Request Server: The request server is a simple special-purpose HTTP, server that (1) builds and delivers custom bombs to student browsers, on demand, and (2) displays the current state of the real-time, A student requests a bomb from the request daemon in two, steps: First, the student points their favorite browser at, For example, http://foo.cs.cmu.edu:15213/. From this, we can guess that to pass phase_1, we need to enter the correct string. Binary Bomb Lab :: Phase 6. I think the second number should be. Regardless, I'm not falling for it this time. From this mapping table, we can figure out the un-cyphered version of giants. You will have to run through the reverse engineering process, but there won't be much in the way of complicated assembly to decipher or tricky mental hoops to jump through. As its currently written, your answer is unclear. You signed in with another tab or window. The first number must be between 0 and 7. We can now see the assembly code. Also note that the binary follow the AT&T standard so instruction operations are reversed (e.g. phase 2, variant "a" for phase 3, variant "c" for phase 4, and so on. phase_4 I inputed the word 'blah' and continued to run the program. Any numbers entered after the first 6 can be anything. The solution for the bomb lab of cs:app. 0x00401100 4989e5 mov r13, rsp. A tag already exists with the provided branch name. Such bombs are called "notifying bombs. It also might be easier to visualize the operations by using an online disambler like https://onlinedisassembler.com/ to see a full graph. CS3330: Lab 1 (Bomb Lab) Otherwise, the bomb explodes by printing " Also, where the arrow is, it's comparing the current node with the next node. On the bright side, at least now we know that our string should come out of the loop as giants. The first number we can try to be 6 and the second must be 682. You encounter with a loop and you can't find out what it is doing easily. Next it takes the address of the memory location within the array indexed by the third user input and places in the empty adjacent element designated by the second user input. For homework: defuse phases 2 and 3. Ahhhh, recursion, right? Check to see if the incremented character pointer is not null terminated. Have a nice day! Cannot retrieve contributors at this time. This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. Each bomb phase tests a different aspect of machine language programs: Phase 4: recursive calls and the stack discipline, Phases get progressively harder. Not the answer you're looking for? input.txt Public speaking is very easy. In addition, most, phase variants are parameterized by randomly chosen constants that are, assigned when a particular bomb is constructed. Phase 1. First, setup your bomb directory. Increment %rdx by 1 to point to the next character byte and move to %eax. A loop is occurring. Your goal is to set breakpoints and step through the binary code using gdb to figure out the program inputs that defuse the bombs (and make you gain points). These lines indicate that if the first argument equal the last one(right before this line), then we get 0. Lets use that address in memory and see what it contains as a string. Next, as we scan through each operation, we see that a register is being incremented at , followed by a jump-less-than statement right afterwards that takes us back up to . phase_2 Could there be a randomization of stages or two planned routes through the bomb? This second phase deals with numbers so lets try to enter the array of numbers 0 1 2 3 4 5. d = 12 When we hit phase_1, we can see the following code: Custom, notifying bombs are constrained to run on a specific set of Linux, hosts determined by the instructor. A tag already exists with the provided branch name. Assignment #3: Bomb Lab - CS356 Introduction to Computer Systems You can start and stop the autograding service as often as. I then did the same for the possible second pointer arguement which would be in %rsi with x/s $rsi and get 'When I get angry, Mr. Bigglesworth gets upset.'. I also wanted to see groupings of strings that may have similar prefixes and so I sorted the strings program output and looked for anything interesting in that manner. Each time the "bomb explodes", it notifies the server, resulting in a (-)1/5 point deduction from the final score for the lab. We have created a stand-alone user-level autograding service that, handles all aspects of the Bomb Lab for you: Students download their, bombs from a server. "make stop" kills all of the running, servers. Make sure you update this. 