From 53a74c43c0a0fcc52c5b8584d1684074d66e23d4 Mon Sep 17 00:00:00 2001
From: Sean Young <sean@mess.org>
Date: Tue, 5 Dec 2023 14:25:41 +0000
Subject: [PATCH] do not serialize executable accounts

---
 programs/bpf_loader/src/serialization.rs | 51 +++++++++++++++---------
 1 file changed, 33 insertions(+), 18 deletions(-)

diff --git a/programs/bpf_loader/src/serialization.rs b/programs/bpf_loader/src/serialization.rs
index f9cbc2e752c54d..de60231759c5e6 100644
--- a/programs/bpf_loader/src/serialization.rs
+++ b/programs/bpf_loader/src/serialization.rs
@@ -335,8 +335,13 @@ fn serialize_parameters_unaligned(
                 s.write::<u8>(account.is_writable() as u8);
                 let vm_key_addr = s.write_all(account.get_key().as_ref());
                 let vm_lamports_addr = s.write::<u64>(account.get_lamports().to_le());
-                s.write::<u64>((account.get_data().len() as u64).to_le());
-                let vm_data_addr = s.write_account(&mut account)?;
+                let vm_data_addr = if account.is_executable() {
+                    s.write::<u64>(0u64.to_le());
+                    0
+                } else {
+                    s.write::<u64>((account.get_data().len() as u64).to_le());
+                    s.write_account(&mut account)?
+                };
                 let vm_owner_addr = s.write_all(account.get_owner().as_ref());
                 s.write::<u8>(account.is_executable() as u8);
                 s.write::<u64>((account.get_rent_epoch()).to_le());
@@ -389,7 +394,7 @@ pub fn deserialize_parameters_unaligned<I: IntoIterator<Item = usize>>(
             }
             start += size_of::<u64>() // lamports
                 + size_of::<u64>(); // data length
-            if copy_account_data {
+            if copy_account_data && !borrowed_account.is_executable() {
                 let data = buffer
                     .get(start..start + pre_len)
                     .ok_or(InstructionError::InvalidArgument)?;
@@ -471,8 +476,13 @@ fn serialize_parameters_aligned(
                 let vm_key_addr = s.write_all(borrowed_account.get_key().as_ref());
                 let vm_owner_addr = s.write_all(borrowed_account.get_owner().as_ref());
                 let vm_lamports_addr = s.write::<u64>(borrowed_account.get_lamports().to_le());
-                s.write::<u64>((borrowed_account.get_data().len() as u64).to_le());
-                let vm_data_addr = s.write_account(&mut borrowed_account)?;
+                let vm_data_addr = if borrowed_account.is_executable() {
+                    s.write::<u64>(0u64.to_le());
+                    0
+                } else {
+                    s.write::<u64>((borrowed_account.get_data().len() as u64).to_le());
+                    s.write_account(&mut borrowed_account)?
+                };
                 s.write::<u64>((borrowed_account.get_rent_epoch()).to_le());
                 accounts_metadata.push(SerializedAccountMetadata {
                     original_data_len: borrowed_account.get_data().len(),
@@ -535,11 +545,14 @@ pub fn deserialize_parameters_aligned<I: IntoIterator<Item = usize>>(
                 borrowed_account.set_lamports(lamports)?;
             }
             start += size_of::<u64>(); // lamports
-            let post_len = LittleEndian::read_u64(
+            let mut post_len = LittleEndian::read_u64(
                 buffer
                     .get(start..)
                     .ok_or(InstructionError::InvalidArgument)?,
             ) as usize;
+            if borrowed_account.is_executable() {
+                post_len = pre_len;
+            }
             start += size_of::<u64>(); // data length
             if post_len.saturating_sub(pre_len) > MAX_PERMITTED_DATA_INCREASE
                 || post_len > MAX_PERMITTED_DATA_LENGTH as usize
@@ -549,19 +562,21 @@ pub fn deserialize_parameters_aligned<I: IntoIterator<Item = usize>>(
             // The redundant check helps to avoid the expensive data comparison if we can
             let alignment_offset = (pre_len as *const u8).align_offset(BPF_ALIGN_OF_U128);
             if copy_account_data {
-                let data = buffer
-                    .get(start..start + post_len)
-                    .ok_or(InstructionError::InvalidArgument)?;
-                match borrowed_account
-                    .can_data_be_resized(post_len)
-                    .and_then(|_| borrowed_account.can_data_be_changed())
-                {
-                    Ok(()) => borrowed_account.set_data_from_slice(data)?,
-                    Err(err) if borrowed_account.get_data() != data => return Err(err),
-                    _ => {}
+                if !borrowed_account.is_executable() {
+                    let data = buffer
+                        .get(start..start + post_len)
+                        .ok_or(InstructionError::InvalidArgument)?;
+                    match borrowed_account
+                        .can_data_be_resized(post_len)
+                        .and_then(|_| borrowed_account.can_data_be_changed())
+                    {
+                        Ok(()) => borrowed_account.set_data_from_slice(data)?,
+                        Err(err) if borrowed_account.get_data() != data => return Err(err),
+                        _ => {}
+                    }
+                    start += pre_len; // data
                 }
-                start += pre_len; // data
-            } else {
+            } else if !borrowed_account.is_executable() {
                 // See Serializer::write_account() as to why we have this
                 // padding before the realloc region here.
                 start += BPF_ALIGN_OF_U128.saturating_sub(alignment_offset);