Portál AbcLinuxu, 12. května 2025 10:45
/etc/shadowzkousel jsem
echo "mojeheslo" | md5sumale vysledek se neshodoval se zaznamem v souboru shadow. Zajimalo by me jakym zpusobem se vytvareji zasifrovana hesla. Mam distribuci Ubuntu 7.10
$ cat /etc/pam.d/common-password # # /etc/pam.d/common-password - password-related modules common to all services # # This file is included from other service-specific PAM config files, # and should contain a list of modules that define the services to be # used to change user passwords. The default is pam_unix. # Explanation of pam_unix options: # # The "nullok" option allows users to change an empty password, else # empty passwords are treated as locked accounts. # # The "md5" option enables MD5 passwords. Without this option, the # default is Unix crypt. # # The "obscure" option replaces the old `OBSCURE_CHECKS_ENAB' option in # login.defs. # # You can also use the "min" option to enforce the length of the new # password. # # See the pam_unix manpage for other options. password required pam_unix.so nullok obscure md5 # Alternate strength checking for password. Note that this # requires the libpam-cracklib package to be installed. # You will need to comment out the password line above and # uncomment the next two in order to use this. # (Replaces the `OBSCURE_CHECKS_ENAB', `CRACKLIB_DICTPATH') # # password required pam_cracklib.so retry=3 minlen=6 difok=3 # password required pam_unix.so use_authtok nullok md5Diky za vysvetleni!
28.12.2007 23:01
kozzi | skóre: 55
| blog: vse_o_vsem
| Pacman (Bratrušov)
$1$
chpasswd nebo si můžete napsat vlastní nadstavbu nad knihovní funkci crypt(). Pokud vám jde o pochopení používaných algoritmů, tak to není na odpověď do poradny, spíš na článek.
$ chpasswd bash: chpasswd: command not found $ apt-cache search chpasswd $
deb http://ftp.cz.debian.org/debian jessie main contrib non-free$ chpasswd bash: chpasswd: command not found $ whereis chpasswd chpasswd: /usr/sbin/chpasswd /usr/share/man/man8/chpasswd.8.gz $
deb http://ftp.cz.debian.org/debian jessie main contrib non-free
/* * Encrypt the password, then wipe the cleartext password. */ cp = pw_encrypt (pass, crypt_make_salt ()); memzero (pass, sizeof pass);A když se podívaš jak je definovaná funkce pw_encrypt v souboru contrib/pwdauth.c tak zjištíš zaprvé
/* * Define HAVE_PW_ENCRYPT to use pw_encrypt() instead of crypt(). * pw_encrypt() is like the standard crypt(), except that it may * support better password hashing algorithms. ...Takže jde vlastne o standartni fci z glibc, o ktere si muzeme precist nasledujici text z glibc manualu..
32.3 Encrypting Passwords
=========================
-- Function: char * crypt (const char *KEY, const char *SALT)
The `crypt' function takes a password, KEY, as a string, and a
SALT character array which is described below, and returns a
printable ASCII string which starts with another salt. It is
believed that, given the output of the function, the best way to
find a KEY that will produce that output is to guess values of KEY
until the original value of KEY is found.
The SALT parameter does two things. Firstly, it selects which
algorithm is used, the MD5-based one or the DES-based one.
Secondly, it makes life harder for someone trying to guess
passwords against a file containing many passwords; without a
SALT, an intruder can make a guess, run `crypt' on it once, and
compare the result with all the passwords. With a SALT, the
intruder must run `crypt' once for each different salt.
For the MD5-based algorithm, the SALT should consist of the string
`$1$', followed by up to 8 characters, terminated by either
another `$' or the end of the string. The result of `crypt' will
be the SALT, followed by a `$' if the salt didn't end with one,
followed by 22 characters from the alphabet `./0-9A-Za-z', up to
34 characters total. Every character in the KEY is significant.
For the DES-based algorithm, the SALT should consist of two
characters from the alphabet `./0-9A-Za-z', and the result of
`crypt' will be those two characters followed by 11 more from the
same alphabet, 13 in total. Only the first 8 characters in the
KEY are significant.
The MD5-based algorithm has no limit on the useful length of the
password used, and is slightly more secure. It is therefore
preferred over the DES-based algorithm.
When the user enters their password for the first time, the SALT
should be set to a new string which is reasonably random. To
verify a password against the result of a previous call to
`crypt', pass the result of the previous call as the SALT.
