chore: initial commit

README.md

+# Labo 4
+## Exercise 3
+Les fichiers finaux pour l'exercise 3 se situent dans `out/ex3-a.py` et `out/ex3-b.py`.
+
+Vous pouvez utiliser le script `ex3.sh` pour regénérer ces fichiers.
+
+## Exercise 4
+Les fichiers finaux pour l'exercise 3 se situent dans `out/ex4-good.py` et `out/ex4-evil.py`.
+
+Vous pouvez utiliser le script `ex4.sh` pour regénérer ces fichiers.
\ No newline at end of file

ex3.sh

+#!/usr/bin/env bash
+set -euo pipefail
+
+FASTCOLL=./bin/md5_fastcoll
+OUTDIR=./out
+TEMPLATEDIR=./templates
+
+mkdir -p $OUTDIR
+head -n 4 $TEMPLATEDIR/ex3.py > $OUTDIR/.ex3.prefix.bin
+
+$FASTCOLL -p $OUTDIR/.ex3.prefix.bin -o $OUTDIR/.ex3.data1.bin $OUTDIR/.ex3.data2.bin
+
+python3 ./replace.py "{BIN}" $TEMPLATEDIR/ex3.py $OUTDIR/.ex3.data1.bin $OUTDIR/ex3-a.py 0
+python3 ./replace.py "{BIN}" $TEMPLATEDIR/ex3.py $OUTDIR/.ex3.data2.bin $OUTDIR/ex3-b.py 0
+
+chmod +x $OUTDIR/ex3-a.py
+chmod +x $OUTDIR/ex3-b.py
+
+md5sum $OUTDIR/ex3-a.py $OUTDIR/ex3-b.py
+
+echo "$OUTDIR/ex3-a.py"
+$OUTDIR/ex3-a.py
+
+echo "$OUTDIR/ex3-b.py"
+$OUTDIR/ex3-b.py

ex4.sh

+#!/usr/bin/env bash
+set -euo pipefail
+
+FASTCOLL=./bin/md5_fastcoll
+OUTDIR=./out
+TEMPLATEDIR=./templates
+
+mkdir -p $OUTDIR
+head -n 4 $TEMPLATEDIR/ex4.py > $OUTDIR/.ex4.prefix.bin
+
+$FASTCOLL -p $OUTDIR/.ex4.prefix.bin -o $OUTDIR/.ex4.data1.bin $OUTDIR/.ex4.data2.bin
+
+python3 ./replace.py "{GOOD_BIN}" $TEMPLATEDIR/ex4.py $OUTDIR/.ex4.data1.bin $OUTDIR/.ex4-base.py 128
+
+python3 ./replace.py "{BIN}" $OUTDIR/.ex4-base.py $OUTDIR/.ex4.data1.bin $OUTDIR/ex4-good.py 0
+python3 ./replace.py "{BIN}" $OUTDIR/.ex4-base.py $OUTDIR/.ex4.data2.bin $OUTDIR/ex4-evil.py 0
+
+chmod +x $OUTDIR/ex4-good.py
+chmod +x $OUTDIR/ex4-evil.py
+
+md5sum $OUTDIR/ex4-good.py $OUTDIR/ex4-evil.py
+
+echo "$OUTDIR/ex4-good.py"
+$OUTDIR/ex4-good.py
+
+echo "$OUTDIR/ex4-evil.py"
+$OUTDIR/ex4-evil.py

out/.ex3.data1.bin

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+Ii/FҐxLUlǥ9::Z) :K7lDBVgpZDq67wR#
Q]YSP'&ZF'TOZ.
V|ϫ#
\ No newline at end of file

out/.ex3.data2.bin

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+Ii/FҐxLUΖlǥ9::Z) :K7mDBVgpZD67wR#
Q]YSP'&ZF'TO0Z.
V|ϫ#
\ No newline at end of file

out/.ex3.prefix.bin

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""

out/.ex4-base.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+{BIN}
+""", "iso-8859-1")
+
+good_blob = bytes(r"""
+\fR9e<")I`<o#:^RǁK;kT<6ʀt9q؁m_MbD7OrunmUIDͽڠ(L+ͬϬ~rƆ%ErATR)<Rd
+""", "iso-8859-1")
+
+if blob == good_blob:
+    print("Bonjour")
+else:
+    print("You've been hacked\n" * 100)

out/.ex4.data1.bin

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+\fR9e<")I`<o#:^RǁK;kT<6ʀt9q؁m_MbD7OrunmUIDͽڠ(L+ͬϬ~rƆ%ErATR)<Rd
\ No newline at end of file

