X86 will pass setup_data region while necessary, these regions could be
overwitten by kernel due to kaslr.
Thus iterate and add setup regions to mem_avoid[] in this patch.
Set max mem avoid entries 32, hopefully it will be enough.
Signed-off-by: Dave Young <dyo...@redhat.com>
---
arch/x86/boot/compressed/aslr.c | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
Index: linux-2.6/arch/x86/boot/compressed/aslr.c
===================================================================
--- linux-2.6.orig/arch/x86/boot/compressed/aslr.c
+++ linux-2.6/arch/x86/boot/compressed/aslr.c
@@ -110,8 +110,9 @@ struct mem_vector {
unsigned long size;
};
-#define MEM_AVOID_MAX 5
+#define MEM_AVOID_MAX 32
static struct mem_vector mem_avoid[MEM_AVOID_MAX];
+static int mem_avoid_nr;
static bool mem_contains(struct mem_vector *region, struct mem_vector *item)
{
@@ -135,6 +136,28 @@ static bool mem_overlaps(struct mem_vect
return true;
}
+static void mem_avoid_setup_data(void)
+{
+ struct setup_data *data;
+ u64 pa_data;
+
+ if (mem_avoid_nr >= MEM_AVOID_MAX) {
+ debug_putstr("KASLR: too many setup_data ranges.\n");
+ return;
+ }
+
+ pa_data = real_mode->hdr.setup_data;
+ while (pa_data) {
+ data = (struct setup_data *)pa_data;
+ if (pa_data < CONFIG_RANDOMIZE_BASE_MAX_OFFSET) {
+ mem_avoid[mem_avoid_nr].start = pa_data;
+ mem_avoid[mem_avoid_nr].size = sizeof(*data) +
data->len;
+ mem_avoid_nr++;
+ }
+ pa_data = data->next;
+ }
+}
+
static void mem_avoid_init(unsigned long input, unsigned long input_size,
unsigned long output, unsigned long output_size)
{
@@ -177,6 +200,9 @@ static void mem_avoid_init(unsigned long
/* Avoid stack memory. */
mem_avoid[4].start = (unsigned long)free_mem_end_ptr;
mem_avoid[4].size = BOOT_STACK_SIZE;
+ mem_avoid_nr = 5;
+
+ mem_avoid_setup_data();
}
/* Does this memory vector overlap a known avoided area? */
@@ -184,7 +210,7 @@ static bool mem_avoid_overlap(struct mem
{
int i;
- for (i = 0; i < MEM_AVOID_MAX; i++) {
+ for (i = 0; i < mem_avoid_nr; i++) {
if (mem_overlaps(img, &mem_avoid[i]))
return true;
}
--
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