diff options
Diffstat (limited to 'HeapLAB/safe_unlink')
-rwxr-xr-x | HeapLAB/safe_unlink/pwntools_template.py | 70 | ||||
-rwxr-xr-x | HeapLAB/safe_unlink/safe_unlink | bin | 0 -> 15936 bytes |
2 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() diff --git a/HeapLAB/safe_unlink/safe_unlink b/HeapLAB/safe_unlink/safe_unlink Binary files differnew file mode 100755 index 0000000..83b07b1 --- /dev/null +++ b/HeapLAB/safe_unlink/safe_unlink |