Return Styles: Pseud0ch, Terminal, Valhalla, NES, Geocities, Blue Moon. Entire thread

Iris Action

Name: Anonymous 2012-08-07 20:06

Hey nerds, why doesn't this code work?
http://pastie.org/private/29v95lljikryiiehtdpoq

I'm trying to extract images from a game pack file. It worked fine on the trial/demo version of the game, but fails on the full version of the game [ https://thepiratebay.se/torrent/7512447/ ]

I really don't understand.

Name: Anonymous 2012-08-07 20:07



#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct kcap_dirent {
 char fname[64];
 int unk0;
 int unk1;
 unsigned int offs;
 unsigned int len;
 int unk3;
} *dents;

FILE *in;

void make_dir_r(char *path) {
 char *slpos;
 if(slpos=strrchr(path,'\\')) { /* WIN32 */
  *slpos = 0;
  make_dir_r(path);
  *slpos = '\\'; /* WIN32 */
 }
 mkdir(path);
}

FILE *make_f(char *path) {
 char *slpos;
 if(slpos=strrchr(path,'\\')) { /* WIN32 */
  *slpos = 0;
  make_dir_r(path);
  *slpos = '\\'; /* WIN32 */
 }
 return fopen(path,"wb");
}

int main(int argc, char **argv) {
 char sig[4];
 unsigned int n;
 int i;
 if(argc<2) {
  fprintf(stderr,"usage: kcap_ext infile [outdir]\n");
  return 1;
 }
 if(!(in=fopen(argv[1],"rb"))) {
  fprintf(stderr,"error opening %s for reading\n",argv[1]);
  return 2;
 }
 fread(sig,1,4,in);
 if(memcmp(sig,"KCAP",4)) {
  fprintf(stderr,"file signature error\n");
  return 3;
 }
 fread(&n,1,4,in);
 dents = malloc(sizeof(struct kcap_dirent)*n);
 if(!dents) {
  fprintf(stderr,"memory allocation error\n");
  return 4;
 }
 fread(dents,sizeof(struct kcap_dirent),n,in);
 if(argv[2] && (mkdir(argv[2]),chdir(argv[2]))) {
  fprintf(stderr,"error changing directory to %s\n",argv[2]);
  return 5;
 }
 for(i=0;i<n;i++) {
  int j,k;
  char buf[4096];
  FILE *out;
  printf("%s %d %d\n",dents[i].fname,dents[i].offs,dents[i].len);
  fseek(in,dents[i].offs,SEEK_SET);
  out = make_f(dents[i].fname);
  for(k=0;k<dents[i].len;k+=j) {
   j=fread(buf,1,k<dents[i].len-4096 ? 4096 : dents[i].len-k,in);
   if(!j)
    break;
   fwrite(buf,1,j,out);
  }
  fclose(out);
 }
 return 0;
}

Name: Anonymous 2012-08-07 20:12

do your own debugging, ``faggot''

Name: Anonymous 2012-08-07 20:14

>>3
I did for several hours, I am retarded and not a nerd.

Name: Anonymous 2012-08-07 20:28

>>4
Sorry, I only help fellow nerds.  Eat shit and die, neurotypical shitfag.

Name: Anonymous 2012-08-07 20:37

I think handling strings manually as character arrays is a micro-optimization, mistaking the trees for the forest.

Name: Anonymous 2012-08-07 21:07

>>4
You wrote a program. You are a nerd. That is all.

Name: Anonymous 2012-08-07 23:14

Posts full page of dense, disgusting C code with manual string handling
"DOESN'T WORK"
no error message
no explanation
no test data
<sup>HAX MY ANUS</sup>

Name: Anonymous 2012-08-07 23:15

HOLY SHIT I BBCODE FAILED

That's what I get for not going on /prog/ for years :(

Name: Anonymous 2012-08-08 0:36

>>8
It compiles and runs fine. It just can't extract the archive properly on the full-game version, but works on the trial.

If you bothered to read the entire post you would have seen that.

Name: Anonymous 2012-08-08 0:51

>>6
If the language has an O(1) substring operation (e.g. Perl and BASIC), strings are character arrays. C strings are more like cdr-coded linked lists.

Name: Anonymous 2012-08-08 1:05

>>11
Strings are character arrays, but dealing with that should always be separated from your real code.

Name: Anonymous 2012-08-08 1:07

return fopen(path,"wb");
Oh god, thanks for reminding me once again how shitty C is. That line is just begging for leaks.

Name: Cudder !MhMRSATORI!fR8duoqGZdD/iE5 2012-08-08 6:45

>>10
If you bothered to POST THE ERROR MESSAGE maybe we'd know what's going on.

I would know, because I wrote that code and put in those error messages for a reason.

>>13
0/10. There's not even a malloc() there.

Name: Anonymous 2012-08-08 6:52

>>14
There's not even a malloc() there.
Are your palms hairy, too? fopen uses malloc internally.

Name: Anonymous 2012-08-08 11:53

>>14
that's the thing. there IS no error message. it just outputs corrupt files.

Name: Anonymous 2012-08-08 11:57

>>14
Files and sockets can leak.

