Callouts: filter smtp response for bad chars before using in our smtp response. ...

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

diff --git a/src/src/verify.c b/src/src/verify.c
index 4422b4ad109bed885ca8063ab25c4db237f289b9..60579668bc0cc173f6766d7f4afd6ea1549142df 100644 (file)
--- a/src/src/verify.c
+++ b/src/src/verify.c
@@ -1001,6 +1001,26 @@ no_conn:
          string_sprintf("response to \"%s\" was: %s",
                          big_buffer, string_printing(sx.buffer));
 
+       /* RFC 5321 section 4.2: the text portion of the response may have only
+       HT, SP, Printable US-ASCII.  Deal with awkward chars by cutting the
+       received message off before passing it onward.  Newlines are ok; they
+       just become a multiline response (but wrapped in the error code we
+       produce). */
+
+       for (uschar * s = sx.buffer;
+            *s && s < sx.buffer + sizeof(sx.buffer);
+            s++)
+         {
+         uschar c = *s;
+         if (c != '\t' && c != '\n' && (c < ' ' || c > '~'))
+           {
+           if (s - sx.buffer < sizeof(sx.buffer) - 12)
+             memcpy(s, "(truncated)", 12);
+           else
+             *s = '\0';
+           break;
+           }
+         }
        addr->user_message = options & vopt_is_recipient
          ? string_sprintf("Callout verification failed:\n%s", sx.buffer)
          : string_sprintf("Called:   %s\nSent:     %s\nResponse: %s",