x86/boot: Fix memremap of setup_indirect structures

As documented, the setup_indirect structure is nested inside
the setup_data structures in the setup_data list. The code currently
accesses the fields inside the setup_indirect structure but only
the sizeof(struct setup_data) is being memremapped. No crash
occurred but this is just due to how the area is remapped under the
covers.

Properly memremap both the setup_data and setup_indirect structures
in these cases before accessing them.

Fixes: b3c72fc9a78e ("x86/boot: Introduce setup_indirect")
Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1645668456-22036-2-git-send-email-ross.philipson@oracle.com

1 files changed, 28 insertions, 9 deletions

diff --git a/arch/x86/kernel/kdebugfs.c b/arch/x86/kernel/kdebugfs.c
index 64b6da95af98..e2e89bebcbc3 100644
--- a/arch/x86/kernel/kdebugfs.c
+++ b/arch/x86/kernel/kdebugfs.c
@@ -88,11 +88,13 @@ create_setup_data_node(struct dentry *parent, int no,
 
 static int __init create_setup_data_nodes(struct dentry *parent)
 {
+	struct setup_indirect *indirect;
 	struct setup_data_node *node;
 	struct setup_data *data;
-	int error;
+	u64 pa_data, pa_next;
 	struct dentry *d;
-	u64 pa_data;
+	int error;
+	u32 len;
 	int no = 0;
 
 	d = debugfs_create_dir("setup_data", parent);
@@ -112,12 +114,29 @@ static int __init create_setup_data_nodes(struct dentry *parent)
 			error = -ENOMEM;
 			goto err_dir;
 		}
-
-		if (data->type == SETUP_INDIRECT &&
-		    ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
-			node->paddr = ((struct setup_indirect *)data->data)->addr;
-			node->type  = ((struct setup_indirect *)data->data)->type;
-			node->len   = ((struct setup_indirect *)data->data)->len;
+		pa_next = data->next;
+
+		if (data->type == SETUP_INDIRECT) {
+			len = sizeof(*data) + data->len;
+			memunmap(data);
+			data = memremap(pa_data, len, MEMREMAP_WB);
+			if (!data) {
+				kfree(node);
+				error = -ENOMEM;
+				goto err_dir;
+			}
+
+			indirect = (struct setup_indirect *)data->data;
+
+			if (indirect->type != SETUP_INDIRECT) {
+				node->paddr = indirect->addr;
+				node->type  = indirect->type;
+				node->len   = indirect->len;
+			} else {
+				node->paddr = pa_data;
+				node->type  = data->type;
+				node->len   = data->len;
+			}
 		} else {
 			node->paddr = pa_data;
 			node->type  = data->type;
@@ -125,7 +144,7 @@ static int __init create_setup_data_nodes(struct dentry *parent)
 		}
 
 		create_setup_data_node(d, no, node);
-		pa_data = data->next;
+		pa_data = pa_next;
 
 		memunmap(data);
 		no++;