commit 130cd2711b06cc8ba4b98b9c5aa78bf873412a5d
Author: Adrien Bourmault <neox@a-lec.org>
Date:   Wed May 4 14:44:59 2022 +0200

    Initial commit

diff --git a/captcha.sh b/captcha.sh
new file mode 100755
index 0000000..8800e74
--- /dev/null
+++ b/captcha.sh
@@ -0,0 +1,181 @@
+#!/bin/bash
+
+# Copyright © 2021 Adrien Bourmault (neox@a-lec.org)
+# Copyright © 2021 Echolib (echolib@dismail.de)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This script is an example captcha script.
+# It takes the text to recognize in the captcha image as a parameter.
+# It return the image binary as a result. ejabberd support PNG, JPEG and GIF.
+
+# The whole idea of the captcha script is to let server admins adapt it to
+# their own needs. The goal is to be able to make the captcha generation as
+# unique as possible, to make the captcha challenge difficult to bypass by
+# a bot.
+# Server admins are thus supposed to write and use their own captcha generators.
+
+# This script relies on ImageMagick.
+# It is NOT compliant with ImageMagick forks like GraphicsMagick.
+
+INPUT=$1
+LENINPUT=${#INPUT}
+DIGITS=(zéros uns deux trois quatres cinqs six septs huits neufs dix)
+DIGIT=(zéro un deux trois quatre cinq six sept huit neuf dix)
+
+
+# ****************************************************************************
+# 
+# Tools
+#
+# ****************************************************************************
+
+
+# Loops 10 times (should be enough) to check if a TARGET number is in INPUT
+GENERATE__NOTIN() {
+for i in {1..10}
+do
+   FALSENBR=`seq 1 9 | sort -R | head -n 1`
+   ! [[ $INPUT =~ $FALSENBR ]] \
+      && break
+done
+}
+
+
+# ****************************************************************************
+#
+# Captcha shapes
+#
+# ****************************************************************************
+
+
+# REPLACEs a random number in INPUT by another one randomized
+REPLACE() {
+NAME="REPLACE"
+PLACE=`seq 1 6 | sort -R | head -n 1`
+TARGET=`echo "$INPUT" | head -c $PLACE | tail -c 1`
+
+GENERATE__NOTIN
+NAME+="-$FALSENBR-$TARGET"
+NEWINPUT=${INPUT//$TARGET/$FALSENBR}
+INSTRUCTIONS1="Recopiez ce nombre"
+INSTRUCTIONS2="en changeant les ${DIGITS[FALSENBR]} en ${DIGITS[TARGET]}"
+}
+
+
+# REVERSEs INPUT. Ask to Add first or last number in random. 
+REVERSE() {
+NAME="REVERSE"
+RFL=`seq 1 2 | sort -R | head -n 1` # Rand First (1) or Last (2)
+ADDNBR=${DIGITS[ADDNBR]}
+
+for ((i=$LENINPUT-1;i>=0;i--))
+do
+   NEWINPUT="$NEWINPUT${INPUT:$i:1}"
+done
+
+if (( $RFL == 1 ));then
+   ADDNBR="${INPUT:0:1}"
+   NAME+="_FIRST"
+   NEWINPUT=${NEWINPUT:0:$LENINPUT-1} # Do not show first INPUT NBR
+   INSTRUCTIONS1="Écrivez le chiffre ${DIGIT[$ADDNBR]} puis le nombre "
+   INSTRUCTIONS2="en recopiant de DROITE à GAUCHE ←"
+else
+   ADDNBR="${INPUT:$LENINPUT-1:1}"
+   NAME+="_LAST"
+   NEWINPUT=${NEWINPUT:1:$LENINPUT-1} # Do not show last INPUT NBR
+   INSTRUCTIONS1="Recopiez de DROITE à GAUCHE ←"
+   INSTRUCTIONS2="et terminez par le chiffre ${DIGIT[$ADDNBR]}"
