X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/79e5ebf9e9bb833ce004be65c04b2f8eea91c337..654056e44fc93a0ee7c09d1228933e8af6862206:/src/src/spf.c

diff --git a/src/src/spf.c b/src/src/spf.c
index fd9831c43..1981d81b6 100644
--- a/src/src/spf.c
+++ b/src/src/spf.c
@@ -3,9 +3,9 @@
 *************************************************/
 
 /* SPF support.
+   Copyright (c) The Exim Maintainers 2015 - 2022
    Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 - 2014
    License: GPL
-   Copyright (c) The Exim Maintainers 2015 - 2020
 */
 
 /* Code for calling spf checks via libspf-alt. Called from acl.c. */
@@ -34,15 +34,17 @@ SPF_response_t  *spf_response_2mx = NULL;
 SPF_dns_rr_t  * spf_nxdomain = NULL;
 
 
-void
-spf_lib_version_report(FILE * fp)
+gstring *
+spf_lib_version_report(gstring * g)
 {
 int maj, min, patch;
+
 SPF_get_lib_version(&maj, &min, &patch);
-fprintf(fp, "Library version: spf2: Compile: %d.%d.%d\n",
+g = string_fmt_append(g, "Library version: spf2: Compile: %d.%d.%d\n",
 	SPF_LIB_VERSION_MAJOR, SPF_LIB_VERSION_MINOR, SPF_LIB_VERSION_PATCH);
-fprintf(fp, "                       Runtime: %d.%d.%d\n",
+g = string_fmt_append(g,    "                       Runtime: %d.%d.%d\n",
 	 maj, min, patch);
+return g;
 }
 
 
@@ -72,15 +74,15 @@ int dns_rc;
 
 DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup '%s'\n", domain);
 
-/* Shortcircuit SPF RR lookups by returning HOST_NOT_FOUND (shortest code path
-in libspf2).  They were obsoleted by RFC 6686/7208 years ago. see bug #1294
-*/
+/* Shortcircuit SPF RR lookups by returning NO_DATA.  They were obsoleted by
+RFC 6686/7208 years ago. see bug #1294 */
 
 if (rr_type == T_SPF)
   {
-  HDEBUG(D_host_lookup) debug_printf("faking HOST_NOT_FOUND for SPF RR(99) lookup\n");
-  srr.herrno = HOST_NOT_FOUND;
+  HDEBUG(D_host_lookup) debug_printf("faking NO_DATA for SPF RR(99) lookup\n");
+  srr.herrno = NO_DATA;
   SPF_dns_rr_dup(&spfrr, &srr);
+  store_free_dns_answer(dnsa);
   return spfrr;
   }
 
@@ -92,7 +94,7 @@ switch (dns_rc = dns_lookup(dnsa, US domain, rr_type, NULL))
   case DNS_NODATA:	srr.herrno = NO_DATA;		break;
   case DNS_FAIL:
   default:		srr.herrno = NO_RECOVERY;	break;
-  } 
+  }
 
 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
      rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
@@ -101,6 +103,7 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
 if (found == 0)
   {
   SPF_dns_rr_dup(&spfrr, &srr);
+  store_free_dns_answer(dnsa);
   return spfrr;
   }
 
@@ -117,6 +120,7 @@ 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:
 	{
@@ -132,6 +136,7 @@ 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",
@@ -139,9 +144,12 @@ 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)
@@ -172,6 +180,7 @@ if (!(srr.num_rr = found))
 
 /* spfrr->rr must have been malloc()d for this */
 SPF_dns_rr_dup(&spfrr, &srr);
+store_free_dns_answer(dnsa);
 return spfrr;
 }
 
@@ -219,6 +228,7 @@ spf_init(void)
 {
 SPF_dns_server_t * dc;
 int debug = 0;
+const uschar *s;
 
 DEBUG(D_receive) debug = 1;
 
@@ -241,11 +251,16 @@ if (!(spf_server = SPF_server_new_dns(dc, debug)))
   DEBUG(D_receive) debug_printf("spf: SPF_server_new() failed.\n");
   return FALSE;
   }
-  /* Quick hack to override the outdated explanation URL.
-  See https://www.mail-archive.com/mailop@mailop.org/msg08019.html */
-  SPF_server_set_explanation(spf_server, "Please%_see%_http://www.open-spf.org/Why?id=%{S}&ip=%{C}&receiver=%{R}", &spf_response);
-  if (SPF_response_errcode(spf_response) != SPF_E_SUCCESS)
-    log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", SPF_strerror(SPF_response_errcode(spf_response)));
+  /* Override the outdated explanation URL.
+  See https://www.mail-archive.com/mailop@mailop.org/msg08019.html
+  Used to work as "Please%_see%_http://www.open-spf.org/Why?id=%{S}&ip=%{C}&receiver=%{R}",
+  but is broken now (May 18th, 2020) */
+if (!(s = expand_string(spf_smtp_comment_template)))
+  log_write(0, LOG_MAIN|LOG_PANIC_DIE, "expansion of spf_smtp_comment_template failed");
+
+SPF_server_set_explanation(spf_server, CCS s, &spf_response);
+if (SPF_response_errcode(spf_response) != SPF_E_SUCCESS)
+  log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", SPF_strerror(SPF_response_errcode(spf_response)));
 
 return TRUE;
 }
@@ -397,8 +412,12 @@ if (spf_result_guessed)
   g = string_cat(g, US" (best guess record for domain)");
 
 s = expand_string(US"$sender_address_domain");
+if (s && *s)
+  return string_append(g, 2, US" smtp.mailfrom=", s);
+
+s = sender_helo_name;
 return s && *s
-  ? string_append(g, 2, US" smtp.mailfrom=", s)
+  ? string_append(g, 2, US" smtp.helo=", s)
   : string_cat(g, US" smtp.mailfrom=<>");
 }