This patch adds support for bundling the xen.efi hypervisor, the xen.cfg
configuration file, the Linux kernel and initrd, as well as the XSM, and
CPU microcode into a single "unified" EFI executable. The resulting EFI
executable can be invoked directly from the UEFI Boot Manager, removing
the need to use a separate loader like grub as well as removing
dependencies on local filesystem access.
It is inspired by systemd-boot's unified kernel technique and borrows the
function to locate PE sections from systemd's LGPL'ed code. During EFI
boot, Xen looks at its own loaded image to locate the PE sections for
the configuration, kernel, etc, which are included after building xen.efi
using objcopy to add named sections for each input file. This allows an
administrator to update the components independently without requiring
rebuilding xen.
The unified image can also be signed by sbsigntool for verification
by UEFI Secure Boot. If secure boot is enabled, the Xen command line
arguments are ignored. Unlike the shim based verification, the signature
covers the entire Xen+config+kernel+initrd unified file. This also ensures
that properly configured platforms will measure the entire runtime into
the TPM for unsealing secrets or remote attestation.
Signed-off-by: Trammell Hudson <hudson@trmm.net>
diff --git a/xen/Makefile b/xen/Makefile
index a87bb225dc..e4e4c6d5c1 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -355,7 +355,7 @@ $(TARGET): delete-unfresh-files
$(MAKE) -C tools
$(MAKE) -f $(BASEDIR)/Rules.mk include/xen/compile.h
[ -e include/asm ] || ln -sf asm-$(TARGET_ARCH) include/asm
- [ -e arch/$(TARGET_ARCH)/efi ] && for f in boot.c runtime.c compat.c efi.h;\
+ [ -e arch/$(TARGET_ARCH)/efi ] && for f in boot.c pe.c runtime.c compat.c efi.h;\
do test -r arch/$(TARGET_ARCH)/efi/$$f || \
ln -nsf ../../../common/efi/$$f arch/$(TARGET_ARCH)/efi/; \
done; \
diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index 6527cb0bdf..483dec465d 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -395,7 +395,7 @@ static void __init efi_arch_cfg_file_early(EFI_FILE_HANDLE dir_handle, char *sec
blexit(L"Unable to create new FDT");
}
-static void __init efi_arch_cfg_file_late(EFI_FILE_HANDLE dir_handle, char *section)
+static void __init efi_arch_cfg_file_late(EFI_LOADED_IMAGE * image, EFI_FILE_HANDLE dir_handle, char *section)
{
}
diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile
index 4b2b010a80..ae666aa14c 100644
--- a/xen/arch/x86/efi/Makefile
+++ b/xen/arch/x86/efi/Makefile
@@ -8,7 +8,7 @@ cmd_objcopy_o_ihex = $(OBJCOPY) -I ihex -O binary $< $@
boot.init.o: buildid.o
-EFIOBJ := boot.init.o compat.o runtime.o
+EFIOBJ := boot.init.o pe.init.o compat.o runtime.o
$(call cc-option-add,cflags-stack-boundary,CC,-mpreferred-stack-boundary=4)
$(EFIOBJ): CFLAGS-stack-boundary := $(cflags-stack-boundary)
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 7188c9a551..e2650c0440 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -276,9 +276,11 @@ static void __init efi_arch_cfg_file_early(EFI_FILE_HANDLE dir_handle, char *sec
{
}
-static void __init efi_arch_cfg_file_late(EFI_FILE_HANDLE dir_handle, char *section)
+static void __init efi_arch_cfg_file_late(EFI_LOADED_IMAGE * image, EFI_FILE_HANDLE dir_handle, char *section)
{
union string name;
+ if ( read_section(image, ".ucode", &ucode, NULL) )
+ return;
name.s = get_value(&cfg, section, "ucode");
if ( !name.s )
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 0273f79152..ba691b1890 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -156,6 +156,7 @@ SECTIONS
__note_gnu_build_id_end = .;
} :note :text
#elif defined(BUILD_ID_EFI)
+ . = ALIGN(32); /* workaround binutils section overlap bug */
