About
There is no description available for this level.
| Vulnerability Type |
Stack
|
| Position Independent Executable |
No
|
| Read only relocations |
No
|
| Non-Executable stack |
Yes
|
| Non-Executable heap |
Yes
|
| Address Space Layout Randomisation |
Yes
|
| Source Fortification |
No
|
Source code
1#include "../common/common.c"
2
3/*
4 * The aim of this level is to redirect code execution by overwriting an entry
5 * in the global offset table.
6 */
7
8void callme()
9{
10 printf("Hmmm, how did this happen?\n");
11 system("exec /bin/sh");
12}
13
14void echo(char *string)
15{
16 printf("You said, \"");
17 printf(string);
18 printf("\"\n");
19 fflush(stdout);
20}
21
22int main(int argc, char **argv, char **envp)
23{
24 int fd;
25 char *p;
26
27 background_process(NAME, UID, GID);
28 fd = serve_forever(PORT);
29 set_io(fd);
30
31 printf("Basic echo server. Type 'quit' to exit\n");
32
33 while(1) {
34 char input[1024];
35 memset(input, 0, sizeof(input));
36
37 fgets(input, sizeof(input)-1, stdin);
38 if(strlen(input) == 0 || strncmp(input, "quit", 4) == 0) {
39 exit(0);
40 }
41
42 if((p = strchr(input, '\r')) != NULL) *p = 0;
43 if((p = strchr(input, '\n')) != NULL) *p = 0;
44
45 echo(input);
46 }
47}
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