45 lines
801 B
C
45 lines
801 B
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <signal.h>
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#define FLAGSIZE_MAX 64
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char flag[FLAGSIZE_MAX];
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void sigsegv_handler(int sig) {
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printf("%s\n", flag);
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fflush(stdout);
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exit(1);
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}
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void vuln(char *input){
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char buf2[16];
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strcpy(buf2, input);
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}
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int main(int argc, char **argv){
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FILE *f = fopen("flag.txt","r");
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if (f == NULL) {
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printf("%s %s", "Please create 'flag.txt' in this directory with your",
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"own debugging flag.\n");
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exit(0);
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}
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fgets(flag,FLAGSIZE_MAX,f);
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signal(SIGSEGV, sigsegv_handler); // Set up signal handler
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gid_t gid = getegid();
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setresgid(gid, gid, gid);
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printf("Input: ");
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fflush(stdout);
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char buf1[100];
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gets(buf1);
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vuln(buf1);
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printf("The program will exit now\n");
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return 0;
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}
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