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Enforce response body size limits in payjoin-cli #808

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28 changes: 22 additions & 6 deletions Cargo-minimal.lock
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Original file line number Diff line number Diff line change
Expand Up @@ -2787,6 +2787,7 @@ dependencies = [
"clap 4.5.45",
"config",
"dirs",
"futures",
"http-body-util",
"hyper",
"hyper-util",
Expand Down Expand Up @@ -3410,12 +3411,14 @@ dependencies = [
"sync_wrapper",
"tokio",
"tokio-rustls",
"tokio-util",
"tower",
"tower-http",
"tower-service",
"url",
"wasm-bindgen",
"wasm-bindgen-futures",
"wasm-streams",
"web-sys",
"webpki-roots 1.0.7",
]
Expand Down Expand Up @@ -4421,9 +4424,9 @@ dependencies = [

[[package]]
name = "tokio-util"
version = "0.7.1"
version = "0.7.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "0edfdeb067411dba2044da6d1cb2df793dd35add7888d73c16e3381ded401764"
checksum = "1d68074620f57a0b21594d9735eb2e98ab38b17f80d3fcb189fca266771ca60d"
dependencies = [
"bytes",
"futures-core",
Expand Down Expand Up @@ -5111,9 +5114,9 @@ dependencies = [

[[package]]
name = "wasm-bindgen-futures"
version = "0.4.19"
version = "0.4.37"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "1fe9756085a84584ee9457a002b7cdfe0bfff169f45d2591d8be1345a6780e35"
checksum = "c02dbc21516f9f1f04f187958890d7e6026df8d16540b7ad9492bc34a67cea03"
dependencies = [
"cfg-if 1.0.0",
"js-sys",
Expand Down Expand Up @@ -5153,11 +5156,24 @@ dependencies = [
"unicode-ident",
]

[[package]]
name = "wasm-streams"
version = "0.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b65dc4c90b63b118468cf747d8bf3566c1913ef60be765b5730ead9e0a3ba129"
dependencies = [
"futures-util",
"js-sys",
"wasm-bindgen",
"wasm-bindgen-futures",
"web-sys",
]

[[package]]
name = "web-sys"
version = "0.3.37"
version = "0.3.64"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "2d6f51648d8c56c366144378a33290049eafdd784071077f6fe37dae64c1c4cb"
checksum = "9b85cbef8c220a6abc02aefd892dfc0fc23afb1c6a426316ec33253a3877249b"
dependencies = [
"js-sys",
"wasm-bindgen",
Expand Down
16 changes: 16 additions & 0 deletions Cargo-recent.lock
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Original file line number Diff line number Diff line change
Expand Up @@ -2881,6 +2881,7 @@ dependencies = [
"clap 4.6.1",
"config",
"dirs",
"futures",
"http-body-util",
"hyper",
"hyper-util",
Expand Down Expand Up @@ -3548,12 +3549,14 @@ dependencies = [
"sync_wrapper",
"tokio",
"tokio-rustls",
"tokio-util",
"tower",
"tower-http",
"tower-service",
"url",
"wasm-bindgen",
"wasm-bindgen-futures",
"wasm-streams",
"web-sys",
"webpki-roots 1.0.8",
]
Expand Down Expand Up @@ -5277,6 +5280,19 @@ dependencies = [
"unicode-ident",
]

[[package]]
name = "wasm-streams"
version = "0.4.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "15053d8d85c7eccdbefef60f06769760a563c7f0a9d6902a13d35c7800b0ad65"
dependencies = [
"futures-util",
"js-sys",
"wasm-bindgen",
"wasm-bindgen-futures",
"web-sys",
]

[[package]]
name = "web-sys"
version = "0.3.102"
Expand Down
4 changes: 3 additions & 1 deletion payjoin-cli/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ path = "src/main.rs"
default = ["v2"]
native-certs = ["reqwest/rustls-tls-native-roots"]
_manual-tls = ["reqwest/rustls-tls", "payjoin/_manual-tls", "tokio-rustls"]
v1 = ["payjoin/v1", "hyper", "hyper-util", "http-body-util"]
v1 = ["payjoin/v1", "futures", "hyper", "hyper-util", "http-body-util"]

@DanGould DanGould Jul 1, 2026

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Suggested change
v1 = ["payjoin/v1", "futures", "hyper", "hyper-util", "http-body-util"]
v1 = ["payjoin/v1", "futures", "hyper", "hyper-util", "http-body-util", "reqwest/stream"]

v2 = ["payjoin/v2", "payjoin/io"]

