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 on: October 09, 2021, 12:08:35 AM 
Started by Dakusan - Last post by Dakusan

The following is a tutorial on mounting a dd image of a TrueCrypt system-level-encrypted volume. This tutorial was tested and written against Ubuntu 16.04.2 LTS.

Trying to mount your loopback device with losetup or mount doesn’t quite work. If you tried, you’d get an error like the following:

No such file or directory:

Instead, use sudo kpartx -va IMAGE_FILENAME.This will give you something like the following:

add map loop2p1 (253:0): 0 204800 linear 7:2 2048
add map loop2p2 (253:1): 0 976564224 linear 7:2 206848
This shows you the partitions in the image and which loopback devices they are mounted to. In my case, loop2 and loop2p2, which I will continue using for the rest of this tutorial.
So this mounts the following:
  • /dev/loop2: The primary loopback device
  • /dev/mapper/loop2p*: The partition loopback devices (in my case, loop2p1 and loop2p2)

If you attempt to mount loop2p2 with TrueCrypt or VeraCrypt as a system partition, no matter the password, you will get the error “Partition device required”.
To fix this we need to get the loop2p2 to show up in /dev and make an edit to the VeraCrypt source code.

You can run the following command to see the loopback partition devices and their sizes. This is where I am pulling loop2p2 from.

lsblk /dev/loop2
This will give the following:

loop2       7:2    0 465.8G  1 loop
??loop2p2 253:1    0 465.7G  1 part
??loop2p1 253:0    0   100M  1 part

Run the following command to create /dev/loop2p* block devices:

sudo partx -a /dev/loop2

Run the following commands to download and compile VeraCrypt:

sudo apt-get install git yasm libfuse-dev libwxgtk3.0-dev #yasm requires universe repository
git clone https://github.com/veracrypt/VeraCrypt
cd VeraCrypt/src
nano Platform/Unix/FilesystemPath.cpp #You can use the editor of your choice for this

In Platform/Unix/FilesystemPath.cpp make the following change:
After the following 2 lines of code in the FilesystemPath::ToHostDriveOfPartition() function, currently Line 78:

#ifdef TC_LINUX
       path = StringConverter::StripTrailingNumber (StringConverter::ToSingle (Path));
Add the following:

string pathStr = StringConverter::ToSingle (path);
size_t t = pathStr.find("loop");
if(t != string::npos)
   path = pathStr.substr (0, pathStr.size() - 1);
Then continue to run the following commands to finish up:

Main/veracrypt -m system,ro,nokernelcrypto -tc /dev/loop2p2 YOUR_MOUNT_LOCATION

VeraCrypt parameter information:

  • If you don’t include the “nokernelcrypto” option, you will get the following error:

    device-mapper: reload ioctl on veracrypt1 failed: Device or resource busy
    Command failed
  • the “ro” is if you want to mount in readonly
  • “-tc” means the volume was created in TrueCrypt (not VeraCrypt)

  • Doing this in Windows is a lot easier. You just need to use a program called Arsenal Image Mounter to mount the drive, and then mount the partition in TrueCrypt (or VeraCrypt).

 on: January 19, 2020, 01:11:48 AM 
Started by Dakusan - Last post by Dakusan

I’ve always thought that the RSA and Diffie–Hellman public key encryption algorithm systems are beautiful in their complex simplicity. While there are countless articles out there explaining how to implement them, I have never really found one that I think describes the math behind then in a simple way, so I thought I’d give a crack at it.

Both algorithms are derived from 3 math axioms:
  1. This is called Modular exponentiation (hereby referred to as modexp). In the following, x is a prime numbers and p is an integer less than x.
    1. p^(x  ) mod x = p (e.x. 12^(17  ) mod 17 = 12)
    2. p^(x-1) mod x = 1 (e.x. 12^(17-1) mod 17 = 1 )
  2. A further derivation from the above formulas shows that we can combine primes and they work in the same manner. In the following, x and y are prime numbers and p is  an integer less than x*y.
    1. p^((x-1)*(y-1)  ) mod (x*y) = 1 (e.x. 12^((13-1)*(17-1)  ) mod (13*17) = 1 )
      Note: This formula is not used in RSA but it helps demonstrate how the formulas from part 1 becomes formula 2b.
      Due to how modexp works with primes, values of p that are multiples of x or y do not work with 2a.
    2. p^((x-1)*(y-1)+1) mod (x*y) = p (e.x. 12^((13-1)*(17-1)+1) mod (13*17) = 12)
  3. The final axiom is how modexp can be split apart the same way as in algebra where (x^a)^b === x^(a*b). For any integers p, x, y, and m:
    (p^(x*y) mod m) === ((p^x mod m)^y mod m)

With these 3 axioms we have everything we need to explain how RSA works. To execute an RSA exchange, encrypted from Bob and decrypted by Alice, the following things are needed.

