fuzz: add a payer proof deserialization target

diff --git a/fuzz/fuzz-fake-hashes/src/bin/payer_proof_deser_target.rs b/fuzz/fuzz-fake-hashes/src/bin/payer_proof_deser_target.rs
new file mode 100644
index 0000000..c7f9d86
--- /dev/null
+++ b/fuzz/fuzz-fake-hashes/src/bin/payer_proof_deser_target.rs
@@ -0,0 +1,137 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+// This file is auto-generated by gen_target.sh based on target_template.txt
+// To modify it, modify target_template.txt and run gen_target.sh instead.
+
+#![cfg_attr(feature = "libfuzzer_fuzz", no_main)]
+#![cfg_attr(rustfmt, rustfmt_skip)]
+
+#[cfg(not(fuzzing))]
+compile_error!("Fuzz targets need cfg=fuzzing");
+
+#[cfg(not(hashes_fuzz))]
+compile_error!("Fuzz target does not support cfg(not(hashes_fuzz))");
+
+#[cfg(not(secp256k1_fuzz))]
+compile_error!("Fuzz targets need cfg=secp256k1_fuzz");
+
+extern crate lightning_fuzz;
+use lightning_fuzz::payer_proof_deser::*;
+use lightning_fuzz::utils::test_logger;
+
+#[cfg(feature = "afl")]
+#[macro_use] extern crate afl;
+#[cfg(feature = "afl")]
+fn main() {
+	fuzz!(|data| {
+		payer_proof_deser_test(&data, test_logger::DevNull {});
+	});
+}
+
+#[cfg(feature = "honggfuzz")]
+#[macro_use] extern crate honggfuzz;
+#[cfg(feature = "honggfuzz")]
+fn main() {
+	loop {
+		fuzz!(|data| {
+			payer_proof_deser_test(&data, test_logger::DevNull {});
+		});
+	}
+}
+
+#[cfg(feature = "libfuzzer_fuzz")]
+#[macro_use] extern crate libfuzzer_sys;
+#[cfg(feature = "libfuzzer_fuzz")]
+fuzz_target!(|data: &[u8]| {
+	payer_proof_deser_test(data, test_logger::DevNull {});
+});
+
+#[cfg(feature = "stdin_fuzz")]
+fn main() {
+	use std::io::Read;
+
+	// On macOS, panic=abort causes the process to send SIGABRT which can leave it
+	// stuck in an uninterruptible state due to the ReportCrash daemon. Using
+	// process::exit in a panic hook avoids this by terminating cleanly.
+	#[cfg(target_os = "macos")]
+	std::panic::set_hook(Box::new(|panic_info| {
+		use std::io::Write;
+		let _ = std::io::stdout().flush();
+		eprintln!("{}\n{}", panic_info, std::backtrace::Backtrace::force_capture());
+		let _ = std::io::stderr().flush();
+		std::process::exit(1);
+	}));
+
+	let mut data = Vec::with_capacity(8192);
+	std::io::stdin().read_to_end(&mut data).unwrap();
+	if std::env::var_os("LDK_FUZZ_SUPPRESS_LOGS").is_some() {
+		payer_proof_deser_test(&data, test_logger::DevNull {});
+	} else {
+		payer_proof_deser_test(&data, test_logger::Stdout {});
+	}
+}
+
+#[test]
+fn run_test_cases() {
+	use std::fs;
+	use std::io::Read;
+	use lightning_fuzz::utils::test_logger::StringBuffer;
+
+	use std::sync::{atomic, Arc};
+	{
+		let data: Vec<u8> = vec![0];
+		payer_proof_deser_test(&data, test_logger::DevNull {});
+	}
+	let mut threads = Vec::new();
+	let threads_running = Arc::new(atomic::AtomicUsize::new(0));
+	if let Ok(tests) = fs::read_dir("../test_cases/payer_proof_deser") {
+		for test in tests {
+			let mut data: Vec<u8> = Vec::new();
+			let path = test.unwrap().path();
+			fs::File::open(&path).unwrap().read_to_end(&mut data).unwrap();
+			threads_running.fetch_add(1, atomic::Ordering::AcqRel);
+
+			let thread_count_ref = Arc::clone(&threads_running);
+			let main_thread_ref = std::thread::current();
+			threads.push((path.file_name().unwrap().to_str().unwrap().to_string(),
+				std::thread::spawn(move || {