[dependencies]
Expand All @@ -32,6 +32,7 @@ bitcoind-async-client = "0.14.0"
clap = { version = "4.5.45", features = ["derive"] }
config = "0.15.17"
dirs = "6.0.0"
futures = { version = "0.3.21", optional = true }
http-body-util = { version = "0.1.3", optional = true }
hyper = { version = "1.8.0", features = ["http1", "server"], optional = true }
hyper-util = { version = "0.1.18", optional = true }
Expand All @@ -42,6 +43,7 @@ r2d2_sqlite = "0.22.0"
reqwest = { version = "0.12.23", default-features = false, features = [
"json",
"rustls-tls",
"stream",

@DanGould DanGould Jul 1, 2026

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This feature seems to only be used in v1, so rather than defining it here you should be able to define it in v1 = [ ... ], above.

] }
rusqlite = { version = "0.29.0", features = ["bundled"] }
serde = { version = "1.0.228", features = ["derive"] }
Expand Down
25 changes: 25 additions & 0 deletions payjoin-cli/src/app/mod.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,12 @@
use std::collections::HashMap;

#[cfg(feature = "v1")]
use anyhow::anyhow;
use anyhow::Result;
#[cfg(feature = "v1")]
use futures::{Stream, StreamExt};
#[cfg(feature = "v1")]
use hyper::body::Bytes;
use payjoin::bitcoin::psbt::Psbt;
use payjoin::bitcoin::{self, Address, Amount, FeeRate};
use tokio::signal;
Expand Down Expand Up @@ -103,3 +109,22 @@ async fn handle_interrupt(tx: watch::Sender<()>) {
}
let _ = tx.send(());
}

#[cfg(feature = "v1")]
pub async fn read_limited_body<S, E>(mut stream: S, expected_len: usize) -> Result<Vec<u8>>
where
S: Stream<Item = Result<Bytes, E>> + Unpin,
E: std::error::Error + Send + Sync + 'static,
{
let mut body = Vec::with_capacity(expected_len);

while let Some(chunk) = stream.next().await {
let chunk = chunk.map_err(|e| anyhow!("Error reading body chunk: {}", e))?;
if body.len() + chunk.len() > expected_len {
return Err(anyhow!("Body exceeds expected size of {expected_len} bytes"));
}
body.extend_from_slice(&chunk);
}

Ok(body)
}
Comment on lines +113 to +130

@DanGould DanGould Jul 1, 2026

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Because this is only called in payjoin-cli/src/app/v1.rs it ought to have dependencies declared there and be defined there. This'll get rid of all the feature gates in this file, too.

79 changes: 48 additions & 31 deletions payjoin-cli/src/app/v1.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -22,9 +22,14 @@ use tokio::sync::watch;
use super::config::Config;
use super::wallet::BitcoindWallet;
use super::App as AppTrait;
use crate::app::{handle_interrupt, http_agent};
use crate::app::{handle_interrupt, http_agent, read_limited_body};
use crate::db::Database;

/// 4M block size limit with base64 encoding overhead => maximum reasonable size of content-length
/// 4_000_000 * 4 / 3 fits in u32
const MAX_CONTENT_LENGTH: usize = 4_000_000 * 4 / 3;

#[derive(Clone)]
struct Headers<'a>(&'a hyper::HeaderMap);
impl payjoin::receive::v1::Headers for Headers<'_> {
fn get_header(&self, key: &str) -> Option<&str> {
Expand Down Expand Up @@ -71,36 +76,33 @@ impl AppTrait for App {
let http = http_agent(&self.config)?;
let body = String::from_utf8(req.body.clone()).unwrap();
println!("Sending Original PSBT to {}", req.url);
let response = match http
let response = http
.post(req.url)
.header("Content-Type", req.content_type)
.body(body.clone())
.send()
.await
{
Ok(response) => response,
Err(e) => {
tracing::error!("HTTP request failed: {e}");
println!("Payjoin failed. To broadcast the fallback transaction, run:");
println!(
" bitcoin-cli -rpcwallet=<wallet> sendrawtransaction {:#}",
serialize_hex(&fallback_tx)
);
return Err(anyhow!("HTTP request failed: {e}"));
}
};
let psbt = match ctx.process_response(&response.bytes().await?) {
Ok(psbt) => psbt,
Err(e) => {
tracing::error!("Error processing response: {e:?}");
println!("Payjoin failed. To broadcast the fallback transaction, run:");
println!(
" bitcoin-cli -rpcwallet=<wallet> sendrawtransaction {:#}",
serialize_hex(&fallback_tx)
);
return Err(anyhow!("Failed to process response {e}"));
}
};
.with_context(|| "HTTP request failed")?;
println!("Sent fallback transaction txid: {}", fallback_tx.compute_txid());
println!("Sent fallback transaction hex: {:#}", serialize_hex(&fallback_tx));

