X-Git-Url: https://git.netwichtig.de/gitweb/?a=blobdiff_plain;f=src%2Fsrc%2Fdns.c;h=e3845978c36de35610681faa3ea8bc58a63f68f4;hb=fc55624df0c1956b7b6b4ae35605a6b95704d022;hp=0f0b435de288b9f7ca8bad0421086387f88daafc;hpb=75c121f07a85b4029458f11b113a4655114af126;p=user%2Fhenk%2Fcode%2Fexim.git

diff --git a/src/src/dns.c b/src/src/dns.c
index 0f0b435de..e3845978c 100644
--- a/src/src/dns.c
+++ b/src/src/dns.c
@@ -40,7 +40,7 @@ fakens_search(const uschar *domain, int type, uschar *answerptr, int size)
 {
 int len = Ustrlen(domain);
 int asize = size;                  /* Locally modified */
-uschar name[256];
+uschar * name;
 uschar utilname[256];
 uschar *aptr = answerptr;          /* Locally modified */
 struct stat statbuf;
@@ -48,8 +48,7 @@ struct stat statbuf;
 /* Remove terminating dot. */
 
 if (domain[len - 1] == '.') len--;
-Ustrncpy(name, domain, len);
-name[len] = 0;
+name = string_copyn(domain, len);
 
 /* Look for the fakens utility, and if it exists, call it. */
 
@@ -240,8 +239,7 @@ uschar *pp = buffer;
 if (Ustrchr(string, ':') == NULL)
 #endif
   {
-  int i;
-  for (i = 0; i < 4; i++)
+  for (int i = 0; i < 4; i++)
     {
     const uschar *ppp = p;
     while (ppp > string && ppp[-1] != '.') ppp--;
@@ -250,7 +248,7 @@ if (Ustrchr(string, ':') == NULL)
     *pp++ = '.';
     p = ppp - 1;
     }
-  Ustrcpy(pp, "in-addr.arpa");
+  Ustrcpy(pp, US"in-addr.arpa");
   }
 
 /* Handle IPv6 address; convert to binary so as to fill out any
@@ -259,7 +257,6 @@ abbreviation in the textual form. */
 #if HAVE_IPV6
 else
   {
-  int i;
   int v6[4];
   (void)host_aton(string, v6);
 
@@ -267,13 +264,10 @@ else
   nibble, and look in the ip6.int domain. The domain was subsequently
   changed to ip6.arpa. */
 
-  for (i = 3; i >= 0; i--)
-    {
-    int j;
-    for (j = 0; j < 32; j += 4)
+  for (int i = 3; i >= 0; i--)
+    for (int j = 0; j < 32; j += 4)
       pp += sprintf(CS pp, "%x.", (v6[i] >> j) & 15);
-    }
-  Ustrcpy(pp, "ip6.arpa.");
+  Ustrcpy(pp, US"ip6.arpa.");
 
   /* Another way of doing IPv6 reverse lookups was proposed in conjunction
   with A6 records. However, it fell out of favour when they did. The
@@ -287,12 +281,12 @@ else
   Ustrcpy(pp, "\\[x");
   pp += 3;
 
-  for (i = 0; i < 4; i++)
+  for (int i = 0; i < 4; i++)
     {
     sprintf(pp, "%08X", v6[i]);
     pp += 8;
     }
-  Ustrcpy(pp, "].ip6.arpa.");
+  Ustrcpy(pp, US"].ip6.arpa.");
   **************************************************/
 
   }
@@ -467,11 +461,10 @@ static const uschar *
 dns_extract_auth_name(const dns_answer * dnsa)	/* FIXME: const dns_answer */
 {
 dns_scan dnss;
-dns_record * rr;
 const HEADER * h = (const HEADER *) dnsa->answer;
 
 if (h->nscount && h->aa)
-  for (rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
+  for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
        rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
     if (rr->type == (h->ancount ? T_NS : T_SOA))
       return string_copy(rr->name);
@@ -621,7 +614,7 @@ Returns:     the return code
 static int
 dns_return(const uschar * name, int type, int rc)
 {
-tree_node *node = store_get_perm(sizeof(tree_node) + 290);
+tree_node *node = store_get_perm(sizeof(tree_node) + 290, TRUE);
 dns_fail_tag(node->name, name, type);
 node->data.val = rc;
 (void)tree_insertnode(&tree_dns_fails, node);
@@ -716,7 +709,11 @@ lookup, which constructs the names itself, so they should be OK. Besides,
 bitstring labels don't conform to normal name syntax. (But the aren't used any
 more.)
 