The variableVariable nameWho has itWho uses itDescription
Prime Numbers 1 and 2Prime1, Prime2AliceAliceAlice will use these to derive variables PubKey, PrivKey, and Modulo. In our examples we use small numbers, but in reality, very large primes will be used, generally of at least 256 bit size.
Public keyPubKeyAlice, BobBobAlice sends this to Bob so he can encrypt data to her. Bob uses it as an exponent in a modexp.
Private keyPrivKeyAliceAliceAlice uses this to decrypt what Bob sends her. Alice uses it as an exponent in a modexp.
ModuloModuloBob, AliceBob, AliceAlice sends this to Bob. They both use it as a modulo in a modexp
Payload DataPayloadThe data bob starts with and turns into EncryptedPayload. Alice derives Payload back from EncryptedPayload

Now, let’s start with axiom 2b:
Payload^((Prime1-1)*(Prime2-1)+1) mod (Prime1*Prime2) = Payload

Let’s change this up so the exponent is just 2 multiplications so we can use axiom 3 on it. We need to find 2 integers to become PubKey and PrivKey such that:

And Modulo is Prime1*Prime2.
So we now have:
Payload^(PubKey*PrivKey) mod Modulo = Payload

Now, using axiom 3, we can turn it into this:
(Payload^PubKey mod Modulo)^PrivKey mod Modulo = Payload

Now, we can split this up into:
Bob calculates and sends to Alice: Payload^PubKey mod Modulo=EncryptedPayload
Alice uses the received EncryptedPayload and performs: EncryptedPayload^PrivKey mod Modulo = Payload

And the process is complete!

However, there is 1 caveat that I didn’t cover which makes the encryption that what we currently have weak. The calculation of PubKey and PrivKey from Prime1 and Prime2 needs to follow some rather specific complex rules to make the keys strong. Without this, an attacker may be able to figure out Prime1 and Prime2 from the Modulo and PubKey, and could then easily derive PrivKey from it. I generally see the PubKey as 65535, or another power of 2 minus 1.

 on: January 10, 2020, 05:23:33 PM 
Started by Dakusan - Last post by Dakusan
Original post for My Tmux config can be found at https://www.castledragmire.com/Posts/My_Tmux_config.
Originally posted on: 01/11/20

Tmux is a great alternative to gnu screen. I can’t believe I’ve never posted my custom Tmux config for Cygwin after all the work I put into it years ago. So here it is. Its features include:

  • Uses ctrl+a, like gnu screen, instead of ctrl+b
  • Mouse interaction is enabled
  • Tab bar/windows:
    • Current tab is highlighted in cyan
    • Cycle through tabbed windows with a click on its tab or ctrl+arrowkeys
    • Reorder tabbed windows with a drag of its tab or alt+arrowkeys
    • ctrl+a,/ to rename a tab on the tab bar
    • Create new window with ctrl+a,c
  • Panes
    • Create split panes with vertical=ctrl+a,| and horizontal=ctrl+a,-
    • Move around panes with click or ctrl+shift+arrowkeys
    • Resize panes by dragging on the separator bar or use ctrl+shift+alt+arrowkeys
    • Panes automatically resize to fit OS window
  • Clipboard/highlighting
    • Copy text to clipboard by highlighting it. Had to use a minor hack to fix a cygwin selection problem
    • Paste from clipboard with right click
    • Middle mouse button+drag starts copy mode
      • When in copy mode, u runs the selection as a command in a separate window (Instead of “cygstart” for cygwin, use “xdg-open” for linux, or “open” for MacOS X)
    • Double click selects word
    • Double middle click runs the word under the mouse as a command
  • Start the session on the current bash directory
  • Escape time is lowered for quicker response to scroll buffer access (ctrl+a,pageup)

