|
| 1 | +package malleable |
| 2 | + |
| 3 | +import ( |
| 4 | + "fmt" |
| 5 | + "sort" |
| 6 | + |
| 7 | + "github.com/0xsequence/ethkit/go-ethereum/crypto" |
| 8 | + v3 "github.com/0xsequence/go-sequence/core/v3" |
| 9 | +) |
| 10 | + |
| 11 | +// maxUint16 defines the maximum allowed value for size validation of sections using uint16 wire format. |
| 12 | +const ( |
| 13 | + maxUint16 = 0xFFFF |
| 14 | +) |
| 15 | + |
| 16 | +type BuilderOptions struct { |
| 17 | + ValidateRepeats bool |
| 18 | + MergeAdjacentStatic bool |
| 19 | + MaxOffset uint32 |
| 20 | + MaxSize uint32 |
| 21 | +} |
| 22 | + |
| 23 | +type Builder struct { |
| 24 | + payload *v3.CallsPayload |
| 25 | + options BuilderOptions |
| 26 | + malleable []Selector |
| 27 | + repeats []repeatSelector |
| 28 | +} |
| 29 | + |
| 30 | +type repeatSelector struct { |
| 31 | + a Selector |
| 32 | + b Selector |
| 33 | +} |
| 34 | + |
| 35 | +type Plan struct { |
| 36 | + Static []StaticSection |
| 37 | + Repeat []RepeatSection |
| 38 | +} |
| 39 | + |
| 40 | +func (p *Plan) DebugString() string { |
| 41 | + out := "static:" |
| 42 | + for _, s := range p.Static { |
| 43 | + out += fmt.Sprintf(" [t=%d c=%d s=%d]", s.TIndex, s.CIndex, s.Size) |
| 44 | + } |
| 45 | + out += " repeat:" |
| 46 | + for _, r := range p.Repeat { |
| 47 | + out += fmt.Sprintf(" [t=%d c=%d s=%d t2=%d c2=%d]", r.TIndex, r.CIndex, r.Size, r.TIndex2, r.CIndex2) |
| 48 | + } |
| 49 | + return out |
| 50 | +} |
| 51 | + |
| 52 | +func NewBuilder(payload *v3.CallsPayload, opts *BuilderOptions) *Builder { |
| 53 | + options := BuilderOptions{ |
| 54 | + MaxOffset: 0xFFFF, |
| 55 | + MaxSize: 0xFFFF, |
| 56 | + ValidateRepeats: false, |
| 57 | + MergeAdjacentStatic: true, |
| 58 | + } |
| 59 | + if opts != nil { |
| 60 | + if opts.MaxOffset != 0 { |
| 61 | + options.MaxOffset = opts.MaxOffset |
| 62 | + } |
| 63 | + if opts.MaxSize != 0 { |
| 64 | + options.MaxSize = opts.MaxSize |
| 65 | + } |
| 66 | + options.ValidateRepeats = opts.ValidateRepeats |
| 67 | + options.MergeAdjacentStatic = opts.MergeAdjacentStatic |
| 68 | + } |
| 69 | + |
| 70 | + return &Builder{ |
| 71 | + payload: payload, |
| 72 | + options: options, |
| 73 | + } |
| 74 | +} |
| 75 | + |
| 76 | +func (b *Builder) Malleable(sel Selector) *Builder { |
| 77 | + b.malleable = append(b.malleable, sel) |
| 78 | + return b |
| 79 | +} |
| 80 | + |
| 81 | +func (b *Builder) Repeat(a Selector, b2 Selector) *Builder { |
| 82 | + b.repeats = append(b.repeats, repeatSelector{a: a, b: b2}) |
| 83 | + return b |
| 84 | +} |
| 85 | + |
| 86 | +func (b *Builder) Build() ([]byte, *Plan, error) { |
| 87 | + if b.payload == nil { |
| 88 | + return nil, nil, fmt.Errorf("payload is nil") |
| 89 | + } |
| 90 | + if len(b.payload.Calls) > 128 { |
| 91 | + return nil, nil, fmt.Errorf("too many calls (%d): tindex is 7-bit", len(b.payload.Calls)) |
| 92 | + } |
| 93 | + |
| 94 | + exByCall := make([][]Span, len(b.payload.Calls)) |
| 95 | + |
| 96 | + addExclude := func(r ByteRange) error { |
| 97 | + if r.CallIndex < 0 || r.CallIndex >= len(b.payload.Calls) { |
| 98 | + return fmt.Errorf("tindex out of range: %d", r.CallIndex) |
| 99 | + } |
| 100 | + dataLen := len(b.payload.Calls[r.CallIndex].Data) |
| 101 | + if r.Offset < 0 || r.Size < 0 { |
| 102 | + return fmt.Errorf("span offset/size negative") |
| 103 | + } |
| 104 | + if r.Size > dataLen || r.Offset > dataLen-r.Size { |
