DRAFT: migtd: harden EnableLogArea handling (reserved validation + gated set_max_level)

src/migtd/src/bin/migtd/cvmemu.rs

@@ -14,9 +14,7 @@ use alloc::vec::Vec;
 use migtd;
 use migtd::driver::vmcall_raw::panic_with_guest_crash_reg_report;
 use migtd::migration::event;
-use migtd::migration::logging::{
-    create_logarea, enable_logarea, init_vmm_logger, u8_to_levelfilter,
-};
+use migtd::migration::logging::{create_logarea, enable_logarea, init_vmm_logger};
 use migtd::migration::session::{exchange_msk, report_status};
 use migtd::migration::MigrationResult;
 
@@ -480,12 +478,6 @@ fn handle_pre_mig_emu() -> i32 {
                             .map(|_| MigrationResult::Success)
                             .unwrap_or_else(|e| e);
 
-                            log::info!(migration_request_id = wfr_info.mig_request_id;
-                                "Setting log level to {}\n",
-                                wfr_info.log_max_level
-                            );
-                            log::set_max_level(u8_to_levelfilter(wfr_info.log_max_level));
-
                             if status == MigrationResult::Success {
                                 log::trace!(migration_request_id = wfr_info.mig_request_id; "Successfully completed Enable LogArea\n");
                             } else {

src/migtd/src/bin/migtd/main.rs

@@ -573,12 +573,6 @@ fn handle_pre_mig() {
                             .map(|_| MigrationResult::Success)
                             .unwrap_or_else(|e| e);
 
-                            log::info!( migration_request_id = wfr_info.mig_request_id;
-                                "Setting log level to {}\n",
-                                wfr_info.log_max_level
-                            );
-                            log::set_max_level(u8_to_levelfilter(wfr_info.log_max_level));
-
                             if status == MigrationResult::Success {
                                 log::trace!(migration_request_id = wfr_info.mig_request_id; "Successfully completed Enable LogArea\n");
                             } else {

src/migtd/src/migration/logging.rs

@@ -307,6 +307,9 @@ pub async fn enable_logarea(log_max_level: u8, request_id: u64, data: &mut Vec<u
         LOGGING_INFORMATION
             .logarea_initialized
             .store(true, Ordering::SeqCst);
+        // Keep the crate-global log gate in sync with the per-MigTD gate so
+        // both filters agree; only done on the validated success path.
+        log::set_max_level(u8_to_levelfilter(log_max_level));
         #[cfg(not(test))]
         log::info!( migration_request_id = request_id;
             "enable_logarea: Logging has been enabled with MaxLevel: {}\n",
@@ -316,7 +319,7 @@ pub async fn enable_logarea(log_max_level: u8, request_id: u64, data: &mut Vec<u
         Ok(())
     } else {
         log::error!( migration_request_id = request_id;
-            "enable_logarea: Logging has been enabled with MaxLevel: {}\n",
+            "enable_logarea: rejected request with invalid MaxLogLevel: {}\n",
             log_max_level
         );
         data.extend_from_slice(

src/migtd/src/migration/mod.rs

@@ -29,29 +29,6 @@ use r_efi::efi::Guid;
 use rust_std_stub::io;
 use scroll::{Pread, Pwrite};
 
-/// Implement `read_from_bytes(data_length, payload)` for a fixed-size
-/// `#[derive(Pread)]` struct. Validates `data_length == size_of::<Self>()`
-/// and rejects payloads with trailing bytes.
-#[cfg(feature = "vmcall-raw")]
-macro_rules! impl_read_from_bytes {
-    ($t:ty) => {
-        #[cfg(feature = "vmcall-raw")]
-        impl $t {
-            pub fn read_from_bytes(
-                data_length: u32,
-                payload: &[u8],
-            ) -> core::result::Result<Self, MigrationResult> {
-                if data_length != core::mem::size_of::<Self>() as u32 {
-                    return Err(MigrationResult::InvalidParameter);
-                }
-                payload
-                    .pread(0)
-                    .map_err(|_| MigrationResult::InvalidParameter)
-            }
-        }
-    };
-}
-
 /// Implement `read_from_bytes(data_length, payload)` for a struct whose layout
 /// starts with `mig_request_id: u64` followed by optional data bytes.
 /// Accepts either the full struct or just the `mig_request_id` (with the
@@ -239,7 +216,24 @@ pub struct EnableLogAreaInfo {
 }
 
 #[cfg(feature = "vmcall-raw")]
-impl_read_from_bytes!(EnableLogAreaInfo);
+impl EnableLogAreaInfo {
+    pub fn read_from_bytes(
+        data_length: u32,
+        payload: &[u8],
+    ) -> core::result::Result<Self, MigrationResult> {
+        if data_length != core::mem::size_of::<Self>() as u32 {
+            return Err(MigrationResult::InvalidParameter);
+        }
+        let info: Self = payload
+            .pread(0)
+            .map_err(|_| MigrationResult::InvalidParameter)?;
+        // GHCI 1.5 v6 Table 3-50: reserved bytes MUST be zero.
+        if info.reserved.iter().any(|&b| b != 0) {
+            return Err(MigrationResult::InvalidParameter);
+        }
+        Ok(info)
+    }
+}
 
 #[repr(C)]
 #[derive(Debug, Pread, Pwrite)]