dm-ima: Handle race between rename and table swap

a device rename could happen after do_resume() removed the inactive
table that it was swapping to out of the hash cell, but before it was
made the active table. In this case, the table metadata would still
have the old name. Update the swapped table's metadata to avoid this.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

diff --git a/drivers/md/dm-ima.c b/drivers/md/dm-ima.c
index f563c4381489f5b7b733c7abb46cd4c7b815ba02..47af99c9b79c6f712259855eebf06e15297dee24 100644 (file)
--- a/drivers/md/dm-ima.c
+++ b/drivers/md/dm-ima.c
@@ -373,6 +373,19 @@ void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap,
                kfree(md->ima.active_table.device_metadata);
                md->ima.active_table = context->table;
                memset(&context->table, 0, sizeof(context->table));
+               if (md->ima.active_table.device_metadata) {
+                       /*
+                        * A rename could have happened while the swap was
+                        * going on. In that case, the saved table info would
+                        * still have the old name. Update the metadata to be
+                        * sure that it has the current name
+                        */
+                       struct dm_ima_device_table_metadata *table = &md->ima.active_table;
+                       fix_context_strings(context);
+                       dm_ima_copy_device_data(md, table->device_metadata,
+                                               context, table->num_targets);
+                       table->device_metadata_len = strlen(table->device_metadata);
+               }
        }
 
        if (md->ima.active_table.device_metadata) {