gui-init: Eliminate extra TPM owner password prompts in TPM reset

We just set the TPM owner password, so there's no need to make the user
enter it again.  Eliminates some failure modes if the user mistypes it
or enters the wrong password.

Allow optionally passing in the TPM owner password in tpmr seal,
check_tpm_counter(), seal-totp, and generate_totp_htop().  The user is
still prompted if the password is needed but was not provided, so
existing uses in other contexts continue to work unchanged.

Prompt for the password in reset_tpm() and pass it down to each of the
above.

Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>

initrd/bin/gui-init

@@ -150,9 +150,10 @@ prompt_update_checksums()
 
 generate_totp_htop()
 {
+  tpm_password="$1"	# May be empty, will prompt if needed and empty
   TRACE "Under /bin/gui-init:generate_totp_htop"
   echo "Scan the QR code to add the new TOTP secret"
-  if /bin/seal-totp "$BOARD_NAME"; then
+  if /bin/seal-totp "$BOARD_NAME" "$tpm_password"; then
     if [ -x /bin/hotp_verification ]; then
       echo "Once you have scanned the QR code, hit Enter to configure your HOTP USB Security Dongle (e.g. Librem Key or Nitrokey)"
       read
@@ -509,13 +510,39 @@ prompt_totp_mismatch()
   fi
 }
 
+prompt_new_owner_password() {
+  read -s -p "New TPM owner password: " key_password
+  echo
+
+  if [ -z "$key_password" ]; then
+    echo "Empty owner password is not allowed" >&2
+    return 1
+  fi
+
+  read -s -p "Repeat owner password: " key_password2
+  echo
+
+  if [ "$key_password" != "$key_password2" ]; then
+    echo "Key passwords do not match" >&2
+    return 1
+  fi
+}
+
 reset_tpm()
 {
   TRACE "Under /bin/gui-init:reset_tpm"
   if [ "$CONFIG_TPM" = "y" ]; then
     if (whiptail $BG_COLOR_WARNING --title 'Reset the TPM' \
         --yesno "This will clear the TPM and TPM password, replace them with new ones!\n\nDo you want to proceed?" 0 80) then
-      /bin/tpm-reset
+
+      if ! prompt_new_owner_password; then
+        echo "Press Enter to return to the menu..."
+        read
+        echo
+        return 1
+      fi
+
+      tpmr reset "$key_password"
 
       # now that the TPM is reset, remove invalid TPM counter files
       mount_boot
@@ -524,7 +551,7 @@ reset_tpm()
       rm -f /boot/kexec_primhdl_hash.txt
 
       # create Heads TPM counter before any others
-      check_tpm_counter /boot/kexec_rollback.txt \
+      check_tpm_counter /boot/kexec_rollback.txt "" "$key_password" \
       || die "Unable to find/create tpm counter"
       counter="$TPM_COUNTER"
 
@@ -535,7 +562,7 @@ reset_tpm()
       || die "Unable to create rollback file"
       mount -o ro,remount /boot
 
-      generate_totp_htop
+      generate_totp_htop "$key_password"
     else
       echo "Returning to the main menu"
     fi

initrd/bin/seal-totp

@@ -15,6 +15,7 @@ HOST="$1"
 if [ -z "$HOST" ]; then
 	HOST="TPMTOTP"
 fi
+TPM_PASSWORD="$2"
 
 TOTP_SECRET="/tmp/secret/totp.key"
 TOTP_SEALED="/tmp/secret/totp.sealed"
@@ -41,7 +42,7 @@ DEBUG "Sealing TOTP neglecting PCR5 involvement (Dynamically loaded kernel modul
 DEBUG "Sealing TOTP without PCR6 involvement (LUKS header consistency is not firmware integrity attestation related)"
 # pcr 7 is containing measurements of user injected stuff in cbfs
 tpmr pcrread -a 7 "$pcrf"
-tpmr seal "$TOTP_SECRET" "$TPM_NVRAM_SPACE" 0,1,2,3,4,7 "$pcrf" 312 \
+tpmr seal "$TOTP_SECRET" "$TPM_NVRAM_SPACE" 0,1,2,3,4,7 "$pcrf" 312 "" "$TPM_PASSWORD" \
 	|| die "Unable to write sealed secret to NVRAM"
 shred -n 10 -z -u "$TOTP_SEALED" 2> /dev/null
 