DECL_SECTION(.buildid) {
__note_gnu_build_id_start = .;
*(.buildid)
diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 5a520bf21d..258433331f 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -102,6 +102,7 @@ union string {
struct file {
UINTN size;
+ bool need_to_free;
union {
EFI_PHYSICAL_ADDRESS addr;
void *ptr;
@@ -121,6 +122,8 @@ static CHAR16 *s2w(union string *str);
static char *w2s(const union string *str);
static bool read_file(EFI_FILE_HANDLE dir_handle, CHAR16 *name,
struct file *file, char *options);
+static bool read_section(EFI_LOADED_IMAGE * image,
+ char * name, struct file *file, char *options);
static size_t wstrlen(const CHAR16 * s);
static int set_color(u32 mask, int bpp, u8 *pos, u8 *sz);
static bool match_guid(const EFI_GUID *guid1, const EFI_GUID *guid2);
@@ -330,13 +333,13 @@ static void __init noreturn blexit(const CHAR16 *str)
if ( !efi_bs )
efi_arch_halt();
- if ( cfg.addr )
+ if ( cfg.addr && cfg.need_to_free)
efi_bs->FreePages(cfg.addr, PFN_UP(cfg.size));
- if ( kernel.addr )
+ if ( kernel.addr && kernel.need_to_free)
efi_bs->FreePages(kernel.addr, PFN_UP(kernel.size));
- if ( ramdisk.addr )
+ if ( ramdisk.addr && ramdisk.need_to_free)
efi_bs->FreePages(ramdisk.addr, PFN_UP(ramdisk.size));
- if ( xsm.addr )
+ if ( xsm.addr && xsm.need_to_free)
efi_bs->FreePages(xsm.addr, PFN_UP(xsm.size));
efi_arch_blexit();
@@ -589,6 +592,21 @@ static char * __init split_string(char *s)
return NULL;
}
+static void __init display_file_info(CHAR16 * name, struct file * file, char * options)
+{
+ if ( file == &cfg )
+ return;
+
+ PrintStr(name);
+ PrintStr(L": ");
+ DisplayUint(file->addr, 2 * sizeof(file->addr));
+ PrintStr(L"-");
+ DisplayUint(file->addr + file->size, 2 * sizeof(file->addr));
+ PrintStr(newline);
+
+ efi_arch_handle_module(file, name, options);
+}
+
static bool __init read_file(EFI_FILE_HANDLE dir_handle, CHAR16 *name,
struct file *file, char *options)
{
@@ -619,6 +637,7 @@ static bool __init read_file(EFI_FILE_HANDLE dir_handle, CHAR16 *name,
what = what ?: L"Seek";
else
{
+ file->need_to_free = true;
file->addr = min(1UL << (32 + PAGE_SHIFT),
HYPERVISOR_VIRT_END - DIRECTMAP_VIRT_START);
ret = efi_bs->AllocatePages(AllocateMaxAddress, EfiLoaderData,
@@ -632,16 +651,7 @@ static bool __init read_file(EFI_FILE_HANDLE dir_handle, CHAR16 *name,
else
{
file->size = size;
- if ( file != &cfg )
- {
- PrintStr(name);
- PrintStr(L": ");
- DisplayUint(file->addr, 2 * sizeof(file->addr));
- PrintStr(L"-");
- DisplayUint(file->addr + size, 2 * sizeof(file->addr));
- PrintStr(newline);
- efi_arch_handle_module(file, name, options);
- }
+ display_file_info(name, file, options);
ret = FileHandle->Read(FileHandle, &file->size, file->ptr);
if ( !EFI_ERROR(ret) && file->size != size )
@@ -665,6 +675,25 @@ static bool __init read_file(EFI_FILE_HANDLE dir_handle, CHAR16 *name,
return true;
}
+static bool __init read_section(EFI_LOADED_IMAGE * image,
+ char * const name, struct file *file, char *options)
+{
+ /* skip the leading "." in the section name */
+ union string name_string = { .s = name + 1 };
+
+ file->ptr = (void*) pe_find_section(image->ImageBase, image->ImageSize, name, &file->size);
+ if ( !file->ptr )
+ return false;
+
+ file->need_to_free = false;
+
+ s2w(&name_string);
+ display_file_info(name_string.w, file, options);
+ efi_bs->FreePool(name_string.w);
+
+ return true;
+}
+
static void __init pre_parse(const struct file *cfg)
{
char *ptr = cfg->ptr, *end = ptr + cfg->size;
@@ -968,6 +997,26 @@ static void __init setup_efi_pci(void)
efi_bs->FreePool(handles);
}
+/*
+ * Logic should remain sync'ed with linux/arch/x86/xen/efi.c
+ * Secure Boot is enabled iff 'SecureBoot' is set and the system is
+ * not in Setup Mode.