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14 fun7 ??? I cannot describe the question better . CS107 Assignment 5: Binary bomb - Stanford University ', After solving stage 3 you likely get the string 'Halfway there! First you must enter two integers and the bomb will detonate if you enter more or less than that. You've defused the bomb!'. phase_6 greatwhite.ics.cs.cmu.edu You create a table using the method above, and then you get the answer to be "ionefg". The bomb explodes if the number of steps to get to the number 15 in the sequence does not equal 9, or if the second input number does not equal the sum of the . A note to the reader: For explanation on how to set up the lab environment see the "Introduction" section of the post. From this, we can deduce that the input for phase_2 should be 1 2 4 8 16 32. Assignment #3: Bomb Lab (due on Tue, Feb 21, 2023 by 11:59pm) Introduction. Bomb Lab: Phase 5. Are you sure you want to create this branch? In this part, we are given two functions phase_4() and func4(). Each binary bomb is a program, running a sequence of phases. Cannot retrieve contributors at this time. Then you set a breakpoint at 4010b3 and find the target string to be "flyers". Option 1: The simplest approach for offering the offline Bomb Lab is. CIA_MKUltraBrainwashing_Drugs . Are you sure you want to create this branch? 'But finding it and solving it are quite different' - Main daemon (bomblab.pl). This continuous through all the user inputed indices and finally places the value zero in the last remaining empty element in the array. Otherwise, the bomb explodes by printing "BOOM!! There are many things going on with shuffling of variables between registers, some bit shifting, and either a subtraction or an addition being applied to some of the hard coded constants. [RE] Linux Bomb Walkthrough - Part2 (Phases 1-3) - [McB]Defence Informal Explanations of Phases 1 through 6: I have spent approximately 26 hours on this assignment. Use arg1 and address ebp-0x20 as arguments of function read_six_numbers. which to blow yourself up. First, interesting sections/function names: The binary bomb is a very good exercise to learn the assembly language.I started this exercise for fun. @Jester so I looked at your reply to another question which is extremely similar to my question, actually the same exact question. c = 1 The bomb has blown up. There are no explicit handins and the lab is self-grading. You will get full credit for defusing phases 2 and 3 with less than 30 explosions. Solved this is binary bomb lab phase 5.I didn't solve phase - Chegg Breakpoints can be set at specific memory addresses, the start of functions, and line numbers. Let's have a look at the phase_4 function. A note to the reader: For explanation on how to set up the lab environment see the "Introduction" section of the post. While layout asm is helpful, also helpful to view the complete disassembled binary. Bomb_Lab/Analysis.md at master MarkHyphen/Bomb_Lab GitHub Here is the assembly code: The list of numbers I've inputed is this: So far from my understanding, two conditions need to be met: compare %ecx is 115 line 103 initialize_bomb I try a input sequence "aaaaaa" and get the value after transitions doesn't change at all, which means that the output of a given input is unique. I will list some transitions here: The ascii code of "flyers" should be "102, 108, 121, 101, 114, 115". From the above annotations, we can see that there is a loop. Can you still use Commanders Strike if the only attack available to forego is an attack against an ally? This part is a little bit trickier. I will likely take another shot at figureing out exactly how to come up with the solution by following the implemented logic but I eventually brute forced it, which took a whole 30 seconds to figure out. The bomb explodes if the number calculated by this function does not equal 49. There is also a test that the first user inputed number is less than or equal to 14. As we have learned from the past phases, fixed values are almost always important. I found the memory position for the beginning of phase_1 and placed a break point there. any particular student, is quiet, and hence can run on any host. Defusing the binary bomb. The second number is simply linked to the first number: 0 must be followed by 704, 1 by 848, 2 by 736, 3 by 346, 4 by 607, 5 by 147, 6 by 832, and 7 by 536. There is also a "secret phase" that, only appears if students append a certain string to the solution to, Each phase has three variants: "a", "b", and "c". The request server also creates a copy of the bomb and its, - Result Server (bomblab-resultd.pl). However, it. * See src/README for more information about the anatomy of bombs and, how they are constructed. ', It is not clear what may be the