The following short program is an example of how to use `crypt' the
first time a password is entered. Note that the SALT generation is
just barely acceptable; in particular, it is not unique between
machines, and in many applications it would not be acceptable to let an
attacker know what time the user's password was last set.
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <crypt.h>
int
main(void)
{
unsigned long seed[2];
char salt[] = "$1$........";
const char *const seedchars =
"./0123456789ABCDEFGHIJKLMNOPQRST"
"UVWXYZabcdefghijklmnopqrstuvwxyz";
char *password;
int i;
/* Generate a (not very) random seed.
You should do it better than this... */
seed[0] = time(NULL);
seed[1] = getpid() ^ (seed[0] >> 14 & 0x30000);
/* Turn it into printable characters from `seedchars'. */
for (i = 0; i < 8; i++)
salt[3+i] = seedchars[(seed[i/5] >> (i%5)*6) & 0x3f];
/* Read in the user's password and encrypt it. */
password = crypt(getpass("Password:"), salt);
/* Print the results. */
puts(password);
return 0;
}
The next program shows how to verify a password. It prompts the user
for a password and prints "Access granted." if the user types `GNU libc
manual'.
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <crypt.h>
int
main(void)
{
/* Hashed form of "GNU libc manual". */
const char *const pass = "$1$/iSaq7rB$EoUw5jJPPvAPECNaaWzMK/";
char *result;
int ok;
/* Read in the user's password and encrypt it,
passing the expected password in as the salt. */
result = crypt(getpass("Password:"), pass);
/* Test the result. */
ok = strcmp (result, pass) == 0;
puts(ok ? "Access granted." : "Access denied.");
return ok ? 0 : 1;
}
-- Function: char * crypt_r (const char *KEY, const char *SALT, struct
crypt_data * DATA)
The `crypt_r' function does the same thing as `crypt', but takes
an extra parameter which includes space for its result (among
other things), so it can be reentrant. `data->initialized' must be
cleared to zero before the first time `crypt_r' is called.
The `crypt_r' function is a GNU extension.
The `crypt' and `crypt_r' functions are prototyped in the header
`crypt.h'.
Z cehoz teda vyplyva ze hash jednoho retezce muze byt ruzny, protoze zalezi jeste na salt, ktery se voli pri tvorbe toho hesla.. navic muze heslo byt DES nebo MD5. Takze obycejnym hranim si s pipe a md5sum to asi nepujde.. Pro dalsi info doporucuju stahnout si manual ke gnu libc a cist..
gcc -lcrypt -o checkPasswd checkPasswd.c
Dostal jsem pocitac na kterem je jakasi stara distribuce linuxu. A nemam k tomu heslo.
Kdyz z neho vyndam HDD, pripojim si ho do sveho pocitace, a stahnu si soubor /etc/passwd a shadow. Tak bez zdrojovych kodu te stare distribuce nemam sanci zmenit rootovske heslo, nebo pridat si vlastni ucet?
29.12.2007 12:59
pdp7 | skóre: 33
| blog: Mravenec_v_LCD_monitoru
| Zákupy u České lípy
29.12.2007 14:37
Jakub Lucký | skóre: 40
| Praha
root password (or type Ctrl-D to continue):
29.12.2007 14:00
Jakub Lucký | skóre: 40
| Praha
a-zA-Z0-9./', je to DES. Je-li na začátku $2a$, je to blowfish. Je-li tam něco jiného, bude to něco jiného.
a-zA-Z0-9/.' a je-li jich třináct, pak je to téměř jistě tradiční DES.
30.12.2007 10:44
stativ | skóre: 54
| blog: SlaNé roury
30.12.2007 10:53
stativ | skóre: 54
| blog: SlaNé roury
chpasswd (OpenSuSE 10.3) se podle dokumentace (i podle pokusů) řídí souborem /etc/default/passwd a není-li tam algoritmus definován, použije DES. Neoznačil bych to za díru pam_unix2, ale spíš za chybu (nebo vlastnost - podle vkusu) chpasswd (že se neřídí PAM).