+fi
+NAME+="-$ADDNBR"
+}
+
+
+# Add FALSE NBR to INPUT at three randomized place
+NOTIN() {
+NAME="NOTIN"
+GENERATE__NOTIN
+PLACE=(`seq 0 $((LENINPUT-1)) | sort -R | head -n 3 | sort -n`)
+for i in `seq 0 $((LENINPUT-1))`
+do
+   (( $i == ${PLACE[0]} )) \
+      && NEWINPUT+="$FALSENBR"
+   (( $i == ${PLACE[1]} )) \
+      && NEWINPUT+="$FALSENBR"
+   (( $i == ${PLACE[2]} )) \
+      && NEWINPUT+="$FALSENBR"
+   NEWINPUT="$NEWINPUT${INPUT:$i:1}"
+done
+NAME+="-$FALSENBR"
+INSTRUCTIONS1="Recopiez ce nombre sans les ${DIGITS[FALSENBR]}"
+}
+
+
+# Take a random NBR from INPUT. Calculate X
+CALCUL() {
+PLACE=`seq 1 $((LENINPUT)) | sort -R | head -n 1`
+TARGET=`echo "$INPUT" | head -c $PLACE | tail -c 1`
+NEWINPUT=${INPUT//$TARGET/X}
+
+RC=`seq 1 2 | sort -R | head -n 1` # 1 = - | 2 = +
+if (( $RC == 1 ));then
+   FALSENBR=`seq $TARGET 10 | sort -R | head -n 1`
+   RESUME=$(( FALSENBR - TARGET ))
+   INSTRUCTIONS1="Calculez: ${DIGIT[FALSENBR]} moins ${DIGIT[RESUME]} et copiez"
+   NAME="CALCULM-$FALSENBR-$RESUME"
+else
+   FALSENBR=`seq 1 4 | sort -R | head -n 1`
+   if (( $FALSENBR <= $TARGET ));then
+      RESULT=$(( TARGET + FALSENBR ))
+      RESUME=$(( TARGET - FALSENBR ))
+      INSTRUCTIONS1="Calculez: ${DIGIT[FALSENBR]} plus ${DIGIT[RESUME]} et copiez"
+      NAME="CALCULP-$FALSENBR-$RESUME"
+   else
+      RESULT=$(( FALSENBR - TARGET ))
+      RESUME=$(( TARGET - RESULT ))
+      INSTRUCTIONS1="Calculez: ${DIGIT[RESULT]} plus ${DIGIT[RESUME]} et copiez"
+      NAME="CALCULP-$RESULT-$RESUME"
+   fi
+fi
+INSTRUCTIONS2="en remplaçant chaque X par la somme"
+}
+
+
+# ****************************************************************************
+#
+# Random captcha shape choice (aka main)
+#
+# ****************************************************************************
+
+MODULES=(CALCUL NOTIN REPLACE REVERSE)
+RMODULE=`seq 0 $(( ${#MODULES[@]} - 1)) | sort -R | head -n 1`
+eval "${MODULES[RMODULE]}"
+
+TEXT="$NEWINPUT"
+CHAPRILURI=/var/lib/ejabberd/chapril_captchas/$(date "+%Y-%m-%d-%H%M%S")_${NAME}_${INPUT}.png
+
+convert -size 300x70 xc:none -pointsize 20 \
+	\( -clone 0 -fill black \
+	-stroke black -strokewidth 1 \
+	-font Helvetica-Narrow  -annotate "0x0+0+0"     "\n $INSTRUCTIONS1" \
+	-font Helvetica-Bold    -annotate  "0x0+0+22"   "\n   $TEXT" \
+   -font Helvetica-Narrow  -annotate "0x0+0+44"    "\n $INSTRUCTIONS2" \
+	-roll +$ROLL_X+0 \
+	-wave "$WAVE1_AMPLITUDE"x"$WAVE1_LENGTH" \
+	-roll -$ROLL_X+0 \) \
+	-flatten -crop 300x70 +repage -quality 500 \
+   -depth 11 png:"$CHAPRILURI"
+
+convert -size 300x70 xc:none -pointsize 20 \
+	\( -clone 0 -fill black \
+	-stroke black -strokewidth 1 \
+	-font Helvetica-Narrow  -annotate "0x0+0+0"  "\n $INSTRUCTIONS1" \
+	-font Helvetica-Bold    -annotate "0x0+0+22" "\n   $TEXT" \
+	-font Helvetica-Narrow  -annotate "0x0+0+44" "\n $INSTRUCTIONS2" \
+	-roll +$ROLL_X+0 \
+	-wave "$WAVE1_AMPLITUDE"x"$WAVE1_LENGTH" \
+	-roll -$ROLL_X+0 \) \
