{"record":{"id":"d3888501ccb363f8","repo":"XTLS/Xray-core","slug":"padding-turn-d-w","errorCode":null,"errorMessage":"padding turn %d: %w","messagePattern":"padding turn (.+?): %w","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"transport/internet/finalmask/xmc/padding.go","lineNumber":103,"sourceCode":"\t\tif turn.direction != paddingClientToServer && turn.direction != paddingServerToClient {\n\t\t\treturn fmt.Errorf(\"padding turn %d has invalid direction: %d\", i, turn.direction)\n\t\t}\n\t\tif err := validatePaddingDelayRange(turn.startDelay); err != nil {\n\t\t\treturn fmt.Errorf(\"padding turn %d has an invalid start delay: %w\", i, err)\n\t\t}\n\t\tif err := validatePaddingDelayRange(turn.chunkDelay); err != nil {\n\t\t\treturn fmt.Errorf(\"padding turn %d has an invalid chunk delay: %w\", i, err)\n\t\t}\n\t\tif turn.writeChunkMinLength < 0 || turn.writeChunkLength < turn.writeChunkMinLength || turn.writeChunkLength > maxPaddingChunkLength {\n\t\t\treturn fmt.Errorf(\"padding turn %d has an invalid write chunk range: %d-%d\", i, turn.writeChunkMinLength, turn.writeChunkLength)\n\t\t}\n\t\tif len(turn.variants) > 0 && turn.writeChunkLength != 0 {\n\t\t\treturn fmt.Errorf(\"padding turn %d combines variants with generated write chunks\", i)\n\t\t}\n\n\t\tminLength, maxLength, err := paddingTurnBounds(turn)\n\t\tif err != nil {\n\t\t\treturn fmt.Errorf(\"padding turn %d: %w\", i, err)\n\t\t}\n\t\thasSendRange := turn.sendMinLength != 0 || turn.sendMaxLength != 0\n\t\tif hasSendRange {\n\t\t\tif len(turn.variants) > 0 {\n\t\t\t\treturn fmt.Errorf(\"padding turn %d combines variants with a send range\", i)\n\t\t\t}\n\t\t\tif turn.sendMinLength < minLength || turn.sendMaxLength < turn.sendMinLength || turn.sendMaxLength > maxLength {\n\t\t\t\treturn fmt.Errorf(\"padding turn %d has an invalid send range: %d-%d\", i, turn.sendMinLength, turn.sendMaxLength)\n\t\t\t}\n\t\t}\n\t\tif i == 0 && minLength-firstTurnPrefixLength < 1 {\n\t\t\treturn fmt.Errorf(\"padding turn 0 is too short for %d prefix bytes\", firstTurnPrefixLength)\n\t\t}\n\t\tif i == 0 && len(turn.variants) > 0 {\n\t\t\tfor j, variant := range turn.variants {\n\t\t\t\tif _, _, err = trimPaddingPrefix(variant, firstTurnPrefixLength); err != nil {\n\t\t\t\t\treturn fmt.Errorf(\"padding turn 0 variant %d: %w\", j, err)\n\t\t\t\t}","sourceCodeStart":85,"sourceCodeEnd":121,"githubUrl":"https://github.com/XTLS/Xray-core/blob/7d214f8b094f75322fa3990f8aadad1c912f24f5/transport/internet/finalmask/xmc/padding.go#L85-L121","documentation":"validatePaddingSchedule wrapped a paddingTurnBounds failure for turn i: either an invalid min/max length range (min < 1, max < min, or max > 8 MiB), variants combined with a non-zero length range, a variant with no chunks, chunk/delay count mismatch, an invalid variant chunk length or delay, an over-long variant, or an out-of-range sendVariants index.","triggerScenarios":"Hand-written or generated turns with minLength 0, ranges exceeding maxPaddingTurnLength (8 MiB), variant structs with empty chunks or delays arrays shorter than chunks, or sendVariants referencing nonexistent variant indices.","commonSituations":"Forks authoring new traffic-shape profiles; converting captured traffic traces into variants and dropping empty entries; config-driven schedules with unvalidated indices.","solutions":["Read the wrapped message ('invalid range', 'variant N has no chunks', 'invalid send variant index', etc.) to identify the exact field","Ensure 1 <= minLength <= maxLength <= 8*1024*1024 for range turns, and minLength=maxLength=0 when variants are set","Give every variant at least one chunk, delays arrays of length 0 or equal to chunks, chunk lengths in 1..48 KiB, and sendVariants indices within range","Validate schedules in unit tests before shipping them"],"exampleFix":"// before\nturn := paddingTurn{variants: vs, minLength: 100, maxLength: 200}\n\n// after\nturn := paddingTurn{variants: vs} // range must be unset when variants present","handlingStrategy":"validation","validationCode":"func validTurnBounds(turn paddingTurn) bool {\n    if len(turn.variants) == 0 {\n        return turn.minLength >= 1 && turn.maxLength >= turn.minLength && turn.maxLength <= 8*1024*1024\n    }\n    if turn.minLength != 0 || turn.maxLength != 0 {\n        return false\n    }\n    for _, v := range turn.variants {\n        if len(v.chunks) == 0 {\n            return false\n        }\n        if len(v.delays) != 0 && len(v.delays) != len(v.chunks) {\n            return false\n        }\n        for _, c := range v.chunks {\n            if c < 1 || c > 48*1024 {\n                return false\n            }\n        }\n    }\n    for _, i := range turn.sendVariants {\n        if i < 0 || i >= len(turn.variants) {\n            return false\n        }\n    }\n    return true\n}","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Run schedule validation in unit tests for every shipped profile","Sanitize converted traffic traces (drop empty variants, clamp lengths)","Bounds-check sendVariants indices when they come from config"],"tags":["go","padding","validation","schedule","variants"],"backgroundTag":null,"analyzedSha":"7d214f8b094f75322fa3990f8aadad1c912f24f5","analyzedAt":"2026-08-15T14:26:24.325Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}