This library includes configuration options to prevent denial-of-service attacks through excessive memory allocation when processing untrusted Avro data. Users should configure appropriate limits based on their use case.

Users processing untrusted Avro data must configure appropriate size limits using the Config struct. Adjust these values based on your legitimate data requirements. Lower values provide better protection but may reject valid large datasets.

cfg := avro.Config{
    MaxByteSliceSize:  102_400, // 100 kiB - limit for bytes/string types
    MaxSliceAllocSize: 10_000,  // 10k - limit for array lengths
    MaxMapAllocSize:   10_000,  // 10k - limit for map sizes
}
api := cfg.Freeze()

// Now use the frozen API for untrusted data, e.g.:
err := api.Unmarshal(schema, untrustedData, &result)

Alternatively update the defaults globally:

avro.DefaultConfig = avro.Config{
    MaxByteSliceSize:  102_400, // 100 kiB - limit for bytes/string types
    MaxSliceAllocSize: 10_000,  // 10k - limit for array lengths
    MaxMapAllocSize:   10_000,  // 10k - limit for map sizes
}.Freeze()

// Now use the Avro functionality for untrusted data, e.g.:
decoder, err := avro.NewDecoder(schema, untrustedReader)

1. MaxByteSliceSize: Controls the maximum size of individual bytes or string values. Default: 1 MiB. Set to -1 to disable (not recommended for untrusted input).

2. MaxSliceAllocSize: Controls the maximum length of an individual array. Default: unlimited. Set this to a reasonable value based on your expected data size.

3. MaxMapAllocSize: Controls the maximum capacity of an individual map. Default: unlimited. Set this to a reasonable value based on your expected data size.