| 105 | + return fmt.Errorf("span out of bounds: offset=%d size=%d > %d", r.Offset, r.Size, dataLen) |
| 106 | + } |
| 107 | + exByCall[r.CallIndex] = append(exByCall[r.CallIndex], Span{Start: r.Offset, Len: r.Size}) |
| 108 | + return nil |
| 109 | + } |
| 110 | + |
| 111 | + for _, sel := range b.malleable { |
| 112 | + ranges, err := sel.Resolve(b.payload) |
| 113 | + if err != nil { |
| 114 | + return nil, nil, fmt.Errorf("malleable %s: %w", sel.String(), err) |
| 115 | + } |
| 116 | + for _, r := range ranges { |
| 117 | + if err := addExclude(r); err != nil { |
| 118 | + return nil, nil, fmt.Errorf("malleable %s: %w", sel.String(), err) |
| 119 | + } |
| 120 | + } |
| 121 | + } |
| 122 | + |
| 123 | + var repeats []RepeatSection |
| 124 | + for _, rp := range b.repeats { |
| 125 | + rangesA, err := rp.a.Resolve(b.payload) |
| 126 | + if err != nil { |
| 127 | + return nil, nil, fmt.Errorf("repeat a %s: %w", rp.a.String(), err) |
| 128 | + } |
| 129 | + rangesB, err := rp.b.Resolve(b.payload) |
| 130 | + if err != nil { |
| 131 | + return nil, nil, fmt.Errorf("repeat b %s: %w", rp.b.String(), err) |
| 132 | + } |
| 133 | + if len(rangesA) != 1 || len(rangesB) != 1 { |
| 134 | + return nil, nil, fmt.Errorf("repeat expects single range per selector") |
| 135 | + } |
| 136 | + a := rangesA[0] |
| 137 | + bb := rangesB[0] |
| 138 | + if a.Size != bb.Size { |
| 139 | + return nil, nil, fmt.Errorf("repeat size mismatch: %d vs %d", a.Size, bb.Size) |
| 140 | + } |
| 141 | + if err := addExclude(a); err != nil { |
| 142 | + return nil, nil, fmt.Errorf("repeat a: %w", err) |
| 143 | + } |
| 144 | + if err := addExclude(bb); err != nil { |
| 145 | + return nil, nil, fmt.Errorf("repeat b: %w", err) |
| 146 | + } |
| 147 | + if b.options.ValidateRepeats { |
| 148 | + sectionA, err := a.Slice(b.payload) |
| 149 | + if err != nil { |
| 150 | + return nil, nil, err |
| 151 | + } |
| 152 | + sectionB, err := bb.Slice(b.payload) |
| 153 | + if err != nil { |
| 154 | + return nil, nil, err |
| 155 | + } |
| 156 | + if crypto.Keccak256Hash(sectionA) != crypto.Keccak256Hash(sectionB) { |
| 157 | + return nil, nil, fmt.Errorf("repeat section mismatch") |
| 158 | + } |
| 159 | + } |
| 160 | + if a.Offset > maxUint16 || bb.Offset > maxUint16 { |
| 161 | + return nil, nil, fmt.Errorf("repeat offset exceeds uint16 range (max %d): a.Offset=%d b.Offset=%d", maxUint16, a.Offset, bb.Offset) |
| 162 | + } |
| 163 | + if a.Size > maxUint16 { |
| 164 | + return nil, nil, fmt.Errorf("repeat size exceeds uint16 range (max %d): a.Size=%d", maxUint16, a.Size) |
| 165 | + } |
| 166 | + repeats = append(repeats, RepeatSection{ |
| 167 | + TIndex: uint8(a.CallIndex), |
| 168 | + CIndex: uint16(a.Offset), |
| 169 | + Size: uint16(a.Size), |
| 170 | + TIndex2: uint8(bb.CallIndex), |
| 171 | + CIndex2: uint16(bb.Offset), |
| 172 | + }) |
| 173 | + } |
| 174 | + |
| 175 | + var statics []SpanWithCall |
| 176 | + for t := range b.payload.Calls { |
| 177 | + length := len(b.payload.Calls[t].Data) |
| 178 | + ex := mergeSpans(exByCall[t]) |
| 179 | + cursor := 0 |
| 180 | + for _, s := range ex { |
| 181 | + if cursor < s.Start { |
| 182 | + statics = append(statics, SpanWithCall{CallIndex: t, Span: Span{Start: cursor, Len: s.Start - cursor}}) |
| 183 | + } |
| 184 | + cursor = max(cursor, s.Start+s.Len) |
| 185 | + } |
| 186 | + if cursor < length { |
| 187 | + statics = append(statics, SpanWithCall{CallIndex: t, Span: Span{Start: cursor, Len: length - cursor}}) |