+	-flatten -crop 300x70 +repage -quality 500 -depth 11 png:-
diff --git a/exemples/CALCUL.png b/exemples/CALCUL.png
new file mode 100644
index 0000000..09032e1
Binary files /dev/null and b/exemples/CALCUL.png differ
diff --git a/exemples/NOTIN.png b/exemples/NOTIN.png
new file mode 100644
index 0000000..fdfaf1a
Binary files /dev/null and b/exemples/NOTIN.png differ
diff --git a/exemples/REPLACE.png b/exemples/REPLACE.png
new file mode 100644
index 0000000..a87c3c9
Binary files /dev/null and b/exemples/REPLACE.png differ
diff --git a/exemples/REVERSE.png b/exemples/REVERSE.png
new file mode 100644
index 0000000..0ac1995
Binary files /dev/null and b/exemples/REVERSE.png differ
diff --git a/exemples/REVERSE2.png b/exemples/REVERSE2.png
new file mode 100644
index 0000000..70cfc07
Binary files /dev/null and b/exemples/REVERSE2.png differ
diff --git a/experimental.sh b/experimental.sh
new file mode 100755
index 0000000..8fda410
--- /dev/null
+++ b/experimental.sh
@@ -0,0 +1,231 @@
+#!/bin/bash
+
+# Copyright © 2021 Adrien Bourmault (neox@a-lec.org)
+# Copyright © 2021 Echolib (echolib@dismail.de)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This script is an example captcha script.
+# It takes the text to recognize in the captcha image as a parameter.
+# It return the image binary as a result. ejabberd support PNG, JPEG and GIF.
+
+# The whole idea of the captcha script is to let server admins adapt it to
+# their own needs. The goal is to be able to make the captcha generation as
+# unique as possible, to make the captcha challenge difficult to bypass by
+# a bot.
+# Server admins are thus supposed to write and use their own captcha generators.
+
+# This script relies on ImageMagick.
+# It is NOT compliant with ImageMagick forks like GraphicsMagick.
+
+INPUT=$1
+LENINPUT=${#INPUT}
+DIGITS=(zéros uns deux trois quatres cinqs six septs huits neufs dix)
+DIGIT=(zéro un deux trois quatre cinq six sept huit neuf dix)
+
+
+# ****************************************************************************
+# 
+# Tools
+#
+# ****************************************************************************
+
+
+# Generate a number that is not in INPUT. Loop 10 times (should be enough)
+GENERATE__NOTIN() {
+for i in {1..10}
+do
+   FALSENBR=`seq 1 9 | sort -R | head -n 1`
+   ! [[ $INPUT =~ $FALSENBR ]] \
+      && break
+done
+}
+
+
+# ****************************************************************************
+#
+# Captcha shapes
+#
+# ****************************************************************************
+
+
+# REPLACEs a random number in INPUT by another one randomized
+REPLACE() {
+NAME="REPLACE"
+PLACE=`seq 1 6 | sort -R | head -n 1`
+TARGET=`echo "$INPUT" | head -c $PLACE | tail -c 1`
+
+GENERATE__NOTIN
+NAME+="-$FALSENBR-$TARGET"
+NEWINPUT=${INPUT//$TARGET/$FALSENBR}
+INSTRUCTIONS1="Recopiez ce nombre"
+INSTRUCTIONS2="en changeant les ${DIGITS[FALSENBR]} en ${DIGITS[TARGET]}"
+}
+
+
+# REVERSEs INPUT. Ask to Add first or last number in random. 
