CS:APP Bomb_lab

实验步骤

准备工作

使用tar -vxf将炸弹压缩包解压,cd进入,可以从bomb.c中看出实验的用意以及程序的大致
逻辑,bomb为可执行程序,使用gdb调试该程序.

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(gdb) b read_line 
Breakpoint 1 at 0x40155c
(gdb) b explode_bomb
Breakpoint 2 at 0x4014e4

给read_line函数打上断点,以便每次输入运行一关.给explode_bomb打上断点,以便在炸弹爆炸
前可以处理.

phase_1

获得phase_1汇编代码

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(gdb) disas phase_1
Dump of assembler code for function phase_1:
0x0000000000400e80 <+0>: sub $0x8,%rsp
0x0000000000400e84 <+4>: mov $0x4024a0,%esi
0x0000000000400e89 <+9>: callq 0x40127e <strings_not_equal>
0x0000000000400e8e <+14>: test %eax,%eax
0x0000000000400e90 <+16>: je 0x400e97 <phase_1+23>
0x0000000000400e92 <+18>: callq 0x4014e4 <explode_bomb>
0x0000000000400e97 <+23>: add $0x8,%rsp
0x0000000000400e9b <+27>: retq
End of assembler dump.

可见,此题是将我们输入的字符串与地址0x4024a0处字符串比较,不等则爆炸.查看该字符串.

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(gdb) x/s 0x4024a0
0x4024a0 <__dso_handle+344>: "We have to stand with our North Korean allies."

那么答案是We have to stand with our North Korean allies.

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