V8.00.000.2025.06.17

Signed-off-by: Marc S. Weidner <msw@coresecret.dev>

func/cdi_4500_user/4520_accounts_setup.sh

@@ -58,10 +58,11 @@ accounts_setup() {
 
   ### Update pam modules for 2fa.
   mkdir -p "${var_target}/root/.ciss/cdi/backup/etc/pam.d"
-  write_pam_login "${var_target}"
+  write_pam_login  "${var_target}"
-  write_pam_sshd  "${var_target}"
+  write_pam_sshd   "${var_target}"
-  write_pam_su    "${var_target}"
+  write_pam_su     "${var_target}"
-  write_pam_sudo  "${var_target}"
+  write_pam_su-l   "${var_target}"
+  write_pam_sudo-i "${var_target}"
 
   ### Prepare the '2fa'-seed variable.
   read_totp_seed
@@ -1195,10 +1196,7 @@ write_pam_su() {
 auth     sufficient pam_rootok.so
 
 # Hardening of '/bin/su': only members of the group 'sudo' can su to root.
-auth     required   pam_wheel.so use_uid group=sudo
+auth     required   pam_wheel.so group=sudo
-
-# Reuse a recent successful su-auth within the TTL:
-auth     sufficient pam_timestamp.so
 
 # Standard password for the target account (root or other):
 @include common-auth
@@ -1220,8 +1218,6 @@ auth     required   pam_google_authenticator.so
 
 @include common-account
 @include common-session
-# Keep a ticket to avoid re-prompts during this shell session:
-session  optional     pam_timestamp.so
 
 # vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf
 EOF
@@ -1241,7 +1237,7 @@ EOF
 readonly -f write_pam_su
 
 #######################################
-# Writes CISS Header for '/etc/pam.d/sudo'.
+# Writes CISS Header for '/etc/pam.d/su-l'.
 # Globals:
 #   None
 # Arguments:
@@ -1249,15 +1245,81 @@ readonly -f write_pam_su
 # Returns:
 #   0: on success
 #######################################
-write_pam_sudo() {
+write_pam_su-l() {
   ### Declare Arrays, HashMaps, and Variables.
   declare -r  var_target="$1"
 
-  mv "${var_target}/etc/pam.d/sudo" "${var_target}/root/.ciss/cdi/backup/etc/pam.d/sudo"
+  mv "${var_target}/etc/pam.d/su-l" "${var_target}/root/.ciss/cdi/backup/etc/pam.d/su-l"
 
-  insert_header   "${var_target}/etc/pam.d/sudo"
+  insert_header   "${var_target}/etc/pam.d/su-l"
-  insert_comments "${var_target}/etc/pam.d/sudo"
+  insert_comments "${var_target}/etc/pam.d/su-l"
-  cat << EOF >>   "${var_target}/etc/pam.d/sudo"
+  cat << EOF >>   "${var_target}/etc/pam.d/su-l"
+#
+# PAM configuration for the su-l service
+#
+
+# If caller is already root, allow quickly without further auth:
+auth     sufficient pam_rootok.so
+
+# Hardening of '/bin/su': only members of the group 'sudo' can su to root.
+auth     required   pam_wheel.so group=sudo
+
+# Standard password for the target account (root or other):
+@include common-auth
+
+
+# ===== CISS 2FA block  ========
+
+# If gate returns SUCCESS => skip next two lines (no TOTP).
+auth                [success=2 default=ignore] pam_exec.so quiet /usr/local/libexec/ciss_pam_2fa_gate.sh
+
+# For listed users: enforce that the secret file exists, else deny without prompting.
+# pam_google_authenticator will itself fail if the file is absent; we add a clear hint before it.
+# No 'nullok' here: listed users MUST have a secret; missing -> hard fail.
+auth     required   pam_echo.so file=/etc/ciss/pam_su_l_totp.prompt
+auth     required   pam_google_authenticator.so
+
+# ===== CISS 2FA block end =====
+
+
+@include common-account
+@include common-session
+
+# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf
+EOF
+
+  do_log "info" "file_only" "4520() Written: [/etc/pam.d/su-l]."
+
+  cat << 'EOF' >| "${var_target}/etc/ciss/pam_su_l_totp.prompt"
+Please enter the 6-digit TOTP or 8-digit Backup code of the target user:
+EOF
+  chmod 0444 "${var_target}/etc/ciss/pam_su_l_totp.prompt"
+  do_log "info" "file_only" "4520() Written: [/etc/ciss/pam_su_l_totp.prompt]."
+
+  return 0
+}
+### Prevents accidental 'unset -f'.
+# shellcheck disable=SC2034
+readonly -f write_pam_su-l
+
+#######################################
+# Writes CISS Header for '/etc/pam.d/sudo-i'.
+# Globals:
+#   None
+# Arguments:
+#   1: TARGET
+# Returns:
+#   0: on success
+#######################################
+write_pam_sudo-i() {
+  ### Declare Arrays, HashMaps, and Variables.
+  declare -r  var_target="$1"
+
+  mv "${var_target}/etc/pam.d/sudo-i" "${var_target}/root/.ciss/cdi/backup/etc/pam.d/sudo-i"
+
+  insert_header   "${var_target}/etc/pam.d/sudo-i"
+  insert_comments "${var_target}/etc/pam.d/sudo-i"
+  cat << EOF >>   "${var_target}/etc/pam.d/sudo-i"
 #
 # PAM configuration for the sudo service
 #
@@ -1277,7 +1339,7 @@ auth                [success=2 default=ignore] pam_exec.so quiet /usr/local/libe
 # For listed users: enforce that the secret file exists, else deny without prompting.
 # pam_google_authenticator will itself fail if the file is absent; we add a clear hint before it.
 # No 'nullok' here: listed users MUST have a secret; missing -> hard fail.
-auth     required   pam_echo.so file=/etc/ciss/pam_sudo_totp.prompt
+auth     required   pam_echo.so file=/etc/ciss/pam_sudo_i_totp.prompt
 auth     required   pam_google_authenticator.so
 
