Re: FW: ls -l Segmentation fault

[Todd C . Miller]

On Tue, 26 Mar 2024 12:45:09 -0700, guent...@openbsd.org wrote:

> Someone want to craft a diff for ls to handle that (and scan the tree for 
> other unchecked localtime(<uncontrolled data>) calls)?  Not sure if 
> POSIX's ls spec has an out for how to print the time for such a thing.

Another option is to just use the epoch for invalid timestamps.
POSIX doesn't appear to offer guidance in this.  NetBSD prints a
string of '?' and FreeBSD prints "bad date val".

 - todd

Index: bin/ls/print.c
===================================================================
RCS file: /cvs/src/bin/ls/print.c,v
retrieving revision 1.40
diff -u -p -u -r1.40 print.c
--- bin/ls/print.c      7 Oct 2023 11:51:08 -0000       1.40
+++ bin/ls/print.c      26 Mar 2024 19:54:54 -0000
@@ -241,6 +241,7 @@ static void
 printtime(time_t ftime)
 {
        char f_date[DATELEN];
+       struct tm *tm;
        static time_t now;
        static int now_set = 0;
 
@@ -252,9 +253,14 @@ printtime(time_t ftime)
        /*
         * convert time to string, and print
         */
+       if ((tm = localtime(&ftime)) == NULL) {
+               /* Invalid time stamp, just display the epoch. */
+               ftime = 0;
+               tm = localtime(&ftime);
+       }
        if (strftime(f_date, sizeof(f_date), f_sectime ? "%b %e %H:%M:%S %Y" :
            (ftime <= now - SIXMONTHS || ftime > now) ? "%b %e  %Y" :
-           "%b %e %H:%M", localtime(&ftime)) == 0)
+           "%b %e %H:%M", tm) == 0)
                f_date[0] = '\0';
 
        printf("%s ", f_date);