+ */
+static bool __init efi_secure_boot(void)
+{
+ static const __initconst EFI_GUID global_guid = EFI_GLOBAL_VARIABLE;
+ uint8_t secboot, setupmode;
+ UINTN secboot_size = sizeof(secboot);
+ UINTN setupmode_size = sizeof(setupmode);
+
+ if ( efi_rs->GetVariable(L"SecureBoot", (EFI_GUID *)&global_guid, NULL, &secboot_size, &secboot) != EFI_SUCCESS )
+ return false;
+ if ( efi_rs->GetVariable(L"SetupMode", (EFI_GUID *)&global_guid, NULL, &setupmode_size, &setupmode) != EFI_SUCCESS )
+ return false;
+
+ return secboot == 1 && setupmode == 0;
+}
+
static void __init efi_variables(void)
{
EFI_STATUS status;
@@ -1144,8 +1193,8 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
static EFI_GUID __initdata shim_lock_guid = SHIM_LOCK_PROTOCOL_GUID;
EFI_LOADED_IMAGE *loaded_image;
EFI_STATUS status;
- unsigned int i, argc;
- CHAR16 **argv, *file_name, *cfg_file_name = NULL, *options = NULL;
+ unsigned int i, argc = 0;
+ CHAR16 **argv = NULL, *file_name, *cfg_file_name = NULL, *options = NULL;
UINTN gop_mode = ~0;
EFI_SHIM_LOCK_PROTOCOL *shim_lock;
EFI_GRAPHICS_OUTPUT_PROTOCOL *gop = NULL;
@@ -1153,6 +1202,7 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
bool base_video = false;
char *option_str;
bool use_cfg_file;
+ bool secure = false;
__set_bit(EFI_BOOT, &efi_flags);
__set_bit(EFI_LOADER, &efi_flags);
@@ -1171,8 +1221,10 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
PrintErrMesg(L"No Loaded Image Protocol", status);
efi_arch_load_addr_check(loaded_image);
+ secure = efi_secure_boot();
- if ( use_cfg_file )
+ /* If UEFI Secure Boot is enabled, do not parse the command line */
+ if ( use_cfg_file && !secure )
{
UINTN offset = 0;
@@ -1230,6 +1282,8 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
PrintStr(L"Xen " __stringify(XEN_VERSION) "." __stringify(XEN_SUBVERSION)
XEN_EXTRAVERSION " (c/s " XEN_CHANGESET ") EFI loader\r\n");
+ if ( secure )
+ PrintStr(L"UEFI Secure Boot enabled\r\n");
efi_arch_relocate_image(0);
@@ -1249,9 +1303,13 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
/* Get the file system interface. */
dir_handle = get_parent_handle(loaded_image, &file_name);
- /* Read and parse the config file. */
- if ( !cfg_file_name )
+ if ( read_section(loaded_image, ".config", &cfg, NULL) )
{
+ PrintStr(L"Using unified config file\r\n");
+ }
+ else if ( !cfg_file_name )
+ {
+ /* Read and parse the config file. */
CHAR16 *tail;
while ( (tail = point_tail(file_name)) != NULL )
@@ -1303,26 +1361,36 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
efi_arch_cfg_file_early(dir_handle, section.s);
option_str = split_string(name.s);
- read_file(dir_handle, s2w(&name), &kernel, option_str);
- efi_bs->FreePool(name.w);
-
- if ( !EFI_ERROR(efi_bs->LocateProtocol(&shim_lock_guid, NULL,
- (void **)&shim_lock)) &&
- (status = shim_lock->Verify(kernel.ptr, kernel.size)) != EFI_SUCCESS )
- PrintErrMesg(L"Dom0 kernel image could not be verified", status);
- name.s = get_value(&cfg, section.s, "ramdisk");
- if ( name.s )
+ if ( !read_section(loaded_image, ".kernel", &kernel, option_str) )
{
- read_file(dir_handle, s2w(&name), &ramdisk, NULL);
+ read_file(dir_handle, s2w(&name), &kernel, option_str);
efi_bs->FreePool(name.w);
+
+ if ( !EFI_ERROR(efi_bs->LocateProtocol(&shim_lock_guid, NULL,
+ (void **)&shim_lock)) &&
+ (status = shim_lock->Verify(kernel.ptr, kernel.size)) != EFI_SUCCESS )
+ PrintErrMesg(L"Dom0 kernel image could not be verified", status);
}
- name.s = get_value(&cfg, section.s, "xsm");
- if ( name.s )
+ if ( !read_section(loaded_image, ".ramdisk", &ramdisk, NULL) )
{
- read_file(dir_handle, s2w(&name), &xsm, NULL);
- efi_bs->FreePool(name.w);
+ name.s = get_value(&cfg, section.s, "ramdisk");
+ if ( name.s )
+ {
