46 lines
1.6 KiB
Go
46 lines
1.6 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: BUSL-1.1
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package vault
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import (
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"crypto/rand"
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"fmt"
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)
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// memzero is used to zero out a byte buffer. This specific format is optimized
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// by the compiler to use memclr to improve performance. See this code review:
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// https://codereview.appspot.com/137880043
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//
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// Use of memzero is not a guarantee against memory analysis as described in
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// the Vault threat model:
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// https://www.vaultproject.io/docs/internals/security.html . Vault does not
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// provide guarantees against memory analysis or raw memory dumping by
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// operators, however it does minimize this exposure by zeroing out buffers
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// that contain secrets as soon as they are no longer used. Starting with Go
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// 1.5, the garbage collector was changed to become a "generational copying
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// garbage collector." This change to the garbage collector makes it
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// impossible for Vault to guarantee a buffer with a secret has not been
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// copied during a garbage collection. It is therefore possible that secrets
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// may be exist in memory that have not been wiped despite a pending memzero
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// call. Over time any copied data with a secret will be reused and the
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// memory overwritten thereby mitigating some of the risk from this threat
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// vector.
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func memzero(b []byte) {
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if b == nil {
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return
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}
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for i := range b {
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b[i] = 0
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}
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}
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// randbytes is used to create a buffer of size n filled with random bytes
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func randbytes(n int) []byte {
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buf := make([]byte, n)
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if _, err := rand.Read(buf); err != nil {
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panic(fmt.Sprintf("failed to generate %d random bytes: %v", n, err))
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}
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return buf
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}
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