To use this, save the file to ~/.tmux.conf

#Set current directory setting for cygwin
set-environment -g CHERE_INVOKING 1

#Mouse interaction
set -g mouse on

#Lower escape timing from 500ms to 50ms for quicker response to scroll-buffer access
set -s escape-time 50

#Window always takes up largest possible max size
set-window-option -g aggressive-resize

#Highlight active window in tab-bar at bottom in cyan
set-window-option -g window-status-current-bg cyan

#Reorder windows in status bar by drag & drop
bind-key -n MouseDrag1Status swap-window -t=

#Copy to clipboard on text selection in cygwin. Move cursor position 1 to the right before copy to bypass a bug
bind -Tcopy-mode MouseDragEnd1Pane send-keys -X cursor-right\; send -X copy-selection-and-cancel\; run-shell -b "tmux show-buffer > /dev/clipboard"

#Paste from clipboard with right click in cygwin
bind-key -n MouseDown3Pane run-shell 'tmux set-buffer -b winclip "$(cat /dev/clipboard)"'\; paste-buffer -db winclip

#Middle drag starts copy mode
bind -n MouseDrag2Pane copy-mode -M

#When in copy mode, "u" runs the selection as a command in a separate window (Instead of "cygstart" for cygwin, use "xdg-open" for linux, or "open" for MacOS X)
bind -Tcopy-mode u send -X copy-selection-and-cancel\; run-shell -b "tmux show-buffer | xargs cygstart"

#Double click selects word
bind-key -n DoubleClick1Pane copy-mode -M\; send-keys -X select-word

#Double middle click runs the word under the mouse as a command. See description for MouseDown3Pane above
bind-key -n DoubleClick2Pane copy-mode -M\; send-keys -X select-word\; send -X copy-selection-and-cancel\; run-shell -b "tmux show-buffer | xargs cygstart"

#Remap prefix to Control+a
set -g prefix C-a
unbind C-b
#bind 'C-a C-a' to type 'C-a'
bind C-a send-prefix

#Start in CWD when creating or splitting tabs; move the splitting planes keys to | and -
bind '|' split-window -h -c '#{pane_current_path}'  # Split panes horizontal
bind '-' split-window -v -c '#{pane_current_path}'  # Split panes vertically
bind c new-window -c '#{pane_current_path}' # Create new window
unbind '"'
unbind %

#prefix, / -- Renames window, but starts blank
bind-key / command-prompt "rename-window '%%'"

#Select next/prev window with Ctrl+(Left|Right)
bind-key -n C-Right next-window
bind-key -n C-Left previous-window

#Reorder window with Alt+(Left|Right)
bind-key -n M-Left swap-window -t -1
bind-key -n M-Right swap-window -t +1

#Switch panes using Ctrl+Shift+arrow
bind -n C-S-Left select-pane -L
bind -n C-S-Right select-pane -R
bind -n C-S-Up select-pane -U
bind -n C-S-Down select-pane -D

#Resize panes using Ctrl+Shift+Alt+arrow
bind-key -n C-S-M-Up resize-pane -U 1
bind-key -n C-S-M-Down resize-pane -D 1
bind-key -n C-S-M-Left resize-pane -L 1
bind-key -n C-S-M-Right resize-pane -R 1

 on: September 24, 2019, 04:59:08 PM 
Started by Dakusan - Last post by Dakusan
Original post for Fixing VeraCrypt EFI Boot can be found at https://www.castledragmire.com/Posts/Fixing_VeraCrypt_EFI_Boot.
Originally posted on: 09/24/19

I recently decided to swap around my hard drives to different SATA slots so my most used hard drives were on the fastest ports. Unfortunately, when I did this, my computer stopped booting to Windows. I never did figure out why my bootable EFI partitions only showed up randomly in BIOS depending on which hard drives were plugged in, but I found a configuration the computer liked and I was able to see the Microsoft Boot EFI partition and EFI boots on my USB keys.

The next step was to get the computer actually booting to something I could run commands on. When I try to boot directly to the EFI shell, the resolution is always screwed up and I can only see the top half of what should be visible, so I can’t actually see the command line I am typing too. This actually happens to everything I directly boot to that uses console text. The way around this for me is that I need to boot to the BIOS setup, and from there tell it to boot immediately to the EFI option of my choice when exiting the BIOS. From there, the proper resolution is used and everything is visible.

