blob: bb57385c45c295ebe2ea68282b24de45c18f37ac (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
#!/bin/bash
# Copyright © 2021 Adrien Bourmault (neox@os-k.eu)
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 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=$1
TRANSFORMATIONS=(INTRUDER SUM)
DIGIT=(zero one two three four five six seven eight nine ten)
if test -n "${BASH_VERSION:-''}" ; then
get_random ()
{
R=$RANDOM
}
else
for n in $(od -A n -t u2 -N 64 /dev/urandom); do RL="$RL$n "; done
get_random ()
{
R=${RL%% *}
RL=${RL#* }
}
fi
INTRUDER()
{
NUMBERS=$(echo "$INPUT" | grep -o . | tr '\n' ' ')
SORTED_UNIQ_NUM=$(echo "${NUMBERS[@]}" | sort -u | tr '\n' ' ')
SORT_RANDOM_CMD="$( ( echo x|sort -R >&/dev/null && echo "sort -R" ) || ( echo x|shuf >&/dev/null && echo shuf ) || echo cat)"
RANDOM_DIGITS=$(echo 123456789 | grep -o . | eval "$SORT_RANDOM_CMD" | tr '\n' ' ')
INTRUDER=-1
for i in $RANDOM_DIGITS
do
if [[ ! " ${SORTED_UNIQ_NUM[@]} " =~ ${i} ]]; then
INTRUDER=$i
break
fi
done
# Worst case
if [[ $INTRUDER -eq "-1" ]]
then
printf "Type %s \n without changes" "$INPUT"
return
fi
for num in ${NUMBERS}
do
get_random
R=$((R % 100))
if [[ $R -lt 60 ]]; then
NEWINPUT=${NEWINPUT}${num}${INTRUDER}
else
NEWINPUT=${NEWINPUT}${num}
fi
done
get_random
R=$((R % 100))
if [[ $R -lt 50 ]]; then
printf "Type %s by\n deleting the %s" "$NEWINPUT" "${DIGIT[$INTRUDER]}"
else
printf "Enter %s by\n removing the %s" "$NEWINPUT" "${DIGIT[$INTRUDER]}"
fi
}
SUM()
{
get_random
RA=$((R % 100))
if [[ $((INPUT % 2)) -eq 0 ]]; then
A=$((INPUT - RA))
B=$RA
else
B=$((INPUT - RA))
A=$RA
fi
get_random
R=$((R % 100))
if [[ $R -lt 25 ]]; then
printf "Type the result\n of %s + %s" "$A" "$B"
elif [[ $R -lt 50 ]]; then
printf "SUMx\n %s and %s" "$A" "$B"
elif [[ $R -lt 75 ]]; then
printf "Add\n %s and %s" "$A" "$B"
else
printf "Enter the result\n of %s + %s" "$A" "$B"
fi
}
get_random
RAND_ITALIC=$((R % 25))
get_random
RAND_ANGLE=$((R % 3))
get_random
RAND_INDEX=$((R % ${#TRANSFORMATIONS[@]}))
convert -size 300x60 xc:none -pointsize 20 \
\( -clone 0 -fill black \
-stroke black -strokewidth 1 \
-annotate "${RAND_ANGLE}x${RAND_ITALIC}+0+0" "\n $(${TRANSFORMATIONS[$RAND_INDEX]})" \
-roll +"$ROLL_X"+0 \
-wave "$WAVE1_AMPLITUDE"x"$WAVE1_LENGTH" \
-roll -"$ROLL_X"+0 \) \
-flatten -crop 300x60 +repage -quality 500 -depth 11 png:-
|
