Add explanation of common usage

[p5sagit/p5-mst-13.2.git] / taint.c

/*
 * "...we will have peace, when you and all your works have perished--and
 * the works of your dark master to whom you would deliver us.  You are a
 * liar, Saruman, and a corrupter of men's hearts."  --Theoden
 */

#include "EXTERN.h"
#include "perl.h"

void
taint_not(s)
char *s;
{
    if (euid != uid)
        croak("No %s allowed while running setuid", s);
    if (egid != gid)
        croak("No %s allowed while running setgid", s);
}

void
taint_proper(f, s)
char *f;
char *s;
{
    if (tainting) {
	DEBUG_u(fprintf(stderr,"%s %d %d %d\n",s,tainted,uid, euid));
	if (tainted) {
	    char *ug = 0;
	    if (euid != uid)
		ug = " while running setuid";
	    else if (egid != gid)
		ug = " while running setgid";
	    else if (tainting)
		ug = " while running with -T switch";
	    if (ug) {
		if (!unsafe)
		    croak(f, s, ug);
		else if (dowarn)
		    warn(f, s, ug);
	    }
	}
    }
}

void
taint_env()
{
    SV** svp;

    if (tainting) {
	MAGIC *mg = 0;
	svp = hv_fetch(GvHVn(envgv),"PATH",4,FALSE);
	if (!svp || *svp == &sv_undef ||
	  ((mg = mg_find(*svp, 't')) && mg->mg_len & 1))
	{
	    tainted = TRUE;
	    if (mg && MgTAINTEDDIR(mg))
		taint_proper("Insecure directory in %s%s", "$ENV{PATH}");
	    else
		taint_proper("Insecure %s%s", "$ENV{PATH}");
	}
	svp = hv_fetch(GvHVn(envgv),"IFS",3,FALSE);
	if (svp && *svp != &sv_undef &&
	  (mg = mg_find(*svp, 't')) && mg->mg_len & 1)
	{
	    tainted = TRUE;
	    taint_proper("Insecure %s%s", "$ENV{IFS}");
	}
    }
}