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/*
** This program checks to see if your version of seteuid works.
** Compile it, make it setuid root, and run it as yourself (NOT as
** root). If it won't compile or outputs any MAYDAY messages, don't
** define USESETEUID in conf.h.
**
** NOTE: It is not sufficient to have seteuid in your library.
** You must also have saved uids that function properly.
**
** Compilation is trivial -- just "cc t_seteuid.c". Make it setuid,
** root and then execute it as a non-root user.
*/
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#ifdef __hpux
#define seteuid(e) setresuid(-1, e, -1)
#endif
main()
{
int fail = 0;
uid_t realuid = getuid();
printuids("initial uids", realuid, 0);
if (geteuid() != 0)
{
printf("SETUP ERROR: re-run setuid root\n");
exit(1);
}
if (getuid() == 0)
{
printf("SETUP ERROR: must be run by a non-root user\n");
exit(1);
}
if (seteuid(1) < 0)
printf("seteuid(1) failure\n");
printuids("after seteuid(1)", realuid, 1);
if (geteuid() != 1)
{
fail++;
printf("MAYDAY! Wrong effective uid\n");
}
/* do activity here */
if (seteuid(0) < 0)
{
fail++;
printf("seteuid(0) failure\n");
}
printuids("after seteuid(0)", realuid, 0);
if (geteuid() != 0)
{
fail++;
printf("MAYDAY! Wrong effective uid\n");
}
if (getuid() != realuid)
{
fail++;
printf("MAYDAY! Wrong real uid\n");
}
printf("\n");
if (seteuid(2) < 0)
{
fail++;
printf("seteuid(2) failure\n");
}
printuids("after seteuid(2)", realuid, 2);
if (geteuid() != 2)
{
fail++;
printf("MAYDAY! Wrong effective uid\n");
}
/* do activity here */
if (seteuid(0) < 0)
{
fail++;
printf("seteuid(0) failure\n");
}
printuids("after seteuid(0)", realuid, 0);
if (geteuid() != 0)
{
fail++;
printf("MAYDAY! Wrong effective uid\n");
}
if (getuid() != realuid)
{
fail++;
printf("MAYDAY! Wrong real uid\n");
}
if (fail)
{
printf("\nThis system cannot use seteuid\n");
exit(1);
}
printf("\nIt is safe to define USESETEUID on this system\n");
exit(0);
}
printuids(str, r, e)
char *str;
int r, e;
{
printf("%s (should be %d/%d): r/euid=%d/%d\n", str, r, e,
getuid(), geteuid());
}
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