out/.ex4.data2.bin

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+\fR9e<")I`<!o#:^RǁK;kT<6Jt9q؁m_Mb&D7OrunmUIDͽڠL+ͬϬ~rƆ%Er ATR)w<Rd
\ No newline at end of file

out/.ex4.prefix.bin

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""

out/ex3-a.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+Ii/FҐxLUlǥ9::Z) :K7lDBVgpZDq67wR#
Q]YSP'&ZF'TOZ.
V|ϫ#
+""", "iso-8859-1")
+print(blob)
\ No newline at end of file

out/ex3-b.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+Ii/FҐxLUΖlǥ9::Z) :K7mDBVgpZD67wR#
Q]YSP'&ZF'TO0Z.
V|ϫ#
+""", "iso-8859-1")
+print(blob)
\ No newline at end of file

out/ex4-a.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+}>-|%ߒ{wWgAUC
+CFcGWn_SRQ3$ff<S(>vOMmAl'D&Іφ?s%
+""", "iso-8859-1")
+
+good_blob = bytes(r"""
+}>-|%ߒ{wWgAUC
+CFcGWn_SRQ3$ff<S(>vOMmAl'D&Іφ?s%
+""", "iso-8859-1")
+
+if blob == good_blob:
+    print("Bonjour")
+else:
+    print("You've been hacked\n" * 100)

out/ex4-b.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+}>-|%ߒ{WgAUC
+CFcGn_SQ3$ff<S>vOMmAl'Df&Іφ?s%
+""", "iso-8859-1")
+
+good_blob = bytes(r"""
+}>-|%ߒ{wWgAUC
+CFcGWn_SRQ3$ff<S(>vOMmAl'D&Іφ?s%
+""", "iso-8859-1")
+
+if blob == good_blob:
+    print("Bonjour")
+else:
+    print("You've been hacked\n" * 100)

out/ex4-evil.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+\fR9e<")I`<!o#:^RǁK;kT<6Jt9q؁m_Mb&D7OrunmUIDͽڠL+ͬϬ~rƆ%Er ATR)w<Rd
+""", "iso-8859-1")
+
+good_blob = bytes(r"""
+\fR9e<")I`<o#:^RǁK;kT<6ʀt9q؁m_MbD7OrunmUIDͽڠ(L+ͬϬ~rƆ%ErATR)<Rd
+""", "iso-8859-1")
+
+if blob == good_blob:
+    print("Bonjour")
+else:
+    print("You've been hacked\n" * 100)

out/ex4-good.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+\fR9e<")I`<o#:^RǁK;kT<6ʀt9q؁m_MbD7OrunmUIDͽڠ(L+ͬϬ~rƆ%ErATR)<Rd
+""", "iso-8859-1")
+
+good_blob = bytes(r"""
+\fR9e<")I`<o#:^RǁK;kT<6ʀt9q؁m_MbD7OrunmUIDͽڠ(L+ͬϬ~rƆ%ErATR)<Rd
+""", "iso-8859-1")
+
+if blob == good_blob:
+    print("Bonjour")
+else:
+    print("You've been hacked\n" * 100)

replace.py

+#!/usr/bin/env python3
+
+#Search the pattern given in the first argument
+#in the file given in the second argument and replace it with the binary content of the file given in the third argument
+#and save the output in the file given in the fourth argument
+
+import re
+import sys
+
+def replace_bin(pattern: str, source_file: str, binary_file: str, output_file: str, prefix_size: int):
+    # Read the source file
+    with open(source_file, 'rb') as file:
+        source = file.read()
+
+    # Read the binary file
+    with open(binary_file, 'rb') as file:
+        data = file.read()
+
+    source = source.split(pattern.encode(), 1)
+    with open(output_file, 'wb') as file:
+        if prefix_size != 0:
+            file.write(source[0])
+            data = data[prefix_size:]
+
+        file.write(data)
+        file.write(source[1])
+
+if __name__ == "__main__":
+    pattern = sys.argv[1]
+    source_file = sys.argv[2]
+    binary_file = sys.argv[3]
+    output_file = sys.argv[4]
+    prefix_size = sys.argv[5]
+
+    replace_bin(pattern, source_file, binary_file, output_file, int(prefix_size))

templates/ex3.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+{BIN}
+""", "iso-8859-1")
+print(blob)
\ No newline at end of file

templates/ex4.py

+#!/usr/bin/env python3
+# coding: iso-8859-1
+#0123456789001234567890012345678900123456789001234567890012345678
+blob = bytes(r"""
+{BIN}
+""", "iso-8859-1")
+
+good_blob = bytes(r"""
+{GOOD_BIN}
+""", "iso-8859-1")
+
+if blob == good_blob:
+    print("Bonjour")
+else:
+    print("You've been hacked\n" * 100)