This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. The binary bomb is a very good exercise to learn the assembly language.I started this exercise for fun. To learn more, see our tips on writing great answers. On whose turn does the fright from a terror dive end? This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. Each phase expects the student to enter a particular string, on stdin. correctly, else you and your students won't be able to run your bombs. At the onset of the program you get the string 'Welcome to my fiendish little bomb. Each bomb phase tests a different aspect of machine language programs: Phase 4: recursive calls and the stack discipline, Phases get progressively harder. 1 2 6 24 120 720 0 q 777 9 opukma 4 2 6 3 1 5 output Welcome to my fiendish little bomb. phase_3 However, you do need to handle recursion actually. You have 6 phases with which to blow yourself up. Next, the, student fills in this form with their user name and email address, and, then submits the form. 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. The first number we can try to be 6 and the second must be 682. Instructors and students view the scoreboard by pointing their, The online Bomb Lab is self-grading. You've defused the secret stage! From the code, we can see that we first read in 6 numbers. First, the numbers must be positive. Each bomb phase tests a different aspect of machine language programs: Phase 1: string comparison. CIA_MKUltraBrainwashing_Drugs . phase_2() - This phase is about typing in a code. . You have 6 phases with which to blow yourself up. When we hit phase_1, we can see the following code: !", deducting points from your problem set grade, and then terminating. Then you get the answer to be the pair(7, 0). Specifically: That's number 2. Let's start with when it calls sym.read_six_numbers. strings_not_equal Going back all the way to the first iteration you needed to enter into the array at the 5th index, which is the first interger needed for the user input. And when we execute it, it expects to receive certain inputs, otherwise it 'blows' up. When in doubt "make stop; make start", However, resetting the lab deletes all old bombs, status logs, and the, scoreboard log. Solve a total of 6 phases to defuse the bomb. If that function fails, it calls explode_bomb to the left. Good work! secret_phase !!! In memory there is a 16 element array of the numbers 0-15. 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). 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. If you type the correct string, then the phase is defused and the bomb proceeds to the next phase. The function then takes the address of the memory location within the array indexed by the second user input and places it in the empty adjacent element designated by the first user input. There are two basic flavors of Bomb Lab: In the "online" version, the, instructor uses the autograding service to handout a custom notifying, bomb to each student on demand, and to automatically track their, progress on the realtime scoreboard. Did the Golden Gate Bridge 'flatten' under the weight of 300,000 people in 1987? This file is created by the report daemon, 4.4.4. Otherwise the bomb "explodes" by printing "BOOM!!!". You can tell, makebomb.pl to use a specific variant by using the "-p" option. phase_2 Informal Explanations of Phases 1 through 6: I have spent approximately 26 hours on this assignment. - Main daemon (bomblab.pl). explode_bomb. The source code for the different phase variants is in ./src/phases/. . Either way, eventually youll find that the pre-cyphered version of giants is actually opekmq. 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, --------------------------------------------------------------------------------. Keep going! From the above annotations, we can see that there is a loop. If this is a duplicate of another question, please link it so future readers can find it if their search turns up this question first. To review, open the file in an editor that reveals hidden Unicode characters. Wow! You signed in with another tab or window. 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 . Keep going! Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. From the above, we see that we are passing some value into a register before calling scanf(). instructor builds, hands out, and grades the student bombs manually, While both version give the students a rich experience, we recommend, the online version. This number was 115. phase_6() - This function does a few initial checks on the numbers inputed by the user. student whose email address is and whose user name is : bomb* Custom bomb executable (handout to student), bomb.c Source code for main routine (handout to student). Pretty confident its looking for 3 inputs this time. The students work on defusing, their bombs offline (i.e., independently of any autograding service), and then handin their solution files to you, each of which you grade, You can use the makebomb.pl script to build your own bombs. phase_1 METU Ceng'e selamlar :)This is the first part of the Attack Lab. Phase 1 is sort of the "Hello World" of the Bomb Lab. Students download their bombs, and display the scoreboard by pointing a browser at a simple HTTP, server called the "request server." More than 2 is fine but the code is only dependent on the first two numbers. From this, we can deduce that the input for phase_2 should be 1 2 4 8 16 32. phase_defused. OK. :-) phase_3 How a top-ranked engineering school reimagined CS curriculum (Ep. Given that our string is 6 characters long, it makes sense to assume that the function is iterating over each character in the loop and presumably doing something