new tomb command 'passwd' can change a key password

usage: tomb passwd /path/to/keyfile.key
 documented in man page
 adds feature #46
 adds internal func safe_file()
 adds parameters for askpass() function messaging

doc/tomb-open.1

@@ -66,6 +66,12 @@ command will list them on the terminal. The special
 fails if the tomb is in use by running processes, the command
 \fIslam\fR can be used to force close.
 
+.B
+.IP "passwd"
+Changes the password of a tomb key file specified in the \fIfirst
+argument\fR. It will need the old password to decode the key file, it
+will then reencode it using the new password.
+
 .B
 .IP "slam"
 Closes a tomb like the command \fIclose\fR does, but in case it is in
@@ -135,8 +141,12 @@ Display version and quit
 .B
 .IP "-q"
 Run more quietly
+.B
 .IP "-D"
 Print more information while running, for debugging purposes
+.B
+.IP "--no-color"
+Don't use colors; useful for old terminals or integration in other scripts
 
 
 .SH HOOKS

doc/tomb-status.1

@@ -66,6 +66,12 @@ command will list them on the terminal. The special
 fails if the tomb is in use by running processes, the command
 \fIslam\fR can be used to force close.
 
+.B
+.IP "passwd"
+Changes the password of a tomb key file specified in the \fIfirst
+argument\fR. It will need the old password to decode the key file, it
+will then reencode it using the new password.
+
 .B
 .IP "slam"
 Closes a tomb like the command \fIclose\fR does, but in case it is in
@@ -135,8 +141,12 @@ Display version and quit
 .B
 .IP "-q"
 Run more quietly
+.B
 .IP "-D"
 Print more information while running, for debugging purposes
+.B
+.IP "--no-color"
+Don't use colors; useful for old terminals or integration in other scripts
 
 
 .SH HOOKS

doc/tomb.1

@@ -66,6 +66,12 @@ command will list them on the terminal. The special
 fails if the tomb is in use by running processes, the command
 \fIslam\fR can be used to force close.
 
+.B
+.IP "passwd"
+Changes the password of a tomb key file specified in the \fIfirst
+argument\fR. It will need the old password to decode the key file, it
+will then reencode it using the new password.
+
 .B
 .IP "slam"
 Closes a tomb like the command \fIclose\fR does, but in case it is in

src/tomb

@@ -27,6 +27,7 @@ TOMBOPENEXEC="tomb-open"
 typeset -a OLDARGS
 for arg in ${argv}; do OLDARGS+=($arg); done
 STEGHIDE=1
+MKTEMP=1
 MOUNTOPTS="rw,noatime,nodev"
 
 #declare global variables
@@ -102,6 +103,11 @@ check_bin() {
         exit 1
     fi
  
+    which mktemp > /dev/null
+    if [ $?! = 0 ]; then
+        MKTEMP=0
+    fi
+    
     # check for tomb-open script
     if [ "$0" = "./tomb" ]; then
 	TOMBOPENEXEC="./tomb-open"
@@ -122,6 +128,19 @@ safe_dir() {
     print "$dir"
 }
 
+
+safe_file() {
+    local tmpdir tmpfile
+    
+    if [ "$MKTEMP" = "1" ]; then
+        mktemp -u /dev/shm/$1.$$.XXXXXXX
+        # this return needs to output ONLY the file
+    else 
+	tmpfile="/dev/shm/$1.$$.$RANDOM.$RANDOM"
+	print $tmpfile
+    fi
+}
+
 #check if there is swap activated
 check_swap() {
     # Return 0 if NO swap is used, 1 if swap is used
@@ -152,11 +171,14 @@ ask_password() {
 	GTK2_RC=/usr/share/themes/tomb/gtk-2.0-key/gtkrc
     fi
 
