1 /*- 2 * Copyright (c) 2002-2003 Networks Associates Technology, Inc. 3 * Copyright (c) 2004-2017 Dag-Erling Smørgrav 4 * All rights reserved. 5 * 6 * This software was developed for the FreeBSD Project by ThinkSec AS and 7 * Network Associates Laboratories, the Security Research Division of 8 * Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 9 * ("CBOSS"), as part of the DARPA CHATS research program. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. The name of the author may not be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifdef HAVE_CONFIG_H 37 # include "config.h" 38 #endif 39 40 #include <sys/param.h> 41 42 #include <stdlib.h> 43 #include <string.h> 44 45 #include <security/pam_appl.h> 46 #include <security/openpam.h> 47 48 #include "openpam_impl.h" 49 #include "openpam_strlset.h" 50 51 static const char authtok_prompt[] = "Password:"; 52 static const char authtok_prompt_remote[] = "Password for %u@%h:"; 53 static const char oldauthtok_prompt[] = "Old Password:"; 54 static const char newauthtok_prompt[] = "New Password:"; 55 56 /* 57 * OpenPAM extension 58 * 59 * Retrieve authentication token 60 */ 61 62 int 63 pam_get_authtok(pam_handle_t *pamh, 64 int item, 65 const char **authtok, 66 const char *prompt) 67 { 68 char prompt_buf[1024]; 69 size_t prompt_size; 70 const void *oldauthtok, *prevauthtok, *promptp; 71 const char *prompt_option, *default_prompt; 72 const void *lhost, *rhost; 73 char *resp, *resp2; 74 int pitem, r, style, twice; 75 76 ENTER(); 77 *authtok = NULL; 78 twice = 0; 79 switch (item) { 80 case PAM_AUTHTOK: 81 pitem = PAM_AUTHTOK_PROMPT; 82 prompt_option = "authtok_prompt"; 83 default_prompt = authtok_prompt; 84 r = pam_get_item(pamh, PAM_RHOST, &rhost); 85 if (r == PAM_SUCCESS && rhost != NULL) { 86 r = pam_get_item(pamh, PAM_HOST, &lhost); 87 if (r == PAM_SUCCESS && lhost != NULL) { 88 if (strcmp(rhost, lhost) != 0) 89 default_prompt = authtok_prompt_remote; 90 } 91 } 92 r = pam_get_item(pamh, PAM_OLDAUTHTOK, &oldauthtok); 93 if (r == PAM_SUCCESS && oldauthtok != NULL) { 94 default_prompt = newauthtok_prompt; 95 twice = 1; 96 } 97 break; 98 case PAM_OLDAUTHTOK: 99 pitem = PAM_OLDAUTHTOK_PROMPT; 100 prompt_option = "oldauthtok_prompt"; 101 default_prompt = oldauthtok_prompt; 102 twice = 0; 103 break; 104 default: 105 RETURNC(PAM_BAD_CONSTANT); 106 } 107 if (openpam_get_option(pamh, "try_first_pass") || 108 openpam_get_option(pamh, "use_first_pass")) { 109 r = pam_get_item(pamh, item, &prevauthtok); 110 if (r == PAM_SUCCESS && prevauthtok != NULL) { 111 *authtok = prevauthtok; 112 RETURNC(PAM_SUCCESS); 113 } else if (openpam_get_option(pamh, "use_first_pass")) { 114 RETURNC(r == PAM_SUCCESS ? PAM_AUTH_ERR : r); 115 } 116 } 117 /* pam policy overrides the module's choice */ 118 if ((promptp = openpam_get_option(pamh, prompt_option)) != NULL) 119 prompt = promptp; 120 /* no prompt provided, see if there is one tucked away somewhere */ 121 if (prompt == NULL) { 122 r = pam_get_item(pamh, pitem, &promptp); 123 if (r == PAM_SUCCESS && promptp != NULL) 124 prompt = promptp; 125 } 126 /* fall back to hardcoded default */ 127 if (prompt == NULL) 128 prompt = default_prompt; 129 /* expand */ 130 prompt_size = sizeof prompt_buf; 131 r = openpam_subst(pamh, prompt_buf, &prompt_size, prompt); 132 if (r == PAM_SUCCESS && prompt_size <= sizeof prompt_buf) 133 prompt = prompt_buf; 134 style = openpam_get_option(pamh, "echo_pass") ? 