From d8d544e17e5816cc75ecb4e8238ec7e5e0c47fa3 Mon Sep 17 00:00:00 2001
From: Alex Pyattaev <alex.pyattaev@anza.xyz>
Date: Wed, 5 Mar 2025 09:04:58 +0000
Subject: [PATCH] comments from review

---
 gossip/src/crds_value.rs | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/gossip/src/crds_value.rs b/gossip/src/crds_value.rs
index 256c74392ee8fa..f97e29816340dc 100644
--- a/gossip/src/crds_value.rs
+++ b/gossip/src/crds_value.rs
@@ -15,7 +15,11 @@ use {
     solana_sanitize::{Sanitize, SanitizeError},
     solana_signature::Signature,
     solana_signer::Signer,
-    std::borrow::{Borrow, Cow},
+    std::{
+        borrow::{Borrow, Cow},
+        io::Cursor,
+        mem::MaybeUninit,
+    },
 };
 
 /// CrdsValue that is replicated across the cluster
@@ -228,13 +232,17 @@ impl<'de> Deserialize<'de> for CrdsValue {
             data: CrdsData,
         }
         let CrdsValue { signature, data } = CrdsValue::deserialize(deserializer)?;
-        let mut buffer = [0u8; PACKET_DATA_SIZE];
+        // To compute the hash of the received CrdsData we need to re-serialize it
+        // PACKET_DATA_SIZE is always enough since we have just received the value in a packet
+        let mut buffer: MaybeUninit<[u8; PACKET_DATA_SIZE]> = MaybeUninit::uninit();
+        // SAFETY: we are only using this buffer to store serialize results
+        let buf_ref = unsafe { buffer.assume_init_mut() };
         let position = {
-            let mut cursor = std::io::Cursor::new(buffer.as_mut());
+            let mut cursor = Cursor::new(buf_ref.as_mut());
             bincode::serialize_into(&mut cursor, &data).map_err(serde::de::Error::custom)?;
             cursor.position() as usize
         };
-        let hash = solana_sha256_hasher::hashv(&[signature.as_ref(), &buffer[0..position]]);
+        let hash = solana_sha256_hasher::hashv(&[signature.as_ref(), &buf_ref[0..position]]);
         Ok(Self {
             signature,
             data,