 # ===== CISS 2FA block end =====
@@ -1285,7 +1347,7 @@ auth     required   pam_google_authenticator.so
 
 # Accounts, sessions:
 @include common-account
-@include common-session-noninteractive
+@include common-session
 
 # Maintain a pam_timestamp ticket on successful sudo to suppress re-prompts.
 session  optional   pam_timestamp.so
@@ -1293,19 +1355,19 @@ session  optional   pam_timestamp.so
 # vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf
 EOF
 
-  do_log "info" "file_only" "4520() Written: [/etc/pam.d/sudo]."
+  do_log "info" "file_only" "4520() Written: [/etc/pam.d/sudo-i]."
 
-  cat << 'EOF' >| "${var_target}/etc/ciss/pam_sudo_totp.prompt"
+  cat << 'EOF' >| "${var_target}/etc/ciss/pam_sudo_i_totp.prompt"
 Please enter your 6-digit TOTP or 8-digit Backup code:
 EOF
-  chmod 0444 "${var_target}/etc/ciss/pam_sudo_totp.prompt"
+  chmod 0444 "${var_target}/etc/ciss/pam_sudo_i_totp.prompt"
-  do_log "info" "file_only" "4520() Written: [/etc/ciss/pam_sudo_totp.prompt]."
+  do_log "info" "file_only" "4520() Written: [/etc/ciss/pam_sudo_i_totp.prompt]."
 
   return 0
 }
 ### Prevents accidental 'unset -f'.
 # shellcheck disable=SC2034
-readonly -f write_pam_sudo
+readonly -f write_pam_sudo-i
 
 #######################################
 # Use the official ohmyzsh-installer but force non-interactive behavior; do not run zsh; do not chsh.

includes/target/usr/local/libexec/ciss_pam_2fa_gate.sh

@@ -21,11 +21,61 @@ set -Ceuo pipefail
 ### Declare Arrays, HashMaps, and Variables.
 declare -g VAR_MAP_FILE="/etc/ciss/2fa.map"
 declare -g VAR_POLICY="${CISS_POLICY:-strict}"
+declare -g VAR_BINDING="${CISS_SU_BINDING:-caller}"
+declare -g VAR_U=""
 
 ### PAM variables provided by pam_exec:
-declare -g VAR_U="${PAM_USER:-}"
 declare -g VAR_S="${PAM_SERVICE:-}"
 
+#######################################
+# Which identity to check in the 2FA map per PAM service.
+# - $PAM_USER  = target  user (su/sudo: usually "root")
+# - $PAM_RUSER = calling user
+# Globals:
+#   PAM_RUSER
+#   PAM_USER
+#   VAR_BINDING
+#   VAR_S
+# Arguments:
+#   None
+# Returns:
+#   0: on success
+#######################################
+identify_subject() {
+  # shellcheck disable=SC2249
+  case "${VAR_S,,}" in
+
+    login|sshd)
+      echo "${PAM_USER:-}"
+      ;;
+
+    sudo|sudo-i)
+      ### Enforce 2FA policy by caller for sudo.
+      echo "${PAM_RUSER:-${PAM_USER:-}}"
+      ;;
+
+    su|su-l)
+      ### Default: Bind su policy to the caller. Set CISS_SU_BINDING="target" if you want policy bound to the target account.
+      case "${VAR_BINDING,,}" in
+
+        caller) echo "${PAM_RUSER:-${PAM_USER:-}}" ;;
+        target) echo "${PAM_USER:-}"               ;;
+
+      esac
+      ;;
+
+    *)
+      echo "${PAM_USER:-}"
+      ;;
+
+  esac
+
+  return 0
+}
+### Prevents accidental 'unset -f'.
+# shellcheck disable=SC2034
+readonly -f identify_subject
+
 #######################################
 # Read flag for user and service (0/1), default: empty (not found).
 # Globals:
@@ -84,12 +134,14 @@ readonly -f read_flag
 map_service_to_col() {
   declare -r  var_s="${1}"
   case "${var_s}" in
-    login) echo 2 ;;
+    login)        echo 2 ;;
-    sshd)  echo 3 ;;
+    sshd)         echo 3 ;;
-    su)    echo 4 ;;
+    su|su-l)      echo 4 ;;
-    sudo)  echo 5 ;;
+    sudo|sudo-i)  echo 5 ;;
     *)     echo 0 ;; # Unknown services => behave as "not enforced".
   esac
+
+  return 0
 }
 ### Prevents accidental 'unset -f'.
 # shellcheck disable=SC2034
@@ -109,6 +161,10 @@ readonly -f map_service_to_col
 #   1: on failure
 #######################################
 main() {
+  VAR_U="$(identify_subject)"
+  ### On missing User, behave like "not listed" (skip GA).
+  [[ -n "${VAR_U}" ]] || exit 0
+
   ### On missing map, behave like "not listed" (skip GA), analogous to onerr=ignore.
   if [[ ! -r "${VAR_MAP_FILE}" || -z "${VAR_U}" || -z "${VAR_S}" ]]; then
     exit 0