Bound peer payload size

[ryardley]

⚠️ Potential issue | 🟠 Major

🧩 Analysis chain

🏁 Script executed:

# Find pinned bincode version(s)
fd -HI "^Cargo.toml$" | xargs -I{} rg -n '^\s*bincode\s*=' {}

# Find decode callsites and whether bounded config APIs are already used
rg -n 'bincode::deserialize|bincode::serde::decode_from_slice|with_limit|DefaultOptions|config::standard' crates

Repository: gnosisguild/enclave

Length of output: 4391

---

🏁 Script executed:

# Get the file context around the target lines
cat -n crates/net/src/net_sync_manager.rs | sed -n '40,55p'

# Check the full function and its surrounding context
cat -n crates/net/src/net_sync_manager.rs | sed -n '35,65p'

Repository: gnosisguild/enclave

Length of output: 1666

---

🌐 Web query:

bincode 1.3.3 bounded deserialization size limit configuration API

💡 Result:

In bincode 1.3.3, the bounded deserialization size limit is configured via the Options API:

use bincode::Options;

let opts = bincode::DefaultOptions::new().with_limit(1024); // bytes
let value: MyType = opts.deserialize(&bytes)?;

with_limit(limit: u64) switches the size limit from “unlimited” (default) to a bounded limit and will error if (de)serialization exceeds it. [1], [2]

For streaming reads:

use bincode::Options;

let opts = bincode::DefaultOptions::new().with_limit(1024 * 1024);
let value: MyType = opts.deserialize_from(reader)?;

Bincode’s docs explicitly call out enabling a maximum size (bounded) configuration for untrusted inputs. [3]

Legacy/deprecated API (still present in 1.3.3) is bincode::config::Config::limit(...), but it’s deprecated since 1.3.0 in favor of DefaultOptions/Options. [4]

Sources: [1] (docs.rs) [2] (mnemos.dev) [3] (docs.rs) [4] (doc.cuprate.org)

Citations:

• 1: https://docs.rs/hydroflow_plus/latest/hydroflow_plus/bincode/config/struct.DefaultOptions.html?utm_source=openai
• 2: https://mnemos.dev/doc/bincode/config/trait.options?utm_source=openai
• 3: https://docs.rs/crate/bincode/%3C2.0
• 4: https://doc.cuprate.org/bincode/config/struct.Config.html?utm_source=openai

---

Apply bounded deserialization for untrusted peer sync payloads.

Line 46 deserializes untrusted network bytes without size limits, enabling memory-exhaustion attacks. Use bincode::DefaultOptions::new().with_limit(size).deserialize(&value) to enforce a maximum payload size for bincode 1.3.3.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/net/src/net_sync_manager.rs` around lines 45 - 47, The try_from
implementation deserializes untrusted bytes without size limits; change it to
use bincode bounded deserialization by calling
bincode::DefaultOptions::new().with_limit(MAX_SYNC_PAYLOAD_SIZE).deserialize(&value)
instead of bincode::deserialize(&value), and keep the existing context("failed
to deserialize sync response") on the Result; add a clearly named constant
(e.g., MAX_SYNC_PAYLOAD_SIZE) for the maximum allowed bytes (choose an
appropriate u64) and reference that constant in the call so try_from enforces a
safe payload size for untrusted peer sync payloads.

Originally posted by @coderabbitai[bot] in #1358 (comment)