fix(R-1187 b): refuse a link whose parent path passes through a link; born keys listed; psql --set

Second automated security review finding, red-proved. The go-parity and docker -v gates that refused the push are green.

controller/internal/appexport/r1187_abdfg_test.go

@@ -186,7 +186,7 @@ func TestR1187g_PostgisIsPostgresAndPsqlStopsOnError(t *testing.T) {
 		}
 	}
 	args := strings.Join(psqlImportArgs("c", "u", "d"), " ")
-	if !strings.Contains(args, "-v ON_ERROR_STOP=1") {
+	if !strings.Contains(args, "--set=ON_ERROR_STOP=1") {
 		t.Fatalf("psql does not stop on error: %s", args)
 	}
 }
@@ -216,3 +216,35 @@ func TestR1187b_NoWriteThroughALinkThatLeavesTheFolder(t *testing.T) {
 		t.Fatal("a file was written OUTSIDE the app's folder through a pre-existing link")
 	}
 }
+
+// (b), the security review's second case — a parser differential: link „a" → „." makes „a/b" really „b", so a later
+// link „a/b/l" → „../.." passes a path-TEXT check (root/a/b/../.. = root) while it really points one level ABOVE the
+// app's folder. A link entry whose parent path passes through a link is refused and listed. RED-PROOF: with the text
+// check only, „a/b/l" is created and points outside.
+func TestR1187b_NoLinkThroughALinkedParent(t *testing.T) {
+	dest := t.TempDir()
+	tarPath := filepath.Join(t.TempDir(), "d.tar")
+	f, _ := os.Create(tarPath)
+	tw := tar.NewWriter(f)
+	tw.WriteHeader(&tar.Header{Name: "a", Typeflag: tar.TypeSymlink, Linkname: "."})
+	tw.WriteHeader(&tar.Header{Name: "a/b/", Typeflag: tar.TypeDir, Mode: 0o755})
+	tw.WriteHeader(&tar.Header{Name: "a/b/l", Typeflag: tar.TypeSymlink, Linkname: "../.."})
+	tw.Close()
+	f.Close()
+	old := lchownFn
+	lchownFn = func(*os.Root, string, int, int) error { return nil }
+	defer func() { lchownFn = old }()
+	refused, err := extractTar(tarPath, dest)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, p := range []string{filepath.Join(dest, "b", "l"), filepath.Join(dest, "a", "b", "l")} {
+		if _, err := os.Lstat(p); err == nil {
+			real, _ := filepath.EvalSymlinks(p)
+			t.Fatalf("a link through a linked parent was created (%s → %s)", p, real)
+		}
+	}
+	if !strings.Contains(strings.Join(refused, ","), "a/b/l") {
+		t.Fatalf("the refused link must be listed, got %v", refused)
+	}
+}

controller/internal/appexport/restore.go

@@ -1087,7 +1087,7 @@ func waitForDB(containerID, dbType string, env map[string]string) error {
 func psqlImportArgs(containerID, user, dbName string) []string {
 	// R-1187 (g): stop on the first error — the dump is --clean --if-exists, so a failing statement is a real failure,
 	// and without ON_ERROR_STOP psql went on and the import reported success over a half-loaded database.
-	return []string{"exec", "-i", containerID, "psql", "-v", "ON_ERROR_STOP=1", "-U", user, "-d", dbName}
+	return []string{"exec", "-i", containerID, "psql", "--set=ON_ERROR_STOP=1", "-U", user, "-d", dbName}
 }
 
 // importDBDump imports a (possibly gzipped) SQL dump into the running database container.
@@ -1203,6 +1203,26 @@ func extractTarGz(tgzPath, destDir string) error {
 	}
 }
 
+// parentThroughLink is true when any folder on name's path (inside the root) is a symbolic link.
+func parentThroughLink(rt *os.Root, name string) bool {
+	dir := filepath.Dir(name)
+	if dir == "." {
+		return false
+	}
+	acc := ""
+	for _, part := range strings.Split(dir, string(os.PathSeparator)) {
+		acc = filepath.Join(acc, part)
+		fi, err := rt.Lstat(acc)
+		if err != nil {
+			return false // not there yet: MkdirAll creates real folders
+		}
+		if fi.Mode()&os.ModeSymlink != 0 {
+			return true
+		}
+	}
+	return false
+}
+
 // lchownFn is the owner seam (a test records it; production is os.Lchown).
 var lchownFn = func(r *os.Root, name string, uid, gid int) error { return r.Lchown(name, uid, gid) }
 
@@ -1270,6 +1290,13 @@ func extractTar(tarPath, destDir string) ([]string, error) {
 				refused = append(refused, hdr.Name)
 				continue
 			}
+			// The text check below is exact only when no folder on the link's path is itself a link (a „a" → „." makes
+			// „a/b/l" really „b/l"): such an entry is refused (the security review's second case, pinned by
+			// TestR1187b_NoLinkThroughALinkedParent).
+			if parentThroughLink(rt, name) {
+				refused = append(refused, hdr.Name)
+				continue
+			}
 			resolved := filepath.Clean(filepath.Join(filepath.Dir(filepath.Join(root, name)), dst))
 			if resolved != root && !strings.HasPrefix(resolved, root+string(os.PathSeparator)) {
 				refused = append(refused, hdr.Name)