initrd/bin/tpmr

@@ -262,7 +262,9 @@ tpm2_seal() {
 	pcrl="$3" #0,1,2,3,4,5,6,7 (does not include algorithm prefix)
 	pcrf="$4"
 	sealed_size="$5"	# Not used for TPM2
-	pass="$6"
+	pass="$6"	# May be empty to seal with no password
+	tpm_password="$7"	# Owner password - will prompt if needed and not empty
+	# Owner password is always needed for TPM2.
 
 	mkdir -p "$SECRET_DIR"
 	bname="`basename $file`"
@@ -313,13 +315,12 @@ tpm2_seal() {
 	tpm2 load -Q -C "/tmp/$PRIMARY_HANDLE_FILE" \
 		-u "$SECRET_DIR/$bname.priv" -r "$SECRET_DIR/$bname.pub" \
 		-c "$SECRET_DIR/$bname.seal.ctx"
-	read -s -p "TPM owner password: " key_password
+	prompt_tpm_password
-	echo # new line after password prompt
 	# remove possible data occupying this handle
-	tpm2 evictcontrol -Q -C o -P "$(tpm2_password_hex "$key_password")" \
+	tpm2 evictcontrol -Q -C o -P "$(tpm2_password_hex "$tpm_password")" \
 		-c "$handle" 2>/dev/null || true
 	DO_WITH_DEBUG --mask-position 6 \
-		tpm2 evictcontrol -Q -C o -P "$(tpm2_password_hex "$key_password")" \
+		tpm2 evictcontrol -Q -C o -P "$(tpm2_password_hex "$tpm_password")" \
 		-c "$SECRET_DIR/$bname.seal.ctx" "$handle"
 }
 tpm1_seal() {
@@ -329,7 +330,8 @@ tpm1_seal() {
 	pcrl="$3" #0,1,2,3,4,5,6,7 (does not include algorithm prefix)
 	pcrf="$4"
 	sealed_size="$5"
-	pass="$6"
+	pass="$6"	# May be empty to seal with no password
+	tpm_password="$7"	# Owner password - will prompt if needed and not empty
 
 	sealed_file="$SECRET_DIR/tpm1_seal_sealed.bin"
 	trap "cleanup_shred '$sealed_file'" EXIT
@@ -368,8 +370,7 @@ tpm1_seal() {
 		tpm physicalpresence -s \
 			|| warn "Warning: Unable to assert physical presence"
 
-		read -s -p "TPM Owner password: " tpm_password
+		prompt_tpm_password
-		echo
 
 		tpm nv_definespace -in "$index" -sz "$sealed_size" \
 			-pwdo "$tpm_password" -per 0 \

initrd/etc/functions

@@ -247,19 +247,30 @@ confirm_gpg_card()
 	fi
 }
 
+# Prompt for an owner password if it is not already set in tpm_password.  Sets
+# tpm_password.  Tools should optionally accept a TPM password on the command
+# line, since some flows need it multiple times and only one prompt is ideal.
+prompt_tpm_password() {
+	if [ -n "$tpm_password" ]; then
+		return 0;
+	fi
+
+	read -s -p "TPM Owner password: " tpm_password
+	echo # new line after password prompt
+}
 
 check_tpm_counter()
 {
   TRACE "Under /etc/functions:check_tpm_counter"
   LABEL=${2:-3135106223}
+  tpm_password="$3"
 	# if the /boot.hashes file already exists, read the TPM counter ID
 	# from it.
 	if [ -r "$1" ]; then
 		TPM_COUNTER=`grep counter- "$1" | cut -d- -f2`
 	else
 		warn "$1 does not exist; creating new TPM counter"
-		read -s -p "TPM Owner password: " tpm_password
+		prompt_tpm_password
-		echo
 		tpmr counter_create \
 			-pwdo "$tpm_password" \
 			-pwdc '' \