khenaidoo | 106c61a | 2021-08-11 18:05:46 -0400 | [diff] [blame] | 1 | package sarama |
| 2 | |
| 3 | import ( |
| 4 | "crypto/hmac" |
| 5 | "crypto/sha256" |
| 6 | "crypto/sha512" |
| 7 | "hash" |
| 8 | ) |
| 9 | |
| 10 | // ScramFormatter implementation |
| 11 | // @see: https://github.com/apache/kafka/blob/99b9b3e84f4e98c3f07714e1de6a139a004cbc5b/clients/src/main/java/org/apache/kafka/common/security/scram/internals/ScramFormatter.java#L93 |
| 12 | type scramFormatter struct { |
| 13 | mechanism ScramMechanismType |
| 14 | } |
| 15 | |
| 16 | func (s scramFormatter) mac(key []byte) (hash.Hash, error) { |
| 17 | var m hash.Hash |
| 18 | |
| 19 | switch s.mechanism { |
| 20 | case SCRAM_MECHANISM_SHA_256: |
| 21 | m = hmac.New(sha256.New, key) |
| 22 | |
| 23 | case SCRAM_MECHANISM_SHA_512: |
| 24 | m = hmac.New(sha512.New, key) |
| 25 | default: |
| 26 | return nil, ErrUnknownScramMechanism |
| 27 | } |
| 28 | |
| 29 | return m, nil |
| 30 | } |
| 31 | |
| 32 | func (s scramFormatter) hmac(key []byte, extra []byte) ([]byte, error) { |
| 33 | mac, err := s.mac(key) |
| 34 | if err != nil { |
| 35 | return nil, err |
| 36 | } |
| 37 | |
| 38 | if _, err := mac.Write(extra); err != nil { |
| 39 | return nil, err |
| 40 | } |
| 41 | return mac.Sum(nil), nil |
| 42 | } |
| 43 | |
| 44 | func (s scramFormatter) xor(result []byte, second []byte) { |
| 45 | for i := 0; i < len(result); i++ { |
| 46 | result[i] = result[i] ^ second[i] |
| 47 | } |
| 48 | } |
| 49 | |
| 50 | func (s scramFormatter) saltedPassword(password []byte, salt []byte, iterations int) ([]byte, error) { |
| 51 | mac, err := s.mac(password) |
| 52 | if err != nil { |
| 53 | return nil, err |
| 54 | } |
| 55 | |
| 56 | if _, err := mac.Write(salt); err != nil { |
| 57 | return nil, err |
| 58 | } |
| 59 | if _, err := mac.Write([]byte{0, 0, 0, 1}); err != nil { |
| 60 | return nil, err |
| 61 | } |
| 62 | |
| 63 | u1 := mac.Sum(nil) |
| 64 | prev := u1 |
| 65 | result := u1 |
| 66 | |
| 67 | for i := 2; i <= iterations; i++ { |
| 68 | ui, err := s.hmac(password, prev) |
| 69 | if err != nil { |
| 70 | return nil, err |
| 71 | } |
| 72 | |
| 73 | s.xor(result, ui) |
| 74 | prev = ui |
| 75 | } |
| 76 | |
| 77 | return result, nil |
| 78 | } |