/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2018, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file policy_parse.c
* \brief Code to parse address policies.
**/
#define EXPOSE_ROUTERDESC_TOKEN_TABLE
#include "core/or/or.h"
#include "core/or/policies.h"
#include "feature/dirparse/parsecommon.h"
#include "feature/dirparse/policy_parse.h"
#include "feature/dirparse/routerparse.h"
#include "feature/dirparse/unparseable.h"
#include "lib/memarea/memarea.h"
#include "core/or/addr_policy_st.h"
static addr_policy_t *router_parse_addr_policy_private(directory_token_t *tok);
/** Parse the addr policy in the string s and return it. If
* assume_action is nonnegative, then insert its action (ADDR_POLICY_ACCEPT or
* ADDR_POLICY_REJECT) for items that specify no action.
*
* Returns NULL on policy errors.
*
* Set *malformed_list to true if the entire policy list should be
* discarded. Otherwise, set it to false, and only this item should be ignored
* on error - the rest of the policy list can continue to be processed and
* used.
*
* The addr_policy_t returned by this function can have its address set to
* AF_UNSPEC for '*'. Use policy_expand_unspec() to turn this into a pair
* of AF_INET and AF_INET6 items.
*/
MOCK_IMPL(addr_policy_t *,
router_parse_addr_policy_item_from_string,(const char *s, int assume_action,
int *malformed_list))
{
directory_token_t *tok = NULL;
const char *cp, *eos;
/* Longest possible policy is
* "accept6 [ffff:ffff:..255]/128:10000-65535",
* which contains a max-length IPv6 address, plus 26 characters.
* But note that there can be an arbitrary amount of space between the
* accept and the address:mask/port element.
* We don't need to multiply TOR_ADDR_BUF_LEN by 2, as there is only one
* IPv6 address. But making the buffer shorter might cause valid long lines,
* which parsed in previous versions, to fail to parse in new versions.
* (These lines would have to have excessive amounts of whitespace.) */
char line[TOR_ADDR_BUF_LEN*2 + 32];
addr_policy_t *r;
memarea_t *area = NULL;
tor_assert(malformed_list);
*malformed_list = 0;
s = eat_whitespace(s);
/* We can only do assume_action on []-quoted IPv6, as "a" (accept)
* and ":" (port separator) are ambiguous */
if ((*s == '*' || *s == '[' || TOR_ISDIGIT(*s)) && assume_action >= 0) {
if (tor_snprintf(line, sizeof(line), "%s %s",
assume_action == ADDR_POLICY_ACCEPT?"accept":"reject", s)<0) {
log_warn(LD_DIR, "Policy %s is too long.", escaped(s));
return NULL;
}
cp = line;
tor_strlower(line);
} else { /* assume an already well-formed address policy line */
cp = s;
}
eos = cp + strlen(cp);
area = memarea_new();
tok = get_next_token(area, &cp, eos, routerdesc_token_table);
if (tok->tp == ERR_) {
log_warn(LD_DIR, "Error reading address policy: %s", tok->error);
goto err;
}
if (tok->tp != K_ACCEPT && tok->tp != K_ACCEPT6 &&
tok->tp != K_REJECT && tok->tp != K_REJECT6) {
log_warn(LD_DIR, "Expected 'accept' or 'reject'.");
goto err;
}
/* Use the extended interpretation of accept/reject *,
* expanding it into an IPv4 wildcard and an IPv6 wildcard.
* Also permit *4 and *6 for IPv4 and IPv6 only wildcards. */
r = router_parse_addr_policy(tok, TAPMP_EXTENDED_STAR);
if (!r) {
goto err;
}
/* Ensure that accept6/reject6 fields are followed by IPv6 addresses.
* AF_UNSPEC addresses are only permitted on the accept/reject field type.
