X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/1ddb1855402d48ad735e46abaf0d662e45600ecd..fa1c8faf169384bebaa8d172f491574c45ae2aa4:/src/src/spf.c

diff --git a/src/src/spf.c b/src/src/spf.c
index e3df789fb..2e3f861eb 100644
--- a/src/src/spf.c
+++ b/src/src/spf.c
@@ -3,9 +3,10 @@
 *************************************************/
 
 /* SPF support.
+   Copyright (c) The Exim Maintainers 2015 - 2023
    Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 - 2014
    License: GPL
-   Copyright (c) The Exim Maintainers 2015 - 2021
+   SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 /* Code for calling spf checks via libspf-alt. Called from acl.c. */
@@ -70,7 +71,6 @@ SPF_dns_rr_t srr = {
   .hook = NULL,				/* misc information */
   .source = spf_dns_server
 };
-int dns_rc;
 
 DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup '%s'\n", domain);
 
@@ -86,20 +86,22 @@ if (rr_type == T_SPF)
   return spfrr;
   }
 
-switch (dns_rc = dns_lookup(dnsa, US domain, rr_type, NULL))
+switch (dns_lookup(dnsa, US domain, rr_type, NULL))
   {
-  case DNS_SUCCEED:	srr.herrno = NETDB_SUCCESS;	break;
   case DNS_AGAIN:	srr.herrno = TRY_AGAIN;		break;
   case DNS_NOMATCH:	srr.herrno = HOST_NOT_FOUND;	break;
   case DNS_NODATA:	srr.herrno = NO_DATA;		break;
   case DNS_FAIL:
   default:		srr.herrno = NO_RECOVERY;	break;
+  case DNS_SUCCEED:
+    srr.herrno = NETDB_SUCCESS;
+    for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
+	 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
+      /* Need to alloc space for all records, so no early-out */
+      if (rr->type == rr_type) found++;
+    break;
   }
 
-for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
-     rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
-  if (rr->type == rr_type) found++;
-
 if (found == 0)
   {
   SPF_dns_rr_dup(&spfrr, &srr);
@@ -120,6 +122,7 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
     switch(rr_type)
       {
       case T_MX:
+	if (rr->size < 2) continue;
 	s += 2;	/* skip the MX precedence field */
       case T_PTR:
 	{
@@ -135,6 +138,7 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
 	gstring * g = NULL;
 	uschar chunk_len;
 
+	if (rr->size < 1+6) continue;		/* min for version str */
 	if (strncmpic(rr->data+1, US SPF_VER_STR, 6) != 0)
 	  {
 	  HDEBUG(D_host_lookup) debug_printf("not an spf record: %.*s\n",
@@ -142,9 +146,12 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
 	  continue;
 	  }
 
-	for (int off = 0; off < rr->size; off += chunk_len)
+	/* require 1 byte for the chunk_len */
+	for (int off = 0; off < rr->size - 1; off += chunk_len)
 	  {
-	  if (!(chunk_len = s[off++])) break;
+	  if (  !(chunk_len = s[off++])
+	     || rr->size < off + chunk_len	/* ignore bogus size chunks */
+	     ) break;
 	  g = string_catn(g, s+off, chunk_len);
 	  }
 	if (!g)
@@ -204,7 +211,7 @@ spf_nxdomain = SPF_dns_rr_new_init(spf_dns_server,
   "", ns_t_any, 24 * 60 * 60, HOST_NOT_FOUND);
 if (!spf_nxdomain)
   {
-  free(spf_dns_server);
+  store_free(spf_dns_server);
   return NULL;
   }
 
@@ -334,7 +341,8 @@ else for (int i = 0; i < SPF_response_messages(spf_response); i++)
 Return: OK/FAIL  */
 
 int
-spf_process(const uschar **listptr, uschar *spf_envelope_sender, int action)
+spf_process(const uschar ** listptr, const uschar * spf_envelope_sender,
+  int action)
 {
 int sep = 0;
 const uschar *list = *listptr;
@@ -400,20 +408,31 @@ gstring *
 authres_spf(gstring * g)
 {
 uschar * s;
-if (!spf_result) return g;
-
-g = string_append(g, 2, US";\n\tspf=", spf_result);
-if (spf_result_guessed)
-  g = string_cat(g, US" (best guess record for domain)");
+if (spf_result)
+  {
+  int start = 0;		/* Compiler quietening */
+  DEBUG(D_acl) start = gstring_length(g);
 
-s = expand_string(US"$sender_address_domain");
-if (s && *s)
-  return string_append(g, 2, US" smtp.mailfrom=", s);
+  g = string_append(g, 2, US";\n\tspf=", spf_result);
+  if (spf_result_guessed)
+    g = string_cat(g, US" (best guess record for domain)");
 
-s = sender_helo_name;
-return s && *s
-  ? string_append(g, 2, US" smtp.helo=", s)
-  : string_cat(g, US" smtp.mailfrom=<>");
+  s = expand_string(US"$sender_address_domain");
+  if (s && *s)
+    g = string_append(g, 2, US" smtp.mailfrom=", s);
+  else
+    {
+    s = sender_helo_name;
+    g = s && *s
+      ? string_append(g, 2, US" smtp.helo=", s)
+      : string_cat(g, US" smtp.mailfrom=<>");
+    }
+  DEBUG(D_acl) debug_printf("SPF:\tauthres '%.*s'\n",
+		  gstring_length(g) - start - 3, g->s + start + 3);
+  }
+else
+  DEBUG(D_acl) debug_printf("SPF:\tno authres\n");
+return g;
 }