| 1 | // SPDX-License-Identifier: AGPL-3.0-or-later |
| 2 | |
| 3 | // Package scrub masks configured secret values from runner log output. |
| 4 | package scrub |
| 5 | |
| 6 | import ( |
| 7 | "sort" |
| 8 | "strings" |
| 9 | ) |
| 10 | |
| 11 | const Mask = "***" |
| 12 | |
| 13 | type Scrubber struct { |
| 14 | values []string |
| 15 | replacer *strings.Replacer |
| 16 | tail string |
| 17 | replacements uint64 |
| 18 | } |
| 19 | |
| 20 | func New(values []string) *Scrubber { |
| 21 | values = normalize(values) |
| 22 | if len(values) == 0 { |
| 23 | return &Scrubber{} |
| 24 | } |
| 25 | pairs := make([]string, 0, len(values)*2) |
| 26 | for _, v := range values { |
| 27 | pairs = append(pairs, v, Mask) |
| 28 | } |
| 29 | return &Scrubber{values: values, replacer: strings.NewReplacer(pairs...)} |
| 30 | } |
| 31 | |
| 32 | func (s *Scrubber) Scrub(chunk []byte) []byte { |
| 33 | if s == nil || s.replacer == nil { |
| 34 | return append([]byte(nil), chunk...) |
| 35 | } |
| 36 | combined := s.tail + string(chunk) |
| 37 | keep := s.pendingSuffixLen(combined) |
| 38 | if keep == len(combined) { |
| 39 | s.tail = combined |
| 40 | return nil |
| 41 | } |
| 42 | emit := combined[:len(combined)-keep] |
| 43 | s.tail = combined[len(combined)-keep:] |
| 44 | s.replacements += countReplacements(emit, s.values) |
| 45 | return []byte(s.replacer.Replace(emit)) |
| 46 | } |
| 47 | |
| 48 | func (s *Scrubber) Flush() []byte { |
| 49 | if s == nil || s.tail == "" { |
| 50 | return nil |
| 51 | } |
| 52 | tail := s.tail |
| 53 | s.tail = "" |
| 54 | if s.replacer == nil { |
| 55 | return []byte(tail) |
| 56 | } |
| 57 | s.replacements += countReplacements(tail, s.values) |
| 58 | return []byte(s.replacer.Replace(tail)) |
| 59 | } |
| 60 | |
| 61 | func (s *Scrubber) Replacements() uint64 { |
| 62 | if s == nil { |
| 63 | return 0 |
| 64 | } |
| 65 | return s.replacements |
| 66 | } |
| 67 | |
| 68 | func normalize(values []string) []string { |
| 69 | seen := map[string]struct{}{} |
| 70 | out := make([]string, 0, len(values)) |
| 71 | for _, v := range values { |
| 72 | if v == "" { |
| 73 | continue |
| 74 | } |
| 75 | if _, ok := seen[v]; ok { |
| 76 | continue |
| 77 | } |
| 78 | seen[v] = struct{}{} |
| 79 | out = append(out, v) |
| 80 | } |
| 81 | sort.Slice(out, func(i, j int) bool { |
| 82 | return len(out[i]) > len(out[j]) |
| 83 | }) |
| 84 | return out |
| 85 | } |
| 86 | |
| 87 | func countReplacements(input string, values []string) uint64 { |
| 88 | var count uint64 |
| 89 | rest := input |
| 90 | for rest != "" { |
| 91 | bestAt := -1 |
| 92 | best := "" |
| 93 | for _, value := range values { |
| 94 | at := strings.Index(rest, value) |
| 95 | if at < 0 { |
| 96 | continue |
| 97 | } |
| 98 | if bestAt == -1 || at < bestAt || (at == bestAt && len(value) > len(best)) { |
| 99 | bestAt = at |
| 100 | best = value |
| 101 | } |
| 102 | } |
| 103 | if bestAt == -1 { |
| 104 | return count |
| 105 | } |
| 106 | count++ |
| 107 | rest = rest[bestAt+len(best):] |
| 108 | } |
| 109 | return count |
| 110 | } |
| 111 | |
| 112 | func (s *Scrubber) pendingSuffixLen(combined string) int { |
| 113 | keep := 0 |
| 114 | for _, secret := range s.values { |
| 115 | max := len(secret) - 1 |
| 116 | if max > len(combined) { |
| 117 | max = len(combined) |
| 118 | } |
| 119 | for n := max; n > keep; n-- { |
| 120 | if strings.HasSuffix(combined, secret[:n]) { |
| 121 | keep = n |
| 122 | break |
| 123 | } |
| 124 | } |
| 125 | } |
| 126 | return keep |
| 127 | } |
| 128 |