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 060d3ef510395e1338bb61071e30ab0b21a0a4ca..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 - 2021
    License: GPL */
 
 /* Portions Copyright (c) 2012, 2013, The Trusted Domain Project;
@@ -53,14 +53,12 @@ static dmarc_exim_p dmarc_policy_description[] = {
 };
 
 
-void
-dmarc_version_report(FILE *f)
+gstring *
+dmarc_version_report(gstring * g)
 {
-const char *implementation, *version;
-
-fprintf(f, "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);
+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);
 }
 
 
@@ -232,8 +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;
@@ -461,7 +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)
@@ -532,7 +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);