+REVERSE() {
+NAME="REVERSE"
+RFL=`seq 1 2 | sort -R | head -n 1` # Rand First (1) or Last (2)
+ADDNBR=${DIGITS[ADDNBR]}
+
+for ((i=$LENINPUT-1;i>=0;i--))
+do
+   NEWINPUT="$NEWINPUT${INPUT:$i:1}"
+done
+
+if (( $RFL == 1 ));then
+   ADDNBR="${INPUT:0:1}"
+   NAME+="_FIRST"
+   NEWINPUT=${NEWINPUT:0:$LENINPUT-1} # Do not show first INPUT NBR
+   INSTRUCTIONS1="Écrivez le chiffre ${DIGIT[$ADDNBR]}"
+   INSTRUCTIONS2="et recopiez de DROITE à GAUCHE ←"
+else
+   ADDNBR="${INPUT:$LENINPUT-1:1}"
+   NAME+="_LAST"
+   NEWINPUT=${NEWINPUT:1:$LENINPUT-1} # Do not show last INPUT NBR
+   INSTRUCTIONS1="Recopiez de DROITE à GAUCHE ←"
+   INSTRUCTIONS2="et terminez par le chiffre ${DIGIT[$ADDNBR]}"
+fi
+NAME+="-$ADDNBR"
+}
+
+
+# Add FALSE NBR to INPUT at three randomized place
+NOTIN() {
+NAME="NOTIN"
+GENERATE__NOTIN
+PLACE=(`seq 0 $((LENINPUT-1)) | sort -R | head -n 3 | sort -n`)
+for i in `seq 0 $((LENINPUT-1))`
+do
+   (( $i == ${PLACE[0]} )) \
+      && NEWINPUT+="$FALSENBR"
+   (( $i == ${PLACE[1]} )) \
+      && NEWINPUT+="$FALSENBR"
+   (( $i == ${PLACE[2]} )) \
+      && NEWINPUT+="$FALSENBR"
+   NEWINPUT="$NEWINPUT${INPUT:$i:1}"
+done
+NAME+="-$FALSENBR"
+INSTRUCTIONS1="Recopiez ce nombre sans les ${DIGITS[FALSENBR]}"
+}
+
+
+# Take a random NBR from INPUT. Calculate X
+CALCUL() {
+PLACE=`seq 1 $((LENINPUT)) | sort -R | head -n 1`
+TARGET=`echo "$INPUT" | head -c $PLACE | tail -c 1`
+NEWINPUT=${INPUT//$TARGET/X}
+
+RC=`seq 1 2 | sort -R | head -n 1` # 1 = - | 2 = +
+if (( $RC == 1 ));then
+   FALSENBR=`seq $TARGET 10 | sort -R | head -n 1`
+   RESUME=$(( FALSENBR - TARGET ))
+   INSTRUCTIONS1="Calculez: ${DIGIT[FALSENBR]} moins ${DIGIT[RESUME]} et copiez"
+   NAME="CALCULM-$FALSENBR-$RESUME"
+else
+   FALSENBR=`seq 1 4 | sort -R | head -n 1`
+   if (( $FALSENBR <= $TARGET ));then
+      RESULT=$(( TARGET + FALSENBR ))
+      RESUME=$(( TARGET - FALSENBR ))
+      INSTRUCTIONS1="Calculez: ${DIGIT[FALSENBR]} plus ${DIGIT[RESUME]} et copiez"
+      NAME="CALCULP-$FALSENBR-$RESUME"
+   else
+      RESULT=$(( FALSENBR - TARGET ))
+      RESUME=$(( TARGET - RESULT ))
+      INSTRUCTIONS1="Calculez: ${DIGIT[RESULT]} plus ${DIGIT[RESUME]} et copiez"
+      NAME="CALCULP-$RESULT-$RESUME"
+   fi
+fi
+INSTRUCTIONS2="en remplaçant chaque X par la somme"
+}
+
+# Sum 2 LAST numbers. Hide LAST or BEFORE LAST
+CALCEND() {
+END1=${INPUT:$LENINPUT-2:1}
+END2=${INPUT:$LENINPUT-1:1}
+ENDS=$(( END1 + END2 ))
+REND=`seq 1 2 | sort -R | head -n 1`
+if (( $REND == 1 ));then
+   # Hide LAST
+   NEWINPUT=${INPUT:0:LENINPUT-1}X
+   NAME="END-${END1}X"
+else