30.12.2007 12:14
stativ | skóre: 54
| blog: SlaNé roury
chpasswd nastavení CRYPT bere v úvahu i při změně hesla, přestože by ho podle dokumentace měl použít jen v případě, že v /etc/shadow zatím žádný hash není… :-)
29.12.2007 21:36
Jakub Lucký | skóre: 40
| Praha
30.12.2007 12:02
Jakub Lucký | skóre: 40
| Praha
. |-- b.lrp |-- cur.lrp |-- dhcpd.lrp |-- etc.lrp |-- etherw.lrp |-- initrd.lrp |-- ipsec.lrp |-- iptables.lrp |-- ldlinux.sys |-- linux |-- local.lrp |-- m.lrp |-- mawk.lrp |-- mc.lrp |-- modules.lrp |-- netutils.lrp |-- nmap.lrp |-- pcmcia.lrp |-- qos-htb.lrp |-- readme |-- root.lrp |-- router.tar |-- ssh.lrp |-- sshd.lrp |-- sshkey.lrp |-- syslinux.cfg |-- syslinux.dpy |-- t.lrp |-- tc.lrp |-- tcpdump.lrp |-- vypis |-- wireless.lrp |-- wireutil.lrp `-- zebedee.lrpA zde rozbalene lrp soubory:
|-- bin | |-- POSIXness | |-- ae | |-- df | |-- e3 | |-- e3em -> e3 | |-- e3ne -> e3 | |-- e3pi -> e3 | |-- e3vi -> e3 | |-- e3ws -> e3 | |-- edit | |-- editor -> e3ne | |-- grep | |-- netstat | |-- ping | |-- run-parts | |-- tinylogin | |-- vi | `-- zebedee |-- etc | |-- | |-- POSIXness.conf | |-- adjtime | |-- cron.d | | |-- cbq | | |-- multicron | | `-- ntpdate | |-- cron.daily | | `-- multicron-d | |-- cron.monthly | | `-- multicron-m -> ../cron.daily/multicron-d | |-- cron.weekly | | `-- multicron-w -> ../cron.daily/multicron-d | |-- crontab | |-- default | | |-- ntp-servers | | |-- pcmcia | | `-- rcS | |-- dhcpd.conf | |-- exports | |-- fstab | |-- group | |-- gshadow | |-- host.conf | |-- hostname | |-- hosts | |-- hosts.allow | |-- hosts.deny | |-- inetd.conf | |-- init.d | | |-- bootmisc.sh | | |-- cbq.init | | |-- checkroot.sh | | |-- cron | | |-- dhcpd | | |-- dyna-tx | | |-- firewall | | |-- halt | | |-- hostname.sh | | |-- htb.init | | |-- hwclock | | |-- ifupdown | | |-- inetd | | |-- ipsec | | |-- modutils | | |-- mountall.sh | | |-- mountnfs.sh | | |-- networking | | |-- ntpdate | | |-- pcmcia | | |-- rc | | |-- rcS | | |-- reboot | | |-- rmnologin | | |-- sendsigs | | |-- single | | |-- sshd | | |-- sysklogd | | |-- umountfs | | |-- urandom | | `-- watchdog | |-- inittab | |-- ioctl.save | |-- iproute2 | | |-- rt_dsfield | | |-- rt_protos | | |-- rt_realms | | |-- rt_scopes | | `-- rt_tables | |-- ipsec | |-- ipsec.conf | |-- ipsec.secrets | |-- issue | |-- issue.net | |-- localtime | |-- lrp.conf | |-- modules | |-- motd | |-- multicron-p -> cron.daily/multicron-d | |-- network | | |-- if-down.d | | |-- if-post-down.d | | | `-- bridge | | |-- if-pre-up.d | | | |-- bridge | | | `-- wireless | | |-- if-up.d | | | `-- bridge | | |-- ifstate | | |-- interfaces | | `-- options | |-- networks | |-- nsswitch.conf | |-- passwd | |-- pcmcia | | |-- cis | | | |-- 3CCFEM556.dat | | | |-- 3CXEM556.dat | | | |-- COMpad2.dat | | | |-- COMpad4.dat | | | |-- DP83903.dat | | | |-- E-CARD.dat | | | |-- LA-PCM.dat | | | |-- MT5634ZLX.dat | | | |-- NE2K.dat | | | |-- PCMLM28.dat | | | |-- PE-200.dat | | | |-- PE520.dat | | | |-- RS-COM-2P.dat | | | `-- tamarack.dat | | |-- config | | |-- config.opts | | |-- fw.conf | | |-- network | | |-- serial | | |-- shared | | |-- wireless | | `-- wireless.opts | |-- profile | |-- protocols | |-- psdevtab | |-- rc.boot | |-- rc0.d | |-- rc1.d | |-- rc2.d | |-- rc3.d | |-- rc4.d | |-- rc5.d | |-- rc6.d | |-- rcS.d | |-- resolv.conf | |-- rpc | |-- securetty | |-- services | |-- shadow | |-- shadow- | |-- shells | |-- shorewall | |-- ssh | | |-- authorized_keys | | |-- moduli | | |-- ssh_config | | |-- ssh_host_dsa_key | | |-- ssh_host_dsa_key.pub | | |-- ssh_host_key | | |-- ssh_host_key.pub | | |-- ssh_host_rsa_key | | |-- ssh_host_rsa_key.pub | | `-- sshd_config | |-- sysconfig | | |-- cbq | | `-- htb | | |-- eth0 | | |-- eth0-2.root | | |-- eth0-2:10.minlatency | | |-- eth0-2:20.maxthroughput | | |-- eth0-2:30.www | | |-- eth0-2:40.default | | |-- eth1 | | |-- eth1-2.root | | |-- eth1-2:10.minlatency | | |-- eth1-2:20.maxthroughput | | |-- eth1-2:30.www | | |-- eth1-2:40.default | | |-- eth2 | | |-- eth2-2.root | | |-- eth2-2:10.minlatency | | |-- eth2-2:20.maxthroughput | | |-- eth2-2:30.www | | `-- eth2-2:40.default | `-- syslog.conf |-- initrd |-- install | `-- doinst.sh |-- ldlinux.sys |-- lib | |-- POSIXness | | |-- POSIXness.linuxrouter | | |-- POSIXness.mail | | `-- POSIXness.system | |-- ipsec | | |-- _confread | | |-- _copyright | | |-- _include | | |-- _keycensor | | |-- _pluto_adns | | |-- _plutoload | | |-- _plutorun | | |-- _realsetup | | |-- _secretcensor | | |-- _startklips | | |-- _updown | | |-- _updown.x509 | | |-- auto | | |-- barf | | |-- eroute | | |-- ikeping | | |-- ipsec | | |-- ipsec_pr.template | | |-- klipsdebug | | |-- look | | |-- manual | | |-- newhostkey | | |-- pf_key | | |-- pluto | | |-- ranbits | | |-- rsasigkey | | |-- send-pr | | |-- setup -> /etc/init.d/ipsec | | |-- showdefaults | | |-- showhostkey | | |-- spi | | |-- spigrp | | |-- tncfg | | `-- whack | |-- iptables | | |-- libipt_DNAT.so | | |-- libipt_DSCP.so | | |-- libipt_ECN.so | | |-- libipt_LOG.so | | |-- libipt_MARK.so | | |-- libipt_MASQUERADE.so | | |-- libipt_MIRROR.so | | |-- libipt_REDIRECT.so | | |-- libipt_REJECT.so | | |-- libipt_SAME.so | | |-- libipt_SNAT.so | | |-- libipt_TARPIT.so | | |-- libipt_TCPMSS.so | | |-- libipt_TOS.so | | |-- libipt_TTL.so | | |-- libipt_ULOG.so | | |-- libipt_ah.so | | |-- libipt_conntrack.so | | |-- libipt_dscp.so | | |-- libipt_ecn.so | | |-- libipt_esp.so | | |-- libipt_helper.so | | |-- libipt_icmp.so | | |-- libipt_iplimit.so | | |-- libipt_length.so | | |-- libipt_limit.so | | |-- libipt_mac.so | | |-- libipt_mark.so | | |-- libipt_multiport.so | | |-- libipt_owner.so | | |-- libipt_physdev.so | | |-- libipt_pkttype.so | | |-- libipt_quota.so | | |-- libipt_rpc.so | | |-- libipt_standard.so | | |-- libipt_state.so | | |-- libipt_stealth.so | | |-- libipt_tcp.so | | |-- libipt_tcpmss.so | | |-- libipt_tos.so | | |-- libipt_ttl.so | | |-- libipt_udp.so | | `-- libipt_unclean.so | |-- libcrypt-2.0.7.so | |-- libcrypt.so.1 -> libcrypt-2.0.7.so | |-- libdl-2.0.7.so | |-- libdl.so.2 -> libdl-2.0.7.so | |-- libm-2.0.7.so | |-- libm.so.6 -> libm-2.0.7.so | |-- libncurses.so.3.4 -> libncurses.so.4 | |-- libncurses.so.4 | |-- libnss_dns-2.0.7.so | |-- libnss_dns.so.1 -> libnss_dns-2.0.7.so | |-- libnss_files-2.0.7.so | |-- libnss_files.so.1 -> libnss_files-2.0.7.so | |-- libproc.so.1.2.6 | |-- libresolv-2.0.7.so | |-- libresolv.so.2 -> libresolv-2.0.7.so | |-- libss.so.2 -> libss.so.2.0 | |-- libss.so.2.0 | |-- libutil-2.0.7.so | |-- libutil.so.1 -> libutil-2.0.7.so | |-- modules | `-- zebedee | `-- server.zbd |-- linux |-- null |-- readme |-- root |-- sbin | |-- arp | |-- cardmgr | |-- clock -> ./hwclock | |-- halt | |-- htb.init | |-- hwclock | |-- ifconfig | |-- ifdown -> ifup | |-- ifup | |-- init | |-- ip | |-- ipsec | |-- iptables | |-- iwconfig | |-- iwevent | |-- iwgetid | |-- iwlist | |-- iwpriv | |-- iwspy | |-- killall5 | |-- klogd | |-- mkswap | |-- pidof -> killall5 | |-- reboot | |-- route | |-- runlevel | |-- shutdown | |-- start-stop-daemon | |-- swapon | |-- syslogd | |-- tc | `-- telinit -> init |-- syslinux.cfg |-- syslinux.dpy |-- usr | |-- adm -> ../var/log | |-- bin | | |-- awk -> /usr/bin/mawk | | |-- backupdisk | | |-- column | | |-- fdformat | | |-- find | | |-- makekey | | |-- mawk | | |-- mc | | |-- mcmfmt | | |-- mcserv | | |-- nmap | | |-- savelog | | |-- scp | | |-- ssh | | |-- ssh-keygen | | |-- top | | `-- xargs | |-- etc | | `-- mc.global | |-- lib | | `-- mc | | |-- bin | | | |-- cons.saver | | | |-- mc.csh | | | |-- mc.sh | | | `-- mcfn_install | | |-- desktop-scripts | | | |-- README.desktop | | | `-- startup.links | | |-- edit.indent.rc | | |-- extfs | | | |-- a | | | |-- deb | | | |-- extfs.ini | | | |-- ftplist | | | |-- hp48 | | | |-- lslR | | | |-- mailfs | | | |-- patchfs | | | |-- readme | | | |-- rpm | | | |-- rpms | | | |-- sfs.ini | | | |-- trpm | | | |-- uar | | | |-- uarj | | | |-- ucpio | | | |-- uha | | | |-- ulha | | | |-- unarj.diff | | | |-- urar | | | |-- uzip | | | `-- uzoo | | |-- faq | | |-- mc-gnome.ext | | |-- mc.csh | | |-- mc.ext | | |-- mc.hint | | |-- mc.hint.cs | | |-- mc.hint.es | | |-- mc.hint.ru | | |-- mc.hlp | | |-- mc.lib | | |-- mc.menu | | |-- mc.sh | | |-- syntax | | | |-- ada95.syntax | | | |-- c.syntax | | | |-- changelog.syntax | | | |-- diff.syntax | | | |-- fortran.syntax | | | |-- html.syntax | | | |-- java.syntax | | | |-- latex.syntax | | | |-- lsm.syntax | | | |-- mail.syntax | | | |-- makefile.syntax | | | |-- ml.syntax | | | |-- nroff.syntax | | | |-- pascal.syntax | | | |-- perl.syntax | | | |-- python.syntax | | | |-- sh.syntax | | | |-- smalltalk.syntax | | | |-- swig.syntax | | | |-- texinfo.syntax | | | `-- unknown.syntax | | `-- term | | |-- README.xterm | | |-- ansi.ti | | |-- linux.ti | | |-- vt100.ti | | |-- xterm.ad | | |-- xterm.tcap | | `-- xterm.ti | |-- local | | `-- bin | | |-- bmon | | |-- fw | | `-- telnet | |-- sbin | | |-- brctl | | |-- cron | | |-- dhcpd | | |-- ether-wake | | |-- icmpinfo | | |-- inetd | | |-- lrcfg | | |-- lrcfg.back | | |-- lrcfg.back.initrd | | |-- lrcfg.back.script | | |-- lrcfg.conf | | |-- lrcfg.conf.packs | | |-- ntpdate | | |-- ntptimeset | | |-- sshd | | |-- tcpd | | |-- tcpdump | | |-- ticker | | |-- traceroute | | `-- watchdog | `-- share | |-- idl | | |-- FileManager.idl | | `-- Makefile.in | |-- locale | | |-- cs | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- da | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- el | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- ko | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- no | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- pt_BR | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- sk | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- sv | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- tr | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- uk | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- wa | | | `-- LC_MESSAGES | | | `-- mc.mo | | |-- zh_CN.GB2312 | | | `-- LC_MESSAGES | | | `-- mc.mo | | `-- zh_TW.Big5 | | `-- LC_MESSAGES | | `-- mc.mo | `-- terminfo | |-- l | | `-- linux | |-- v | | `-- vt100 | `-- x | `-- xterm |-- var | |-- cache | | `-- htb.init | |-- cbq.init | |-- cbq.init-cache | |-- lib | | |-- lrpkg | | | |-- brg.conf | | | |-- brg.list | | | |-- cur.list | | | |-- dhcpd.conf | | | |-- dhcpd.exclude.list | | | |-- dhcpd.help | | | |-- dhcpd.list | | | |-- dhcpd.version | | | |-- etc.exclude.list | | | |-- etc.help | | | |-- etc.list | | | |-- etc.version -> root.version | | | |-- etherw.help | | | |-- etherw.list | | | |-- ipsec.conf | | | |-- ipsec.help | | | |-- ipsec.list | | | |-- ipsec.version | | | |-- iptables.help | | | |-- iptables.list | | | |-- iptables.version | | | |-- local.list | | | |-- m.list | | | |-- mawk.list | | | |-- mawk.version | | | |-- modules.conf | | | |-- modules.exclude.list | | | |-- modules.help | | | |-- modules.list | | | |-- modules.version -> root.version | | | |-- netutils.list | | | |-- nmap.list | | | |-- nmap.version | | | |-- pcmcia.conf | | | |-- pcmcia.help | | | |-- pcmcia.list | | | |-- pcmcia.version | | | |-- qos-htb.help | | | |-- qos-htb.list | | | |-- qos-htb.version | | | |-- root.dev.mod | | | |-- root.dev.own | | | |-- root.exclude.list | | | |-- root.help | | | |-- root.list | | | |-- root.log.links | | | |-- root.net.conf | | | |-- root.pn.links | | | |-- root.sys.conf | | | |-- ssh.conf | | | |-- ssh.help | | | |-- ssh.list | | | |-- ssh.version | | | |-- sshd.conf | | | |-- sshd.help | | | |-- sshd.list | | | |-- sshd.version | | | |-- sshkey.help | | | |-- sshkey.list | | | |-- sshkey.version | | | |-- t.conf | | | |-- t.list | | | |-- tc.help | | | |-- tc.list | | | |-- tc.version | | | |-- tcpdump.help | | | |-- tcpdump.list | | | |-- tcpdump.version | | | |-- wireless.conf | | | |-- wireless.help | | | |-- wireless.list | | | |-- wireless.version | | | |-- wireutil.help | | | |-- wireutil.list | | | |-- wireutil.version | | | |-- zebedee.conf | | | |-- zebedee.help | | | |-- zebedee.list | | | `-- zebedee.version | | |-- misc | | | `-- pcmcia-scheme | | `-- random-seed | `-- spool | `-- cron | `-- crontabs
30.12.2007 13:17
chpasswd -c des') a zkopírujte ho do /etc/shadow na cílovém systému.
http://www.gnu.org/software/libc/manual/html_node/crypt.html - zde píšou, že DES algoritmus používá dva znaky pro "salt" a zbylych 11 je heslo.
Z uvedených zdrojových kódu v jednom z příspěvku je zřejmé, že se "salt" přidá ještě k nezašifrovanému heslu. Ovšem pořád mi není jasný ten mechanismus ověřování zašifrovaného hesla které obsahuje "salt".
Heslo je zašifrováno takto: UlozeneHeslo = crypt(getpass("Password:"), salt); Není mi ale jasné, jak systém určí, jaká hodnota "salt" byla použita při šifrování daného heslo, když je pak to heslo zpětně ověřováno: ZadaneHeslo = crypt(getpass("Password:"), salt);
ok = strcmp (ZadaneHeslo, UlozeneHeslo) == 0;
...
crypt() zadáte uložený hash hesla ze systémové tabulky. Funkce crypt() z něj použije pouze hodnotu salt.
/* Read in the user's password and encrypt it,
passing the expected password in as the salt. */
result = crypt(getpass("Password:"), pass);
Pořád ale nechápu, jak funkce crypt dokáže z řetězce pass najít hodnotu salt, když řetězec pass je zašifrovaný řetězec obsahující heslo a hodnotu salt. Nebo ona snad hodnota salt se přidává již k zašifrovanému heslu?
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