v. 2021.08.14

Patch for simscan-1.4.1 (https://github.com/qmail/simscan/releases) by Roberto Puzzanghera
More info at https://notes.sagredo.eu/en/qmail-notes-185/simscan-38.html

Simscan doesn't pass messages over 250k to spamassassin. This patch let the administrator set the
attachments' size limit in bytes by setting the /var/qmail/control/simsizelimit file.

Furthermore, events where simscan is not activated are now logged at smtpd level (it was logged
only when debug is active).

Note: this patch is alternative to this one
https://notes.sagredo.eu/files/qmail/patches/simscan/simscan-1.4.1_attachments-size-limit.patch
which sets the limit at compilation time.

===================================================================================================

diff -ruN ../simscan-1.4.1_original/simscan.c simscan-1.4.1/simscan.c
--- ../simscan-1.4.1_original/simscan.c	2015-01-23 09:57:43.000000000 +0100
+++ simscan-1.4.1/simscan.c	2021-08-14 11:29:23.134153119 +0200
@@ -253,6 +253,11 @@
  int i = 0;
  int gotrcpt = 0;
  int gotfrom = 0;
+ /* attachments-size-limit patch */
+ char ch, simsizelimit_file[300], buf[32];
+ FILE *simsizelimit;
+ int size_limit=250000, buflen=0, ibuf;
+ /* end attachments-size-limit patch */
 
   /* print out version information if requested */
   if ( argc > 1 && strcmp(argv[1],"-v" )==0 ) {
@@ -546,11 +551,33 @@
 #endif
 
 #ifdef ENABLE_SPAM
-if (msgsize >= 250000) {
-  if ( DebugFlag > 0 ) {
-    fprintf(stderr, "simscan: big file (%lu bytes); skipping SpamAssassin\n",
-      (unsigned long) msgsize);
+/* attachments-size-limit patch */
+// read control/simsizelimit file
+snprintf(simsizelimit_file, sizeof(simsizelimit_file), "%s/simsizelimit", CONTROLDIR);
+simsizelimit = fopen(simsizelimit_file, "r");
+if( simsizelimit != NULL ) {
+  while(1) {
+    ch = fgetc(simsizelimit);
+    if(ch==EOF || ch==' ' || ch=='\n' || ch=='\t' || ch=='\r') {
+      ibuf = atoi(buf);
+      // returns 0 if it's not an integer
+      if (ibuf > 0) size_limit = ibuf;
+      break;
+    }
+    else {
+      buf[buflen] = ch;
+      buflen++;
+    }
   }
+  fclose(simsizelimit);
+}
+if ( DebugFlag > 0 ) fprintf(stderr, "simscan: size limit is %d bytes\n", size_limit);
+if (msgsize >= size_limit) {
+//  if ( DebugFlag > 0 ) { // now logging also when debug is off
+    fprintf(stderr, "simscan: big file (%lu bytes); size limit is %d bytes; skipping SpamAssassin\n",
+      (unsigned long) msgsize, size_limit);
+//  }
+/* end attachments-size-limit patch */
 } else {
   /* re-open the file read only */
   if ( (fd = open(message_name, O_RDONLY)) == -1 ) {