was used which resulted in O(n^2) behaviour; now we get O(n log n) making
DOS attacks harder. The cost is wasted memory use in the larger blocks.
+JH/47 Use explicit alloc/free for DNS lookup workspace. This permits using the
+ same space repeatedly, and a smaller process footprint.
+
+
Exim version 4.94
tree_node *t;
const uschar *found;
int priority, weight, port;
-dns_answer * dnsa = store_get_dns_answer();
+dns_answer * dnsa;
dns_scan dnss;
dns_record *rr;
-int rc, type;
-uschar target[256];
+int rc, type, yield;
+#define TARGET_SIZE 256
+uschar * target = store_get(TARGET_SIZE, TRUE);
/* Work out the domain we are using for the CSA lookup. The default is the
client's HELO domain. If the client has not said HELO, use its IP address
while (isspace(*domain) && *domain != '\0') ++domain;
if (*domain == '\0') domain = sender_helo_name;
-if (domain == NULL) domain = sender_host_address;
-if (sender_host_address == NULL) return CSA_UNKNOWN;
+if (!domain) domain = sender_host_address;
+if (!sender_host_address) return CSA_UNKNOWN;
/* If we have an address literal, strip off the framing ready for turning it
into a domain. The framing consists of matched square brackets possibly
for this domain. The name is filled in now, and the value is filled in when
we return from this function. */
-t = tree_search(csa_cache, domain);
-if (t != NULL) return t->data.val;
+if ((t = tree_search(csa_cache, domain)))
+ return t->data.val;
t = store_get_perm(sizeof(tree_node) + Ustrlen(domain), is_tainted(domain));
Ustrcpy(t->name, domain);
/* Now we are ready to do the actual DNS lookup(s). */
found = domain;
+dnsa = store_get_dns_answer();
switch (dns_special_lookup(dnsa, domain, T_CSA, &found))
{
/* If something bad happened (most commonly DNS_AGAIN), defer. */
default:
- return t->data.val = CSA_DEFER_SRV;
+ yield = CSA_DEFER_SRV;
+ goto out;
/* If we found nothing, the client's authorization is unknown. */
case DNS_NOMATCH:
case DNS_NODATA:
- return t->data.val = CSA_UNKNOWN;
+ yield = CSA_UNKNOWN;
+ goto out;
/* We got something! Go on to look at the reply in more detail. */
SRV records of their own. */
if (Ustrcmp(found, domain) != 0)
- return t->data.val = port & 1 ? CSA_FAIL_EXPLICIT : CSA_UNKNOWN;
+ {
+ yield = port & 1 ? CSA_FAIL_EXPLICIT : CSA_UNKNOWN;
+ goto out;
+ }
/* This CSA SRV record refers directly to our domain, so we check the value
in the weight field to work out the domain's authorization. 0 and 1 are
address in order to authenticate it, so we treat it as unknown; values
greater than 3 are undefined. */
- if (weight < 2) return t->data.val = CSA_FAIL_DOMAIN;
+ if (weight < 2)
+ {
+ yield = CSA_FAIL_DOMAIN;
+ goto out;
+ }
if (weight > 2) continue;
target hostname then break to scan the additional data for its addresses. */
(void)dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, p,
- (DN_EXPAND_ARG4_TYPE)target, sizeof(target));
+ (DN_EXPAND_ARG4_TYPE)target, TARGET_SIZE);
DEBUG(D_acl) debug_printf_indent("CSA target is %s\n", target);
/* If we didn't break the loop then no appropriate records were found. */
-if (!rr) return t->data.val = CSA_UNKNOWN;
+if (!rr)
+ {
+ yield = CSA_UNKNOWN;
+ goto out;
+ }
/* Do not check addresses if the target is ".", in accordance with RFC 2782.