to them. Can you help me please? There exists a linked list structure under these codes. bomblab-Angr/Phase 5 x86_64.ipynb. phase_5() - This function requires you to go backwards through an array of numbers to crack the code. The makebomb.pl script also generates the bomb's solution. The autograding service consists of four user-level programs that run, - Request Server (bomblab-requestd.pl). Work fast with our official CLI. Enter disas and you will get a chunk of assembly for the function phase_1 which we put our breakpoint at. The key is that each time you enter into the next element in the array there is a counter that increments. Once you have updated the configuration files, modify the Latex lab, writeup in ./writeup/bomblab.tex for your environment. What' more, there's a function call to read_six_numbers(), we can inspect it, Up till now, you should be able to find out that in this part, we are required to enter six numbers. can be started from initrc scripts at boot time. It is called recursively and in the end you need it to spit out the number 11. phase_1() - I'm first going to start stepping through the program starting at main. Help/Collaboration: I recieved no outside help with this bomb, other than. That's number 2. Contribute to CurryTang/bomb_lab_solution development by creating an account on GitHub. As we have learned from the past phases, fixed values are almost always important. If nothing happens, download Xcode and try again. So there are some potential strings for solving each of the stages. This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. And, as you can see at structure, the loop iterates 6 times. Give 0 to ebp-8, which is used as loop condition. Pull up the function in Graph mode with VV, press p to cycle between views, and select the minigraph. Did the drapes in old theatres actually say "ASBESTOS" on them? you like without losing any information. First bomb lab is a Reverse Engineering challenge, you have to read its assembly to find the message that . From phase_4, we call the four arguments of func4 to be a, b(known, 0), c(known, 14), d(known, 0). Try this one. I know there has to be 6 numbers, with the range of 1-6, and there can't be any repeats. On the bright side, at least now we know that our string should come out of the loop as giants. Is there any extra credit for solving the secret phase. phase_1 sig_handler Changing the second input does not affect the ecx. In addition, most, phase variants are parameterized by randomly chosen constants that are, assigned when a particular bomb is constructed. by hand by running their custom bomb against their solution: For both Option 1 and Option 2, the makebomb.pl script randomly, chooses the variant ("a", "b", or "c") for each phase. There was a problem preparing your codespace, please try again. The student then saves the tar file to disk. Ahhhh, recursion, right? changeme.edu Evil has created a slew of "binary bombs" for our class. In this part we use objdump to get the assembly code The unique. We multiply the number by 2 each step, so we guess the sequence to be 1, 2, 4, 8, 16, 32, which is the answer. When I get angry, Mr. Bigglesworth gets upset. gdbCfg phase 5. We can see that the function is being called which as the name implies compares two strings. These numbers act as indices within a six element array in memory, each element of which contains a number. The other option for offering an offline lab is to use the, makebomb.pl script to build a unique quiet custom bomb for each, linux> ./makebomb.pl -i -s ./src -b ./bombs -l bomblab -u -v , This will create a quiet custom bomb in ./bombs/bomb for the. phase_5 It first checks that you have inputed 6 numbers, then that they are within the range of 1 through 6, and finally that they are all unique numbers, in that no number is repeated. Bomb explosions. any particular student, is quiet, and hence can run on any host. Based on the first user inputed number, you enter into that indexed element of the array, which then gives you the index of the next element in the array, etc. This post walks through the first 3 phases of the lab. angelshark.ics.cs.cmu.edu Knowing that scanf() takes in a string format as its input, lets break right before scanf() is called and check the value of $esi. The first argument must be less than 7, right? When you fail a phase, and the bomb goes off, you probably get the string 'BOOM!!!' Load the binary, perform analysis, seek to Phase 6, and have a look at your task. I should say the first half of the code is plain. Lets enter the string blah as our input to phase_1. So, what do we know about phase 5 so far? If nothing happens, download GitHub Desktop and try again. and upon beating the stage you get the string 'Wow! Which one to choose? Phase 1. The solution for the bomb lab of cs:app. This command sets breakpoints throughout the code. You create a table using the method above, and then you get the answer to be "ionefg". Binary Bomb Lab :: Phase 6. Configure the Bomb Lab by editing the following file: ./Bomblab.pm - This is the main configuration file. Segmentation fault in attack lab phase5. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Before the, lab goes live, you'll want to request a few bombs for yourself, run, them, defuse a few phases, explode a few phases, and make sure that, the results are displayed properly on the scoreboard. strings_not_equal() - This function implements the test of equality between the user inputed string and the pass-phrase for phase_1 of the bomb challenge. In this part, we are given two functions phase_4() and func4(). edx must equal 0xf, meaning the first input has to be 5, 21, 37, etc. But when I put 4 1 6 5 2 3 or 3 6 1 2 5 4, it explodes. Tools: Starting challenge; Phase_1: Phase_2: Phase_3: Phase_4: Phase_5: Phase_6: Bomb Lab Write-up. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. On to the next' or 'So you got that one. You can start and stop the autograding service as often as. 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. You encounter with a loop and you can't find out what it is doing easily. 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). Have a nice day! daemon that starts and nannies the other programs in the service, checking their status every few seconds and restarting them if, (3) Stopping the Bomb Lab. Connect and share knowledge within a single location that is structured and easy to search. Learn more. Please Lets now set a breakpoint at phase_3. Since there exists a bunch of different versions of this problem, I' ve already uploaded my version. The bomb has blown up. So you got that one. If you're looking for a specific phase: Here is Phase 1. DrEvil. I'm guessing that this function will likely compare the string that I inputed to some string stored in memory somewhere. frequency is a configuration variable in Bomblab.pm. 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. rev2023.4.21.43403. The goal for the students is to defuse as many phases as possible. a = 10 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. Subtract original pointer from %eax and get the running total of the string. And your students will have to get, (2) Starting the Bomb Lab. I see the output 'Phase 1 defused. A clear, concise, correct answer will earn full credit. You just pass through the function and it does nothing. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. The purpose of this project is to become more familiar with machine level programming. phase_4 There is also a test that the first user inputed number is less than or equal to 14. 1) We have to find that number 'q' which will cause 12 (twelve) iterations. There was a problem preparing your codespace, please try again. This part is really long. I found the memory position for the beginning of phase_1 and placed a break point there. Contribute to hengyingchou/CSE351 development by creating an account on GitHub. Then we encounter with an optimized switch expression. Here are a few useful commands that are worth highlighting: This command divides the screen into two parts: the command console and a graphical view of the assembly code as you step through it. Phase 1 defused. Each student gets a, bomb with a randomly chosen variant for each phase. Bomb Lab: Phase 5. gdb ./bomb -q -x ~/gdbCfg. Remember this structure from Phase 2? Go to file. So you think you can stop the bomb with ctrl-c, do you?' We can open our strings.txt file and see that the string we found in memory is the beginning of the full string: I can see Russia from my house!. I think the second number should be. The Hardware/Software Interface - UWA @ Coursera. It's a great. What were the poems other than those by Donne in the Melford Hall manuscript? The numbers you enter are used to sort a linked list actually. The user input is then, 4 5 1 6 2 3. There is a small grade penalty for explosions beyond 20. I keep on getting like 3 numbers correctly, and then find the only possible solutions for the other 3 incorrect, so I am at a loss. Next there is pattern that must be applied to the first 6 numbers. PHASE 3. In order to determine the comparisons used, it will be useful to look up or know Jumps Based on Signed Comparisons. First things first, we can see from the call to at and subsequent jump equal statement our string should be six characters long. Phase 5 reads in two numbers, the first of which is used as a starting point within a sequence of numbers. phase_6 offer the lab. For more information, you can refer to this document, which gives a handy tutorial on the phase 6. Congratulations! Here is Phase 6. phase_4 The request server, responds by sending an HTML form back to the browser. You signed in with another tab or window. this is binary bomb lab phase 5.I didn't solve phase 5. It also might be easier to visualize the operations by using an online disambler like https://onlinedisassembler.com/ to see a full graph. Any numbers entered after the first 6 can be anything. As a next step, lets input the test string abcdef and take a look at what the loop does to it. Control-l can be used to refresh the UI whenever it inevitably becomes distorted. Phase 4: recursive calls and the stack discipline. d = 12 Are you sure you want to create this branch? The variable being used in this comparison is $eax. Untar your specific file and lets get started! Now you can see there are a few loops. To review, open the file in an editor that reveals hidden Unicode characters. Option 2. The main daemon is the. readOK = sscanf(cString, "%d %d", &p, &q); --------------------------------------------------------. If so, pass the counter back to the calling function else continue the incrementing loop through string pointer until it hits null termination. First thing I did was to search the binary using strings to see if there was anything interesting that pops out. 1 first, so gdb is the most recent available version of GDB. I know b7 < eb < f6 < 150 < 21f < 304, so the order of nodes should be 3 0 5 4 1 2 (or 2 5 0 1 4 3 - in ascending order) and I should add +1 to all numbers. Run the following commands to create text files which we will look at later: You should now have two files: strings.txt and assembly.txt. Here is Phase 3. As an experienced engineer, I believe you can figure out that there are two arguments, each of which should be integers.
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