mirror of
https://github.com/golang/go
synced 2024-09-04 23:44:16 +00:00
![Martin Möhrmann](/assets/img/avatar_default.png)
Instead of testing len(slice)+numNewElements > cap(slice) use uint(len(slice)+numNewElements) > uint(cap(slice)) to test if a slice needs to be grown in an append operation. This prevents a possible overflow when len(slice) is near the maximum int value and the addition of a constant number of new elements makes it overflow and wrap around to a negative number which is smaller than the capacity of the slice. Appending a slice to a slice with append(s1, s2...) already used a uint comparison to test slice capacity and therefore was not vulnerable to the same overflow issue. Fixes: #29190 Change-Id: I41733895838b4f80a44f827bf900ce931d8be5ca Reviewed-on: https://go-review.googlesource.com/c/154037 Run-TryBot: Martin Möhrmann <moehrmann@google.com> Reviewed-by: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
38 lines
707 B
Go
38 lines
707 B
Go
// run
|
|
|
|
// Copyright 2018 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package main
|
|
|
|
import (
|
|
"strings"
|
|
)
|
|
|
|
type T struct{}
|
|
|
|
const maxInt = int(^uint(0) >> 1)
|
|
|
|
func main() {
|
|
s := make([]T, maxInt)
|
|
shouldPanic("cap out of range", func() { s = append(s, T{}) })
|
|
var oneElem = make([]T, 1)
|
|
shouldPanic("cap out of range", func() { s = append(s, oneElem...) })
|
|
}
|
|
|
|
func shouldPanic(str string, f func()) {
|
|
defer func() {
|
|
err := recover()
|
|
if err == nil {
|
|
panic("did not panic")
|
|
}
|
|
s := err.(error).Error()
|
|
if !strings.Contains(s, str) {
|
|
panic("got panic " + s + ", want " + str)
|
|
}
|
|
}()
|
|
|
|
f()
|
|
}
|