From a643375f4b175569bc3c03c7a3e758f845c1ccd9 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 4 Mar 2015 13:02:29 +0100 Subject: [PATCH] efi/libstub: Retrieve FDT size when loaded from UEFI config table When allocating memory for the copy of the FDT that the stub modifies and passes to the kernel, it uses the current size as an estimate of how much memory to allocate, and increases it page by page if it turns out to be too small. However, when loading the FDT from a UEFI configuration table, the estimated size is left at its default value of zero, and the allocation loop runs starting from zero all the way up to the allocation size that finally fits the updated FDT. Instead, retrieve the size of the FDT from the FDT header when loading it from the UEFI config table. Signed-off-by: Ard Biesheuvel Reviewed-by: Roy Franz Signed-off-by: Matt Fleming --- drivers/firmware/efi/libstub/arm-stub.c | 7 +++---- drivers/firmware/efi/libstub/efistub.h | 2 +- drivers/firmware/efi/libstub/fdt.c | 7 ++++++- 3 files changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index dcae482..e29560e 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -175,7 +175,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, unsigned long initrd_addr; u64 initrd_size = 0; unsigned long fdt_addr = 0; /* Original DTB */ - u64 fdt_size = 0; /* We don't get size from configuration table */ + unsigned long fdt_size = 0; char *cmdline_ptr = NULL; int cmdline_size = 0; unsigned long new_fdt_addr; @@ -239,8 +239,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, } else { status = handle_cmdline_files(sys_table, image, cmdline_ptr, "dtb=", - ~0UL, (unsigned long *)&fdt_addr, - (unsigned long *)&fdt_size); + ~0UL, &fdt_addr, &fdt_size); if (status != EFI_SUCCESS) { pr_efi_err(sys_table, "Failed to load device tree!\n"); @@ -252,7 +251,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, pr_efi(sys_table, "Using DTB from command line\n"); } else { /* Look for a device tree configuration table entry. */ - fdt_addr = (uintptr_t)get_fdt(sys_table); + fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size); if (fdt_addr) pr_efi(sys_table, "Using DTB from configuration table\n"); } diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 47437b1..e334a01 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -41,7 +41,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table, unsigned long fdt_addr, unsigned long fdt_size); -void *get_fdt(efi_system_table_t *sys_table); +void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size); void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, unsigned long desc_size, efi_memory_desc_t *runtime_map, diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c index 91da56c..ef5d764 100644 --- a/drivers/firmware/efi/libstub/fdt.c +++ b/drivers/firmware/efi/libstub/fdt.c @@ -323,7 +323,7 @@ fail: return EFI_LOAD_ERROR; } -void *get_fdt(efi_system_table_t *sys_table) +void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size) { efi_guid_t fdt_guid = DEVICE_TREE_GUID; efi_config_table_t *tables; @@ -336,6 +336,11 @@ void *get_fdt(efi_system_table_t *sys_table) for (i = 0; i < sys_table->nr_tables; i++) if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) { fdt = (void *) tables[i].table; + if (fdt_check_header(fdt) != 0) { + pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n"); + return NULL; + } + *fdt_size = fdt_totalsize(fdt); break; } -- 2.7.4