Add the flag GRUB_MM_ADD_REGION_IN_RANGE for the grub memory
allocator for it to allocate memory only in a span of
DEFAULT_MAX_COMBINED_SIZE around where EFI loaded grub.
Signed-off-by: Adriano Cordova <adriano.cord...@canonical.com>
---
grub-core/kern/efi/mm.c | 56 ++++++++++++++++++++++++++++++++++++++---
include/grub/mm.h | 1 +
2 files changed, 53 insertions(+), 4 deletions(-)
diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index df238b165..47cd297a5 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -41,6 +41,9 @@
/* The default heap size for GRUB itself in bytes. */
#define DEFAULT_HEAP_SIZE 0x2000000
+/* The default combined size of image and allocated memory regions */
+#define DEFAULT_MAX_COMBINED_SIZE 0x80000000ULL /* 2 GiB */
+
static void *finish_mmap_buf = 0;
static grub_efi_uintn_t finish_mmap_size = 0;
static grub_efi_uintn_t finish_key = 0;
@@ -487,6 +490,38 @@ filter_memory_map (grub_efi_memory_descriptor_t
*memory_map,
return filtered_desc;
}
+static grub_err_t
+check_range (grub_efi_physical_address_t region_start, grub_efi_uint64_t pages)
+{
+ grub_efi_loaded_image_t *image;
+ grub_efi_physical_address_t region_end;
+ grub_efi_physical_address_t range_start, range_end;
+ static grub_efi_physical_address_t image_start;
+ static grub_efi_physical_address_t image_end;
+
+ if (!image_start)
+ {
+ image = grub_efi_get_loaded_image (grub_efi_image_handle);
+ if (!image)
+ return 0;
+ image_start = (grub_efi_physical_address_t) (grub_addr_t)
image->image_base;
+ image_end = image_start + image->image_size;
+ }
+
+ region_end = region_start + PAGES_TO_BYTES(pages);
+
+ range_start = (image_start < region_start) ? image_start : region_start;
+ range_end = (image_end > region_end) ? image_end : region_end;
+
+ if ((range_end - range_start) > DEFAULT_MAX_COMBINED_SIZE)
+ return GRUB_ERR_OUT_OF_MEMORY;
+
+ image_start = range_start;
+ image_end = range_end;
+
+ return GRUB_ERR_NONE;
+}
+
/* Add memory regions. */
static grub_err_t
add_memory_regions (grub_efi_memory_descriptor_t *memory_map,
@@ -496,6 +531,7 @@ add_memory_regions (grub_efi_memory_descriptor_t
*memory_map,
unsigned int flags)
{
grub_efi_memory_descriptor_t *desc;
+ grub_err_t err;
for (desc = memory_map;
desc < memory_map_end;
@@ -512,10 +548,22 @@ add_memory_regions (grub_efi_memory_descriptor_t
*memory_map,
continue;
if (pages > required_pages)
- {
- start += PAGES_TO_BYTES (pages - required_pages);
- pages = required_pages;
- }
+ {
+ start += PAGES_TO_BYTES (pages - required_pages);
+ if ((flags & GRUB_MM_ADD_REGION_IN_RANGE) && check_range(start,
required_pages))
+ {
+ start -= PAGES_TO_BYTES (pages - required_pages);
+ err = check_range(start, required_pages);
+ }
+ pages = required_pages;
+ } else {
+ if ((flags & GRUB_MM_ADD_REGION_IN_RANGE))
+ err = check_range(start, required_pages);
+ }
+
+ if (err != GRUB_ERR_NONE)
+ return err;
+
addr = grub_efi_allocate_pages_real (start, pages,
GRUB_EFI_ALLOCATE_ADDRESS,
diff --git a/include/grub/mm.h b/include/grub/mm.h
index 51ec0b8f9..9a0c99b99 100644
--- a/include/grub/mm.h
+++ b/include/grub/mm.h
@@ -31,6 +31,7 @@
#define GRUB_MM_ADD_REGION_NONE 0
#define GRUB_MM_ADD_REGION_CONSECUTIVE (1 << 0)
+#define GRUB_MM_ADD_REGION_IN_RANGE (1 << 1)
/*
* Function used to request memory regions of `grub_size_t` bytes. The second
--
2.48.1
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