+    title="Insert tomb password"
+    if [ $2 ]; then title="$2"; fi
+
     cat <<EOF | GTK2_RC_FILES=${GTK2_RC} pinentry 2>/dev/null | awk '/^D / { sub(/^D /, ""); print }'
 OPTION ttyname=$TTY
 OPTION lc-ctype=$LANG
-SETTITLE Insert tomb password
+SETTITLE $title
-SETDESC Open tomb: $1
+SETDESC $1
 SETPROMPT Password:
 GETPIN
 EOF
@@ -216,6 +238,7 @@ Commands:
  list       list all open tombs or the one called FILE
  close      close the open tomb called FILE (or all)
  slam       close tomb FILE and kill all pids using it
+ passwd     change the password of a tomb key FILE
 EOF
 if [ "$STEGHIDE" = 1 ]; then
     cat <<EOF
@@ -394,9 +417,9 @@ create_tomb() {
     # here user is prompted for key password
     for c in 1 2 3; do
 	# 3 tries to write two times a matching password
-	tombpass=`exec_as_user ${TOMBEXEC} askpass ${tombname}`
+	tombpass=`exec_as_user ${TOMBEXEC} askpass "Secure key for ${tombname}"`
 	tombpasstmp=$tombpass
-	tombpass=`exec_as_user ${TOMBEXEC} askpass "${tombname} (again)"`
+	tombpass=`exec_as_user ${TOMBEXEC} askpass "Secure key for ${tombname} (again)"`
 	if [ "$tombpasstmp" = "$tombpass" ]; then
 	    break;
 	fi
@@ -569,9 +592,9 @@ mount_tomb() {
     notice "Password is required for key ${keyname}"
     for c in 1 2 3; do
 	if [ $c = 1 ]; then
-	    tombpass=`exec_as_user ${TOMBEXEC} askpass ${keyname}`
+	    tombpass=`exec_as_user ${TOMBEXEC} askpass "Open tomb ${keyname}"`
 	else
-	    tombpass=`exec_as_user ${TOMBEXEC} askpass "$keyname (retry $c)"`
+	    tombpass=`exec_as_user ${TOMBEXEC} askpass "Open tomb $keyname (retry $c)"`
 	fi
     (gpg --batch --passphrase-fd 0 --no-tty --no-options \
         -d "${tombkey}" 2> /dev/null <<< ${tombpass} ) \
@@ -637,9 +660,9 @@ encode_key() {
     # here user is prompted for key password
     for c in 1 2 3; do
 	# 3 tries to write two times a matching password
-	tombpass=`exec_as_user ${TOMBEXEC} askpass ${tombkey}`
+	tombpass=`exec_as_user ${TOMBEXEC} askpass "Steg password for ${tombkey}"`
 	tombpasstmp=$tombpass
-	tombpass=`exec_as_user ${TOMBEXEC} askpass "${tombkey} (again)"`
+	tombpass=`exec_as_user ${TOMBEXEC} askpass "Steg password for ${tombkey} (again)"`
 	if [ "$tombpasstmp" = "$tombpass" ]; then
 	    break;
 	fi
@@ -690,9 +713,9 @@ decode_key() {
     notice "Trying to exhume a key out of image $imagefile"
     for c in 1 2 3; do
 	if [ $c = 1 ]; then
-	    tombpass=`exec_as_user ${TOMBEXEC} askpass ${keyfile}`
+	    tombpass=`exec_as_user ${TOMBEXEC} askpass "Steg password for ${keyfile}"`
 	else
-	    tombpass=`exec_as_user ${TOMBEXEC} askpass "$keyfile (retry $c)"`
+	    tombpass=`exec_as_user ${TOMBEXEC} askpass "Steg password for $keyfile (retry $c)"`
 	fi
 	steghide extract -sf ${imagefile} -p ${tombpass} -xf - \
 	    | awk '
@@ -985,6 +1008,111 @@ umount_tomb() {
     return 0
 }
 