A target of "." indicates there are no valid addresses, so the client cannot
equivalent to weight=1, but we check for it in order to keep load off the
root name servers.) Note that dn_expand() turns "." into "". */
-if (Ustrcmp(target, "") == 0) return t->data.val = CSA_FAIL_NOADDR;
+if (Ustrcmp(target, "") == 0)
+ {
+ yield = CSA_FAIL_NOADDR;
+ goto out;
+ }
/* Scan the additional section of the CSA SRV reply for addresses belonging
to the target. If the name server didn't return any additional data (e.g.
to obtain the target addresses; otherwise we have a definitive result. */
rc = acl_verify_csa_address(dnsa, &dnss, RESET_ADDITIONAL, target);
-if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
+if (rc != CSA_FAIL_NOADDR)
+ {
+ yield = rc;
+ goto out;
+ }
/* The DNS lookup type corresponds to the IP version used by the client. */
/* If something bad happened (most commonly DNS_AGAIN), defer. */
default:
- return t->data.val = CSA_DEFER_ADDR;
+ yield = CSA_DEFER_ADDR;
+ break;
/* If the query succeeded, scan the addresses and return the result. */
case DNS_SUCCEED:
rc = acl_verify_csa_address(dnsa, &dnss, RESET_ANSWERS, target);
- if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
+ if (rc != CSA_FAIL_NOADDR)
+ {
+ yield = rc;
+ break;
+ }
/* else fall through */
/* If the target has no IP addresses, the client cannot have an authorized
case DNS_NOMATCH:
case DNS_NODATA:
- return t->data.val = CSA_FAIL_NOADDR;
+ yield = CSA_FAIL_NOADDR;
+ break;
}
+
+out:
+
+store_free_dns_answer(dnsa);
+return t->data.val = yield;
}
dns_answer * dnsa = store_get_dns_answer();
dns_scan dnss;
rmark reset_point = store_mark();
-gstring * g = NULL;
+gstring * g = string_get_tainted(256, TRUE);
lookup_dnssec_authenticated = NULL;
if (dns_lookup(dnsa, name, T_TXT, NULL) != DNS_SUCCEED)
+ {
+ store_free_dns_answer(dnsa);
return NULL; /*XXX better error detail? logging? */
+ }
/* Search for TXT record */
/* check if this looks like a DKIM record */
if (Ustrncmp(g->s, "v=", 2) != 0 || strncasecmp(CS g->s, "v=dkim", 6) == 0)
{
+ store_free_dns_answer(dnsa);
gstring_release_unused(g);
return string_from_gstring(g);
}
bad:
store_reset(reset_point);
+store_free_dns_answer(dnsa);
return NULL; /*XXX better error detail? logging? */
}
for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
if (rr->type == T_TXT && rr->size > 3)
- return string_copyn(US rr->data, rr->size);
+ {
+ store_free_dns_answer(dnsa);
+ return string_copyn_taint(US rr->data, rr->size, TRUE);
+ }
+store_free_dns_answer(dnsa);
return NULL;
}
dnsbl_cache_block *cb;
int old_pool = store_pool;
uschar * query;
-int qlen;
+int qlen, yield;
/* Construct the specific query domainname */
{
log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
"(ignored): %s...", query);
- return FAIL;
+ yield = FAIL;
+ goto out;
}
/* Look for this query in the cache. */
match_type & MT_ALL ? "=" : "",
bitmask ? '&' : '=', iplist);
}
- return FAIL;
+ yield = FAIL;
+ goto out;
}
}
" not in 127.0/8 and discarded",
keydomain, domain, da->address);
}
- if (!ok) return FAIL;
+ if (!ok)
+ {
+ yield = FAIL;
+ goto out;
+ }
}
/* Either there was no IP list, or the record matched, implying that the
there is indeed an A record at the alternate domain. */
if (domain_txt != domain)
- return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
+ {
+ yield = one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
FALSE, match_type, defer_return);
+ goto out;
+ }
/* If there is no alternate domain, look up a TXT record in the main domain
if it has not previously been cached. */
int len = (rr->data)[0];
if (len > 511) len = 127;
store_pool = POOL_PERM;
- cb->text = string_sprintf("%.*s", len, CUS (rr->data+1));
+ cb->text = string_copyn_taint(CUS (rr->data+1), len, TRUE);
store_pool = old_pool;
break;
}
dnslist_value = addlist;
