protect/protect.go

73 lines
1.8 KiB
Go

/*
Package protect is a wrapper for OpenBSD's pledge(2) and unveil(2) system
calls.
This library is trivial, but I found myself writing it often enough that I
figure it should be a package.
*/
package protect
import (
"regexp"
"strings"
)
// Unveil is a wrapper for OpenBSD's unveil(2). unveil can be used to limit
// a processes view of the filesystem.
//
// The first call to Unveil removes a processes visibility to everything
// except 'path'. Any subsequent calls expand the view to contain those
// paths. Finally a call to UnveilBlock will lock the view in place.
// Preventing access to anything else.
//
// On non-OpenBSD machines this call is a noop.
func Unveil(path string, flags string) error {
return unveil(path, flags)
}
// UnveilBlock locks the Unveil'd paths. Preventing further changes to a
// processes filesystem view.
//
// On non-OpenBSD machines this call is a noop.
func UnveilBlock() error {
return unveilBlock()
}
// Pledge wraps OpenBSD's pledge(2) system call. One can use this to limit
// the system calls a process can make.
//
// On non-OpenBSD machines this call is a noop.
func Pledge(promises string) error {
return pledge(promises)
}
// ReducePledges takes the current list of plpedges and a list of pledges that
// should be removed. The new list is returned and Pledge() will be called
// with the reduced set of pledges.
func ReducePledges(current, toRemove string) (string, error) {
newPledges, err := reduce(current, toRemove)
if err != nil {
return "", err
}
return newPledges, pledge(newPledges)
}
func reduce(a, b string) (string, error) {
var newList []string
currentList := strings.Split(a, " ")
for _, s := range currentList {
match, err := regexp.MatchString(s, b)
if err != nil {
return "", err
}
if !match {
newList = append(newList, s)
}
}
return strings.Join(newList, " "), nil
}