pam_conv -- PAM conversation system
PAM Library (libpam, -lpam)
#include <security/pam_appl.h>
struct pam_message {
int msg_style;
char *msg;
};
struct pam_response {
char *resp;
int resp_retcode;
};
struct pam_conv {
int (*conv)(int, const struct pam_message **,
struct pam_response **, void *);
void *appdata_ptr;
};
The PAM library uses an application-defined callback to communicate with
the user. This callback is specified by the struct pam_conv passed to
pam_start() at the start of the transaction. It is also possible to set
or change the conversation function at any point during a PAM transaction
by changing the value of the PAM_CONV item.
The conversation function's first argument specifies the number of messages
(up to PAM_NUM_MSG) to process. The second argument is a pointer
to a contiguous array of struct pam_message containing the actual messages.
Each message can have one of four types, specified by the msg_style member
of struct pam_message:
PAM_PROMPT_ECHO_OFF
Display a prompt and accept the user's response without
echoing it to the terminal. This is commonly
used for passwords.
PAM_PROMPT_ECHO_ON Display a prompt and accept the user's response,
echoing it to the terminal. This is commonly used
for login names and one-time passphrases.
PAM_ERROR_MSG Display an error message.
PAM_TEXT_INFO Display an informational message.
In each case, the prompt or message to display is pointed to by the msg
member of struct pam_message. It can be up to PAM_MAX_MSG_SIZE characters
long, including the terminating NUL.
On success, the conversation function should allocate and fill a contiguous
array of struct pam_response, one for each message that was passed
in. A pointer to the user's response to each message (or NULL in the
case of informational or error messages) should be stored in the resp
member of the corresponding struct pam_response. Each response can be up
to PAM_MAX_RESP_SIZE characters long, including the terminating NUL.
The resp_retcode member of struct pam_response is unused and should be
set to zero.
The conversation function should store a pointer to this array in the
location pointed to by its third argument. It is the caller's responsibility
to release both this array and the responses themselves, using
free(3). It is the conversation function's responsibility to ensure that
it is legal to do so.
The appdata_ptr member of struct pam_conv is passed unmodified to the
conversation function as its fourth and final argument.
On failure, the conversation function should release any resources it has
allocated, and return one of the predefined PAM error codes.
The conversation function should return one of the following values:
[PAM_BUF_ERR] Memory buffer error.
[PAM_CONV_ERR] Conversation failure.
[PAM_SUCCESS] Success.
[PAM_SYSTEM_ERR] System error.
openpam_ttyconv(3), openpam_nullconv(3), pam(3), pam_error(3),
pam_get_item(3), pam_info(3), pam_prompt(3), pam_set_item(3),
pam_start(3)
X/Open Single Sign-On Service (XSSO) - Pluggable Authentication Modules,
June 1997.
The OpenPAM library and this manual page were developed for the FreeBSD
Project by ThinkSec AS and Network Associates Laboratories, the Security
Research Division of Network Associates, Inc. under DARPA/SPAWAR contract
N66001-01-C-8035 (``CBOSS''), as part of the DARPA CHATS research program.
FreeBSD 5.2.1 May 27, 2002 FreeBSD 5.2.1 [ Back ] |
