Differences between Assembly Code output of the same program
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by ultrajohn
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Published on 2010-06-16T16:56:37Z
Indexed on
2010/06/16
17:12 UTC
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Hit count: 276
assembly
|buffer-overflow
I have been trying to replicate the buffer overflow example3 from this article aleph one
I'm doing this as a practice for a project in a computer security course i'm taking so please, I badly need your help. I've been the following the example, performing the tasks as I go along. My problem is the assembly code dumped by gdb
in my computer (i'm doing this on a debian linux image running on VM Ware) is different from that of the example in the article. There are some constructs which I find confusing.
Here is the one from my computer:
here is the one from the article...
Dump of assembler code for function main:
0x8000490 <main>: pushl %ebp
0x8000491 <main+1>: movl %esp,%ebp
0x8000493 <main+3>: subl $0x4,%esp
0x8000496 <main+6>: movl $0x0,0xfffffffc(%ebp)
0x800049d <main+13>: pushl $0x3
0x800049f <main+15>: pushl $0x2
0x80004a1 <main+17>: pushl $0x1
0x80004a3 <main+19>: call 0x8000470 <function>
0x80004a8 <main+24>: addl $0xc,%esp
0x80004ab <main+27>: movl $0x1,0xfffffffc(%ebp)
0x80004b2 <main+34>: movl 0xfffffffc(%ebp),%eax
0x80004b5 <main+37>: pushl %eax
0x80004b6 <main+38>: pushl $0x80004f8
0x80004bb <main+43>: call 0x8000378 <printf>
0x80004c0 <main+48>: addl $0x8,%esp
0x80004c3 <main+51>: movl %ebp,%esp
0x80004c5 <main+53>: popl %ebp
0x80004c6 <main+54>: ret
0x80004c7 <main+55>: nop
As you can see, there are differences between the two. I'm confuse and I can't understand totally the assembly code from my computer. I would like to know the differences between the two.
How is pushl
different from push
, mov vs movl
, and so on...
what does the expression 0xhexavalue(%register)
means?
I am sorry If I'm asking a lot, But I badly need your help.
Thanks for the help really...
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