time: bound file reads and validate LoadLocation argument

Fixes #18985

Change-Id: I956117f47d1d2b453b4786c7b78c1c944defeca0
Reviewed-on: https://go-review.googlesource.com/36551
Reviewed-by: Ian Lance Taylor <iant@golang.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/time/time_test.go b/src/time/time_test.go
index 2922560f09..90e2abf03e 100644
--- a/src/time/time_test.go
+++ b/src/time/time_test.go
@@ -11,7 +11,9 @@ import (
 	"fmt"
 	"math/big"
 	"math/rand"
+	"os"
 	"runtime"
+	"strings"
 	"testing"
 	"testing/quick"
 	. "time"
@@ -1254,3 +1256,14 @@ func TestZeroMonthString(t *testing.T) {
 		t.Errorf("zero month = %q; want %q", got, want)
 	}
 }
+
+func TestReadFileLimit(t *testing.T) {
+	const zero = "/dev/zero"
+	if _, err := os.Stat(zero); err != nil {
+		t.Skip("skipping test without a /dev/zero")
+	}
+	_, err := ReadFile(zero)
+	if err == nil || !strings.Contains(err.Error(), "is too large") {
+		t.Errorf("readFile(%q) error = %v; want error containing 'is too large'", zero, err)
+	}
+}