dnslist_text = cb->text;
- return OK;
+ yield = OK;
+ goto out;
}
/* There was a problem with the DNS lookup */
defer_return == OK ? US"assumed in list" :
defer_return == FAIL ? US"assumed not in list" :
US"returned DEFER");
- return defer_return;
+ yield = defer_return;
+ goto out;
}
/* No entry was found in the DNS; continue for next domain */
keydomain, domain);
}
-return FAIL;
+yield = FAIL;
+
+out:
+
+store_free_dns_answer(dnsa);
+return yield;
}
/******************************************************************************/
+/* Use store_malloc for DNSA structs, and explicit frees. Using the same pool
+for them as the strings we proceed to copy from them meant they could not be
+released, hence blowing 64k for every DNS lookup. That mounted up. With malloc
+we do have to take care over marking tainted all copied strings. A separate pool
+could be used and would handle that implicitly. */
#define store_get_dns_answer() store_get_dns_answer_trc(CUS __FUNCTION__, __LINE__)
static inline dns_answer *
store_get_dns_answer_trc(const uschar * func, unsigned line)
{
-return store_get_3(sizeof(dns_answer), TRUE, CCS func, line); /* use tainted mem */
+/* return store_get_3(sizeof(dns_answer), TRUE, CCS func, line); use tainted mem */
+return store_malloc_3(sizeof(dns_answer), CCS func, line);
+}
+
+#define store_free_dns_answer(dnsa) store_free_dns_answer_trc(dnsa, CUS __FUNCTION__, __LINE__)
+
+static inline void
+store_free_dns_answer_trc(dns_answer * dnsa, const uschar * func, unsigned line)
+{
+store_free_3(dnsa, CCS func, line);
}
/******************************************************************************/
else
{
*error_num = HOST_NOT_FOUND;
- return NULL;
+ yield = NULL;
+ goto out;
}
/* Handle a host name */
switch(rc)
{
case DNS_SUCCEED: break;
- case DNS_NOMATCH: *error_num = HOST_NOT_FOUND; return NULL;
- case DNS_NODATA: *error_num = NO_DATA; return NULL;
- case DNS_AGAIN: *error_num = TRY_AGAIN; return NULL;
+ case DNS_NOMATCH: *error_num = HOST_NOT_FOUND; yield = NULL; goto out;
+ case DNS_NODATA: *error_num = NO_DATA; yield = NULL; goto out;
+ case DNS_AGAIN: *error_num = TRY_AGAIN; yield = NULL; goto out;
default:
- case DNS_FAIL: *error_num = NO_RECOVERY; return NULL;
+ case DNS_FAIL: *error_num = NO_RECOVERY; yield = NULL; goto out;
}
for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
*alist = NULL;
}
+out:
+
+store_free_dns_answer(dnsa);
return yield;
}
BOOL v6_find_again = FALSE;
BOOL dnssec_fail = FALSE;
int i;
+dns_answer * dnsa;
#ifndef DISABLE_TLS
/* Copy the host name at this point to the value which is used for
return HOST_FOUND;
}
+dnsa = store_get_dns_answer();
+
/* On an IPv6 system, unless IPv6 is disabled, go round the loop up to twice,
looking for AAAA records the first time. However, unless doing standalone
testing, we force an IPv4 lookup if the domain matches dns_ipv4_lookup global.
int type = types[i];
int randoffset = i == (whichrrs & HOST_FIND_IPV4_FIRST ? 1 : 0)
? 500 : 0; /* Ensures v6/4 sort order */
- dns_answer * dnsa = store_get_dns_answer();
dns_scan dnss;
int rc = dns_lookup_timerwrap(dnsa, host->name, type, fully_qualified_name);
{
if (i == 0) /* Just tried for an A record, i.e. end of loop */
{
- if (host->address != NULL) return HOST_FOUND; /* AAAA was found */
- if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
- return HOST_FIND_AGAIN;
- return HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
+ if (host->address != NULL)
+ i = HOST_FOUND; /* AAAA was found */
+ else if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
+ i = HOST_FIND_AGAIN;
+ else
+ i = HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
+ goto out;
}
/* Tried for an AAAA record: remember if this was a temporary
/* Control gets here only if the second lookup (the A record) succeeded.
