mustberoot.subr revision 251264
1if [ ! "$_MUSTBEROOT_SUBR" ]; then _MUSTBEROOT_SUBR=1 2# 3# Copyright (c) 2006-2013 Devin Teske 4# All Rights Reserved. 5# 6# Redistribution and use in source and binary forms, with or without 7# modification, are permitted provided that the following conditions 8# are met: 9# 1. Redistributions of source code must retain the above copyright 10# notice, this list of conditions and the following disclaimer. 11# 2. Redistributions in binary form must reproduce the above copyright 12# notice, this list of conditions and the following disclaimer in the 13# documentation and/or other materials provided with the distribution. 14# 15# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, THE 17# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20# DAMAGES (INLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25# SUCH DAMAGE. 26# 27# $FreeBSD: head/usr.sbin/bsdconfig/share/mustberoot.subr 251264 2013-06-02 20:02:50Z dteske $ 28# 29############################################################ INCLUDES 30 31BSDCFG_SHARE="/usr/share/bsdconfig" 32. $BSDCFG_SHARE/common.subr || exit 1 33f_dprintf "%s: loading includes..." mustberoot.subr 34f_include $BSDCFG_SHARE/dialog.subr 35 36BSDCFG_LIBE="/usr/libexec/bsdconfig" 37f_include_lang $BSDCFG_LIBE/include/messages.subr 38 39############################################################ CONFIGURATION 40# NOTE: These are not able to be overridden/inherited for security purposes. 41 42# 43# Number of tries a user gets to enter his/her password before we log the 44# sudo(8) failure and exit. 45# 46PASSWD_TRIES=3 47 48# 49# While in SECURE mode, should authentication as `root' be allowed? Set to 50# non-NULL to enable authentication as `root', otherwise disabled. 51# 52# WARNING: 53# Unless using a custom sudo(8) configuration, user `root' should not be 54# allowed because no password is required to become `root' when already `root' 55# and therefore, any value entered as password will work. 56# 57SECURE_ALLOW_ROOT= 58 59# 60# While in SECURE mode, should we divulge (through error message) when the 61# requested authentication user does not exist? Set to non-NULL to enable, 62# otherwise a non-existent user is treated like an invalid password. 63# 64SECURE_DIVULGE_UNKNOWN_USER= 65 66############################################################ FUNCTIONS 67 68# f_become_root_via_sudo 69# 70# If not running as root, prompt for sudo(8) credentials to become root. 71# Re-execution of the current program via sudo is automatically handled. 72# 73# The following environment variables effect functionality: 74# 75# USE_XDIALOG Either NULL or Non-NULL. If given a value will indicate 76# that Xdialog(1) should be used instead of dialog(1). 77# 78f_become_root_via_sudo() 79{ 80 local prompt hline height width rows msg 81 82 [ "$( id -u )" = "0" ] && return $SUCCESS 83 84 f_have sudo || f_die 1 "$msg_must_be_root_to_execute" "$pgm" 85 86 # 87 # Ask the user if it's OK to become root via sudo(8) and give them 88 # the option to save this preference (by touch(1)ing a file in the 89 # user's $HOME directory). 90 # 91 local checkpath="${HOME%/}/.bsdconfig_uses_sudo" 92 if [ ! -e "$checkpath" ]; then 93 prompt=$( printf "$msg_you_are_not_root_but" bsdconfig ) 94 msg=$( printf "$msg_always_try_sudo_when_run_as" "$USER" ) 95 local menu_list=" 96 'X' '$msg_cancel_exit' 97 '1' '$msg' 98 '2' '$msg_try_sudo_only_this_once' 99 " # END-QUOTE 100 hline="$hline_arrows_tab_enter" 101 102 eval f_dialog_menu_size height width rows \ 103 \"\$DIALOG_TITLE\" \ 104 \"\$DIALOG_BACKTITLE\" \ 105 \"\$prompt\" \ 106 \"\$hline\" \ 107 $menu_list 108 109 local mtag 110 mtag=$( eval $DIALOG \ 111 --title \"\$DIALOG_TITLE\" \ 112 --backtitle \"\$DIALOG_BACKTITLE\" \ 113 --hline \"\$hline\" \ 114 --ok-label \"\$msg_ok\" \ 115 --cancel-label \"\$msg_cancel\" \ 116 --menu \"\$prompt\" \ 117 $height $width $rows \ 118 $menu_list \ 119 2>&1 >&$DIALOG_TERMINAL_PASSTHRU_FD 120 ) || f_die 121 f_dialog_data_sanitize mtag 122 123 case "$mtag" in 124 X) # Cancel/Exit 125 f_die ;; 126 1) # Always try sudo(8) when run as $user 127 local err 128 if ! err=$( touch "$checkpath" 2>&1 ); then 129 f_dialog_msgbox "$err" 130 else 131 f_show_msg "$msg_created_path" "$checkpath" 132 fi 133 esac 134 else 135 # 136 # This user has created the path signing-off on sudo(8)-use 137 # but let's still give them a short/quick/unobtrusive reminder 138 # 139 f_dialog_info "$msg_becoming_root_via_sudo" 140 [ "$USE_XDIALOG" ] || sleep 0.6 141 fi 142 143 # 144 # Check sudo(8) access before prompting for password. 145 # 146 :| sudo -S -v 2> /dev/null 147 if [ $? -ne $SUCCESS ]; then 148 # 149 # sudo(8) access denied. Prompt for their password. 150 # 151 prompt="$msg_please_enter_password" 152 hline="$hline_alnum_punc_tab_enter" 153 f_dialog_inputbox_size height width \ 154 "$DIALOG_TITLE" \ 155 "$DIALOG_BACKTITLE" \ 156 "$prompt" \ 157 "$hline" 158 159 # 160 # Continue prompting until they either Cancel, succeed 161 # or exceed the number of allowed failures. 162 # 163 local password nfailures=0 retval 164 while [ $nfailures -lt $PASSWD_TRIES ]; do 165 if [ "$USE_XDIALOG" ]; then 166 password=$( $DIALOG \ 167 --title "$DIALOG_TITLE" \ 168 --backtitle "$DIALOG_BACKTITLE" \ 169 --hline "$hline" \ 170 --ok-label "$msg_ok" \ 171 --cancel-label "$msg_cancel" \ 172 --password --inputbox "$prompt" \ 173 $height $width \ 174 2>&1 > /dev/null ) 175 retval=$? 176 177 # Catch X11-related errors 178 [ $retval -eq 255 ] && 179 f_die $retval "$password" 180 else 181 password=$( $DIALOG \ 182 --title "$DIALOG_TITLE" \ 183 --backtitle "$DIALOG_BACKTITLE" \ 184 --hline "$hline" \ 185 --ok-label "$msg_ok" \ 186 --cancel-label "$msg_cancel" \ 187 --insecure \ 188 --passwordbox "$prompt" \ 189 $height $width \ 190 2>&1 >&$DIALOG_TERMINAL_PASSTHRU_FD 191 ) || exit $? 192 fi 193 debug= f_dialog_line_sanitize password 194 195 # 196 # Validate sudo(8) credentials 197 # 198 sudo -S -v 2> /dev/null <<-EOF 199 $password 200 EOF 201 retval=$? 202 unset password # scrub memory 203 if [ $retval -eq $SUCCESS ]; then 204 # Access granted... 205 break 206 else 207 # Access denied... 208 nfailures=$(( $nfailures + 1 )) 209 210 # introduce a short delay 211 if [ $nfailures -lt $PASSWD_TRIES ]; then 212 f_dialog_info "$msg_sorry_try_again" 213 sleep 1 214 fi 215 fi 216 done 217 218 # 219 # If user exhausted number of allowed password tries, log 220 # the security event and exit immediately. 221 # 222 if [ $nfailures -ge $PASSWD_TRIES ]; then 223 msg=$( printf "$msg_nfailed_attempts" "$nfailures" ) 224 logger -p auth.notice -t sudo " " \ 225 "$USER : $msg" \ 226 "; TTY=$(tty)" \ 227 "; PWD=$PWD" \ 228 "; USER=root" \ 229 "; COMMAND=$0" 230 f_die 1 "sudo: $msg" 231 fi 232 fi 233 234 # Use xauth(1) to grant root the ability to use this X11/SSH session 235 if [ "$USE_XDIALOG" -a "$SSH_CONNECTION" -a "$DISPLAY" ]; then 236 f_have xauth || f_die 1 \ 237 "$msg_no_such_file_or_directory" "$pgm" "xauth" 238 local HOSTNAME displaynum 239 HOSTNAME=$(hostname) 240 displaynum="${DISPLAY#*:}" 241 xauth -f ~/.Xauthority extract - $HOSTNAME/unix:$displaynum \ 242 $HOSTNAME:$displaynum | sudo sh -c 'xauth -ivf \ 243 ~root/.Xauthority merge - > /dev/null 2>&1' 244 fi 245 246 # Re-execute ourselves with sudo(8) 247 f_dprintf "%s: Becoming root via sudo(8)..." mustberoot.subr 248 if [ $ARGC -gt 0 ]; then 249 exec sudo "$0" $ARGV 250 else 251 exec sudo "$0" 252 fi 253 exit $? # Never reached unless error 254} 255 256# f_authenticate_some_user 257# 258# Only used if running as root and requires X11 (see USE_XDIALOG below). 259# Prompts the user to enter a username and password to be authenticated via 260# sudo(8) to proceed. 261# 262# The following environment variables effect functionality: 263# 264# USE_XDIALOG Either NULL or Non-NULL. If given a value will indicate 265# that Xdialog(1) should be used instead of dialog(1). 