Next, in the EFI shell, you can run map to see all of the available possible mounts. This should automatically run when the EFI shell starts anyways, so you should already have that information. Any detected EFI partition on any bootable device should be given a mapping of “fs#” where # is a number. In my case, it was fs0. So to mount that, I ran mount fs0 x. “x” could be whatever you want, it doesn’t really matter. It’s analogous to a drive letter in windows, and you can make it any string (within reason, I believe anything alphanumeric should be fine). So next you would run x: to switch to that drive. From there, you can run cd EFI\Microsoft\Boot and then bootmgfw.efi to boot to windows.

Since I use VeraCrypt system encryption, I had to go to “EFI\VeraCrypt” and run DcsBoot.efi to finally boot into Windows through VeraCrypt.

Finally, to get the Windows Boot manager to start with VeraCrypt, run in the Windows command prompt bcdedit /set '{bootmgr}' path \EFI\VeraCrypt\DcsBoot.efi.

 on: August 10, 2019, 10:48:07 PM 
Started by Dakusan - Last post by Dakusan

I recently tried to install Slackware 4.2 64-bit (Linux) onto a new mini PC I just bought. The new PC only supports UEFI so I had major issues getting the darn setup on the install cd to actually run. I never DID actually get the install cd to boot properly on the system, so I used an alternative. While the slack install usb key was in, I also added and loaded up an ubuntu live cd usb key. The following is what I used to run the slackware setup in Ubuntu.

#Login as root
#sudo su

InstallDVDName=SlackDVD #This is whatever you named your slackware usb key

#/mnt will contain the new file system for running the setup
cd /mnt

#Extract the initrd.img from the slackware dvd into /mnt
cat /media/ubuntu/$InstallDVDName/isolinux/initrd.img | gzip -d | cpio -i

#Bind special linux directories into the /mnt folder
for i in proc sys dev tmp; do mount -o bind /$i ./$i; done

#Mount the cdrom folder into /mnt/cdrom
rm cdrom
mount -o bind /media/ubuntu/$InstallDVDName/ ./cdrom

#Set /mnt as our actaul (ch)root
chroot .

#Run the slackware setup

#NOTE: When installing, your package source directory is at /cdrom/slackware64

 on: June 26, 2019, 09:53:33 PM 
Started by Dakusan - Last post by Dakusan

It’s a bit of a pain reading results from batch requests to Mailchimp. Here is a quick and dirty bash script to get and pretty print the JSON output. It could be cleaned up a little, including combining some of the commands, but meh.

#Example variables

#Request the batch information from Mailchimp
curl --request GET --url "https://dummy:$APIKEY@$APIURL/3.0/batches/$BATCHID" 2> /dev/null | \

#Get the URL to the response
grep -oP '"response_body_url":"https:.*?"' | \
grep -oP 'https:[^"]*' | \

#Get the response
xargs wget -O - 2> /dev/null | \

#The response is a .tar.gz file with a single file in it. So get the contents of this file
tar -xzvO 2> /dev/null | \

#Pretty print the json of the full return and the “response” objects within
php -r '$Response=json_decode(file_get_contents("php://stdin"), true); foreach($Response as &$R) $R["response"]=json_decode($R["response"], true); print json_encode($Response, JSON_PRETTY_PRINT);'

 on: April 08, 2019, 09:31:09 PM 
Started by Dakusan - Last post by Dakusan

Part of my workstation’s audio setup uses the RME Babyface Pro. Until the most recent update of their software, the built-in Window’s sound’s master volume for the device was ignored. So while this script isn’t as important as before, I still find it very useful. So the following is an AutoHotkey script which modifies the master volume in the TotalMix FX window via the mousewheel (when alt+ctrl is held down). This expects the TotalMix FX window to be sized as small as it can, and to have a channel selected for the control room’s Main Out. It should look like this:

TotalMix FX Sized For Volume Modification

The script is as follows:

;Function to create lparam/wparam for SendMessage
CalculatePARAM(w1, w2)
   IfLess, w1, 0
      w1 := 65535 + w1 + 1
   IfLess, w2, 0
      w2 := 65535 + w2 + 1

   return (w2<<16 | w1)

;Send a mouse wheel action to a window
SendMouseWheel(WindowHWND, Steps, XPos, YPos)
   WheelStepAmount := 120

