Re: [PATCH 1/6] efistub: pass uefi secureboot flag via fdt params
From: Ard Biesheuvel <ardb@kernel.org>
Date: 2020-09-11 17:06:16
Also in:
linux-doc, linux-efi, linux-integrity, lkml
On Fri, 4 Sep 2020 at 10:29, Chester Lin [off-list ref] wrote:
Add a new UEFI parameter: "linux,uefi-secure-boot" in fdt boot params as other architectures have done in their own boot data. For example, the boot_params->secure_boot in x86. Signed-off-by: Chester Lin <redacted>
Why do we need this flag? Can't the OS simply check the variable directly?
quoted hunk ↗ jump to hunk
--- drivers/firmware/efi/libstub/fdt.c | 39 +++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-)diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c index 11ecf3c4640e..c9a341e4715f 100644 --- a/drivers/firmware/efi/libstub/fdt.c +++ b/drivers/firmware/efi/libstub/fdt.c@@ -136,6 +136,10 @@ static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size, if (status) goto fdt_set_fail; + status = fdt_setprop_var(fdt, node, "linux,uefi-secure-boot", fdt_val32); + if (status) + goto fdt_set_fail; + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { efi_status_t efi_status;@@ -199,6 +203,24 @@ static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map) return EFI_SUCCESS; } +static efi_status_t update_fdt_secboot(void *fdt, u32 secboot) +{ + int node = fdt_path_offset(fdt, "/chosen"); + u32 fdt_val32; + int err; + + if (node < 0) + return EFI_LOAD_ERROR; + + fdt_val32 = cpu_to_fdt32(secboot); + + err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-secure-boot", fdt_val32); + if (err) + return EFI_LOAD_ERROR; + + return EFI_SUCCESS; +} + struct exit_boot_struct { efi_memory_desc_t *runtime_map; int *runtime_entry_count;@@ -208,6 +230,9 @@ struct exit_boot_struct { static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv) { + efi_status_t status; + enum efi_secureboot_mode secboot_status; + u32 secboot_var = 0; struct exit_boot_struct *p = priv; /* * Update the memory map with virtual addresses. The function will also@@ -217,7 +242,19 @@ static efi_status_t exit_boot_func(struct efi_boot_memmap *map, efi_get_virtmap(*map->map, *map->map_size, *map->desc_size, p->runtime_map, p->runtime_entry_count); - return update_fdt_memmap(p->new_fdt_addr, map); + status = update_fdt_memmap(p->new_fdt_addr, map); + + if (status != EFI_SUCCESS) + return status; + + secboot_status = efi_get_secureboot(); + + if (secboot_status == efi_secureboot_mode_enabled) + secboot_var = 1; + + status = update_fdt_secboot(p->new_fdt_addr, secboot_var); + + return status; } #ifndef MAX_FDT_SIZE --2.26.1
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