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9.3

Binary Bomb Phase 5

Asked by Cosmonaut in Assembly Programming Language, C Programming Language

Tags: Binary Bomb Phase 6

Hello,
I am working on the bomblab and am really struggling with the 6th phase.
I understand that it is a linked list and it is looking for the numbers 1-6 in some order.
This is the section that is really confusing me:

0x08048d72 <phase_6+145>:       mov    -0x3c(%ebp),%ecx
0x08048d75 <phase_6+148>:       mov    -0x38(%ebp),%eax
0x08048d78 <phase_6+151>:       mov    %eax,0x8(%ecx)
0x08048d7b <phase_6+154>:       mov    -0x34(%ebp),%edx
0x08048d7e <phase_6+157>:       mov    %edx,0x8(%eax)
0x08048d81 <phase_6+160>:       mov    -0x30(%ebp),%eax
0x08048d84 <phase_6+163>:       mov    %eax,0x8(%edx)
0x08048d87 <phase_6+166>:       mov    -0x2c(%ebp),%edx
0x08048d8a <phase_6+169>:       mov    %edx,0x8(%eax)
0x08048d8d <phase_6+172>:       mov    -0x28(%ebp),%eax
0x08048d90 <phase_6+175>:       mov    %eax,0x8(%edx)
0x08048d93 <phase_6+178>:       movl   $0x0,0x8(%eax)
0x08048d9a <phase_6+185>:       mov    %ecx,%ebx
0x08048d9c <phase_6+187>:       mov    $0x0,%esi
0x08048da1 <phase_6+192>:       mov    0x8(%ebx),%edx
0x08048da4 <phase_6+195>:       mov    (%ebx),%eax
0x08048da6 <phase_6+197>:       cmp    (%edx),%eax
0x08048da8 <phase_6+199>:       jge    0x8048daf <phase_6+206>

I've been able to figure out the numeric values to each node in the linked list that are compared here "cmp    (%edx),%eax"  however, I haven't had any luck figuring out which node goes with what number from the 1-6 set.
I'm also confused about what order they are compared in, at first I thought that eax was the last number and edx was the first and it worked towards the center but that isn't right....
I hope I'm being clear, and any push in the right direction would be greatly appreciated! 
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Dump of assembler code for function phase_6:
0x08048ce1 <phase_6+0>: push   %ebp
0x08048ce2 <phase_6+1>: mov    %esp,%ebp
0x08048ce4 <phase_6+3>: push   %edi
0x08048ce5 <phase_6+4>: push   %esi
0x08048ce6 <phase_6+5>: push   %ebx
0x08048ce7 <phase_6+6>: sub    $0x3c,%esp
0x08048cea <phase_6+9>: lea    -0x24(%ebp),%eax
0x08048ced <phase_6+12>:        mov    %eax,0x4(%esp)
0x08048cf1 <phase_6+16>:        mov    0x8(%ebp),%eax
0x08048cf4 <phase_6+19>:        mov    %eax,(%esp)
0x08048cf7 <phase_6+22>:        call   0x8049383 <read_six_numbers>
0x08048cfc <phase_6+27>:        mov    $0x0,%ebx
0x08048d01 <phase_6+32>:        mov    -0x24(%ebp,%ebx,4),%eax
0x08048d05 <phase_6+36>:        sub    $0x1,%eax
0x08048d08 <phase_6+39>:        cmp    $0x5,%eax
0x08048d0b <phase_6+42>:        jbe    0x8048d12 <phase_6+49>
0x08048d0d <phase_6+44>:        call   0x8049341 <explode_bomb>
0x08048d12 <phase_6+49>:        lea    0x1(%ebx),%edi
0x08048d15 <phase_6+52>:        cmp    $0x6,%edi
0x08048d18 <phase_6+55>:        jne    0x8048d2b <phase_6+74>
0x08048d1a <phase_6+57>:        mov    $0x804a5fc,%ecx
0x08048d1f <phase_6+62>:        mov    $0x1,%eax
0x08048d24 <phase_6+67>:        mov    $0x0,%edx
0x08048d29 <phase_6+72>:        jmp    0x8048d54 <phase_6+115>
 
