cap debug_message

frame/contracts/src/wasm/runtime.rs

@@ -21,7 +21,7 @@ use crate::{
 	exec::{ExecError, ExecResult, Ext, FixSizedKey, TopicOf, VarSizedKey},
 	gas::{ChargedAmount, Token},
 	schedule::HostFnWeights,
-	BalanceOf, CodeHash, Config, Error, SENTINEL,
+	BalanceOf, CodeHash, Config, DebugBufferVec, Error, SENTINEL,
 };
 
 use bitflags::bitflags;
@@ -2345,7 +2345,7 @@ pub mod env {
 	/// Emit a custom debug message.
 	///
 	/// No newlines are added to the supplied message.
-	/// Specifying invalid UTF-8 triggers a trap.
+	/// Specifying invalid UTF-8 just drops the message with no trap.
 	///
 	/// This is a no-op if debug message recording is disabled which is always the case
 	/// when the code is executing on-chain. The message is interpreted as UTF-8 and
@@ -2366,6 +2366,7 @@ pub mod env {
 		str_ptr: u32,
 		str_len: u32,
 	) -> Result<ReturnCode, TrapReason> {
+		let str_len = str_len.min(DebugBufferVec::<E::T>::bound() as u32);
 		ctx.charge_gas(RuntimeCosts::DebugMessage(str_len))?;
 		if ctx.ext.append_debug_buffer("") {
 			let data = ctx.read_sandbox_memory(memory, str_ptr, str_len)?;