* Unlike descriptors, torrcs exit policy accept/reject can be followed by
* either an IPv4 or IPv6 address. */
if ((tok->tp == K_ACCEPT6 || tok->tp == K_REJECT6) &&
tor_addr_family(&r->addr) != AF_INET6) {
/* This is a non-fatal error, just ignore this one entry. */
*malformed_list = 0;
log_warn(LD_DIR, "IPv4 address '%s' with accept6/reject6 field type in "
"exit policy. Ignoring, but continuing to parse rules. (Use "
"accept/reject with IPv4 addresses.)",
tok->n_args == 1 ? tok->args[0] : "");
addr_policy_free(r);
r = NULL;
goto done;
}
goto done;
err:
*malformed_list = 1;
r = NULL;
done:
token_clear(tok);
if (area) {
DUMP_AREA(area, "policy item");
memarea_drop_all(area);
}
return r;
}
/** Given a K_ACCEPT[6] or K_REJECT[6] token and a router, create and return
* a new exit_policy_t corresponding to the token. If TAPMP_EXTENDED_STAR
* is set in fmt_flags, K_ACCEPT6 and K_REJECT6 tokens followed by *
* expand to IPv6-only policies, otherwise they expand to IPv4 and IPv6
* policies */
addr_policy_t *
router_parse_addr_policy(directory_token_t *tok, unsigned fmt_flags)
{
addr_policy_t newe;
char *arg;
tor_assert(tok->tp == K_REJECT || tok->tp == K_REJECT6 ||
tok->tp == K_ACCEPT || tok->tp == K_ACCEPT6);
if (tok->n_args != 1)
return NULL;
arg = tok->args[0];
if (!strcmpstart(arg,"private"))
return router_parse_addr_policy_private(tok);
memset(&newe, 0, sizeof(newe));
if (tok->tp == K_REJECT || tok->tp == K_REJECT6)
newe.policy_type = ADDR_POLICY_REJECT;
else
newe.policy_type = ADDR_POLICY_ACCEPT;
/* accept6/reject6 * produces an IPv6 wildcard address only.
* (accept/reject * produces rules for IPv4 and IPv6 wildcard addresses.) */
if ((fmt_flags & TAPMP_EXTENDED_STAR)
&& (tok->tp == K_ACCEPT6 || tok->tp == K_REJECT6)) {
fmt_flags |= TAPMP_STAR_IPV6_ONLY;
}
if (tor_addr_parse_mask_ports(arg, fmt_flags, &newe.addr, &newe.maskbits,
&newe.prt_min, &newe.prt_max) < 0) {
log_warn(LD_DIR,"Couldn't parse line %s. Dropping", escaped(arg));
return NULL;
}
addr_policy_t *result = addr_policy_get_canonical_entry(&newe);
/* It would be a nasty error to return 'newe', and sometimes
* addr_policy_get_canonical_entry() can return its argument. But in this
* case, it won't, since newe is *not* canonical. We assert here to make
* sure that the compiler knows it too.
*/
tor_assert(result != &newe);
return result;
}
/** Parse an exit policy line of the format "accept[6]/reject[6] private:...".
* This didn't exist until Tor 0.1.1.15, so nobody should generate it in
* router descriptors until earlier versions are obsolete.
*
* accept/reject and accept6/reject6 private all produce rules for both
* IPv4 and IPv6 addresses.
*/
static addr_policy_t *
router_parse_addr_policy_private(directory_token_t *tok)
{
const char *arg;
uint16_t port_min, port_max;
addr_policy_t result;
arg = tok->args[0];
if (strcmpstart(arg, "private"))
return NULL;
arg += strlen("private");
arg = (char*) eat_whitespace(arg);
if (!arg || *arg != ':')
return NULL;
if (parse_port_range(arg+1, &port_min, &port_max)<0)
return NULL;
memset(&result, 0, sizeof(result));
if (tok->tp == K_REJECT || tok->tp == K_REJECT6)
result.policy_type = ADDR_POLICY_REJECT;
else
result.policy_type = ADDR_POLICY_ACCEPT;
result.is_private = 1;
result.prt_min = port_min;
result.prt_max = port_max;
if (tok->tp == K_ACCEPT6 || tok->tp == K_REJECT6) {
log_warn(LD_GENERAL,
"'%s' expands into rules which apply to all private IPv4 and "
"IPv6 addresses. (Use accept/reject private:* for IPv4 and "
"IPv6.)", tok->n_args == 1 ? tok->args[0] : "");
}
return addr_policy_get_canonical_entry(&result);
}