diff options
Diffstat (limited to 'drivers/firmware/efi/memattr.c')
| -rw-r--r-- | drivers/firmware/efi/memattr.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/drivers/firmware/efi/memattr.c b/drivers/firmware/efi/memattr.c index ab85bf8e165a..c38b1a335590 100644 --- a/drivers/firmware/efi/memattr.c +++ b/drivers/firmware/efi/memattr.c @@ -22,6 +22,7 @@ unsigned long __ro_after_init efi_mem_attr_table = EFI_INVALID_TABLE_ADDR; int __init efi_memattr_init(void) { efi_memory_attributes_table_t *tbl; + unsigned long size; if (efi_mem_attr_table == EFI_INVALID_TABLE_ADDR) return 0; @@ -39,7 +40,22 @@ int __init efi_memattr_init(void) goto unmap; } - tbl_size = sizeof(*tbl) + tbl->num_entries * tbl->desc_size; + + /* + * Sanity check: the Memory Attributes Table contains up to 3 entries + * for each entry of type EfiRuntimeServicesCode in the EFI memory map. + * So if the size of the table exceeds 3x the size of the entire EFI + * memory map, there is clearly something wrong, and the table should + * just be ignored altogether. + */ + size = tbl->num_entries * tbl->desc_size; + if (size > 3 * efi.memmap.nr_map * efi.memmap.desc_size) { + pr_warn(FW_BUG "Corrupted EFI Memory Attributes Table detected! (version == %u, desc_size == %u, num_entries == %u)\n", + tbl->version, tbl->desc_size, tbl->num_entries); + goto unmap; + } + + tbl_size = sizeof(*tbl) + size; memblock_reserve(efi_mem_attr_table, tbl_size); set_bit(EFI_MEM_ATTR, &efi.flags); @@ -164,7 +180,7 @@ int __init efi_memattr_apply_permissions(struct mm_struct *mm, bool valid; char buf[64]; - valid = entry_is_valid((void *)tbl->entry + i * tbl->desc_size, + valid = entry_is_valid(efi_memdesc_ptr(tbl->entry, tbl->desc_size, i), &md); size = md.num_pages << EFI_PAGE_SHIFT; if (efi_enabled(EFI_DBG) || !valid) |