| 188 | + } |
| 189 | + } |
| 190 | + |
| 191 | + sort.Slice(statics, func(i, j int) bool { |
| 192 | + if statics[i].CallIndex != statics[j].CallIndex { |
| 193 | + return statics[i].CallIndex < statics[j].CallIndex |
| 194 | + } |
| 195 | + return statics[i].Start < statics[j].Start |
| 196 | + }) |
| 197 | + |
| 198 | + if b.options.MergeAdjacentStatic { |
| 199 | + statics = mergeAdjacentStatics(statics) |
| 200 | + } |
| 201 | + |
| 202 | + staticSections, err := b.encodeStaticSections(statics) |
| 203 | + if err != nil { |
| 204 | + return nil, nil, err |
| 205 | + } |
| 206 | + |
| 207 | + signature, err := EncodeSignature(staticSections, repeats) |
| 208 | + if err != nil { |
| 209 | + return nil, nil, err |
| 210 | + } |
| 211 | + |
| 212 | + return signature, &Plan{Static: staticSections, Repeat: repeats}, nil |
| 213 | +} |
| 214 | + |
| 215 | +type SpanWithCall struct { |
| 216 | + CallIndex int |
| 217 | + Span |
| 218 | +} |
| 219 | + |
| 220 | +func (b *Builder) encodeStaticSections(statics []SpanWithCall) ([]StaticSection, error) { |
| 221 | + var sections []StaticSection |
| 222 | + for _, s := range statics { |
| 223 | + if s.Len == 0 { |
| 224 | + continue |
| 225 | + } |
| 226 | + if s.CallIndex < 0 || s.CallIndex >= len(b.payload.Calls) { |
| 227 | + return nil, fmt.Errorf("tindex out of range: %d", s.CallIndex) |
| 228 | + } |
| 229 | + offset := s.Start |
| 230 | + length := s.Len |
| 231 | + for length > 0 { |
| 232 | + chunk := length |
| 233 | + if uint32(chunk) > b.options.MaxSize { |
| 234 | + chunk = int(b.options.MaxSize) |
| 235 | + } |
| 236 | + if uint32(offset) > b.options.MaxOffset { |
| 237 | + return nil, fmt.Errorf("cindex too large: %d", offset) |
| 238 | + } |
| 239 | + if offset > maxUint16 || chunk > maxUint16 { |
| 240 | + return nil, fmt.Errorf("static section offset/size exceeds uint16 range (max %d): offset=%d chunk=%d", maxUint16, offset, chunk) |
| 241 | + } |
| 242 | + sections = append(sections, StaticSection{ |
| 243 | + TIndex: uint8(s.CallIndex), |
| 244 | + CIndex: uint16(offset), |
| 245 | + Size: uint16(chunk), |
| 246 | + }) |
| 247 | + offset += chunk |
| 248 | + length -= chunk |
| 249 | + } |
| 250 | + } |
| 251 | + return sections, nil |
| 252 | +} |
| 253 | + |
| 254 | +func mergeSpans(spans []Span) []Span { |
| 255 | + if len(spans) == 0 { |
| 256 | + return nil |
| 257 | + } |
| 258 | + sort.Slice(spans, func(i, j int) bool { return spans[i].Start < spans[j].Start }) |
| 259 | + out := []Span{spans[0]} |
| 260 | + for _, s := range spans[1:] { |
| 261 | + last := &out[len(out)-1] |
| 262 | + if s.Start <= last.Start+last.Len { |
| 263 | + end := max(last.Start+last.Len, s.Start+s.Len) |
| 264 | + last.Len = end - last.Start |
| 265 | + } else { |
| 266 | + out = append(out, s) |
| 267 | + } |
| 268 | + } |
| 269 | + return out |
| 270 | +} |
| 271 | + |
| 272 | +func mergeAdjacentStatics(statics []SpanWithCall) []SpanWithCall { |
| 273 | + if len(statics) == 0 { |
| 274 | + return statics |
| 275 | + } |
| 276 | + out := []SpanWithCall{statics[0]} |
| 277 | + for _, s := range statics[1:] { |
| 278 | + last := &out[len(out)-1] |
| 279 | + if s.CallIndex == last.CallIndex && s.Start == last.Start+last.Len { |
| 280 | + last.Len += s.Len |
| 281 | + } else { |
| 282 | + out = append(out, s) |
| 283 | + } |
| 284 | + } |
| 285 | + return out |
| 286 | +} |
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