client: fix mango account reading

client/src/chain_data_fetcher.rs

@@ -2,8 +2,10 @@ use std::sync::{Arc, RwLock};
 
 use crate::chain_data::*;
 
+use anchor_lang::Discriminator;
+
 use mango_v4::accounts_zerocopy::LoadZeroCopy;
-use mango_v4::state::MangoAccountValue;
+use mango_v4::state::{MangoAccount, MangoAccountValue};
 
 use anyhow::Context;
 
@@ -31,7 +33,14 @@ impl AccountFetcher {
 
     pub fn fetch_mango_account(&self, address: &Pubkey) -> anyhow::Result<MangoAccountValue> {
         let acc = self.fetch_raw(address)?;
-        Ok(MangoAccountValue::from_bytes(acc.data())
+
+        let data = acc.data();
+        let disc_bytes = &data[0..8];
+        if disc_bytes != &MangoAccount::discriminator() {
+            anyhow::bail!("not a mango account at {}", address);
+        }
+
+        Ok(MangoAccountValue::from_bytes(&data[8..])
             .with_context(|| format!("loading mango account {}", address))?)
     }
 

liquidator/src/util.rs

@@ -21,11 +21,14 @@ pub fn is_mango_account<'a>(
         return None;
     }
 
-    let mango_account = MangoAccountRefWithHeader::from_bytes(&data[8..]).expect("always ok");
-    if mango_account.fixed.group != *group_id {
-        return None;
+    if let Ok(mango_account) = MangoAccountRefWithHeader::from_bytes(&data[8..]) {
+        if mango_account.fixed.group != *group_id {
+            return None;
+        }
+        Some(mango_account)
+    } else {
+        None
     }
-    Some(mango_account)
 }
 
 pub fn is_mango_bank<'a>(