent); + tor_assert(!strcasecmp(*addrp, + (type == RESOLVED_TYPE_IPV4) ? + vent->ipv4_address : vent->hostname_address)); + log_info(LD_APP, "Map from %s to %s okay.", + safe_str_client(*addrp), + safe_str_client(new_address)); + } +#endif /* 0 */ + + return *addrp; +} + +/** Return 1 if <b>address</b> has funny characters in it like colons. Return + * 0 if it's fine, or if we're configured to allow it anyway. <b>client</b> + * should be true if we're using this address as a client; false if we're + * using it as a server. + */ +int +address_is_invalid_destination(const char *address, int client) +{ + if (client) { + if (get_options()->AllowNonRFC953Hostnames) + return 0; + } else { + if (get_options()->ServerDNSAllowNonRFC953Hostnames) + return 0; + } + + /* It might be an IPv6 address! */ + { + tor_addr_t a; + if (tor_addr_parse(&a, address) >= 0) + return 0; + } + + while (*address) { + if (TOR_ISALNUM(*address) || + *address == '-' || + *address == '.' || + *address == '_') /* Underscore is not allowed, but Windows does it + * sometimes, just to thumb its nose at the IETF. */ + ++address; + else + return 1; + } + return 0; +} + +/** Iterate over all address mappings which have expiry times between + * min_expires and max_expires, inclusive. If sl is provided, add an + * "old-addr new-addr expiry" string to sl for each mapping, omitting + * the expiry time if want_expiry is false. If sl is NULL, remove the + * mappings. + */ +void +addressmap_get_mappings(smartlist_t *sl, time_t min_expires, + time_t max_expires, int want_expiry) +{ + strmap_iter_t *iter; + const char *key; + void *val_; + addressmap_entry_t *val; + + if (!addressmap) + addressmap_init(); + + for (iter = strmap_iter_init(addressmap); !strmap_iter_done(iter); ) { + strmap_iter_get(iter, &key, &val_); + val = val_; + if (val->expires >= min_expires && val->expires <= max_expires) { + if (!sl) { + iter = strmap_iter_next_rmv(addressmap,iter); + addressmap_ent_remove(key, val); + continue; + } else if (val->new_address) { + const char *src_wc = val->src_wildcard ? "*." : ""; + const char *dst_wc = val->dst_wildcard ? "*." : ""; + if (want_expiry) { + if (val->expires < 3 || val->expires == TIME_MAX) + smartlist_add_asprintf(sl, "%s%s %s%s NEVER", + src_wc, key, dst_wc, val->new_address); + else { + char isotime[ISO_TIME_LEN+1]; + format_iso_time(isotime, val->expires); + smartlist_add_asprintf(sl, "%s%s %s%s \"%s\"", + src_wc, key, dst_wc, val->new_address, + isotime); + } + } else { + smartlist_add_asprintf(sl, "%s%s %s%s", + src_wc, key, dst_wc, val->new_address); + } + } + } + iter = strmap_iter_next(addressmap,iter); + } +} |