+ read_file(dir_handle, s2w(&name), &ramdisk, NULL);
+ efi_bs->FreePool(name.w);
+ }
+ }
+
+ if ( !read_section(loaded_image, ".xsm", &xsm, NULL) )
+ {
+ name.s = get_value(&cfg, section.s, "xsm");
+ if ( name.s )
+ {
+ read_file(dir_handle, s2w(&name), &xsm, NULL);
+ efi_bs->FreePool(name.w);
+ }
}
/*
@@ -1358,7 +1426,7 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
}
}
- efi_arch_cfg_file_late(dir_handle, section.s);
+ efi_arch_cfg_file_late(loaded_image, dir_handle, section.s);
efi_bs->FreePages(cfg.addr, PFN_UP(cfg.size));
cfg.addr = 0;
diff --git a/xen/common/efi/efi.h b/xen/common/efi/efi.h
index 2e38d05f3d..d3018f81a1 100644
--- a/xen/common/efi/efi.h
+++ b/xen/common/efi/efi.h
@@ -41,3 +41,6 @@ extern UINT64 efi_apple_properties_addr;
extern UINTN efi_apple_properties_len;
const CHAR16 *wmemchr(const CHAR16 *s, CHAR16 c, UINTN n);
+
+const void * pe_find_section(const UINT8 * image_base, const size_t image_size,
+ const char * section_name, UINTN * size_out);
diff --git a/xen/common/efi/pe.c b/xen/common/efi/pe.c
new file mode 100644
index 0000000000..3440d82598
--- /dev/null
+++ b/xen/common/efi/pe.c
@@ -0,0 +1,181 @@
+/*
+ * xen/common/efi/pe.c
+ *
+ * PE executable header parser.
+ *
+ * Derived from https://github.com/systemd/systemd/blob/master/src/boot/efi/pe.c
+ *
+ * Copyright (C) 2015 Kay Sievers <kay@vrfy.org>
+ * Copyright (C) 2020 Trammell Hudson <hudson@trmm.net>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ */
+
+/*
+ * The "Unified" kernel image can be generated by adding additional
+ * sections to the Xen EFI executable with objcopy, similar to how
+ * systemd-boot uses the stub to add them to the Linux kernel:
+ *
+ * https://wiki.archlinux.org/index.php/systemd-boot#Preparing_a_unified_kernel_image
+ *
+ * The sections for the xen configuration file, the dom0 kernel, dom0 initrd,
+ * XSM and CPU microcode should be added after the Xen `.pad` section, the
+ * ending address of which can be located with:
+ *
+ * objdump -h xen.efi \
+ * | perl -ane '/\.pad/ && printf "0x%016x\n", hex($F[2]) + hex($F[3])'
+ *
+ * All the additional sections are optional and the order does not
+ * matter. The addresses do not need to be contiguous, although
+ * they should not be overlapping.
+ *
+ * objcopy \
+ * --add-section .config=xen.cfg \
+ * --change-section-vma .config=0xffff82d041000000
+ * --add-section .ucode=ucode.bin \
+ * --change-section-vma .ucode=0xffff82d041010000 \
+ * --add-section .xsm=xsm.cfg \
+ * --change-section-vma .xsm=0xffff82d041080000 \
+ * --add-section .kernel=vmlinux \
+ * --change-section-vma .kernel=0xffff82d041100000 \
+ * --add-section .ramdisk=initrd.img \
+ * --change-section-vma .initrd=0xffff82d042000000 \
+ * xen.efi \
+ * xen.unified.efi
+ *
+ * The unified executable can be signed with sbsigntool to make
+ * it usable with UEFI secure boot:
+ *
+ * sbsign \
+ * --key signing.key \
+ * --cert cert.pem \
+ * --output xen.signed.efi \
+ * xen.unified.efi
+ */
+
+#include "efi.h"
+
+struct DosFileHeader {
+ UINT8 Magic[2];
+ UINT16 LastSize;
+ UINT16 nBlocks;
+ UINT16 nReloc;
+ UINT16 HdrSize;
+ UINT16 MinAlloc;
+ UINT16 MaxAlloc;
+ UINT16 ss;
+ UINT16 sp;
+ UINT16 Checksum;
+ UINT16 ip;
+ UINT16 cs;
+ UINT16 RelocPos;
+ UINT16 nOverlay;
+ UINT16 reserved[4];
+ UINT16 OEMId;
+ UINT16 OEMInfo;
+ UINT16 reserved2[10];
+ UINT32 ExeHeader;
+} __attribute__((packed));
+
+#define PE_HEADER_MACHINE_ARM64 0xaa64
+#define PE_HEADER_MACHINE_X64 0x8664
+#define PE_HEADER_MACHINE_I386 0x014c
+
+struct PeFileHeader {
+ UINT16 Machine;
+ UINT16 NumberOfSections;
+ UINT32 TimeDateStamp;
+ UINT32 PointerToSymbolTable;
+ UINT32 NumberOfSymbols;
+ UINT16 SizeOfOptionalHeader;
+ UINT16 Characteristics;
+} __attribute__((packed));
