DMARC: fix use-after-free in dmarc_dns_lookup

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

diff --git a/src/src/dmarc.c b/src/src/dmarc.c
index 5328f4f7da48f279bddb8eb3bb848479a5b0aab7..53c2752ac6cd347183847ed7032d39f7e4470aa5 100644 (file)
--- a/src/src/dmarc.c
+++ b/src/src/dmarc.c
@@ -2,8 +2,8 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 /* DMARC support.
+   Copyright (c) The Exim Maintainers 2019 - 2022
    Copyright (c) Todd Lyons <tlyons@exim.org> 2012 - 2014
-   Copyright (c) The Exim Maintainers 2019
    License: GPL */
 
 /* Portions Copyright (c) 2012, 2013, The Trusted Domain Project;
@@ -51,21 +51,32 @@ static dmarc_exim_p dmarc_policy_description[] = {
   { US"reject",     DMARC_RECORD_P_REJECT },
   { NULL,           0 }
 };
+
+
+gstring *
+dmarc_version_report(gstring * g)
+{
+return string_fmt_append(g, "Library version: dmarc: Compile: %d.%d.%d.%d\n",
+    (OPENDMARC_LIB_VERSION & 0xff000000) >> 24, (OPENDMARC_LIB_VERSION & 0x00ff0000) >> 16,
+    (OPENDMARC_LIB_VERSION & 0x0000ff00) >> 8, OPENDMARC_LIB_VERSION & 0x000000ff);
+}
+
+
 /* Accept an error_block struct, initialize if empty, parse to the
- * end, and append the two strings passed to it.  Used for adding
- * variable amounts of value:pair data to the forensic emails. */
+end, and append the two strings passed to it.  Used for adding
+variable amounts of value:pair data to the forensic emails. */
 
 static error_block *
 add_to_eblock(error_block *eblock, uschar *t1, uschar *t2)
 {
 error_block *eb = store_malloc(sizeof(error_block));
-if (eblock == NULL)
+if (!eblock)
   eblock = eb;
 else
   {
   /* Find the end of the eblock struct and point it at eb */
   error_block *tmp = eblock;
-  while(tmp->next != NULL)
+  while(tmp->next)
     tmp = tmp->next;
   tmp->next = eb;
   }
@@ -76,8 +87,8 @@ return eblock;
 }
 
 /* dmarc_init sets up a context that can be re-used for several
-   messages on the same SMTP connection (that come from the
-   same host with the same HELO string) */
+messages on the same SMTP connection (that come from the
+same host with the same HELO string) */
 
 int
 dmarc_init()
@@ -219,8 +230,9 @@ if (rc == DNS_SUCCEED)
        rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
     if (rr->type == T_TXT && rr->size > 3)
       {
+      uschar *record = string_copyn_taint(US rr->data, rr->size, GET_TAINTED);
       store_free_dns_answer(dnsa);
-      return string_copyn_taint(US rr->data, rr->size, TRUE);
+      return record;
       }
 store_free_dns_answer(dnsa);
 return NULL;
@@ -241,7 +253,7 @@ if (!dmarc_history_file)
   DEBUG(D_receive) debug_printf("DMARC history file not set\n");
   return DMARC_HIST_DISABLED;
   }
-history_file_fd = log_create(dmarc_history_file);
+history_file_fd = log_open_as_exim(dmarc_history_file);
 
 if (history_file_fd < 0)
   {
@@ -448,7 +460,12 @@ if (!dmarc_abort && !sender_host_authenticated)
                  vs == PDKIM_VERIFY_INVALID ? DMARC_POLICY_DKIM_OUTCOME_TMPFAIL :
                  DMARC_POLICY_DKIM_OUTCOME_NONE;
     libdm_status = opendmarc_policy_store_dkim(dmarc_pctx, US sig->domain,
-                                              dkim_result, US"");
+/* The opendmarc project broke its API in a way we can't detect * easily.
+ * The EDITME provides a DMARC_API variable */
+#if DMARC_API >= 100400
+                                               sig->selector,
+#endif
+                                               dkim_result, US"");
     DEBUG(D_receive)
       debug_printf("DMARC adding DKIM sender domain = %s\n", sig->domain);
     if (libdm_status != DMARC_PARSE_OKAY)
@@ -519,7 +536,7 @@ if (!dmarc_abort && !sender_host_authenticated)
   /* Can't use exim's string manipulation functions so allocate memory
   for libopendmarc using its max hostname length definition. */
 
-  dmarc_domain = store_get(DMARC_MAXHOSTNAMELEN, TRUE);
+  dmarc_domain = store_get(DMARC_MAXHOSTNAMELEN, GET_TAINTED);
   libdm_status = opendmarc_policy_fetch_utilized_domain(dmarc_pctx,
     dmarc_domain, DMARC_MAXHOSTNAMELEN-1);
   store_release_above(dmarc_domain + Ustrlen(dmarc_domain)+1);