jochen
fc6c5a92e6
Two holes the review proved. The ask's subject proved nothing — a responder can reach it through a reply — so the engine now verifies the mesh's signature over a fixed context with the key it verifies declarations with, before reading anything, and refuses an ask for another node, expired, good too long, without a nonce, or replayed. And the apply followed a link the hand-over had refused: a component swapped for a link after the record carried root's chmod and chown to its target. A handed-over directory must now still resolve to itself, and is changed only through one descriptor opened from / with no link followed (fchmod, fchown). Tests for the reply guard, the run loop's hook, the fallback renewal on proof and a non-regular fallback; 27 checks each removed in turn, each failing a test.
67 lines
1.9 KiB
Go
67 lines
1.9 KiB
Go
//go:build !linux
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package apply
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// Where there is no openat with O_NOFOLLOW to rely on, the check before use is all: a link below a home is
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// refused, and the call is made by path. The node-engine runs on Linux; this keeps the package building.
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import (
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"os"
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"path/filepath"
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)
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func chmodUnder(home, path string, mode os.FileMode) error {
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if err := refuseLinksUnderHome(path); err != nil {
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return err
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}
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return os.Chmod(path, mode)
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}
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func chmodUnderAs(home, path string, mode os.FileMode, _ int) error {
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return chmodUnder(home, path, mode)
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}
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const kindDir = 1
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func chownUnder(home, path string, uid, gid int) error {
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if err := refuseLinksUnderHome(path); err != nil {
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return err
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}
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return os.Lchown(path, uid, gid)
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}
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func readUnder(home, path string) ([]byte, error) {
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if err := refuseLinksUnderHome(path); err != nil {
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return nil, err
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}
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return os.ReadFile(path)
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}
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func mkdirAllUnder(home, dir string, mode os.FileMode) ([]string, error) {
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if err := refuseLinksUnderHome(dir); err != nil {
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return nil, err
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}
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var made []string
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for d := filepath.Clean(dir); d != home; d = filepath.Dir(d) {
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if _, err := os.Lstat(d); err == nil {
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break
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}
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made = append(made, d)
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}
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return made, os.MkdirAll(dir, mode)
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}
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func writeUnder(home, path string, content []byte, mode os.FileMode) error {
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if err := refuseLinksUnderHome(path); err != nil {
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return err
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}
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return writeAtomicallyByPath(path, content, mode)
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}
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// giveHandedOver is refused where there is no openat with O_NOFOLLOW: a handed-over directory is never changed by
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// path (novox/hq issue 356). The node-engine runs on Linux.
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func giveHandedOver(path string, _ os.FileMode, _, _ int, _ bool) (os.FileMode, int, int, error) {
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return 0, 0, 0, &PlacementRefusedError{Path: path, Why: "a handed-over directory is changed only through a " +
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"descriptor that followed no link, which this system cannot open"}
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}
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