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authorArd Biesheuvel <ardb@kernel.org>2023-04-18 15:49:51 +0200
committerArd Biesheuvel <ardb@kernel.org>2023-04-20 15:45:12 +0200
commit538bc0f40b364f2c7b81f11aa163f723b138b40f (patch)
treebf1902edf9c52086c6b67f3e1d6f441a09300b98 /drivers/firmware
parentbca2f3a9406b89961fbc6c92c52c6fc1fd91d35f (diff)
efi/zboot: Set forward edge CFI compat header flag if supported
Add some plumbing to the zboot EFI header generation to set the newly introduced DllCharacteristicsEx flag associated with forward edge CFI enforcement instructions (BTI on arm64, IBT on x86) x86 does not currently uses the zboot infrastructure, so let's wire it up only for arm64. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/efi/libstub/Makefile.zboot9
-rw-r--r--drivers/firmware/efi/libstub/zboot-header.S49
2 files changed, 39 insertions, 19 deletions
diff --git a/drivers/firmware/efi/libstub/Makefile.zboot b/drivers/firmware/efi/libstub/Makefile.zboot
index 2d7877023604..0a9dcc2b1373 100644
--- a/drivers/firmware/efi/libstub/Makefile.zboot
+++ b/drivers/firmware/efi/libstub/Makefile.zboot
@@ -1,7 +1,8 @@
# SPDX-License-Identifier: GPL-2.0
# to be include'd by arch/$(ARCH)/boot/Makefile after setting
-# EFI_ZBOOT_PAYLOAD, EFI_ZBOOT_BFD_TARGET and EFI_ZBOOT_MACH_TYPE
+# EFI_ZBOOT_PAYLOAD, EFI_ZBOOT_BFD_TARGET, EFI_ZBOOT_MACH_TYPE and
+# EFI_ZBOOT_FORWARD_CFI
quiet_cmd_copy_and_pad = PAD $@
cmd_copy_and_pad = cp $< $@ && \
@@ -44,10 +45,14 @@ OBJCOPYFLAGS_vmlinuz.o := -I binary -O $(EFI_ZBOOT_BFD_TARGET) \
$(obj)/vmlinuz.o: $(obj)/vmlinuz FORCE
$(call if_changed,objcopy)
+aflags-zboot-header-$(EFI_ZBOOT_FORWARD_CFI) := \
+ -DPE_DLL_CHAR_EX=IMAGE_DLLCHARACTERISTICS_EX_FORWARD_CFI_COMPAT
+
AFLAGS_zboot-header.o += -DMACHINE_TYPE=IMAGE_FILE_MACHINE_$(EFI_ZBOOT_MACH_TYPE) \
-DZBOOT_EFI_PATH="\"$(realpath $(obj)/vmlinuz.efi.elf)\"" \
-DZBOOT_SIZE_LEN=$(zboot-size-len-y) \
- -DCOMP_TYPE="\"$(comp-type-y)\""
+ -DCOMP_TYPE="\"$(comp-type-y)\"" \
+ $(aflags-zboot-header-y)
$(obj)/zboot-header.o: $(srctree)/drivers/firmware/efi/libstub/zboot-header.S FORCE
$(call if_changed_rule,as_o_S)
diff --git a/drivers/firmware/efi/libstub/zboot-header.S b/drivers/firmware/efi/libstub/zboot-header.S
index 053aba073594..fb676ded47fa 100644
--- a/drivers/firmware/efi/libstub/zboot-header.S
+++ b/drivers/firmware/efi/libstub/zboot-header.S
@@ -78,9 +78,36 @@ __efistub_efi_zboot_header:
.quad 0 // ExceptionTable
.quad 0 // CertificationTable
.quad 0 // BaseRelocationTable
-#ifdef CONFIG_DEBUG_EFI
+#if defined(PE_DLL_CHAR_EX) || defined(CONFIG_DEBUG_EFI)
.long .Lefi_debug_table - .Ldoshdr // DebugTable
.long .Lefi_debug_table_size
+
+ .section ".rodata", "a"
+ .p2align 2
+.Lefi_debug_table:
+ // EFI_IMAGE_DEBUG_DIRECTORY_ENTRY[]
+#ifdef PE_DLL_CHAR_EX
+ .long 0 // Characteristics
+ .long 0 // TimeDateStamp
+ .short 0 // MajorVersion
+ .short 0 // MinorVersion
+ .long IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS // Type
+ .long 4 // SizeOfData
+ .long 0 // RVA
+ .long .Lefi_dll_characteristics_ex - .Ldoshdr // FileOffset
+#endif
+#ifdef CONFIG_DEBUG_EFI
+ .long 0 // Characteristics
+ .long 0 // TimeDateStamp
+ .short 0 // MajorVersion
+ .short 0 // MinorVersion
+ .long IMAGE_DEBUG_TYPE_CODEVIEW // Type
+ .long .Lefi_debug_entry_size // SizeOfData
+ .long 0 // RVA
+ .long .Lefi_debug_entry - .Ldoshdr // FileOffset
+#endif
+ .set .Lefi_debug_table_size, . - .Lefi_debug_table
+ .previous
#endif
.Lsection_table:
@@ -110,23 +137,11 @@ __efistub_efi_zboot_header:
.set .Lsection_count, (. - .Lsection_table) / 40
+#ifdef PE_DLL_CHAR_EX
+.Lefi_dll_characteristics_ex:
+ .long PE_DLL_CHAR_EX
+#endif
#ifdef CONFIG_DEBUG_EFI
- .section ".rodata", "a"
- .align 2
-.Lefi_debug_table:
- // EFI_IMAGE_DEBUG_DIRECTORY_ENTRY
- .long 0 // Characteristics
- .long 0 // TimeDateStamp
- .short 0 // MajorVersion
- .short 0 // MinorVersion
- .long IMAGE_DEBUG_TYPE_CODEVIEW // Type
- .long .Lefi_debug_entry_size // SizeOfData
- .long 0 // RVA
- .long .Lefi_debug_entry - .Ldoshdr // FileOffset
-
- .set .Lefi_debug_table_size, . - .Lefi_debug_table
- .previous
-
.Lefi_debug_entry:
// EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY
.ascii "NB10" // Signature