Date: Wed, 12 Jan 2000 05:50:01 -0800 (PST) From: Daniel Hagan <dhagan@cs.vt.edu> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/4238 - chpass time delay sensitivity [PATCH] Message-ID: <200001121350.FAA31156@freefall.freebsd.org>
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The following reply was made to PR bin/4238; it has been noted by GNATS.
From: Daniel Hagan <dhagan@cs.vt.edu>
To: John Polstra <jdp@polstra.com>
Cc: freebsd-gnats-submit@freebsd.org, jhb@freebsd.org
Subject: Re: bin/4238 - chpass time delay sensitivity [PATCH]
Date: Wed, 12 Jan 2000 08:45:03 -0500 (EST)
On Tue, 11 Jan 2000, John Polstra wrote:
> I can't decide whether you should be ridiculed mercilessly for this
> disgusting hack, or hailed as a genuine genius. :-) I would rule
> it out in an instant, except that the file's only a temporary file
> anyway. I guess it's OK, but don't tell anybody I said so.
I would vote for the disgusting hack category myself :). I was
complaining to John Baldwin (jhb) about it, and he mentioned the
work-around (I never would have thought of it, being too tied to my
anti-disgusting-hack philosophy). It seems harmless enough in this
special case, but I won't take it personally if someone cans the patch.
> Minor style nit: you should remove the redundant parentheses in the
> gettimeofday() calls.
Ok, taken care of. Here's the updated diff (in context diff format even
;-))
Index: edit.c
===================================================================
RCS file: /src/cvs/src/usr.bin/chpass/edit.c,v
retrieving revision 1.16
diff -c -r1.16 edit.c
*** edit.c 1999/12/21 19:30:09 1.16
--- edit.c 2000/01/12 13:31:30
***************
*** 39,44 ****
--- 39,45 ----
#include <sys/param.h>
#include <sys/stat.h>
+ #include <sys/time.h>
#include <ctype.h>
#include <err.h>
***************
*** 65,72 ****
--- 66,84 ----
struct passwd *pw;
{
struct stat begin, end;
+ struct timeval temp_time[2];
for (;;) {
+ /*
+ * Avoid race condition when user edits file in under a
+ * second by back-dating file.
+ */
+ gettimeofday(&temp_time[0], NULL);
+ gettimeofday(&temp_time[1], NULL);
+ temp_time[1].tv_sec--;
+ if (utimes(tempname, temp_time))
+ pw_error(tempname, 1, 1);
+
if (stat(tempname, &begin))
pw_error(tempname, 1, 1);
pw_edit(1);
--
Daniel Hagan Computer Science CSE
dhagan@cs.vt.edu http://www.cs.vt.edu/~dhagan/
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