From 59d002ce808ce30c6d9927ff9705e1c57f3dd755 Mon Sep 17 00:00:00 2001
From: Felix Hilgers <felix.hilgers@fau.de>
Date: Wed, 11 Dec 2024 00:38:24 +0100
Subject: [PATCH] fix: undefined behavior ebpf

see: https://doc.rust-lang.org/beta/std/ptr/macro.addr_of_mut.html

Signed-off-by: Felix Hilgers <felix.hilgers@fau.de>
---
 rust/backend/ebpf/src/jni_references.rs | 11 ++++++-----
 rust/backend/ebpf/src/sys_sendmsg.rs    | 14 +++++++-------
 rust/backend/ebpf/src/vfs_write.rs      | 15 ++++++++-------
 3 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/rust/backend/ebpf/src/jni_references.rs b/rust/backend/ebpf/src/jni_references.rs
index f443004..129f15c 100644
--- a/rust/backend/ebpf/src/jni_references.rs
+++ b/rust/backend/ebpf/src/jni_references.rs
@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-use core::mem;
+use core::{mem, ptr::addr_of_mut};
 use aya_ebpf::{maps::RingBuf, macros::{uprobe, map}, programs::{ProbeContext}, EbpfContext, helpers::bpf_ktime_get_ns};
 use aya_ebpf::maps::HashMap;
 use aya_log_ebpf::error;
@@ -38,10 +38,11 @@ fn handle_trace(ctx: ProbeContext, method: JNIMethodName) -> u32 {
     let entry_mut = entry.as_mut_ptr();
 
     unsafe {
-        (*entry_mut).pid = pid;
-        (*entry_mut).tid = tid;
-        (*entry_mut).begin_time_stamp = time_stamp;
-        (*entry_mut).method_name = method;
+        (&raw mut (*entry_mut).pid).write(pid);
+        (&raw mut (*entry_mut).pid).write(pid);
+        (&raw mut (*entry_mut).tid).write(tid);
+        (&raw mut (*entry_mut).begin_time_stamp).write(time_stamp);
+        (&raw mut (*entry_mut).method_name).write(method);
     }
 
     entry.submit(0);
diff --git a/rust/backend/ebpf/src/sys_sendmsg.rs b/rust/backend/ebpf/src/sys_sendmsg.rs
index dae1afe..b73788d 100644
--- a/rust/backend/ebpf/src/sys_sendmsg.rs
+++ b/rust/backend/ebpf/src/sys_sendmsg.rs
@@ -2,6 +2,8 @@
 //
 // SPDX-License-Identifier: MIT
 
+use core::ptr::addr_of_mut;
+
 use aya_ebpf::{macros::{tracepoint, map}, maps::{HashMap, RingBuf}, programs::{TracePointContext}, EbpfContext, helpers::gen::bpf_ktime_get_ns};
 use aya_log_ebpf::error;
 use backend_common::{generate_id, SysSendmsgCall};
@@ -84,16 +86,14 @@ pub fn sys_exit_sendmsg(ctx: TracePointContext) -> u32 {
     let entry_mut = entry.as_mut_ptr();
 
     unsafe {
-        (*entry_mut).pid = pid;
-        (*entry_mut).tid = tid;
-        (*entry_mut).begin_time_stamp = data.begin_time_stamp;
-        (*entry_mut).fd = data.fd;
-        (*entry_mut).duration_nano_sec = duration_nano_sec;
+        (&raw mut (*entry_mut).pid).write(pid);
+        (&raw mut (*entry_mut).tid).write(tid);
+        (&raw mut (*entry_mut).begin_time_stamp).write(data.begin_time_stamp);
+        (&raw mut (*entry_mut).fd).write(data.fd);
+        (&raw mut (*entry_mut).duration_nano_sec).write(duration_nano_sec);
     }
 
-
     entry.submit(0);
 
-
     0
 }
diff --git a/rust/backend/ebpf/src/vfs_write.rs b/rust/backend/ebpf/src/vfs_write.rs
index f4f6a83..677c0a5 100644
--- a/rust/backend/ebpf/src/vfs_write.rs
+++ b/rust/backend/ebpf/src/vfs_write.rs
@@ -2,6 +2,8 @@
 //
 // SPDX-License-Identifier: MIT
 
+use core::ptr::addr_of_mut;
+
 use aya_ebpf::{
     macros::{kprobe, map, kretprobe},
     maps::{HashMap, RingBuf},
@@ -97,14 +99,13 @@ pub fn vfs_write_ret(ctx: RetProbeContext) -> Result<(), u32> {
     };
 
     let entry_mut = entry.as_mut_ptr();
-
+    
     unsafe {
-        (*entry_mut).pid = pid;
-        (*entry_mut).tid = tid;
-        (*entry_mut).begin_time_stamp = data.begin_time_stamp;
-        (*entry_mut).fp = data.fp;
-        (*entry_mut).bytes_written = data.bytes_written;
-
+        (&raw mut (*entry_mut).pid).write(pid);
+        (&raw mut (*entry_mut).tid).write(tid);
+        (&raw mut (*entry_mut).begin_time_stamp).write(data.begin_time_stamp);
+        (&raw mut (*entry_mut).fp).write(data.fp);
+        (&raw mut (*entry_mut).bytes_written).write(data.bytes_written);
     }
 
     entry.submit(0);