 
0x08048d2b <phase_6+74>:        lea    -0x24(%ebp,%ebx,4),%esi
0x08048d2f <phase_6+78>:        mov    %edi,%ebx
0x08048d31 <phase_6+80>:        mov    -0x28(%ebp,%edi,4),%eax
0x08048d35 <phase_6+84>:        cmp    0x4(%esi),%eax
0x08048d38 <phase_6+87>:        jne    0x8048d3f <phase_6+94>
0x08048d3a <phase_6+89>:        call   0x8049341 <explode_bomb>
 
0x08048d3f <phase_6+94>:        add    $0x1,%ebx
0x08048d42 <phase_6+97>:        add    $0x4,%esi
0x08048d45 <phase_6+100>:       cmp    $0x5,%ebx
0x08048d48 <phase_6+103>:       jle    0x8048d31 <phase_6+80>
0x08048d4a <phase_6+105>:       mov    %edi,%ebx
0x08048d4c <phase_6+107>:       jmp    0x8048d01 <phase_6+32>
 
0x08048d4e <phase_6+109>:       mov    0x8(%ecx),%ecx
0x08048d51 <phase_6+112>:       add    $0x1,%eax
0x08048d54 <phase_6+115>:       cmp    -0x24(%ebp,%edx,4),%eax
0x08048d58 <phase_6+119>:       jl     0x8048d4e <phase_6+109>
0x08048d5a <phase_6+121>:       mov    %ecx,-0x3c(%ebp,%edx,4)
0x08048d5e <phase_6+125>:       add    $0x1,%edx
0x08048d61 <phase_6+128>:       cmp    $0x5,%edx
0x08048d64 <phase_6+131>:       jg     0x8048d72 <phase_6+145>
0x08048d66 <phase_6+133>:       mov    $0x804a5fc,%ecx
0x08048d6b <phase_6+138>:       mov    $0x1,%eax
0x08048d70 <phase_6+143>:       jmp    0x8048d54 <phase_6+115>
 
0x08048d72 <phase_6+145>:       mov    -0x3c(%ebp),%ecx
0x08048d75 <phase_6+148>:       mov    -0x38(%ebp),%eax
0x08048d78 <phase_6+151>:       mov    %eax,0x8(%ecx)
0x08048d7b <phase_6+154>:       mov    -0x34(%ebp),%edx
0x08048d7e <phase_6+157>:       mov    %edx,0x8(%eax)
0x08048d81 <phase_6+160>:       mov    -0x30(%ebp),%eax
0x08048d84 <phase_6+163>:       mov    %eax,0x8(%edx)
0x08048d87 <phase_6+166>:       mov    -0x2c(%ebp),%edx
0x08048d8a <phase_6+169>:       mov    %edx,0x8(%eax)
0x08048d8d <phase_6+172>:       mov    -0x28(%ebp),%eax
0x08048d90 <phase_6+175>:       mov    %eax,0x8(%edx)
0x08048d93 <phase_6+178>:       movl   $0x0,0x8(%eax)
 
0x08048d9a <phase_6+185>:       mov    %ecx,%ebx
0x08048d9c <phase_6+187>:       mov    $0x0,%esi
0x08048da1 <phase_6+192>:       mov    0x8(%ebx),%edx
0x08048da4 <phase_6+195>:       mov    (%ebx),%eax
0x08048da6 <phase_6+197>:       cmp    (%edx),%eax
0x08048da8 <phase_6+199>:       jge    0x8048daf <phase_6+206>
0x08048daa <phase_6+201>:       call   0x8049341 <explode_bomb>
0x08048daf <phase_6+206>:       mov    0x8(%ebx),%ebx
0x08048db2 <phase_6+209>:       add    $0x1,%esi
0x08048db5 <phase_6+212>:       cmp    $0x5,%esi
0x08048db8 <phase_6+215>:       jne    0x8048da1 <phase_6+192>
0x08048dba <phase_6+217>:       add    $0x3c,%esp
0x08048dbd <phase_6+220>:       pop    %ebx
0x08048dbe <phase_6+221>:       pop    %esi
0x08048dbf <phase_6+222>:       pop    %edi
0x08048dc0 <phase_6+223>:       pop    %ebp
0x08048dc1 <phase_6+224>:       ret
End of assembler dump.
 
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Keywords: Binary Bomb Phase 5
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[+][-]10/27/09 04:20 AM, ID: 25671025Accepted Solution

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Zones: Assembly Programming Language, C Programming Language
Tags: Binary Bomb Phase 6
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Solution Provided By: Infinity08
Participating Experts: 1
Solution Grade: A
 
[+][-]10/27/09 05:01 AM, ID: 25671355Author Comment

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