output string for solving stage 4 or 5. sign in Give 0 to ebp-4, which is used as sum of n0, n1, n2. gdbCfg phase 5. In this repository I will take down my process of solving the bomb lab of CS:APP. Work fast with our official CLI. You have 6 phases with you like without losing any information. As an experienced engineer, I believe you can figure out that there are two arguments, each of which should be integers. Contribute to xmpf/cse351 development by creating an account on GitHub. Each phase expects the student to enter a particular string, on stdin. The two stipulations that you must satisfy to move to the last portion of this phase is that you have incremented the counter to 15 and that the final value when you leave the loop is 0xf (decimal 15). phase_defused METU Ceng'e selamlar :)This is the first part of the Attack Lab. e = 16 So my understanding is that the first input is the starting point of the array, so it should be limited to between 0 and 14, and the second input is the sum of all the values that I visited starting from array[first input]. func4 ??? Using layout asm, we can see the assembly code as we step through the program. How about the next one?'. The Hardware/Software Interface - UWA @ Coursera. @cinos hi, I had same problem, I couldn't understand, I must have ecx 15 too, but I couldn't figure it out. . Can you help me please? The makebomb.pl script also generates the bomb's solution. What I know so far: first input cannot be 15, 31, 47, etc. You just pass through the function and it does nothing. You signed in with another tab or window. Since we know the final value is 6 letters/numbers, we know 72/6 = 12. Bomb explosions. Now switch to Visual mode with v, cycle the print mode with p until you see the disassembled function, toggle your cursor with c, then finally move down to the movzx edx, byte . So we can plug in 6 d characters and get a valid comparison! And your students will have to get, (2) Starting the Bomb Lab. initialize_bomb Buffer Overflow Lab (Attack Lab) - Phase1 - YouTube Defusing CMU's Bomb Lab using GDB - Andrew Wei - GitHub Pages edx must equal 0xf, meaning the first input has to be 5, 21, 37, etc. Readme (27 points) 2 points for explosion suppression, 5 points for each level question. Here is Phase 6. So a should be 7, too. These look like they could pertain to the various phases of the bomb. We can see that our string input blah is being compared with the string Border relations with Canada have never been better.. Each of you will work with a special "binary bomb". ", - Report Daemon (bomblab-reportd.pl). Each line is annotated. If there is a, problem (say because you forgot to update the list of machines the, bombs are allowed to run in src/config.h) you can fix the, configuration, reset the lab, and then request and run more test, CAUTION: If you reset the lab after it's live, you'll lose all your, records of the students bombs and their solutions. skip The unique. requires that you keep the autograding service running non-stop, because handouts, grading, and reporting occur continuously for the, duration of the lab. The code shows as follows: After inspecting the code, you should figure out that the length of the string must be 6. Enter a random string and then we stop at the phase 1 position, then we try printing out the information around 0x402400. This series will focus on CMU's Binary Bomb challenge. I should say the first half of the code is plain. The key is that each time you enter into the next element in the array there is a counter that increments. Link to Bomb Lab Instructions (pdf) in GitHub Repository CSO1 - Bomb lab - University of Virginia School of Engineering and Learn more about bidirectional Unicode characters. If the event was a defusion, the message also, contains the "defusing string" that the student typed to defuse the, Report Daemon: The report daemon periodically scans the scoreboard log, and updates the Web scoreboard. We get the following part, We see a critical keyword Border, right? After solving stage 1 you likely get the string 'Phase 1 defused. Thus on the 14th iteration if I needed a 6, I would need to be in the 14th index of the array on the 13th iteration, then on index 2 of the 12th iteration. I'm getting a feeling that the author wants you to really have to work to get through some of these functions. So far from my understanding, two conditions need to be met: edx must equal 0xf, meaning the first input has to be 5, 21, 37, etc. explode_bomb. The student then saves the tar file to disk. func4() - This function was rather difficult for me to get through logically and so I ultimately had to take it as somewhat as a black box. Tools: Starting challenge; Phase_1: Phase_2: Phase_3: Phase_4: Phase_5: Phase_6: Bomb Lab Write-up. I know that due to x86-64 calling conventions on programs compiled with GCC that %rdi and %rsi may contain pointers to the words to compare. makoshark.ics.cs.cmu.edu, Dunno, lets just get a static printout of the disassembled code and see what comes out. Bomb lab phase 6 github. Programming C Assembly. Instructions. I assume Also run the command i r to see what the values of the variables are. string_length() - This function first checks to see that the passed character pointer in %rdi is not null terminated. 