266# 267f_authenticate_some_user() 268{ 269 local msg hline height width 270 271 f_have sudo || f_die 1 "$msg_must_be_root_to_execute" "$pgm" 272 273 # 274 # Secure-mode has been requested. 275 # 276 277 [ "$USE_XDIALOG" ] || f_die 1 "$msg_secure_mode_requires_x11" 278 [ "$(id -u)" = "0" ] || f_die 1 "$msg_secure_mode_requires_root" 279 280 # 281 # Prompt for sudo(8) credentials. 282 # 283 284 msg="$msg_please_enter_username_password" 285 hline="$hline_alnum_punc_tab_enter" 286 f_xdialog_2inputsbox_size height width \ 287 "$DIALOG_TITLE" \ 288 "$DIALOG_BACKTITLE" \ 289 "$msg" \ 290 "$field_username" "" \ 291 "$field_password" "" 292 height=$(( $height + 2 )) # Add height for --password 293 294 # 295 # Continue prompting until they either Cancel, succeed or exceed the 296 # number of allowed failures. 297 # 298 local user_pass nfailures=0 retval 299 while [ $nfailures -lt $PASSWD_TRIES ]; do 300 user_pass=$( $DIALOG \ 301 --title "$DIALOG_TITLE" \ 302 --backtitle "$DIALOG_BACKTITLE" \ 303 --hline "$hline" \ 304 --ok-label "$msg_ok" \ 305 --cancel-label "$msg_cancel" \ 306 --password --2inputsbox "$msg" \ 307 $height $width \ 308 "$field_username" "" \ 309 "$field_password" "" \ 310 2>&1 > /dev/null ) 311 retval=$? 312 313 # Catch X11-related errors 314 [ $retval -eq 255 ] && f_die $retval "$user_pass" 315 316 # Exit if the user cancelled. 317 [ $retval -eq $SUCCESS ] || exit $retval 318 319 # 320 # Make sure the user exists and is non-root 321 # 322 local user password 323 user="${user_pass%%/*}" 324 password="${user_pass#*/}" 325 unset user_pass # scrub memory 326 if [ ! "$user" ]; then 327 nfailures=$(( $nfailures + 1 )) 328 f_dialog_msgbox "$msg_no_username" 329 continue 330 fi 331 if [ ! "$SECURE_ALLOW_ROOT" ]; then 332 case "$user" in 333 root|toor) 334 nfailures=$(( $nfailures + 1 )) 335 f_show_msg "$msg_user_disallowed" "$user" 336 continue 337 esac 338 fi 339 if ! f_quietly id "$user"; then 340 nfailures=$(( $nfailures + 1 )) 341 if [ "$SECURE_DIVULGE_UNKNOWN_USER" ]; then 342 f_show_msg "$msg_unknown_user" "$user" 343 elif [ $nfailures -lt $PASSWD_TRIES ]; then 344 f_dialog_info "$msg_sorry_try_again" 345 sleep 1 346 fi 347 continue 348 fi 349 350 # 351 # Validate sudo(8) credentials for given user 352 # 353 su -m "$user" <<-EOF 354 sh <<EOS 355 sudo -k 356 sudo -S -v 2> /dev/null <<EOP 357 $password 358 EOP 359 EOS 360 EOF 361 retval=$? 362 unset user 363 unset password # scrub memory 364 365 if [ $retval -eq $SUCCESS ]; then 366 # Access granted... 367 break 368 else 369 # Access denied... 370 nfailures=$(( $nfailures + 1 )) 371 372 # introduce a short delay 373 if [ $nfailures -lt $PASSWD_TRIES ]; then 374 f_dialog_info "$msg_sorry_try_again" 375 sleep 1 376 fi 377 fi 378 done 379 380 # 381 # If user exhausted number of allowed password tries, log 382 # the security event and exit immediately. 383 # 384 if [ $nfailures -ge $PASSWD_TRIES ]; then 385 msg=$( printf "$msg_nfailed_attempts" "$nfailures" ) 386 logger -p auth.notice -t sudo " " \ 387 "${SUDO_USER:-$USER} : $msg" \ 388 "; TTY=$(tty)" \ 389 "; PWD=$PWD" \ 390 "; USER=root" \ 391 "; COMMAND=$0" 392 f_die 1 "sudo: $message" 393 fi 394} 395 396# f_mustberoot_init 397# 398# If not already root, make the switch to root by re-executing ourselves via 399# sudo(8) using user-supplied credentials. 400# 401# The following environment variables effect functionality: 402# 403# SECURE Either NULL or Non-NULL. If given a value will indicate 404# that (while running as root) sudo(8) authentication is 405# required to proceed. 406# 407f_mustberoot_init() 408{ 409 if [ "$(id -u)" != "0" -a ! "$SECURE" ]; then 410 f_become_root_via_sudo 411 elif [ "$SECURE" ]; then 412 f_authenticate_some_user 413 fi 414} 415 416############################################################ MAIN 417 418f_dprintf "%s: Successfully loaded." mustberoot.subr 419 420fi # ! $_MUSTBEROOT_SUBR 421