93 lines
1.9 KiB
Go
93 lines
1.9 KiB
Go
package hmac
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import (
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"crypto/sha1"
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"crypto/sha256"
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"hash"
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"sync"
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)
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// setZeroes sets all bytes from b to zeroes.
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//
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// See https://github.com/golang/go/issues/5373
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func setZeroes(b []byte) {
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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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func (h *hmac) resetTo(key []byte) {
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h.outer.Reset()
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h.inner.Reset()
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setZeroes(h.ipad)
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setZeroes(h.opad)
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if len(key) > h.blocksize {
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// If key is too big, hash it.
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h.outer.Write(key)
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key = h.outer.Sum(nil)
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}
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copy(h.ipad, key)
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copy(h.opad, key)
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for i := range h.ipad {
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h.ipad[i] ^= 0x36
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}
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for i := range h.opad {
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h.opad[i] ^= 0x5c
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}
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h.inner.Write(h.ipad)
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}
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var hmacSHA1Pool = &sync.Pool{
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New: func() interface{} {
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h := New(sha1.New, make([]byte, sha1.BlockSize))
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return h
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},
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}
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// AcquireSHA1 returns new HMAC from pool.
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func AcquireSHA1(key []byte) hash.Hash {
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h := hmacSHA1Pool.Get().(*hmac)
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assertHMACSize(h, sha1.Size, sha1.BlockSize)
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h.resetTo(key)
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return h
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}
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// PutSHA1 puts h to pool.
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func PutSHA1(h hash.Hash) {
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hm := h.(*hmac)
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assertHMACSize(hm, sha1.Size, sha1.BlockSize)
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hmacSHA1Pool.Put(hm)
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}
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var hmacSHA256Pool = &sync.Pool{
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New: func() interface{} {
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h := New(sha256.New, make([]byte, sha256.BlockSize))
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return h
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},
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}
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// AcquireSHA256 returns new HMAC from SHA256 pool.
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func AcquireSHA256(key []byte) hash.Hash {
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h := hmacSHA256Pool.Get().(*hmac)
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assertHMACSize(h, sha256.Size, sha256.BlockSize)
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h.resetTo(key)
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return h
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}
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// PutSHA256 puts h to SHA256 pool.
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func PutSHA256(h hash.Hash) {
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hm := h.(*hmac)
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assertHMACSize(hm, sha256.Size, sha256.BlockSize)
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hmacSHA256Pool.Put(hm)
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}
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// assertHMACSize panics if h.size != size or h.blocksize != blocksize.
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//
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// Put and Acquire functions are internal functions to project, so
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// checking it via such assert is optimal.
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func assertHMACSize(h *hmac, size, blocksize int) {
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if h.size != size || h.blocksize != blocksize {
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panic("BUG: hmac size invalid") // nolint
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}
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}
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