let expected_length = response
.headers()
.get("Content-Length")
.and_then(|val| val.to_str().ok())
.and_then(|s| s.parse::<usize>().ok())
.unwrap_or(MAX_CONTENT_LENGTH);

if expected_length > MAX_CONTENT_LENGTH {
return Err(anyhow!("Response body is too large: {} bytes", expected_length));
}

let body = read_limited_body(response.bytes_stream(), MAX_CONTENT_LENGTH).await?;

let psbt = ctx.process_response(&body).map_err(|e| {
tracing::debug!("Error processing response: {e:?}");
anyhow!("Failed to process response {e}")
})?;

self.process_pj_response(psbt)?;
Comment on lines -74 to 105

@DanGould DanGould Jul 1, 2026

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The println instructions may have changed since your first attempt at this. Please sure the println/error handling behavior doesn't change except for what you've introduced with Content-Length here. I imagine the lines like this

println!("Payjoin failed. To broadcast the fallback transaction, run:");
                println!(
                    "  bitcoin-cli -rpcwallet=<wallet> sendrawtransaction {:#}",
                    serialize_hex(&fallback_tx)
                );

can and should stay.

Ok(())
Expand Down Expand Up @@ -323,12 +325,27 @@ impl App {
) -> Result<Response<BoxBody<Bytes, hyper::Error>>, Error> {
let (parts, body) = req.into_parts();
let headers = Headers(&parts.headers);

let expected_length = headers
.0
.get("Content-Length")
.and_then(|val| val.to_str().ok())
.and_then(|s| s.parse::<usize>().ok())
.unwrap_or(MAX_CONTENT_LENGTH);

if expected_length > MAX_CONTENT_LENGTH {
tracing::error!("Error: Content length exceeds max allowed");
return Err(Error::Implementation(ImplementationError::from(
anyhow!("Content length too large: {expected_length}").into_boxed_dyn_error(),
)));
}

let body =
read_limited_body(body.into_data_stream(), expected_length).await.map_err(|e| {
Error::Implementation(ImplementationError::from(e.into_boxed_dyn_error()))
})?;

let query_string = parts.uri.query().unwrap_or("");
let body = body
.collect()
.await
.map_err(|e| Error::Implementation(ImplementationError::new(e)))?
.to_bytes();
let proposal = UncheckedOriginalPayload::from_request(&body, query_string, headers)?;

let payjoin_proposal = self.process_v1_proposal(proposal)?;
Expand Down
2 changes: 1 addition & 1 deletion payjoin-cli/src/app/v2/mod.rs
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Expand Up @@ -172,7 +172,7 @@ impl AppTrait for App {
let fallback_tx = psbt.clone().extract_tx()?;
let (req, ctx) = payjoin::send::v1::SenderBuilder::from_parts(
psbt,
pj_param,
&PjParam::V1(pj_param.clone()),

@DanGould DanGould Jul 1, 2026

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This function's type signature does not change. Why then introduce this change?

&address,
Some(amount),
)
Expand Down
5 changes: 1 addition & 4 deletions payjoin/src/core/send/error.rs
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Expand Up @@ -120,10 +120,7 @@ impl fmt::Display for ValidationError {
match &self.0 {
Parse => write!(f, "couldn't decode as PSBT or JSON",),
#[cfg(feature = "v1")]
ContentTooLarge => {
use crate::MAX_CONTENT_LENGTH;
write!(f, "content is larger than {MAX_CONTENT_LENGTH} bytes")
}
ContentTooLarge => write!(f, "The response body is too large"),

@DanGould DanGould Jul 1, 2026

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Maybe I'm missing context. What's the rationale for this change?

Proposal(e) => write!(f, "proposal PSBT error: {e}"),
#[cfg(feature = "v2")]
V2Decapsulation(e) => write!(f, "v2 encapsulation error: {e}"),
Expand Down
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