+# change tomb key password
+change_passwd() {
+    if ! option_is_set --ignore-swap && [[ `check_swap out` == 1 ]]; then
+        error "You have swap activated; use --ignore-swap if you want to skip this check"
+        act "Using encryption with swap activated is very bad, because some files, or even your secret key, could be written on hard disk."
+        act "However, it could be that your swap is encrypted. If this is case, this is ok. Then, use --ignore-swap to skip this check"
+        act "You seem to be using `tail -n +2 /proc/swaps|wc -l` swaps:"
+        tail -n +2 /proc/swaps
+        return 1
+    fi
+    local keyfile="${1}"
+
+    # check the keyfile
+    if ! [ -r $keyfile ]; then
+	    error "key not found: $keyfile"
+	    return 1
+    fi
+    
+    file $keyfile | grep PGP > /dev/null
+    if [ $? != 0 ]; then
+	    error "file doesn't seems to be a tomb key: $keyfile"
+	    error "operation aborted."
+	    return 1
+    fi
+
+    local tmpnewkey tmpoldkey c tombpass tombpasstmp
+    
+    tmpnewkey=`safe_file tomb`
+    tmpoldkey=`safe_file tomb`
+    
+
+    notice "Changing password for $keyfile"
+    keyname=`basename $keyfile`
+    for c in 1 2 3; do
+	    if [ $c = 1 ]; then
+	        tombpass=`exec_as_user ${TOMBEXEC} askpass "Type old password for ${keyname}" "Change tomb key password"`
+	    else
+	        tombpass=`exec_as_user ${TOMBEXEC} askpass "Type old password for ${keyname} (retry $c)" "Change tomb key password"`
+	    fi
+        gpg --batch --no-options --no-tty --passphrase-fd 0 -o "${tmpoldkey}" -d $keyfile <<< "$tombpass" &> /dev/null
+        if [ $? = 0 ]; then
+            tombpass="ok"
+            break
+        fi
+    done
+
+    if [ "$tombpass" != "ok" ]; then
+        error "You typed an Invalid old password. Operation aborted."
+        # /dev/null because the file cannot exists
+        ${WIPE[@]} "${tmpnewkey}" 2> /dev/null
+        ${WIPE[@]} "${tmpoldkey}" 2> /dev/null
+        return 1
+    fi
+
+    for c in 1 2 3; do
+	    # 3 tries to write two times a matching password
+	    if [ $c = 1 ]; then
+	        tombpass=`exec_as_user ${TOMBEXEC} askpass "Type the new password for ${keyname}" "Change tomb key password"`
+	    else
+	        tombpass=`exec_as_user ${TOMBEXEC} askpass "Type the new password for ${keyname} (retry $c)" "Change tomb key password"`
+	    fi
+	    tombpasstmp=$tombpass
+	    tombpass=`exec_as_user ${TOMBEXEC} askpass "Type the new password again" "Change tomb key password"`
+	    if [ "$tombpasstmp" = "$tombpass" ]; then
+	        break;
+	    fi
+	    unset tombpasstmp
+	    unset tombpass
+    done
+
+    if [ -z $tombpass ]; then
+	    error "You mistyped the new password. Operation aborted."
+        # /dev/null because the file cannot exists
+        ${WIPE[@]} "${tmpnewkey}" 2> /dev/null
+        ${WIPE[@]} "${tmpoldkey}" 2> /dev/null
+	    return 1
+    fi
+
+    gpg \
+	--openpgp --batch --no-options --no-tty --passphrase-fd 0 \
+	-o "${tmpnewkey}" -c -a ${tmpoldkey} <<< ${tombpass}
+    
+    if [ $? != 0 ]; then
+        error "Cannot change your key passphrase"
+        # /dev/null because the file cannot exists
+        ${WIPE[@]} "${tmpnewkey}" 2> /dev/null
+        ${WIPE[@]} "${tmpoldkey}" 2> /dev/null
+        return 1
+    fi
+
+    # wipe the previous, original, key
+    ${WIPE[@]} "${keyfile}"
+    # copy the new key as the original keyfile name
+    cp "${tmpnewkey}" "${keyfile}"
+
+    act "Cleaning environment"
+    # wipe all temp file
+    ${WIPE[@]} "${tmpnewkey}"
+    ${WIPE[@]} "${tmpoldkey}"
+
+    notice "Your passphrase was successfully updated."
+
+    return 0
+}
+
 # list all tombs mounted in a readable format
 list_tombs() {
     if [ $1 ]; then
@@ -1251,6 +1379,7 @@ main() {
     subcommands_opts[open]="n -nohook=n k: -key=k o: -mount-options=o -ignore-swap"
     subcommands_opts[mount]=${subcommands_opts[open]}
     subcommands_opts[create]="s: -size=s -ignore-swap k: -key=k"
+    subcommands_opts[passwd]="-ignore-swap"
     subcommands_opts[close]=""
     subcommands_opts[help]=""
     subcommands_opts[slam]=""
@@ -1345,6 +1474,7 @@ main() {
 	 umount) check_priv ; umount_tomb ${CMD2} ;;
 	  close) check_priv ; umount_tomb ${CMD2} ;;
 	   slam) check_priv ; SLAM=1; umount_tomb ${CMD2} ;;
+	 passwd) check_priv ; change_passwd ${CMD2} ;;
 	   list) list_tombs ${CMD2} ;;
 	 status) launch_status ${CMD2} ;;
 	   help) usage ;;
@@ -1361,7 +1491,7 @@ main() {
 	# internal commands useful to developers
        'source') return 0 ;;
 	install) check_priv ; install_tomb ;;
-	askpass) ask_password $CMD2 ;;
+	askpass) ask_password ${CMD2} ${CMD3} ;;
 	 mktemp) safe_dir ${CMD2} ;;
       translate) generate_translatable_strings ;;
       __default)