pam_sm_authenticate Subroutine

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Purpose

PAM module-specific implementation of pam_authenticate().

Library

PAM Library (libpam.a)

Syntax

#include <security/pam_appl.h>
#include <security/pam_modules.h>

int pam_sm_authenticate (PAMHandle, Flags, Argc, Argv)
pam_handle_t *PAMHandle;
int Flags;
int Argc;
const char **Argv;

Description

When an application invokes pam_authenticate(), the PAM Framework calls pam_sm_authenticate for each module in the authentication module stack. This allows all the PAM module authors to implement their own authenticate routine. pam_authenticate and pam_sm_authenticate provide an authentication service to verify that the user is allowed access.

Parameters

Item Description
PAMhandle The PAM handle representing the current user authentication session. This handle is obtained by a call to pam_start().
Flags The flags are used to set pam_acct_mgmt options. The recognized flags are:
  • PAM_SILENT
    • No messages should be displayed.
  • PAM_DISALLOW_NULL_AUTHTOK
    • Do not authenticate a user with a NULL authentication token.
Argc The number of module options defined.
Argv The module options. These options are module-dependent. Any modules receiving invalid options should ignore them.

Return Values

Upon successful completion, pam_sm_authenticate returns PAM_SUCCESS. If the routine fails, a different error is returned, depending on the actual error.

Error Codes

Item Description
PAM_AUTH_ERR An error occurred in authentication, usually because of an invalid authentication token.
PAM_CRED_INSUFFICIENT The user has insufficient credentials to access the authentication data.
PAM_AUTHINFO_UNAVAIL The authentication information cannot be retrieved.
PAM_USER_UNKNOWN The user is not known.
PAM_MAXTRIES The maximum number of authentication retries has been reached.
PAM_OPEN_ERR One of the PAM authentication modules could not be loaded.
PAM_SYMBOL_ERR A necessary item is not available to a PAM module.
PAM_SERVICE_ERR An error occurred in a PAM module.
PAM_SYSTEM_ERR A system error occurred.
PAM_BUF_ERR A memory error occurred.
PAM_CONV_ERR A conversation error occurred.
PAM_PERM_DENIED Access permission was denied to the user.