135 PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF; 136 r = pam_prompt(pamh, style, &resp, "%s", prompt); 137 if (r != PAM_SUCCESS) 138 RETURNC(r); 139 if (twice) { 140 r = pam_prompt(pamh, style, &resp2, "Retype %s", prompt); 141 if (r != PAM_SUCCESS) { 142 strlset(resp, 0, PAM_MAX_RESP_SIZE); 143 FREE(resp); 144 RETURNC(r); 145 } 146 if (strcmp(resp, resp2) != 0) { 147 strlset(resp, 0, PAM_MAX_RESP_SIZE); 148 FREE(resp); 149 } 150 strlset(resp2, 0, PAM_MAX_RESP_SIZE); 151 FREE(resp2); 152 } 153 if (resp == NULL) 154 RETURNC(PAM_TRY_AGAIN); 155 r = pam_set_item(pamh, item, resp); 156 strlset(resp, 0, PAM_MAX_RESP_SIZE); 157 FREE(resp); 158 if (r != PAM_SUCCESS) 159 RETURNC(r); 160 r = pam_get_item(pamh, item, (const void **)authtok); 161 RETURNC(r); 162 } 163 164 /* 165 * Error codes: 166 * 167 * =pam_get_item 168 * =pam_prompt 169 * =pam_set_item 170 * !PAM_SYMBOL_ERR 171 * PAM_BAD_CONSTANT 172 * PAM_TRY_AGAIN 173 */ 174 175 /** 176 * The =pam_get_authtok function either prompts the user for an 177 * authentication token or retrieves a cached authentication token, 178 * depending on circumstances. 179 * Either way, a pointer to the authentication token is stored in the 180 * location pointed to by the =authtok argument, and the corresponding PAM 181 * item is updated. 182 * 183 * The =item argument must have one of the following values: 184 * 185 * =PAM_AUTHTOK: 186 * Returns the current authentication token, or the new token 187 * when changing authentication tokens. 188 * =PAM_OLDAUTHTOK: 189 * Returns the previous authentication token when changing 190 * authentication tokens. 191 * 192 * The =prompt argument specifies a prompt to use if no token is cached. 193 * If it is =NULL, the =PAM_AUTHTOK_PROMPT or =PAM_OLDAUTHTOK_PROMPT item, 194 * as appropriate, will be used. 195 * If that item is also =NULL, a hardcoded default prompt will be used. 196 * Additionally, when =pam_get_authtok is called from a service module, 197 * the prompt may be affected by module options as described below. 198 * The prompt is then expanded using =openpam_subst before it is passed to 199 * the conversation function. 200 * 201 * If =item is set to =PAM_AUTHTOK and there is a non-null =PAM_OLDAUTHTOK 202 * item, =pam_get_authtok will ask the user to confirm the new token by 203 * retyping it. 204 * If there is a mismatch, =pam_get_authtok will return =PAM_TRY_AGAIN. 205 * 206 * MODULE OPTIONS 207 * 208 * When called by a service module, =pam_get_authtok will recognize the 209 * following module options: 210 * 211 * ;authtok_prompt: 212 * Prompt to use when =item is set to =PAM_AUTHTOK. 213 * This option overrides both the =prompt argument and the 214 * =PAM_AUTHTOK_PROMPT item. 215 * ;echo_pass: 216 * If the application's conversation function allows it, this 217 * lets the user see what they are typing. 218 * This should only be used for non-reusable authentication 219 * tokens. 220 * ;oldauthtok_prompt: 221 * Prompt to use when =item is set to =PAM_OLDAUTHTOK. 222 * This option overrides both the =prompt argument and the 223 * =PAM_OLDAUTHTOK_PROMPT item. 224 * ;try_first_pass: 225 * If the requested item is non-null, return it without 226 * prompting the user. 227 * Typically, the service module will verify the token, and 228 * if it does not match, clear the item before calling 229 * =pam_get_authtok a second time. 230 * ;use_first_pass: 231 * Do not prompt the user at all; just return the cached 232 * value, or =PAM_AUTH_ERR if there is none. 233 * 234 * >pam_conv 235 * >pam_get_item 236 * >pam_get_user 237 * >openpam_get_option 238 * >openpam_subst 239 */ 240