+   # Hide BEFORE LAST
+   NEWINPUT=${INPUT:0:LENINPUT-2}X$END2
+   NAME="END-X$END2"
+fi
+INSTRUCTIONS1="La somme des 2 derniers chiffres est $ENDS"
+INSTRUCTIONS2="Copiez en remplaçant X par sa valeur"
+}
+
+# Replace 2 X (smaller > bigger | bigger > smaller)
+LEMO() {
+MAXNBR=${INPUT:0:1}
+MINNBR=${INPUT:0:1}
+for i in `seq 1 $((LENINPUT-1))`
+do
+   (( ${INPUT:$i:1} > $MAXNBR )) \
+      && MAXNBR=${INPUT:$i:1}
+   (( ${INPUT:$i:1} < $MINNBR )) \
+      && MINNBR=${INPUT:$i:1}
+done
+
+for i in `seq 0 $((LENINPUT-1))`
+do
+   if (( ${INPUT:$i:1} == $MINNBR ));then
+      INSTRUCTIONS1="Remplacez les X par ${DIGIT[MAXNBR]} et ${DIGIT[MINNBR]}"
+      INSTRUCTIONS2="! le plus PETIT en premier"
+      NAME="LEMO-$MINNBR-$MAXNBR"
+      break
+   elif (( ${INPUT:$i:1} == $MAXNBR ));then
+      INSTRUCTIONS1="Remplacez les X par ${DIGIT[MINNBR]} et ${DIGIT[MAXNBR]}"
+      INSTRUCTIONS2="! Le plus GRAND en premier"
+      NAME="LEMO-$MAXNBR-$MINNBR"
+      break
+   fi
+done
+
+NEWINPUT=`echo $INPUT | sed "s/$MINNBR/X/"`
+NEWINPUT=`echo $NEWINPUT | sed "s/$MAXNBR/X/"`
+}
+
+# ****************************************************************************
+#
+# Random captcha shape choice (aka main)
+#
+# ****************************************************************************
+
+MODULES=(CALCUL CALCEND LEMO NOTIN REPLACE REVERSE)
+RMODULE=`seq 0 $(( ${#MODULES[@]} - 1)) | sort -R | head -n 1`
+eval "${MODULES[RMODULE]}"
+
+TEXT="$NEWINPUT"
+DATE="$(date "+%Y-%m-%d-%H%M%S")"
+CHAPRILURI=/var/lib/ejabberd/chapril_captchas/${DATE}_${NAME}_${INPUT}.png
+
+convert -size 300x70 xc:none -pointsize 20 \
+	\( -clone 0 -fill black \
+	-stroke black -strokewidth 1 \
+	-font Helvetica-Narrow  -annotate "0x0+0+0"     "\n $INSTRUCTIONS1" \
+	-font Helvetica-Bold    -annotate  "0x0+0+22"   "\n   $TEXT" \
+   -font Helvetica-Narrow  -annotate "0x0+0+44"    "\n $INSTRUCTIONS2" \
+	-roll +$ROLL_X+0 \
+	-wave "$WAVE1_AMPLITUDE"x"$WAVE1_LENGTH" \
+	-roll -$ROLL_X+0 \) \
+	-flatten -crop 300x70 +repage -quality 500 \
+   -depth 11 png:"$CHAPRILURI"
+
+convert -size 300x70 xc:none -pointsize 20 \
+	\( -clone 0 -fill black \
+	-stroke black -strokewidth 1 \
+	-font Helvetica-Narrow  -annotate "0x0+0+0"  "\n $INSTRUCTIONS1" \
+	-font Helvetica-Bold    -annotate "0x0+0+22" "\n   $TEXT" \
+	-font Helvetica-Narrow  -annotate "0x0+0+44" "\n $INSTRUCTIONS2" \
+	-roll +$ROLL_X+0 \
+	-wave "$WAVE1_AMPLITUDE"x"$WAVE1_LENGTH" \
+	-roll -$ROLL_X+0 \) \
+	-flatten -crop 300x70 +repage -quality 500 -depth 11 png:-
diff --git a/get_validated_captchas.sh b/get_validated_captchas.sh
