39 lines
1.6 KiB
Rust
39 lines
1.6 KiB
Rust
use crate::instruction::InstructionError;
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use bincode::config::Options;
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/// Deserialize with a limit based the maximum amount of data a program can expect to get.
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/// This function should be used in place of direct deserialization to help prevent OOM errors
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pub fn limited_deserialize<T>(instruction_data: &[u8]) -> Result<T, InstructionError>
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where
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T: serde::de::DeserializeOwned,
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{
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let limit = crate::packet::PACKET_DATA_SIZE as u64;
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bincode::options()
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.with_limit(limit)
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.with_fixint_encoding() // As per https://github.com/servo/bincode/issues/333, these two options are needed
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.allow_trailing_bytes() // to retain the behavior of bincode::deserialize with the new `options()` method
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.deserialize_from(instruction_data)
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.map_err(|_| InstructionError::InvalidInstructionData)
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}
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#[cfg(test)]
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pub mod tests {
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use super::*;
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#[test]
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fn test_limited_deserialize() {
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#[derive(Deserialize, Serialize)]
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enum Foo {
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Bar(Vec<u8>),
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}
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let item = Foo::Bar([1; crate::packet::PACKET_DATA_SIZE - 12].to_vec()); // crate::packet::PACKET_DATA_SIZE - 12: size limit, minus enum variant and vec len() serialized sizes
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let serialized = bincode::serialize(&item).unwrap();
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assert!(limited_deserialize::<Foo>(&serialized).is_ok());
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let item = Foo::Bar([1; crate::packet::PACKET_DATA_SIZE - 11].to_vec()); // Extra byte should bump serialized size over the size limit
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let serialized = bincode::serialize(&item).unwrap();
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assert!(limited_deserialize::<Foo>(&serialized).is_err());
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}
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}
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