1 /* $NetBSD: pam_get_user.c,v 1.2 2014/10/24 18:17:56 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2002-2003 Networks Associates Technology, Inc. 5 * Copyright (c) 2004-2011 Dag-Erling Smørgrav 6 * All rights reserved. 7 * 8 * This software was developed for the FreeBSD Project by ThinkSec AS and 9 * Network Associates Laboratories, the Security Research Division of 10 * Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 11 * ("CBOSS"), as part of the DARPA CHATS research program. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. The name of the author may not be used to endorse or promote 22 * products derived from this software without specific prior written 23 * permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * Id: pam_get_user.c 670 2013-03-17 19:26:07Z des 38 */ 39 40 #ifdef HAVE_CONFIG_H 41 # include "config.h" 42 #endif 43 44 #include <sys/cdefs.h> 45 __RCSID("$NetBSD: pam_get_user.c,v 1.2 2014/10/24 18:17:56 christos Exp $"); 46 47 #include <sys/param.h> 48 49 #include <stdlib.h> 50 51 #include <security/pam_appl.h> 52 #include <security/openpam.h> 53 54 #include "openpam_impl.h" 55 56 static const char user_prompt[] = "Login:"; 57 58 /* 59 * XSSO 4.2.1 60 * XSSO 6 page 52 61 * 62 * Retrieve user name 63 */ 64 65 int 66 pam_get_user(pam_handle_t *pamh, 67 const char **user, 68 const char *prompt) 69 { 70 char prompt_buf[1024]; 71 size_t prompt_size; 72 const void *promptp; 73 char *resp; 74 int r; 75 76 ENTER(); 77 if (pamh == NULL || user == NULL) 78 RETURNC(PAM_SYSTEM_ERR); 79 r = pam_get_item(pamh, PAM_USER, (const void **)user); 80 if (r == PAM_SUCCESS && *user != NULL) 81 RETURNC(PAM_SUCCESS); 82 /* pam policy overrides the module's choice */ 83 if ((promptp = openpam_get_option(pamh, "user_prompt")) != NULL) 84 prompt = promptp; 85 /* no prompt provided, see if there is one tucked away somewhere */ 86 if (prompt == NULL) 87 if (pam_get_item(pamh, PAM_USER_PROMPT, &promptp) && 88 promptp != NULL) 89 prompt = promptp; 90 /* fall back to hardcoded default */ 91 if (prompt == NULL) 92 prompt = user_prompt; 93 /* expand */ 94 prompt_size = sizeof prompt_buf; 95 r = openpam_subst(pamh, prompt_buf, &prompt_size, prompt); 96 if (r == PAM_SUCCESS && prompt_size <= sizeof prompt_buf) 97 prompt = prompt_buf; 98 r = pam_prompt(pamh, PAM_PROMPT_ECHO_ON, &resp, "%s", prompt); 99 if (r != PAM_SUCCESS) 100 RETURNC(r); 101 r = pam_set_item(pamh, PAM_USER, resp); 102 FREE(resp); 103 if (r != PAM_SUCCESS) 104 RETURNC(r); 105 r = pam_get_item(pamh, PAM_USER, (const void **)user); 106 RETURNC(r); 107 } 108 109 /* 110 * Error codes: 111 * 112 * =pam_get_item 113 * =pam_prompt 114 * =pam_set_item 115 * !PAM_SYMBOL_ERR 116 */ 117 118 /** 119 * The =pam_get_user function returns the name of the target user, as 120 * specified to =pam_start. 121 * If no user was specified, nor set using =pam_set_item, =pam_get_user 122 * will prompt for a user name. 123 * Either way, a pointer to the user name is stored in the location 124 * pointed to by the =user argument, and the corresponding PAM item is 125 * updated. 126 * 127 * The =prompt argument specifies a prompt to use if no user name is 128 * cached. 129 * If it is =NULL, the =PAM_USER_PROMPT item will be used. 130 * If that item is also =NULL, a hardcoded default prompt will be used. 131 * Additionally, when =pam_get_user is called from a service module, the 132 * prompt may be affected by module options as described below. 133 * The prompt is then expanded using =openpam_subst before it is passed to 134 * the conversation function. 135 * 136 * MODULE OPTIONS 137 * 138 * When called by a service module, =pam_get_user will recognize the 139 * following module options: 140 * 141 * ;user_prompt: 142 * Prompt to use when asking for the user name. 143 * This option overrides both the =prompt argument and the 144 * =PAM_USER_PROMPT item. 145 * 146 * >pam_conv 147 * >pam_get_item 148 * >pam_get_authtok 149 * >openpam_get_option 150 * >openpam_subst 151 */ 152