1 /* $NetBSD: pam_get_user.c,v 1.4 2023/06/30 21:46:21 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2002-2003 Networks Associates Technology, Inc. 5 * Copyright (c) 2004-2017 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 38 #ifdef HAVE_CONFIG_H 39 # include "config.h" 40 #endif 41 42 #include <sys/cdefs.h> 43 __RCSID("$NetBSD: pam_get_user.c,v 1.4 2023/06/30 21:46:21 christos Exp $"); 44 45 #include <sys/param.h> 46 47 #include <stdlib.h> 48 49 #include <security/pam_appl.h> 50 #include <security/openpam.h> 51 52 #include "openpam_impl.h" 53 54 static const char user_prompt[] = "Login:"; 55 56 /* 57 * XSSO 4.2.1 58 * XSSO 6 page 52 59 * 60 * Retrieve user name 61 */ 62 63 int 64 pam_get_user(pam_handle_t *pamh, 65 const char **user, 66 const char *prompt) 67 { 68 char prompt_buf[1024]; 69 size_t prompt_size; 70 const void *promptp; 71 char *resp; 72 int r; 73 74 ENTER(); 75 r = pam_get_item(pamh, PAM_USER, (const void **)user); 76 if (r == PAM_SUCCESS && *user != NULL) 77 RETURNC(PAM_SUCCESS); 78 /* pam policy overrides the module's choice */ 79 if ((promptp = openpam_get_option(pamh, "user_prompt")) != NULL) 80 prompt = promptp; 81 /* no prompt provided, see if there is one tucked away somewhere */ 82 if (prompt == NULL) { 83 r = pam_get_item(pamh, PAM_USER_PROMPT, &promptp); 84 if (r == PAM_SUCCESS && promptp != NULL) 85 prompt = promptp; 86 } 87 /* fall back to hardcoded default */ 88 if (prompt == NULL) 89 prompt = user_prompt; 90 /* expand */ 91 prompt_size = sizeof prompt_buf; 92 r = openpam_subst(pamh, prompt_buf, &prompt_size, prompt); 93 if (r == PAM_SUCCESS && prompt_size <= sizeof prompt_buf) 94 prompt = prompt_buf; 95 r = pam_prompt(pamh, PAM_PROMPT_ECHO_ON, &resp, "%s", prompt); 96 if (r != PAM_SUCCESS) 97 RETURNC(r); 98 r = pam_set_item(pamh, PAM_USER, resp); 99 FREE(resp); 100 if (r != PAM_SUCCESS) 101 RETURNC(r); 102 r = pam_get_item(pamh, PAM_USER, (const void **)user); 103 RETURNC(r); 104 } 105 106 /* 107 * Error codes: 108 * 109 * =pam_get_item 110 * =pam_prompt 111 * =pam_set_item 112 * !PAM_SYMBOL_ERR 113 */ 114 115 /** 116 * The =pam_get_user function returns the name of the target user, as 117 * specified to =pam_start. 118 * If no user was specified, nor set using =pam_set_item, =pam_get_user 119 * will prompt for a user name. 120 * Either way, a pointer to the user name is stored in the location 121 * pointed to by the =user argument, and the corresponding PAM item is 122 * updated. 123 * 124 * The =prompt argument specifies a prompt to use if no user name is 125 * cached. 126 * If it is =NULL, the =PAM_USER_PROMPT item will be used. 127 * If that item is also =NULL, a hardcoded default prompt will be used. 128 * Additionally, when =pam_get_user is called from a service module, the 129 * prompt may be affected by module options as described below. 130 * The prompt is then expanded using =openpam_subst before it is passed to 131 * the conversation function. 132 * 133 * MODULE OPTIONS 134 * 135 * When called by a service module, =pam_get_user will recognize the 136 * following module options: 137 * 138 * ;user_prompt: 139 * Prompt to use when asking for the user name. 140 * This option overrides both the =prompt argument and the 141 * =PAM_USER_PROMPT item. 142 * 143 * >pam_conv 144 * >pam_get_item 145 * >pam_get_authtok 146 * >openpam_get_option 147 * >openpam_subst 148 */ 149