DNS: explicit alloc/free of workspace

[exim.git] / src / src / dkim.c

diff --git a/src/src/dkim.c b/src/src/dkim.c
index 92adb35897665f650653de3622c639f72800361f..87c9c9197d7c309f463b6f381d1997558efe0a01 100644 (file)
--- a/src/src/dkim.c
+++ b/src/src/dkim.c
@@ -50,11 +50,14 @@ dkim_exim_query_dns_txt(const uschar * name)
 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 */
 
@@ -81,6 +84,7 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
     /* 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);
       }
@@ -90,6 +94,7 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
 
 bad:
 store_reset(reset_point);
+store_free_dns_answer(dnsa);
 return NULL;   /*XXX better error detail?  logging? */
 }
 
@@ -109,12 +114,15 @@ dkim_exim_verify_init(BOOL dot_stuffing)
 {
 dkim_exim_init();
 
-/* There is a store-reset between header & body reception
-so cannot use the main pool. Any allocs done by Exim
-memory-handling must use the perm pool. */
+/* There is a store-reset between header & body reception for the main pool
+(actually, after every header line) so cannot use that as we need the data we
+store per-header, during header processing, at the end of body reception
+for evaluating the signature.  Any allocs done for dkim verify
+memory-handling must use a different pool.  We use a separate one that we
+can reset per message. */
 
 dkim_verify_oldpool = store_pool;
-store_pool = POOL_PERM;
+store_pool = POOL_MESSAGE;
 
 /* Free previous context if there is one */
 
@@ -139,7 +147,7 @@ dkim_exim_verify_feed(uschar * data, int len)
 {
 int rc;
 
-store_pool = POOL_PERM;
+store_pool = POOL_MESSAGE;
 if (  dkim_collect_input
    && (rc = pdkim_feed(dkim_verify_ctx, data, len)) != PDKIM_OK)
   {
@@ -305,7 +313,7 @@ int rc;
 gstring * g = NULL;
 const uschar * errstr = NULL;
 
-store_pool = POOL_PERM;
+store_pool = POOL_MESSAGE;
 
 /* Delete eventual previous signature chain */