-For SRV records, we omit the initial _smtp._tcp. components at the start. */
+For SRV records, we omit the initial _smtp._tcp. components at the start.
+The check has been seen to bite on the destination of a SRV lookup that
+initiall hit a CNAME, for which the next name had only two components.
+RFC2782 makes no mention of the possibiility of CNAMES, but the Wikipedia
+article on SRV says they are not a valid configuration. */
 
 #ifndef STAND_ALONE   /* Omit this for stand-alone tests */
 
@@ -732,8 +729,8 @@ if (check_dns_names_pattern[0] != 0 && type != T_PTR && type != T_TXT)
 
   if (type == T_SRV || type == T_TLSA)
     {
-    while (*checkname++ != '.');
-    while (*checkname++ != '.');
+    while (*checkname && *checkname++ != '.') ;
+    while (*checkname && *checkname++ != '.') ;
     }
 
   if (pcre_exec(regex_check_dns_names, NULL, CCS checkname, Ustrlen(checkname),
@@ -873,7 +870,6 @@ int
 dns_lookup(dns_answer *dnsa, const uschar *name, int type,
   const uschar **fully_qualified_name)
 {
-int i;
 const uschar *orig_name = name;
 BOOL secure_so_far = TRUE;
 
@@ -884,10 +880,10 @@ resolvers hiding behind a config variable. Loop to follow CNAME chains so far,
 but no further...  The testsuite tests the latter case, mostly assuming that the
 former will work. */
 
-for (i = 0; i <= dns_cname_loops; i++)
+for (int i = 0; i <= dns_cname_loops; i++)
   {
   uschar * data;
-  dns_record *rr, cname_rr, type_rr;
+  dns_record cname_rr, type_rr;
   dns_scan dnss;
   int rc;
 
@@ -903,7 +899,7 @@ for (i = 0; i <= dns_cname_loops; i++)
   area in the dnsa block. */
 
   cname_rr.data = type_rr.data = NULL;
-  for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
+  for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
        rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
     if (rr->type == type)
       {
@@ -950,7 +946,8 @@ for (i = 0; i <= dns_cname_loops; i++)
   if (!cname_rr.data)
     return DNS_FAIL;
 
-  data = store_get(256);
+  /* DNS data comes from the outside, hence tainted */
+  data = store_get(256, TRUE);
   if (dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
       cname_rr.data, (DN_EXPAND_ARG4_TYPE)data, 256) < 0)
     return DNS_FAIL;
@@ -1204,7 +1201,8 @@ if (rr->type == T_A)
   uschar *p = US rr->data;
   if (p + 4 <= dnsa_lim)
     {
-    yield = store_get(sizeof(dns_address) + 20);
+    /* the IP is not regarded as tainted */
+    yield = store_get(sizeof(dns_address) + 20, FALSE);
     (void)sprintf(CS yield->address, "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
     yield->next = NULL;
     }
@@ -1217,9 +1215,8 @@ else
   if (rr->data + 16 <= dnsa_lim)
     {
     struct in6_addr in6;
-    int i;
-    for (i = 0; i < 16; i++) in6.s6_addr[i] = rr->data[i];
-    yield = store_get(sizeof(dns_address) + 50);
+    for (int i = 0; i < 16; i++) in6.s6_addr[i] = rr->data[i];
+    yield = store_get(sizeof(dns_address) + 50, FALSE);
     inet_ntop(AF_INET6, &in6, CS yield->address, 50);
     yield->next = NULL;
     }