>Number: 4034
>Category: mod_auth-any
>Synopsis: htpasswd uses small salt
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: apache
>State: open
>Class: sw-bug
>Submitter-Id: apache
>Arrival-Date: Wed Mar 10 17:20:01 PST 1999
>Last-Modified:
>Originator: [EMAIL PROTECTED]
>Organization:
apache
>Release: 1.3.4
>Environment:
FreeBSD wyattearp.stanford.edu 3.1-RELEASE FreeBSD 3.1-RELEASE #1: Sat Mar 6
11:20:34 PST 1999 [EMAIL PROTECTED]:/misc/3.1/usr/src/sys/compile/WYATTEARP
i386
>Description:
Encrypted passwords created by "htpasswd" use 12-bit (two-byte) salts, even on
systems (such as FreeBSD) that use improved password hashing algorithms and can
support longer salts.
>How-To-Repeat:
On a FreeBSD 2.x / 3.x system, configured to use MD5-based password hashing,
create a password file with "htpasswd -c" and note that the salt (between the
second and third dollar signs) is only two bytes long. Compare with the pass-
word strings in /etc/master.passwd, which use longer salts.
>Fix:
The "add_password" routine in htpasswd.c can be enhanced to generate a longer
salt string. Here is a patch that worked for me. Alternatively, the author-
ization code could be rewritten to use a different password scheme altogether.
*** src/support/htpasswd.c.orig Mon Jul 13 04:32:58 1998
--- src/support/htpasswd.c Mon Sep 21 16:21:26 1998
***************
*** 12,17 ****
--- 12,18 ----
#include "ap_config.h"
#include <sys/types.h>
+ #include <sys/time.h>
#include <signal.h>
#ifndef CHARSET_EBCDIC
***************
*** 114,120 ****
static void add_password(char *user, FILE *f)
{
! char *pw, *cpw, salt[3];
pw = strd((char *) getpass("New password:"));
if (strcmp(pw, (char *) getpass("Re-type new password:"))) {
--- 115,122 ----
static void add_password(char *user, FILE *f)
{
! char *pw, *cpw, salt[7];
! struct timeval tv;
pw = strd((char *) getpass("New password:"));
if (strcmp(pw, (char *) getpass("Re-type new password:"))) {
***************
*** 123,131 ****
unlink(tn);
exit(1);
}
! (void) srand((int) time((time_t *) NULL));
! to64(&salt[0], rand(), 2);
! salt[2] = '\0';
cpw = (char *)crypt(pw, salt);
free(pw);
fprintf(f, "%s:%s\n", user, cpw);
--- 125,138 ----
unlink(tn);
exit(1);
}
!
! /* generate longer salt (in case enhanced password code can use it) */
! gettimeofday(&tv, 0);
! srand((unsigned) tv.tv_sec);
! to64(&salt[0], rand(), 3);
! to64(&salt[3], tv.tv_usec, 3);
! salt[6] = '\0';
!
cpw = (char *)crypt(pw, salt);
free(pw);
fprintf(f, "%s:%s\n", user, cpw);
***************
*** 220,225 ****
--- 227,236 ----
{
fputs(command,f);
}
+
+ /* get rid of any excess leftover text in password file */
+ fflush(f);
+ ftruncate(fileno(f), ftell(f));
fclose(f);
fclose(tfp);
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