[sdk] Add a length restriction on poseidon hash input

sdk/program/src/poseidon.rs

@@ -4,6 +4,9 @@
 
 use thiserror::Error;
 
+/// BN254 base field bytes.
+pub const BN254_FIELD_BYTES: usize = 32;
+
 /// Length of Poseidon hash result.
 pub const HASH_BYTES: usize = 32;
 
@@ -233,6 +236,10 @@ pub fn hashv(
             }
         }
 
+        if vals.iter().any(|val| val.len() > BN254_FIELD_BYTES) {
+            return Err(PoseidonSyscallError::InputLargerThanModulus);
+        }
+
         let mut hasher =
             Poseidon::<Fr>::new_circom(vals.len()).map_err(PoseidonSyscallError::from)?;
         let res = match endianness {