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MAGIC - fix bug

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This commit is contained in:
Emman 2021-04-01 09:30:49 +08:00
parent 513b786694
commit cab0150f3c
1 changed files with 12 additions and 4 deletions
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16
cipher/ccm.go
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@ -131,26 +131,34 @@ func (c *ccm) auth(nonce, plaintext, additionalData []byte, tagMask *[ccmBlockSi
out[0] |= byte(14 - c.nonceSize) // L'
binary.BigEndian.PutUint64(out[ccmBlockSize-8:], uint64(len(plaintext)))
copy(out[1:], nonce)
// B0
c.cipher.Encrypt(out[:], out[:])
var block [ccmBlockSize]byte
if n := uint64(len(additionalData)); n > 0 {
// First adata block includes adata length
i := 2
if n <= 0xfeff {
if n <= 0xfeff { // l(a) < (2^16 - 2^8)
binary.BigEndian.PutUint16(block[:i], uint16(n))
} else {
block[0] = 0xfe
block[1] = 0xff
block[0] = 0xff
// If (2^16 - 2^8) <= l(a) < 2^32, then the length field is encoded as
// six octets consisting of the octets 0xff, 0xfe, and four octets
// encoding l(a) in most-significant-byte-first order.
if n < uint64(1<<32) {
block[1] = 0xfe
i = 2 + 4
binary.BigEndian.PutUint32(block[2:i], uint32(n))
} else {
block[1] = 0xff
// If 2^32 <= l(a) < 2^64, then the length field is encoded as ten
// octets consisting of the octets 0xff, 0xff, and eight octets encoding
// l(a) in most-significant-byte-first order.
i = 2 + 8
binary.BigEndian.PutUint64(block[2:i], uint64(n))
}
}
i = copy(block[i:], additionalData)
i = copy(block[i:], additionalData) // first block start with additional data length
c.cmac(out[:], block[:])
c.cmac(out[:], additionalData[i:])
}