(hotfix): Check proof length for priliminary checkpoint screening (#976)

* (hotfix): Check proof length for priliminary checkpoint screening

* Fix unit tests

Author: bewakes

crates/l1tx/src/filter/checkpoint.rs

@@ -6,6 +6,8 @@ use tracing::warn;
 use super::TxFilterConfig;
 use crate::envelope::parser::parse_envelope_payloads;
 
+const PROOF_SIZE_WITH_PUBLIC_PARAMS: usize = 396;
+
 /// Parses envelope from the given transaction. Currently, the only envelope recognizable is
 /// the checkpoint envelope.
 // TODO: we need to change envelope structure and possibly have envelopes for checkpoints and
@@ -62,6 +64,15 @@ fn validate_checkpoint(
         return None;
     }
 
+    // Also check if the proof has a valid size.
+    // FIXME: We should actually be checking the validity of proof, but this is done
+    // for a hotfix.
+    let proof_size = signed_checkpoint.checkpoint().proof().as_bytes().len();
+    // We are allowing proof of size 0 because we support empty proofs.
+    if proof_size != 0 && proof_size < PROOF_SIZE_WITH_PUBLIC_PARAMS {
+        return None;
+    }
+
     Some(signed_checkpoint)
 }
 
@@ -76,7 +87,9 @@ mod test {
     use strata_test_utils::{l2::gen_params, ArbitraryGenerator};
 
     use super::TxFilterConfig;
-    use crate::filter::parse_valid_checkpoint_envelopes;
+    use crate::filter::{
+        checkpoint::PROOF_SIZE_WITH_PUBLIC_PARAMS, parse_valid_checkpoint_envelopes,
+    };
 
     const TEST_ADDR: &str = "bcrt1q6u6qyya3sryhh42lahtnz2m7zuufe7dlt8j0j5";
 
@@ -97,11 +110,12 @@ mod test {
             .map(|_| {
                 let mut gen = ArbitraryGenerator::new();
                 let chainstate: Chainstate = gen.generate();
+                let proof = [1; PROOF_SIZE_WITH_PUBLIC_PARAMS].as_slice();
                 let signed_checkpoint = SignedCheckpoint::new(
                     Checkpoint::new(
                         gen.generate(),
                         gen.generate(),
-                        gen.generate(),
+                        proof.into(),
                         CheckpointSidecar::new(borsh::to_vec(&chainstate).unwrap()),
                     ),
                     gen.generate(),