1) We have to find that number 'q' which will cause 12 (twelve) iterations. changeme.edu Then the tricky part comes. On a roll! Then we take a look at the assembly code above, we see one register eax and an address 0x402400. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. You won't be able, to validate the students handins. lesson and forces them to learn to use a debugger. This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. Please feel free to fork or star this repo if you find it helpful!***. node5 To see the format of how we enter the six numbers, lets set a breakpoint at read_six_numbers. They will likely be either 'Good work! I dont want to go through either solution all the way here, since the first one is a no-brainer and the second one is a little complicated. Welcome to my fiendish little bomb. In order to do this you must look at the various integers within the array and then place them in ascending order by the index of those integer containing elements. Lets set a breakpoint at strings_not_equal. If you type the correct string, then the phase is defused and the bomb proceeds to the next phase. secret_phase !!! There are six of them but some of these could be just added strings outputted upon completion of a stage. phase_4 From the above comments, we deduce that we want to input two space-separated integers. Jumping to the next "instruction" using gdb, Binary Bomb Phase 5 issue (my phase 5 seems to be different from everyone elses), Memory allocation and addressing in Assembly, Tikz: Numbering vertices of regular a-sided Polygon. Have a nice day! The ./bomblab directory contains the following files: Makefile - For starting/stopping the lab and cleaning files, bomblab.pl* - Main daemon that nannies the other servers & daemons, Bomblab.pm - Bomblab configuration file, bomblab-reportd.pl* - Report daemon that continuously updates scoreboard, bomblab-requestd.pl* - Request server that serves bombs to students, bomblab-resultd.pl* - Result server that gets autoresult strings from bombs, bomblab-scoreboard.html - Real-time Web scoreboard, bomblab-update.pl* - Helper to bomblab-reportd.pl that updates scoreboard, bombs/ - Contains the bombs sent to each student, log-status.txt - Status log with msgs from various servers and daemons, log.txt - Scoreboard log of autoresults received from bombs, makebomb.pl* - Helper script that builds a bomb, scores.txt - Summarizes current scoreboard scores for each student, src/ - The bomb source files, writeup/ - Sample Latex Bomb Lab writeup, LabID: Each instance (offering) of the lab is identified by a unique, name, e.g., "f12" or "s13", that the instructor chooses. The Bomb Lab teaches students principles of, machine-level programs, as well as general debugger and reverse, A "binary bomb" is a Linux executable C program that consists of six, "phases." The values came out it the following format: 0x000003b8 So if I order the nodes in ascending order, it should be 6 4 1 2 5 3, but this still wasn't the correct input. Is there any extra credit for solving the secret phase. phase_1 What were the poems other than those by Donne in the Melford Hall manuscript? You signed in with another tab or window. This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. Phase 1 defused. Here are the directions for offering both versions of the lab. Looking for job perks? Each student gets a, bomb with a randomly chosen variant for each phase. Load the binary, perform analysis, seek to Phase 6, and have a look at your task. (Add 16 each time) ecx is compared to rsp, which is 15, so we need ecx to equal to 15. The nefarious Dr. I then continue to run the program until I am prompted for a phrase to input. strings_not_equal The source code for the different phase variants is in ./src/phases/. Cannot retrieve contributors at this time. . There is an accessed memory area that serves as a counter. readOK = sscanf(cString, "%d %d", &p, &q); --------------------------------------------------------. What differentiates living as mere roommates from living in a marriage-like relationship? phase_5 () - This function