PAM_UNIX(8) Linux-PAM PAM_UNIX(8) (NAME) pam_unix - PAM (SYNOPSIS) pam_unix.so [...] (DESCRIPTION) . . /etc/passwd shadow /etc/shadow . account shadow : expire last_change max_change min_change warn_change. PAM_AUTHTOKEN_REQD . shadow(5) . shadow . authentication () . . unix_chkpwd(8) . . . xlock(1) setuid-root . SIGCHLD . fork() . noreap . pam_unix PAM_MAX_RESP_SIZE - . (conversation) . password . ENCRYPT_METHOD /etc/login.defs . session . . syslog(3) . (OPTIONS) debug syslog(3) . audit debug . quiet syslog(3) . nullok . nullok . nullresetok nullok . nullok . try_first_pass . use_first_pass use_first_pass - . nodelay . . use_authtok password ( pam_passwdqc ). authtok_type=type . . nis NIS RPC . remember=n n /etc/security/opasswd . MD5 . pam_pwhistory . shadow shadow . md5 MD5 . bigcrypt DEC C2 . sha256 SHA256 . SHA256 crypt(3) . sha512 SHA512 . SHA512 crypt(3) . blowfish blowfish . blowfish crypt(3) . gost_yescrypt gost-yescrypt . gost-yescrypt crypt(3) . yescrypt yescrypt . yescrypt crypt(3) . rounds=n SHA256 SHA512 blowfish gost-yescrypt yescrypt n . broken_shadow shadow (account) . minlen=n n . DES crypt . no_pass_expiry shadow . pam_unix . sshd . PAM_NEW_AUTHTOK_REQD PAM_AUTHTOK_EXPIRED PAM_SUCCESS . syslog(3) . (MODULE TYPES PROVIDED) (account auth password session) . (RETURN VALUES) PAM_IGNORE . (EXAMPLES) /etc/pam.d/login : # auth required pam_unix.so # account required pam_unix.so # # pam_passwdqc(8) password required pam_passwdqc.so config=/etc/passwdqc.conf password required pam_unix.so use_authtok nullok yescrypt session required pam_unix.so (SEE ALSO) login.defs(5) pam.conf(5) pam.d(5) pam(8) (AUTHOR) pam_unix . Linux-PAM 01/26/2026 PAM_UNIX(8)