Nik Clayton created THRIFT-5131:
-----------------------------------

             Summary: i64 maxint decoding panics with integer-encoding >= 1.1.0
                 Key: THRIFT-5131
                 URL: https://issues.apache.org/jira/browse/THRIFT-5131
             Project: Thrift
          Issue Type: Bug
          Components: Rust - Library
    Affects Versions: 0.13.0
         Environment: % cargo --version --verbose
cargo 1.40.0
release: 1.40.0

% uname -a
Darwin Niks-MacBook-Pro.local 19.3.0 Darwin Kernel Version 19.3.0: Thu Jan 9 
20:58:23 PST 2020; root:xnu-6153.81.5~1/RELEASE_X86_64 x86_64 i386 
MacBookPro15,1 Darwin
            Reporter: Nik Clayton


The Rust library for Thrift uses the integer-encoding crate. In version 1.1.0 
(through at least 1.1.3, the most recent version) of this crate Thrift's usage 
appears to be responsible for a panic in the library when trying to decode i64 
numbers in the range 0x4000_0000_0000_0000 to 0x7FFF_FFFF_FFFF_FFFF.

The integer-encoding crate does not panic when using it directly to encode / 
decode numbers in this range.

To see this, create a scratch crate with "cargo new int_encoding".

Replace the contents of Cargo.toml with the following:

{code}
[package]
name = "int_encoding"
version = "0.1.0"
authors = ["Nik Clayton <nik.clay...@dfinity.org>"]
edition = "2018"

[dependencies]
thrift = "0.13.0"
integer-encoding = "=1.0.8"
{code}

This pins the integer-encoding library to version 1.0.8.

Put the following in src/main.rs:

{code}
use thrift::protocol::{
    TCompactInputProtocol, TCompactOutputProtocol, TFieldIdentifier, 
TInputProtocol,
    TOutputProtocol, TType,
};
use integer_encoding::*;

fn main() {
    let mut field_value = i64::max_value(); // Fails

    // Uncomment the next line to see success
    //field_value = (1i64 << 62) - 1;

    let mut buf;
    println!("Value is: {}, {:X}", field_value, field_value);

    // First check that encoding and decoding works using the integer_encoding
    // library directly.
    buf = field_value.encode_var_vec();
    let (val, _) = VarInt::decode_var(&buf[..]);
    assert_eq!(field_value, val);

    // Clear the buffer, and try encoding the same value using Thrift. This code
    // is almost identical to 
https://docs.rs/thrift/0.13.0/thrift/protocol/index.html
    // except that (a) it's an I64, and (b) the channel is a Vec.
    buf.clear();
    let mut out_protocol = TCompactOutputProtocol::new(&mut buf);

    out_protocol
        .write_field_begin(&TFieldIdentifier::new(
            "max_int",
            TType::I64,
            1,
        ))
        .unwrap();
    out_protocol.write_i64(field_value).unwrap();
    out_protocol.write_field_end().unwrap();
    out_protocol.flush().unwrap();

    let mut in_protocol = TCompactInputProtocol::new(&buf[..]);
    in_protocol.read_field_begin().unwrap();
    assert_eq!(field_value, in_protocol.read_i64().unwrap());
    in_protocol.read_field_end().unwrap();
}
{code}

Run this with "cargo run", it should succeed, and print:

{code}
Value is: 9223372036854775807, 7FFFFFFFFFFFFFFF
{code}

Edit Cargo.toml and change the "integer-encoding" line to

{code}
integer-encoding = "=1.1.3"
{code}

Run with "RUST_BACKTRACE=1 cargo run" and you will see the following panic 
(I've elided the full panic here):

{code}
thread 'main' panicked at 'index 11 out of range for slice of length 10', 
src/libcore/slice/mod.rs:2664:5
stack backtrace:
[...]
  13: integer_encoding::reader::VarIntProcessor::decode
             at 
/Users/nik/d/rs/.cargo-home/registry/src/github.com-1ecc6299db9ec823/integer-encoding-1.1.3/src/reader.rs:56
  14: <R as integer_encoding::reader::VarIntReader>::read_varint
             at 
/Users/nik/d/rs/.cargo-home/registry/src/github.com-1ecc6299db9ec823/integer-encoding-1.1.3/src/reader.rs:104
  15: <thrift::protocol::compact::TCompactInputProtocol<T> as 
thrift::protocol::TInputProtocol>::read_i64
             at 
/Users/nik/d/rs/.cargo-home/registry/src/github.com-1ecc6299db9ec823/thrift-0.13.0/src/protocol/compact.rs:246
  16: int_encoding::main
             at src/main.rs:41
[...]
{code}

As you can see, the panic is coming from the call to Thrift's read_i64(). The 
earlier code that used integer-encoding directly did not panic. That's why I 
think the problem is somewhere in Thrift.

If you edit main.rs and uncomment the line

{code}
//field_value = (1i64 << 62) - 1;
{code}

the panic disappears. I believe this is the largest number that can be used 
without triggering the panic.



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