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38e7177c94
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
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"strings"
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)
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type T struct{}
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const maxInt = int(^uint(0) >> 1)
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func main() {
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s := make([]T, maxInt)
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shouldPanic("cap out of range", func() { s = append(s, T{}) })
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var oneElem = make([]T, 1)
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shouldPanic("cap out of range", func() { s = append(s, oneElem...) })
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}
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func shouldPanic(str string, f func()) {
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defer func() {
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err := recover()
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if err == nil {
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panic("did not panic")
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}
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s := err.(error).Error()
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if !strings.Contains(s, str) {
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panic("got panic " + s + ", want " + str)
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}
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}()
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f()
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}
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