new file mode 100755
index 0000000..968d497
--- /dev/null
+++ b/get_validated_captchas.sh
@@ -0,0 +1,23 @@
+#! /bin/bash
+
+dates=$(zcat /var/log/ejabberd/ejabberd* 2> /dev/null | grep "was registered" \
+	| cut -d[ -f 1 | cut -c 1-16)
+
+SAVEIFS=$IFS   # Save current IFS
+IFS=$'\n'      # Change IFS to new line
+
+dates=($dates) # Split to array
+IFS=$SAVEIFS   # Restore IFS
+
+greppattern=""
+
+for (( i=0; i<${#dates[@]}; i++ ))
+do
+    greppattern="$greppattern -e \"$(echo ${dates[$i]})\""
+done
+
+#echo -e ${greppattern}
+
+grepcommand="ls -lt --full-time /var/lib/ejabberd/chapril_captchas | grep $greppattern | cut -d ' ' -f 9"
+
+eval $grepcommand
diff --git a/readme.md b/readme.md
new file mode 100644
index 0000000..46a529e
--- /dev/null
+++ b/readme.md
@@ -0,0 +1,43 @@
+# Méthodes de génération de captcha pour ejabberd 2x.x 
+
+## Réalisées dans le cadre du service XMPP du Chapril
+
+### Concept 
+
+L'idée derrière ces méthodes de captchas est d'abord la simplicité de lecture pour l'utilisateur:  
+- Pas de déformation du texte  
+- Pas de coloration du texte  
+- Ecrit en français sous la forme d'une consigne se voulant "simple" tout en étant difficile à attaquer par force brute par un bot
+- Compatible avec le système de génération de captcha de ejabberd (la XEP 0158)  
+
+### Exemples
+
+Différentes méthodes sont utilisées.
+
+#### Remplacement (REPLACE)
+
+Une seule forme est disponible:
+
+![Exemple de remplacement](exemples/REPLACE.png)
+
+#### Inversion (REVERSE)
+
+Deux formes sont disponibles:
+
+![Premier exemple d'inversion](exemples/REVERSE.png)
+
+ou encore
+
+![Premier exemple d'inversion](exemples/REVERSE2.png)
+
+#### Intrus (NOTIN)
+
+Une seule forme est disponible:
+
+![Exemple d'intrus](exemples/NOTIN.png)
+
+#### Calcul (CALCUL)
+
+Une seule forme est disponible:
+
+![Exemple de calcul](exemples/CALCUL.png)
\ No newline at end of file
diff --git a/savecaptcha.sh b/savecaptcha.sh
new file mode 100755
index 0000000..a1f196f
--- /dev/null
+++ b/savecaptcha.sh
@@ -0,0 +1,18 @@
+#!/bin/bash
+
+# This script relies on ImageMagick.
+# It is NOT compliant with ImageMagick forks like GraphicsMagick.
+
+RAND_ANGLE=$1
+RAND_ITALIC=$2
+INPUT=$3
+SOLUTION=$4
+
+convert -size 300x60 xc:none -pointsize 20 \
+	\( -clone 0 -fill black \
+	-stroke black -strokewidth 1 \
+	-annotate "${RAND_ANGLE}x${RAND_ITALIC}+0+0" "\n $INPUT" \
+	-roll +$ROLL_X+0 \
+	-wave "$WAVE1_AMPLITUDE"x"$WAVE1_LENGTH" \
+	-roll -$ROLL_X+0 \) \
+	-flatten -crop 300x60 +repage -quality 500 -depth 11 png:"/var/tmp/captcha/${SOLUTION}_$(date "+%Y-%m-%d-%H%M%S").png"