mirror of https://github.com/portainer/portainer
62 lines
1.5 KiB
Go
62 lines
1.5 KiB
Go
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package crypto
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import (
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"crypto/rand"
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"errors"
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"io"
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)
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type Nonce struct {
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val []byte
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}
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func NewNonce(size int) *Nonce {
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return &Nonce{val: make([]byte, size)}
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}
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// NewRandomNonce generates a new initial nonce with the lower byte set to a random value
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// This ensures there are plenty of nonce values availble before rolling over
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// Based on ideas from the Secure Programming Cookbook for C and C++ by John Viega, Matt Messier
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// https://www.oreilly.com/library/view/secure-programming-cookbook/0596003943/ch04s09.html
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func NewRandomNonce(size int) (*Nonce, error) {
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randomBytes := 1
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if size <= randomBytes {
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return nil, errors.New("nonce size must be greater than the number of random bytes")
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}
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randomPart := make([]byte, randomBytes)
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if _, err := rand.Read(randomPart); err != nil {
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return nil, err
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}
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zeroPart := make([]byte, size-randomBytes)
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nonceVal := append(randomPart, zeroPart...)
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return &Nonce{val: nonceVal}, nil
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}
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func (n *Nonce) Read(stream io.Reader) error {
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_, err := io.ReadFull(stream, n.val)
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return err
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}
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func (n *Nonce) Value() []byte {
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return n.val
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}
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func (n *Nonce) Increment() error {
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// Start incrementing from the least significant byte
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for i := len(n.val) - 1; i >= 0; i-- {
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// Increment the current byte
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n.val[i]++
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// Check for overflow
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if n.val[i] != 0 {
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// No overflow, nonce is successfully incremented
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return nil
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}
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}
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// If we reach here, it means the nonce has overflowed
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return errors.New("nonce overflow")
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}
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