However, the address may not be filled in if it was ignored. */
-return host->address
+i = host->address
? HOST_FOUND
: dnssec_fail
? HOST_FIND_SECURITY
: HOST_IGNORED;
+
+out:
+ store_free_dns_answer(dnsa);
+ return i;
}
out:
dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
+store_free_dns_answer(dnsa);
return yield;
}
else
{
*errmsg = US"unsupported dnsdb defer behaviour";
- return DEFER;
+ rc = DEFER;
+ goto out;
}
}
else if (strncmpic(keystring, US"dnssec_", 7) == 0)
else
{
*errmsg = US"unsupported dnsdb dnssec behaviour";
- return DEFER;
+ rc = DEFER;
+ goto out;
}
}
else if (strncmpic(keystring, US"retrans_", 8) == 0)
if ((timeout_sec = readconf_readtime(keystring += 8, ',', FALSE)) <= 0)
{
*errmsg = US"unsupported dnsdb timeout value";
- return DEFER;
+ rc = DEFER;
+ goto out;
}
dns_retrans = timeout_sec;
while (*keystring != ',') keystring++;
if ((retries = (int)strtol(CCS keystring + 6, CSS &keystring, 0)) < 0)
{
*errmsg = US"unsupported dnsdb retry count";
- return DEFER;
+ rc = DEFER;
+ goto out;
}
dns_retry = retries;
}
if (*keystring++ != ',')
{
*errmsg = US"dnsdb modifier syntax error";
- return DEFER;
+ rc = DEFER;
+ goto out;
}
while (isspace(*keystring)) keystring++;
}
if (i >= nelem(type_names))
{
*errmsg = US"unsupported DNS record type";
- return DEFER;
+ rc = DEFER;
+ goto out;
}
keystring = equals + 1;
dns_retrans = save_retrans;
dns_retry = save_retry;
dns_init(FALSE, FALSE, FALSE); /* clr dnssec bit */
- return DEFER; /* always defer */
+ rc = DEFER; /* always defer */
+ goto out;
}
if (defer_mode == PASS) failrc = DEFER; /* defer only if all do */
continue; /* treat defer as fail */
dns_retry = save_retry;
dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
-if (!yield || !yield->ptr) return failrc;
+if (!yield || !yield->ptr)
+ rc = failrc;
+else
+ {
+ *result = string_from_gstring(yield);
+ rc = OK;
+ }
+
+out:
-*result = string_from_gstring(yield);
-return OK;
+store_free_dns_answer(dnsa);
+return rc;
}
HDEBUG(D_host_lookup) debug_printf("faking NO_DATA for SPF RR(99) lookup\n");
srr.herrno = NO_DATA;
SPF_dns_rr_dup(&spfrr, &srr);
+ store_free_dns_answer(dnsa);
return spfrr;
}
if (found == 0)
{
SPF_dns_rr_dup(&spfrr, &srr);
+ store_free_dns_answer(dnsa);
return spfrr;
}
/* spfrr->rr must have been malloc()d for this */
SPF_dns_rr_dup(&spfrr, &srr);
+store_free_dns_answer(dnsa);
return spfrr;
}
string_copy_dnsdomain(uschar *s)
{
uschar *yield;
-uschar *ss = yield = store_get(Ustrlen(s) + 1, is_tainted(s));
+uschar *ss = yield = store_get(Ustrlen(s) + 1, TRUE); /* always treat as tainted */
while (*s != 0)
{
git://git.exim.org / exim.git / commitdiff