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POBinary Bomb Phase 3 Assembly
primarykey
Id
18961406
data
AcceptedAnswerId
18961715
AnswerCount
2
ClosedDate
CommentCount
1
CommunityOwnedDate
CreationDate
2013-09-23T14:08:14.453
FavoriteCount
1
LastActivityDate
2013-11-12T23:45:51.767
LastEditDate
2013-09-23T14:22:54.180
LastEditorUserId
1524450
OwnerUserId
1661566
ParentId
0
PostTypeId
1
Score
0
ViewCount
11867
LastEditorDisplayName
text
Body
Yes, this is homework, and no I'm not asking you to do my homework. I need help with phase 3 of this binary bomb. I didn't have any trouble with phases 1 and 2 but phase 3 is just too much for me. I understand that there should be 3 inputs. I'm pretty sure one of them is a character input and two of them are integers, but I'm not sure in what order. Firstly, here is the disassembled code: <pre><code>0x0000000000401163 <phase_3+0>: sub $0x18,%rsp 0x0000000000401167 <phase_3+4>: lea 0xf(%rsp),%rcx 0x000000000040116c <phase_3+9>: lea 0x14(%rsp),%rdx 0x0000000000401171 <phase_3+14>: lea 0x10(%rsp),%r8 0x0000000000401176 <phase_3+19>: mov $0x402650,%esi 0x000000000040117b <phase_3+24>: mov $0x0,%eax 0x0000000000401180 <phase_3+29>: callq 0x400b80 <sscanf@plt> 0x0000000000401185 <phase_3+34>: cmp $0x2,%eax 0x0000000000401188 <phase_3+37>: jg 0x40118f <phase_3+44> 0x000000000040118a <phase_3+39>: callq 0x4014b1 <explode_bomb> 0x000000000040118f <phase_3+44>: cmpl $0x7,0x14(%rsp) 0x0000000000401194 <phase_3+49>: ja 0x401294 <phase_3+305> 0x000000000040119a <phase_3+55>: mov 0x14(%rsp),%eax 0x000000000040119e <phase_3+59>: xchg %ax,%ax 0x00000000004011a0 <phase_3+61>: jmpq *0x402660(,%rax,8) 0x00000000004011a7 <phase_3+68>: cmpl $0x2c4,0x10(%rsp) 0x00000000004011af <phase_3+76>: nop 0x00000000004011b0 <phase_3+77>: je 0x4012a2 <phase_3+319> 0x00000000004011b6 <phase_3+83>: callq 0x4014b1 <explode_bomb> 0x00000000004011bb <phase_3+88>: mov $0x7a,%eax 0x00000000004011c0 <phase_3+93>: jmpq 0x4012a7 <phase_3+324> 0x00000000004011c5 <phase_3+98>: mov $0x6a,%eax ---Type <return> to continue, or q <return> to quit--- 0x00000000004011ca <phase_3+103>: cmpl $0x327,0x10(%rsp) 0x00000000004011d2 <phase_3+111>: je 0x4012a7 <phase_3+324> 0x00000000004011d8 <phase_3+117>: callq 0x4014b1 <explode_bomb> 0x00000000004011dd <phase_3+122>: mov $0x6a,%eax 0x00000000004011e2 <phase_3+127>: jmpq 0x4012a7 <phase_3+324> 0x00000000004011e7 <phase_3+132>: mov $0x66,%eax 0x00000000004011ec <phase_3+137>: cmpl $0x136,0x10(%rsp) 0x00000000004011f4 <phase_3+145>: je 0x4012a7 <phase_3+324> 0x00000000004011fa <phase_3+151>: callq 0x4014b1 <explode_bomb> 0x00000000004011ff <phase_3+156>: mov $0x66,%eax 0x0000000000401204 <phase_3+161>: jmpq 0x4012a7 <phase_3+324> 0x0000000000401209 <phase_3+166>: mov $0x75,%eax 0x000000000040120e <phase_3+171>: cmpl $0x252,0x10(%rsp) 0x0000000000401216 <phase_3+179>: je 0x4012a7 <phase_3+324> 0x000000000040121c <phase_3+185>: callq 0x4014b1 <explode_bomb> 0x0000000000401221 <phase_3+190>: mov $0x75,%eax 0x0000000000401226 <phase_3+195>: jmpq 0x4012a7 <phase_3+324> 0x000000000040122b <phase_3+200>: mov $0x70,%eax 0x0000000000401230 <phase_3+205>: cmpl $0x240,0x10(%rsp) 0x0000000000401238 <phase_3+213>: je 0x4012a7 <phase_3+324> 0x000000000040123a <phase_3+215>: callq 0x4014b1 <explode_bomb> 0x000000000040123f <phase_3+220>: mov $0x70,%eax 0x0000000000401244 <phase_3+225>: jmp 0x4012a7 <phase_3+324> ---Type <return> to continue, or q <return> to quit--- 0x0000000000401246 <phase_3+227>: cmpl $0x269,0x10(%rsp) 0x000000000040124e <phase_3+235>: xchg %ax,%ax 0x0000000000401250 <phase_3+237>: je 0x4012a2 <phase_3+319> 0x0000000000401252 <phase_3+239>: callq 0x4014b1 <explode_bomb> 0x0000000000401257 <phase_3+244>: mov $0x7a,%eax 0x000000000040125c <phase_3+249>: jmp 0x4012a7 <phase_3+324> 0x000000000040125e <phase_3+251>: mov $0x6b,%eax 0x0000000000401263 <phase_3+256>: cmpl $0x201,0x10(%rsp) 0x000000000040126b <phase_3+264>: je 0x4012a7 <phase_3+324> 0x000000000040126d <phase_3+266>: callq 0x4014b1 <explode_bomb> 0x0000000000401272 <phase_3+271>: mov $0x6b,%eax 0x0000000000401277 <phase_3+276>: jmp 0x4012a7 <phase_3+324> 0x0000000000401279 <phase_3+278>: mov $0x74,%eax 0x000000000040127e <phase_3+283>: cmpl $0x358,0x10(%rsp) 0x0000000000401286 <phase_3+291>: je 0x4012a7 <phase_3+324> 0x0000000000401288 <phase_3+293>: callq 0x4014b1 <explode_bomb> 0x000000000040128d <phase_3+298>: mov $0x74,%eax 0x0000000000401292 <phase_3+303>: jmp 0x4012a7 <phase_3+324> 0x0000000000401294 <phase_3+305>: callq 0x4014b1 <explode_bomb> 0x0000000000401299 <phase_3+310>: mov $0x75,%eax 0x000000000040129e <phase_3+315>: xchg %ax,%ax 0x00000000004012a0 <phase_3+317>: jmp 0x4012a7 <phase_3+324> 0x00000000004012a2 <phase_3+319>: mov $0x7a,%eax ---Type <return> to continue, or q <return> to quit--- 0x00000000004012a7 <phase_3+324>: cmp 0xf(%rsp),%al 0x00000000004012ab <phase_3+328>: je 0x4012b2 <phase_3+335> 0x00000000004012ad <phase_3+330>: callq 0x4014b1 <explode_bomb> 0x00000000004012b2 <phase_3+335>: add $0x18,%rsp 0x00000000004012b6 <phase_3+339>: retq </code></pre> I inputted something like 4 112 z, just to try it out and run through the steps. The code runs up to <code>0x0000000000401230 <phase_3+205>: cmpl $0x240,0x10(%rsp)</code> What I'm really confused about is what 0x10(%rsp) indicates. I looked at the decimal value stored in rsp and it's in the negatives. It seems like the first input of 4 worked out fine, and the code kept running, but I'm wondering why it's comparing rsp to 576, and what the 0x10 in front of it indicates. Any sort of insight would be helpful.
Tags
<assembly><x86>
Title
Binary Bomb Phase 3 Assembly
singulars
PostAcceptedAnswerId
1. PO
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 PostTypePostTypeId
 PTAnswer
PostParentId
1. This table or related slice is empty.
PostTypePostTypeId
1. PTQuestion
UserLastEditorUserId
1. USMichael
UserOwnerUserId
1. USMan Person
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1. PL
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 LTLinked
PostLinksRelatedPostIdPostId
1. PL
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 LTLinked
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. PO
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 PTAnswer
2. PO
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 PTAnswer
VotesPostIdCreationDate
1. VO
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 POBinary Bomb Phase 3 Assembly
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 This table or related slice is empty.
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2. VO
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 POBinary Bomb Phase 3 Assembly
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CommentsPostId
1. COIt's not comparing `rsp` with 576, it's comparing the 32-bit value stored at `(rsp + 0x10)` with 576.
 singulars
 PostPostId
 POBinary Bomb Phase 3 Assembly
 UserUserId
 USMichael

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