+					let string_logger = StringBuffer::new();
+
+					let panic_logger = string_logger.clone();
+					let res = if ::std::panic::catch_unwind(move || {
+						payer_proof_deser_test(&data, panic_logger);
+					}).is_err() {
+						Some(string_logger.into_string())
+					} else { None };
+					thread_count_ref.fetch_sub(1, atomic::Ordering::AcqRel);
+					main_thread_ref.unpark();
+					res
+				})
+			));
+			while threads_running.load(atomic::Ordering::Acquire) > 32 {
+				std::thread::park();
+			}
+		}
+	}
+	let mut failed_outputs = Vec::new();
+	for (test, thread) in threads.drain(..) {
+		if let Some(output) = thread.join().unwrap() {
+			println!("\nOutput of {}:\n{}\n", test, output);
+			failed_outputs.push(test);
+		}
+	}
+	if !failed_outputs.is_empty() {
+		println!("Test cases which failed: ");
+		for case in failed_outputs {
+			println!("{}", case);
+		}
+		panic!();
+	}
+}
diff --git a/fuzz/src/bin/gen_target.sh b/fuzz/src/bin/gen_target.sh
index 868a076..9626871 100755
--- a/fuzz/src/bin/gen_target.sh
+++ b/fuzz/src/bin/gen_target.sh
@@ -34,6 +34,7 @@ GEN_FAKE_HASHES_TEST onion_message
 GEN_FAKE_HASHES_TEST peer_crypt
 GEN_FAKE_HASHES_TEST process_network_graph
 GEN_FAKE_HASHES_TEST process_onion_failure
+GEN_FAKE_HASHES_TEST payer_proof_deser
 GEN_FAKE_HASHES_TEST refund_deser
 GEN_FAKE_HASHES_TEST router
 GEN_FAKE_HASHES_TEST zbase32
diff --git a/fuzz/src/lib.rs b/fuzz/src/lib.rs
index 25c2fff..be5b34a 100644
--- a/fuzz/src/lib.rs
+++ b/fuzz/src/lib.rs
@@ -36,6 +36,7 @@ pub mod lsps_message;
 pub mod offer_deser;
 pub mod onion_hop_data;
 pub mod onion_message;
+pub mod payer_proof_deser;
 pub mod peer_crypt;
 pub mod process_network_graph;
 pub mod process_onion_failure;
diff --git a/fuzz/src/payer_proof_deser.rs b/fuzz/src/payer_proof_deser.rs
new file mode 100644
index 0000000..adccbe5
--- /dev/null
+++ b/fuzz/src/payer_proof_deser.rs
@@ -0,0 +1,31 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use crate::utils::test_logger;
+use core::convert::TryFrom;
+use lightning::offers::payer_proof::PayerProof;
+use lightning::util::ser::Writeable;
+
+#[inline]
+pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
+	if let Ok(payer_proof) = PayerProof::try_from(data.to_vec()) {
+		let mut bytes = Vec::with_capacity(data.len());
+		payer_proof.write(&mut bytes).unwrap();
+		assert_eq!(data, bytes);
+	}
+}
+
+pub fn payer_proof_deser_test<Out: test_logger::Output>(data: &[u8], out: Out) {
+	do_test(data, out);
+}
+
+#[no_mangle]
+pub extern "C" fn payer_proof_deser_run(data: *const u8, datalen: usize) {
+	do_test(unsafe { std::slice::from_raw_parts(data, datalen) }, test_logger::DevNull {});
+}
diff --git a/fuzz/targets.h b/fuzz/targets.h
index ef8e899..3a0699d 100644
--- a/fuzz/targets.h
+++ b/fuzz/targets.h
@@ -12,6 +12,7 @@ void onion_message_run(const unsigned char* data, size_t data_len);
 void peer_crypt_run(const unsigned char* data, size_t data_len);
 void process_network_graph_run(const unsigned char* data, size_t data_len);
 void process_onion_failure_run(const unsigned char* data, size_t data_len);
+void payer_proof_deser_run(const unsigned char* data, size_t data_len);
 void refund_deser_run(const unsigned char* data, size_t data_len);
 void router_run(const unsigned char* data, size_t data_len);
 void zbase32_run(const unsigned char* data, size_t data_len);