🚀 go-pugleaf

shellutils-1.6/src/date.c has a bug in that if you pass an invalid format to
it, like "date +%O", then date will go into an infinite loop allocating memory
forever.  Below is a possible fix.  Another fix would be to limit the max
size of 'out' in routine 'show_date' to some "reasonable" value, say like 10k
and if the limit was reached, assume an invalid format.

*** date.c.ORG	Wed Aug 26 09:22:38 1992
--- date.c	Wed Aug 26 09:23:54 1992
***************
*** 175,180 ****
--- 175,181 ----
        printf ("%20.20s", asctime (tm));
        format = "%Z %Y";
      }
+   if( check_format( format, tm ) ) return;
    do
      {
        out_length += 200;
***************
*** 183,188 ****
--- 184,216 ----
    while (strftime (out, out_length, format, tm) == 0);
    printf ("%s\n", out);
    free (out);
+ }
+ 
+ /*
+  * Validate each part of the format.  Assume that no single part will produce
+  * more than TMP_BUF_SIZE characters of output.
+  */
+ #define TMP_BUF_SIZE 100
+ 
+ check_format( format, tm )
+   char *format;
+   struct tm *tm;
+ {
+   char buf[TMP_BUF_SIZE];
+   char op[3];
+ 
+   while( *format ) {
+     op[0] = *format++;
+     if( *format ) op[1] = *format++;
+     else op[1] = 0;
+     op[2] = 0;
+     if( strftime( buf, TMP_BUF_SIZE, op, tm ) == 0 )
+       {
+       printf("Unknown option '%s'\n", op );
+       return(1);
+       }
+     }
+   return(0);
  }
  
  void
-- 
W. Tait Cyrus                   Software Engineer
Convex Computer Corporation     cyrus@convex.com
2075 Research Parkway Suite B   719-594-4900 ext 41
Colorado Springs, CO 80920