   ;Calculate and execute the message
   WinGetPos, ScreenX, ScreenY,,, ahk_id %WindowHWND%
   wparam := CalculatePARAM(0, Steps*WheelStepAmount)
   lparam := CalculatePARAM(XPos+ScreenX, YPos+ScreenY)
   SendMessage, %WM_MOUSEWHEEL%, %wparam%, %lparam%,, ahk_id %WindowHWND%

ControlGet, ControlHWND, Hwnd,,AfxFrameOrView100s1,RME TotalMix
if ControlHWND
   SendMouseWheel(ControlHWND, 1, 36, 428)

ControlGet, ControlHWND, Hwnd,,AfxFrameOrView100s1,RME TotalMix
if ControlHWND
   SendMouseWheel(ControlHWND, -1, 36, 428)

 on: January 30, 2019, 12:52:47 AM 
Started by Dakusan - Last post by clowg
PS:  There is a new API available for Playlist importing:https://forums.plex.tv/t/can-plexamp-read-and-use-m3u-playlists/234179/32

 on: January 30, 2019, 12:38:42 AM 
Started by Dakusan - Last post by clowg
Hi @Dakusan

I have come back to your script/.exe because Plex threw away one of my previously imported m3u Playlists.Im getting this error:
PlexPlaylistImporter.exe -p "D:\PlexServer\Plex Media Server\Plug-in Support\Databases\com.plexapp.plugins.library.db" "D:\7mc\plexplaylistimporter\top 550 songs.m3u" Top550SongsPlex playlist is not already created. Would you like to create it now (y/n)? y
DB Error: no such collation sequence: naturalsort

This is on Windows 10 x64, on the Plex Server console.  The exe worked really hard for about 10 minutes before coming up with the playlist creation question, and then immediately failed with the error.Any ideas on that one?

 on: December 29, 2018, 04:48:03 AM 
Started by Dakusan - Last post by Dakusan
Original post for MD5Sum List Script can be found at https://www.castledragmire.com/Posts/MD5Sum_List_Script.
Originally posted on: 12/29/18

#This script takes a newline delimited file list from STDIN for md5 hashing
#This script requires the `md5sum`, `pv`, `paste`, `bc`, and 'numfmt' commands

#The output of the md5s are stored in the file specified by the first parameter
#The format for each md5 hash to the output file is "$FileName\t$Hash\n"

#File sizes are always output in megabytes with 3 decimal places
#While calculating the hashes the script keeps the user informed of the progress of both the current file and all the files as follows:
#1) "Hashing: $FileName ($FileSize MiB)\n"
#2) The progress of the hash of the file ran through `pv`, with the size precalculated for file progress percents
#3) "Finished $TotalProgressPercent% ($ProcessedBytes/$TotalBytes MiB)\n\n"

#Get $Outfile from the first argument and the $FileList from STDIN (newline delimited)
FileList=`cat /dev/stdin`

#Format a byte count in MegaBytes with comma grouping and 3 decimal places
MbFmtNoExt ()
   echo "scale=3; $1/1024/1024" | bc | echo -n `xargs numfmt --grouping`

#Add " MiB" to the end of MbFmtNoExt
MbFmt ()
   echo `MbFmtNoExt $1`" MiB"

#Calculate and output the total size of the file list
echo -n "Calculating total size: "
TotalSize=`echo "$FileList" | xargs -d"\n" stat --printf="%s\n" | paste -s -d+ | bc`
MbFmt $TotalSize
echo #Add an extra newline

#Run over the list (newline delimited)
for FileName in `echo "$FileList"`
   #Output the file size and name to STDOUT
   FileSize=`stat --printf="%s" "$FileName"`
   echo "Hashing: $FileName ("`MbFmt $FileSize`")"

   #Output the filename to $OutFile
   echo -n $FileName$'\t' >> $OutFile

   #Run the md5 calculation with `pv` progress
   #Output the hash to $OutFile after the FileName and a tab
   cat "$FileName" | pv -s $FileSize | md5sum | awk '{print $1}' >> $OutFile

   #Output the current progress for the entire file list
   #Format: "Finished $TotalProgressPercent% ($ProcessedBytes/$TotalBytes MiB)\n\n"
   echo -n "Finished "
   printf "%.3f" `echo "scale=4; $CalculatedBytes*100/$TotalSize" | bc`
   echo "% ("`MbFmtNoExt $CalculatedBytes`"/"`MbFmt $TotalSize`$')\n'

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