constification

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

diff --git a/src/src/spf.c b/src/src/spf.c
index 100e22243502edbd3739a954b68ac20a9e1e6cd2..2e3f861eba6a7ee32c7047f4c42eef4fee00ec0f 100644 (file)
--- a/src/src/spf.c
+++ b/src/src/spf.c
@@ -3,7 +3,7 @@
 *************************************************/
 
 /* SPF support.
-   Copyright (c) The Exim Maintainers 2015 - 2022
+   Copyright (c) The Exim Maintainers 2015 - 2023
    Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 - 2014
    License: GPL
    SPDX-License-Identifier: GPL-2.0-or-later
@@ -97,7 +97,8 @@ switch (dns_lookup(dnsa, US domain, rr_type, NULL))
     srr.herrno = NETDB_SUCCESS;
     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++; break; }
+      /* Need to alloc space for all records, so no early-out */
+      if (rr->type == rr_type) found++;
     break;
   }
 
@@ -121,6 +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:
        {
@@ -136,6 +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",
@@ -143,9 +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)
@@ -335,7 +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;