no failure on init_module failing to read args

Signed-off-by: Quentin JEROME <[email protected]>
kunai-project · Oct 10, 2023 · 76d5ff6 · 76d5ff6
1 parent d41d60a
commit 76d5ff6
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Showing 2 changed files with 35 additions and 7 deletions.
diff --git a/kunai-ebpf/src/error.rs b/kunai-ebpf/src/error.rs
@@ -63,16 +63,36 @@ pub enum ProbeError {
     CgroupError(cgroup::Error),
 }
 
-#[macro_export]
+/// log a ProbeError using Aya log
 macro_rules! log_err {
     ($ctx:expr, $err:expr) => {
-        //aya_log_ebpf::error!($ctx, "{}: {}", $err.name(), $err.description());
-        aya_log_ebpf::error!($ctx, "{}", $err.name());
+        log_err!($ctx, "", $err)
+    };
+    ($ctx:expr, $msg:expr, $err:expr) => {
+        if $msg.is_empty() {
+            aya_log_ebpf::error!($ctx, "{}", $err.name())
+        } else {
+            aya_log_ebpf::error!($ctx, "{}: {}", $msg, $err.name())
+        }
     };
 }
 
 pub(crate) use log_err;
 
+/// if Result is an Err(BpfError), log it with Aya log
+macro_rules! log_result_err {
+    ($ctx:expr, $res:expr) => {
+        log_result_err!($ctx, "", $res)
+    };
+    ($ctx:expr, $msg:expr, $res:expr) => {
+        if let Err(e) = $res {
+            log_err!($ctx, $msg, e)
+        }
+    };
+}
+
+pub(crate) use log_result_err;
+
 impl From<syscalls::Error> for ProbeError {
     fn from(value: syscalls::Error) -> Self {
         Self::SyscallError(value)

diff --git a/kunai-ebpf/src/probes/init_module.rs b/kunai-ebpf/src/probes/init_module.rs
@@ -65,10 +65,18 @@ unsafe fn try_sys_enter_init_module(ctx: &TracePointContext) -> ProbeResult<()>
     // setting event data
     event.data.umod = args.umod;
     event.data.len = args.len;
-    event
-        .data
-        .uargs
-        .read_user_str_bytes(args.uargs as *const u8)?;
+
+    // Aya currently reports an error on empty string being read
+    // so until Aya is upgraded some errors might pop up while there
+    // is none.
+    log_result_err!(
+        ctx,
+        "failed to read uargs",
+        event
+            .data
+            .uargs
+            .read_user_str_bytes(args.uargs as *const u8)
+    );
 
     INIT_MODULE_TRACKING
         .insert(&key, event, 0)