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Fix Size computation for allocation Integer overflow #4527

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Fix Size computation for allocation Integer overflow #4527

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6 changes: 5 additions & 1 deletion internal/pkg/danger/buf.go
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,11 @@ func (b *Buf) Reset() {
}

func (b *Buf) grow(n int) {
buf := make([]byte, len(b.buf), 2*cap(b.buf)+n)
newCap := 2*cap(b.buf) + n
if newCap < 0 {
panic("danger.Buf.grow: size computation overflow")
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This is an internal method that only has 2 calls in this file, one that already explicitly handles a negative count the same way bytes.Buffer does in Go itself https://cs.opensource.google/go/go/+/refs/tags/go1.24.0:src/bytes/buffer.go;l=164-170

fleet-server/internal/pkg/danger/buf.go

Lines 41 to 48 in ba68a24

func (b *Buf) Grow(n int) {
if n < 0 {
panic("danger.Buf.Grow: negative count")
}
if cap(b.buf)-len(b.buf) < n {
b.grow(n)
}
}

And another that uses an explicitly non-negative constant:

fleet-server/internal/pkg/danger/buf.go

Lines 66 to 74 in ba68a24

func (b *Buf) WriteRune(r rune) (int, error) {
if r < utf8.RuneSelf {
b.buf = append(b.buf, byte(r))
return 1, nil
}
l := len(b.buf)
if cap(b.buf)-l < utf8.UTFMax {
b.grow(utf8.UTFMax)
}

This change seems unnecessary.

}
buf := make([]byte, len(b.buf), newCap)
copy(buf, b.buf)
b.buf = buf
}
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