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kern/efi/mm: Change grub_efi_mm_add_regions() to keep track of map allocation size

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If the map was too big for the initial allocation, it was freed and replaced
with a bigger one, but the free call still used the hard-coded size.

Seems like this wasn't hit for a long time, because most firmware maps
fit into 12K.

This bug was triggered on Project Mu firmware with a big memory map, and
results in the heap getting trashed and the firmware ASSERTING on
corrupted heap guard values when GRUB exits.

Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Mate Kukri authored and Daniel Kiper committed 2024-06-20 15:30:32 +02:00
1 parent b990df0bef
commit dc0a3a27d6
1 file changed
+7 -7
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grub-core/kern/efi/mm.c
+7 -7
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@@ -574,13 +574,15 @@ grub_efi_mm_add_regions (grub_size_t required_bytes, unsigned int flags)
grub_efi_memory_descriptor_t *memory_map_end; grub_efi_memory_descriptor_t *memory_map_end;
grub_efi_memory_descriptor_t *filtered_memory_map; grub_efi_memory_descriptor_t *filtered_memory_map;
grub_efi_memory_descriptor_t *filtered_memory_map_end; grub_efi_memory_descriptor_t *filtered_memory_map_end;
grub_efi_uintn_t alloc_size;
grub_efi_uintn_t map_size; grub_efi_uintn_t map_size;
grub_efi_uintn_t desc_size; grub_efi_uintn_t desc_size;
grub_err_t err; grub_err_t err;
int mm_status; int mm_status;
/* Prepare a memory region to store two memory maps. */ /* Prepare a memory region to store two memory maps. */
memory_map = grub_efi_allocate_any_pages (2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE)); alloc_size = 2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE);
memory_map = grub_efi_allocate_any_pages (alloc_size);
if (! memory_map) if (! memory_map)
return grub_error (GRUB_ERR_OUT_OF_MEMORY, "cannot allocate memory for memory map"); return grub_error (GRUB_ERR_OUT_OF_MEMORY, "cannot allocate memory for memory map");
@@ -591,14 +593,13 @@ grub_efi_mm_add_regions (grub_size_t required_bytes, unsigned int flags)
if (mm_status == 0) if (mm_status == 0)
{ {
grub_efi_free_pages grub_efi_free_pages ((grub_efi_physical_address_t)(grub_addr_t) memory_map, alloc_size);
((grub_efi_physical_address_t) ((grub_addr_t) memory_map),
2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE));
/* Freeing/allocating operations may increase memory map size. */ /* Freeing/allocating operations may increase memory map size. */
map_size += desc_size * 32; map_size += desc_size * 32;
memory_map = grub_efi_allocate_any_pages (2 * BYTES_TO_PAGES (map_size)); alloc_size = 2 * BYTES_TO_PAGES (map_size);
memory_map = grub_efi_allocate_any_pages (alloc_size);
if (! memory_map) if (! memory_map)
return grub_error (GRUB_ERR_OUT_OF_MEMORY, "cannot allocate memory for new memory map"); return grub_error (GRUB_ERR_OUT_OF_MEMORY, "cannot allocate memory for new memory map");
@@ -642,8 +643,7 @@ grub_efi_mm_add_regions (grub_size_t required_bytes, unsigned int flags)
#endif #endif
/* Release the memory maps. */ /* Release the memory maps. */
grub_efi_free_pages ((grub_addr_t) memory_map, grub_efi_free_pages ((grub_efi_physical_address_t)(grub_addr_t) memory_map, alloc_size);
2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE));
return GRUB_ERR_NONE; return GRUB_ERR_NONE;
} }