GDB入门学习之gef插件的使用

GDB

gdb安装

brew update
brew install gdb

然后将gdbserver push到手机

cd /Users/chennan/Library/Android/sdk/ndk/21.3.6528147/prebuilt/android-arm/gdbserver
adb push gdbserver /data/local/tmp
chmod u+x gdbserver
./gdbserver :11678 ./hello
adb forward tcp:11678 tcp:11678

安装gdb的插件gef

wget -q -O- https://github.com/hugsy/gef/raw/master/gef.sh | sh

初识Gef界面

使用到的指令

target remote localhost:11678
b main #给函数main下断点
disassemble main #查看main函数汇编代码
b *0xaaaaa3d4 #地址下断点
info b 查看有哪些断点，会显示断点类型
ni 单步步过
n 源码层面步过
p/x *0xaaaaa3d4 #按照16进制打印地址的内容

首先给main函数位置打个断点,

通过 disassemble main可以dump出main函数的汇编代码

gef➤  b main
Breakpoint 1 at 0xaaaaa3e0
gef➤  disassemble main
Dump of assembler code for function main:
   0xaaaaa3d4 <+0>:	push	{r11, lr}
   0xaaaaa3d8 <+4>:	mov	r11, sp
   0xaaaaa3dc <+8>:	sub	sp, sp, #24
   0xaaaaa3e0 <+12>:	mov	r2, #0
   0xaaaaa3e4 <+16>:	str	r2, [r11, #-4]
   0xaaaaa3e8 <+20>:	str	r0, [r11, #-8]
   0xaaaaa3ec <+24>:	str	r1, [sp, #12]
   0xaaaaa3f0 <+28>:	ldr	r0, [pc, #32]	; 0xaaaaa418 <main+68>
   0xaaaaa3f4 <+32>:	add	r0, pc, r0
   0xaaaaa3f8 <+36>:	str	r2, [sp, #8]
   0xaaaaa3fc <+40>:	bl	0xaaaaa340 <printf@plt>
   0xaaaaa400 <+44>:	ldr	r1, [sp, #8]
   0xaaaaa404 <+48>:	str	r0, [sp, #4]
   0xaaaaa408 <+52>:	mov	r0, r1
   0xaaaaa40c <+56>:	mov	sp, r11
   0xaaaaa410 <+60>:	pop	{r11, lr}
   0xaaaaa414 <+64>:	bx	lr
   0xaaaaa418 <+68>:	andeq	r0, r0, r8, lsr #32
End of assembler dump.
gef➤  b *0xaaaaa3d4 #地址下断点的方式前面加*
Breakpoint 2 at 0xaaaaa3d4
gef➤  info b 查看有哪些断点，会显示断点类型
Num     Type           Disp Enb Address    What
1       breakpoint     keep y   0xaaaaa3e0 <main+12>
2       breakpoint     keep y   0xaaaaa3d4 <main>
gef➤  c 执行到断点

注意观察下图变化