.\" $OpenBSD: authenticate.3,v 1.13 2011/01/24 01:50:25 schwarze Exp $ .\" .\" Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by Berkeley Software Design, .\" Inc. .\" 4. 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The .Fn auth_userokay function provides a single function call interface. Provided with a user's name in .Ar name , and an optional .Ar style , .Ar type , and .Ar password , the .Fn auth_userokay function returns a simple yes/no response. A return value of 0 implies failure; a non-zero return value implies success. If .Ar style is not .Dv NULL , it specifies the desired style of authentication to be used. If it is .Dv NULL then the default style for the user is used. In this case, .Ar name may include the desired style by appending it to the user's name with a single colon .Pq Sq \&: as a separator. If .Ar type is not .Dv NULL then it is used as the authentication type (such as .Dq auth-myservice ) . If .Ar password is .Dv NULL then .Fn auth_userokay operates in an interactive mode with the user on standard input, output, and error. If .Ar password is specified, .Fn auth_userokay operates in a non-interactive mode and only tests the specified passwords. This non-interactive method does not work with challenge-response authentication styles. For security reasons, when a .Ar password is specified, .Fn auth_userokay will zero out its value before it returns. .Pp The .Fn auth_usercheck function operates the same as the .Fn auth_userokay function except that it does not close the BSD Authentication session created. Rather than returning the status of the session, it returns a pointer to the newly created BSD Authentication session. .Pp The .Fn auth_userchallenge function takes the same .Ar name , style , and .Ar type arguments as does .Fn auth_userokay . However, rather than authenticating the user, it returns a possible challenge in the pointer pointed to by .Ar challengep . The return value of the function is a pointer to a newly created BSD Authentication session. This challenge, if not .Dv NULL , should be displayed to the user. In any case, the user should provide a password which is the .Ar response in a call to .Fn auth_userresponse . In addition to the password, the pointer returned by .Fn auth_userchallenge should be passed in as .Ar as and the value of .Va more should be non-zero if the program wishes to allow more attempts. If .Va more is zero then the session will be closed. The .Fn auth_userresponse function closes the BSD Authentication session and has the same return value as .Fn auth_userokay . For security reasons, when a .Ar response is specified, .Fn auth_userresponse will zero out its value before it returns. .Pp The .Fn auth_approval function calls the approval script for the user of the specified .Ar type . The string .Dq approve- will be prepended to .Ar type if missing. The resulting type is used to look up an entry in .Pa /etc/login.conf for the user's class. If the entry is missing, the generic entry for .Dq approve will be used. The .Ar name argument will be passed to the approval program as the name of the user. The .Ar lc argument points to a login class structure. If it is .Dv NULL then a login class structure will be looked up for the class of user .Ar name . The .Fn auth_approval function returns a value of 0 on failure to approve the user. .Pp Prior to actually calling the approval script, the account's expiration time, the associated nologin file, and existence of the account's home directory .Po if .Li requirehome is set for this class .Pc are checked. Failure on any of these points causes the .Fn auth_approval function to return a value of 0 and not actually call the approval script. .Pp The .Fn auth_cat function opens .Ar file for reading and copies its contents to standard output. It returns 0 if it was unable to open .Ar file and 1 otherwise. .Pp The .Fn auth_checknologin function must be provided with a pointer to a login class. If the class has a .Dq nologin entry defined and it points to a file that can be opened, the contents of the file will be copied to standard output and .Xr exit 3 will be called with a value of 1. If the class does not have the field .Dq ignorenologin and the file .Pa /etc/nologin exists its contents will be copied to standard output and .Xr exit 3 will be called with a value of 1. .Pp The .Fn auth_verify function is a front end to the .Xr auth_call 3 function. It will open a BSD Authentication session, if needed, and will set the style and user name based on the .Ar style and .Ar name arguments, if not .Dv NULL . Values for the style and user name in an existing BSD Authentication session will be replaced and the old values freed (if the calling program has obtained pointers to the style or user name via .Xr auth_getitem 3 , those pointers will become invalid). The variable arguments are passed to .Fn auth_call via the .Xr auth_set_va_list 3 function. The, possibly created, BSD Authentication session is returned. The .Xr auth_getstate 3 or .Xr auth_close 3 function should be used to determine the outcome of the authentication request. .Pp The .Fn auth_mkvalue function takes a NUL-terminated string pointed to by .Ar value and returns a NUL-terminated string suitable for passing back to a calling program on the back channel. This function is for use by the login scripts themselves. The string returned should be freed by .Xr free 3 when it is no longer needed. A value of .Dv NULL is returned if no memory was available for the new copy of the string. .Sh SEE ALSO .Xr auth_subr 3 , .Xr getpwent 3 , .Xr pw_dup 3 .Sh CAVEATS The .Fn auth_approval , .Fn auth_usercheck , .Fn auth_userokay , and .Fn auth_userchallenge functions call .Xr getpwnam 3 or .Xr getpwuid 3 , overwriting the static storage used by the .Xr getpwent 3 family of routines. The calling program must either make a local copy of the passwd struct pointer via the .Xr pw_dup 3 function or, for .Fn auth_approval and .Fn auth_usercheck only, use the .Xr auth_setpwd 3 function to copy the passwd struct into a BSD Authentication session structure which can then be passed to .Fn auth_approval or .Fn auth_usercheck .