1 files changed, 70 insertions, 0 deletions
diff --git a/HeapLAB/safe_unlink/pwntools_template.py b/HeapLAB/safe_unlink/pwntools_template.py
new file mode 100755
index 0000000..ff1c1b2
--- /dev/null
+++ b/HeapLAB/safe_unlink/pwntools_template.py
@@ -0,0 +1,70 @@
+#!/usr/bin/python3
+from pwn import *
+
+elf = context.binary = ELF("safe_unlink")
+libc = elf.libc
+
+gs = '''
+continue
+'''
+def start():
+    if args.GDB:
+        return gdb.debug(elf.path, gdbscript=gs)
+    else:
+        return process(elf.path)
+
+# Index of allocated chunks.
+index = 0
+
+# Select the "malloc" option; send size.
+# Returns chunk index.
+def malloc(size):
+    global index
+    io.send("1")
+    io.sendafter("size: ", f"{size}")
+    io.recvuntil("> ")
+    index += 1
+    return index - 1
+
+# Select the "edit" option; send index & data.
+def edit(index, data):
+    io.send("2")
+    io.sendafter("index: ", f"{index}")
+    io.sendafter("data: ", data)
+    io.recvuntil("> ")
+
+# Select the "free" option; send index.
+def free(index):
+    io.send("3")
+    io.sendafter("index: ", f"{index}")
+    io.recvuntil("> ")
+
+io = start()
+
+# This binary leaks the address of puts(), use it to resolve the libc load address.
+io.recvuntil("puts() @ ")
+libc.address = int(io.recvline(), 16) - libc.sym.puts
+io.recvuntil("> ")
+io.timeout = 0.1
+
+# =============================================================================
+
+# =-=-=- EXAMPLE -=-=-=
+
+# Print the address of m_array, where the program stores pointers to its allocated chunks.
+log.info(f"m_array @ 0x{elf.sym.m_array:02x}")
+
+# Request 2 small chunks.
+chunk_A = malloc(0x88)
+chunk_B = malloc(0x88)
+
+# Prepare fake chunk metadata.
+fd = 0xdeadbeef
+bk = 0xcafebabe
+prev_size = 0x90
+fake_size = 0x90
+edit(chunk_A, p64(fd) + p64(bk) + p8(0)*0x70 + p64(prev_size) + p64(fake_size))
+
+# =============================================================================
+
+io.interactive()