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, 30 insertions, 11 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index bc0657f0deed..f267205f2d5a 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -995,8 +995,10 @@ early_param("memmap", parse_memmap_opt);
  */
 void __init e820__reserve_setup_data(void)
 {
+	struct setup_indirect *indirect;
 	struct setup_data *data;
-	u64 pa_data;
+	u64 pa_data, pa_next;
+	u32 len;
 
 	pa_data = boot_params.hdr.setup_data;
 	if (!pa_data)
@@ -1004,6 +1006,14 @@ void __init e820__reserve_setup_data(void)
 
 	while (pa_data) {
 		data = early_memremap(pa_data, sizeof(*data));
+		if (!data) {
+			pr_warn("e820: failed to memremap setup_data entry\n");
+			return;
+		}
+
+		len = sizeof(*data);
+		pa_next = data->next;
+
 		e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
 
 		/*
@@ -1015,18 +1025,27 @@ void __init e820__reserve_setup_data(void)
 						 sizeof(*data) + data->len,
 						 E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
 
-		if (data->type == SETUP_INDIRECT &&
-		    ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
-			e820__range_update(((struct setup_indirect *)data->data)->addr,
-					   ((struct setup_indirect *)data->data)->len,
-					   E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
-			e820__range_update_kexec(((struct setup_indirect *)data->data)->addr,
-						 ((struct setup_indirect *)data->data)->len,
-						 E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
+		if (data->type == SETUP_INDIRECT) {
+			len += data->len;
+			early_memunmap(data, sizeof(*data));
+			data = early_memremap(pa_data, len);
+			if (!data) {
+				pr_warn("e820: failed to memremap indirect setup_data\n");
+				return;
+			}
+
+			indirect = (struct setup_indirect *)data->data;
+
+			if (indirect->type != SETUP_INDIRECT) {
+				e820__range_update(indirect->addr, indirect->len,
+						   E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
+				e820__range_update_kexec(indirect->addr, indirect->len,
+							 E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
+			}
 		}
 
-		pa_data = data->next;
-		early_memunmap(data, sizeof(*data));
+		pa_data = pa_next;
+		early_memunmap(data, len);
 	}
 
 	e820__update_table(e820_table);