Name: Anonymous 2012-08-08 12:55

>>16
Did you delete your shitpost on /jp/ or did the janitor do it?

Please respond, it's very important.

Name: Anonymous 2012-08-08 22:23

>>18
I went to bed like an hour after asking (my IP changed anyways so I couldn't delete it if I wanted to), I think it got pruned off the board automatically from no replies.

Name: Cudder !MhMRSATORI!fR8duoqGZdD/iE5 2012-08-09 1:30

>>15,17
Seriously, did you illiterates not read the whole thing or just didn't notice the fclose()?

And if there's a leak in the C library, then that's not my problem because how the bloody fuck is one supposed to free that memory without having received a pointer to it? If your C library is knackered, I'm not going to care one bit!

Name: Cudder !MhMRSATORI!fR8duoqGZdD/iE5 2012-08-09 1:35

Now back to that bloke's problem.

>>16
If the file sizes look fine they may have added another encryption layer on top. Can't help you there. Or can I? Maybe if you give more information, like uploading some of the samples of output it's produced, or at least pieces of the header. Anything that can be used as evidence that you're not just being an idiotthere's another layer of encryption.

Name: Anonymous 2012-08-09 5:11

chack om ^________^

Name: Anonymous 2012-08-09 6:25

>>21
It's xored.

Key: https://raw.github.com/gist/57813ba6de7127e54b9f/bfb6699a705e8bb8528531828fd6e0c834476ae2/kcap.h

Name: Anonymous 2012-08-09 11:29

>>21
I assumed you would have just download the data.pack and tried to debug on it. Seems like it'd be easier than sending a corrupted image onto some filelocker. http://www.mediafire.com/?iezcmmgxay641oe

Name: Anonymous 2012-08-10 0:10

>>23
What do I do with this?

regards, not OP.

Name: Anonymous 2012-08-10 0:36

Cudder, are you really a woman?

Name: Anonymous 2012-08-10 5:41

>>26
Are you seriously considering believing that for even a modicum of a fucking second?
Are you really that daft?

Name: Cudder !MhMRSATORI!fR8duoqGZdD/iE5 2012-08-10 6:07

>>23
Lots of ciphers use xor with plaintext as their final step. Unless you found that 64KB block directly embedded in the file I would say it's probably a keystream generated from a much more concise description.

>>24
I'm not downloading 600M+ to solve someone else's problem.

Name: Anonymous 2012-08-10 10:37

>>28
I would say it's probably a keystream generated from a much more concise description.
Awesome story onee-san.

Write him a function to xor the files using that key, it would take you 5 minutes at most.

Name: Anonymous 2012-08-10 11:53

>>28
I'm not downloading 600M+

So what are you? Australian, or Canadian? That took less than 5 minutes to download. Such is the beauty of living in a wonderful country like Finland.

Name: Anonymous 2012-08-10 16:08

>>30
I'm sure there are poorfag internet plans in Finlan too.

Name: Anonymous 2012-08-10 19:56

>>31
No. It's illegal to offer such plans, unless you're not the only company that provides service to that area. And all plans on all ISPs are about the same because the government pretty much forces competition like that. It's nice.

Name: Anonymous 2012-08-10 20:02

>>32
So poor people are stuck with just not having internet at all, rather than slow internet?

Name: Anonymous 2012-08-10 20:02

>>32
Glad I don't live in a communist shithole then.

Name: Anonymous 2012-08-10 20:52

>>33
No, it's cheap as fuck. Also if you're poor they provide you with basic service (1/1 Mbit), and in 2015 it will be 100/100 Mbit minimum. Price stays low; basic plan (aka minimum they offer) is less than 5€/year, and is given free to those on our welfare system which also pays very generously.

Name: Anonymous 2012-08-10 21:02

>>35
back to /GNU/, ``communist shitehead''!

Name: Anonymous 2012-08-10 21:11

>>36
/polecat kebabs/

Name: Cudder !MhMRSATORI!fR8duoqGZdD/iE5 2012-08-11 6:37

>>29
Is there really 64KB of key in the executable?

>>30
I'm not going through the whole process for little gain. I don't have the time nor interest to do that.

You want to do that work? Go ahead. I'm not.

Name: Anonymous 2012-08-11 7:16

>>38
>Is there really 64KB of key in the executable?
I don't know. What does it change?

Name: Anonymous 2012-08-11 23:00

>>38
want to do that work?
Sure, I'd love to do it, but I have no knowledge of how to do stuff like this, and I've boggled my mind at it already.

You did it just fine the first time, and even said it was easy to do. What's the issue now?
Cudder !MhMRSATORI!!FBeUS42x4uM Thu Dec 01 03:52:03 2011
Does it contains large changes in brightness?
Cudder !MhMRSATORI!!FBeUS42x4uM Thu Dec 01 04:19:04 2011
That was easy.
I'm not trying to be an asshole, I'm just confused why you did it before with "little gain", and now you won't simply see what was changed and modify your code so this shit can be extracted.
Newer Posts
Don't change these.
Name: Email:
Entire Thread Thread List
All trademarks and copyrights on this site are owned by their respective parties. All comments and posts are the responsibility of their own posters.
- Tinychan + 2ch Mode -