requires you to go backwards through an array of numbers to crack the code. A tag already exists with the provided branch name. Finally, we can see down at the bottom of the function that is being called after the contents of %eax and the fixed address 0x804980b have been pushed onto the stack. A tag already exists with the provided branch name. Entering this string defuses phase_1. How about saving the world? Additional Notes on the Online Bomb Lab, * Since the request server and report daemon both need to execute, bombs, you must include $SERVER_NAME in the list of legal machines in, * All of the servers and daemons are stateless, so you can stop ("make, stop") and start ("make start") the lab as many times as you like. Then you get the answer to be the pair(7, 0). It appears that there may be a secret stage. Each bomb phase tests a different aspect of machine language programs: Phase 1: string comparison. node6 Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. CSO1 - Bomb lab. I know there has to be 6 numbers, with the range of 1-6, and there can't be any repeats. phase_5 Curses, you've found the secret phase! Lets clear all our previous breakpoints and set a new one at phase_2. I tried many methods of solution on internet. Phase 1: There are two main ways of getting the answer. aseje owo nla. And when we execute it, it expects to receive certain inputs, otherwise it 'blows' up. Binary Bomb Lab :: Phase 4 - Zach Alexander Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. We can inspect its structure directly using gdb. The "main daemon" starts and nannies the, request server, result server, and report deamon, ensuring that, exactly one of these processes (and itself) is running at any point in, time. Then, we can take a look at the fixed value were supposed to match and go from there: Woah. solution to each bomb is available to the instructor. What does the power set mean in the construction of Von Neumann universe? In this write-up, I will show you how i solve bomb lab challenge. phase_3 A binary bomb is a program that consists of a sequence of six phases. Type "./makebomb.pl -h" to see its arguments. read_six_numbers() - Checks that the user inputed at least 6 numbers and if less than 6 numbers then detonate the bomb. sc2225/Bomb-Lab - Github First, the numbers must be positive. ", Quiet Bomb: If compiled with the NONOTIFY option, then the bomb, doesn't send any messages when it explodes or is defused. Let's inspect the code at first. Once we enter the function, we can check the registers that store the first two inputs: $rdi and $rsi. You signed in with another tab or window. Dump of assembler code for function phase_5: 0x0000000000401002 <+0>: sub $0x18,%rsp ; rsp = rsp - 24, 0x0000000000401006 <+4>: lea 0x8(%rsp),%rcx ; rcx = *(rsp + 8) (function argument), 0x000000000040100b <+9>: lea 0xc(%rsp),%rdx ; rdx = *(rsp + 12) (function argument), 0x0000000000401010 <+14>: mov $0x401ebe,%esi ; esi = "%d %d", 0x0000000000401015 <+19>: mov $0x0,%eax ; eax = 0, 0x000000000040101a <+24>: callq 0x400ab0 <__isoc99_sscanf@plt>, 0x000000000040101f <+29>: cmp $0x1,%eax ; if (eax > 1) goto 0x401029, 0x0000000000401022 <+32>: jg 0x401029 , 0x0000000000401024 <+34>: callq 0x40163d ; if (eax <= 1) explode_bomb(), 0x0000000000401029 <+39>: mov 0xc(%rsp),%eax ; eax = *(rsp + 12) ::function parameter, 0x000000000040102d <+43>: and $0xf,%eax ; eax = eax & 0xf (last 2 bits), 0x0000000000401030 <+46>: mov %eax,0xc(%rsp) ; *(rsp + 12) = eax, 0x0000000000401034 <+50>: cmp $0xf,%eax ; if (eax == 0xf) explode_bomb(), 0x0000000000401037 <+53>: je 0x401065 , 0x0000000000401039 <+55>: mov $0x0,%ecx ; ecx = 0, 0x000000000040103e <+60>: mov $0x0,%edx ; edx = 0, 0x0000000000401043 <+65>: add $0x1,%edx ; edx = edx + 0x1, 0x0000000000401046 <+68>: cltq ; sign extend eax to quadword (rax), 0x0000000000401048 <+70>: mov 0x401ba0(,%rax,4),%eax ; eax = *(rax * 4 + 0x401ba0), 0x000000000040104f <+77>: add %eax,%ecx ; ecx = ecx + eax, 0x0000000000401051 <+79>: cmp $0xf,%eax ; if (eax != 0xf) goto 0x401043 (inc edx), 0x0000000000401054 <+82>: jne 0x401043 , 0x0000000000401056 <+84>: mov %eax,0xc(%rsp) ; *(rsp + 12) = eax, 0x000000000040105a <+88>: cmp $0xc,%edx ; if (edx != 12) explode_bomb(), 0x000000000040105d <+91>: jne 0x401065 , 0x000000000040105f <+93>: cmp 0x8(%rsp),%ecx ; if (ecx == *(rsp + 8)) goto 0x40106a, 0x0000000000401063 <+97>: je 0x40106a , 0x0000000000401065 <+99>: callq 0x40163d ; explode_bomb(), 0x000000000040106a <+104>: add $0x18,%rsp ; rsp = rsp + 24, 0x000000000040106e <+108>: retq ; return, --------------------------------------------------------------------------------.
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