+
+struct PeHeader {
+ UINT8 Magic[4];
+ struct PeFileHeader FileHeader;
+} __attribute__((packed));
+
+struct PeSectionHeader {
+ UINT8 Name[8];
+ UINT32 VirtualSize;
+ UINT32 VirtualAddress;
+ UINT32 SizeOfRawData;
+ UINT32 PointerToRawData;
+ UINT32 PointerToRelocations;
+ UINT32 PointerToLinenumbers;
+ UINT16 NumberOfRelocations;
+ UINT16 NumberOfLinenumbers;
+ UINT32 Characteristics;
+} __attribute__((packed));
+
+const void * __init pe_find_section(const CHAR8 * image, const UINTN image_size,
+ const char * section_name, UINTN * size_out)
+{
+ const struct DosFileHeader * dos = (const void*) image;
+ const struct PeHeader * pe;
+ const struct PeSectionHeader * sect;
+ const UINTN name_len = strlen(section_name);
+ UINTN offset = 0;
+
+ if ( name_len > sizeof(sect->Name) )
+ return NULL;
+
+ if ( image_size < sizeof(*dos) )
+ return NULL;
+ if ( memcmp(dos->Magic, "MZ", 2) != 0 )
+ return NULL;
+
+ offset = dos->ExeHeader;
+ pe = (const void *) &image[offset];
+
+ offset += sizeof(*pe);
+ if ( image_size < offset)
+ return NULL;
+
+ if ( memcmp(pe->Magic, "PE\0\0", 4) != 0 )
+ return NULL;
+
+ /* PE32+ Subsystem type */
+#if defined(__ARM__)
+ if (pe->FileHeader.Machine != PE_HEADER_MACHINE_ARM64)
+ return NULL;
+#elif defined(__x86_64__)
+ if (pe->FileHeader.Machine != PE_HEADER_MACHINE_X64)
+ return NULL;
+#else
+ /* unknown architecture */
+ return NULL;
+#endif
+
+ offset += pe->FileHeader.SizeOfOptionalHeader;
+
+ for (UINTN i = 0 ; i < pe->FileHeader.NumberOfSections ; i++)
+ {
+ sect = (const void *) &image[offset];
+ if ( image_size < offset + sizeof(*sect) )
+ return NULL;
+
+ if ( memcmp(sect->Name, section_name, name_len) != 0
+ || image_size < sect->VirtualSize + sect->VirtualAddress )
+ {
+ offset += sizeof(*sect);
+ continue;
+ }
+
+ if ( size_out )
+ *size_out = sect->VirtualSize;
+
+ return &image[sect->VirtualAddress];
+ }
+
+ return NULL;
+}
On 28.08.2020 13:51, Trammell Hudson wrote: > This patch adds support for bundling the xen.efi hypervisor, the xen.cfg > configuration file, the Linux kernel and initrd, as well as the XSM, and > CPU microcode into a single "unified" EFI executable. The resulting EFI > executable can be invoked directly from the UEFI Boot Manager, removing > the need to use a separate loader like grub as well as removing > dependencies on local filesystem access. > > It is inspired by systemd-boot's unified kernel technique and borrows the > function to locate PE sections from systemd's LGPL'ed code. During EFI > boot, Xen looks at its own loaded image to locate the PE sections for > the configuration, kernel, etc, which are included after building xen.efi > using objcopy to add named sections for each input file. This allows an > administrator to update the components independently without requiring > rebuilding xen. > > The unified image can also be signed by sbsigntool for verification > by UEFI Secure Boot. If secure boot is enabled, the Xen command line > arguments are ignored. Unlike the shim based verification, the signature > covers the entire Xen+config+kernel+initrd unified file. This also ensures > that properly configured platforms will measure the entire runtime into > the TPM for unsealing secrets or remote attestation. > > Signed-off-by: Trammell Hudson <hudson@trmm.net> I realize this patch is now stale, and hence there's little point looking over it. As indicated elsewhere I don't think the gitlab model is suitable here, so may I ask that you post an up-to-date patch to the list again? Thanks, Jan
Hi,
On 28/08/2020 12:51, Trammell Hudson wrote:
> This patch adds support for bundling the xen.efi hypervisor, the xen.cfg
> configuration file, the Linux kernel and initrd, as well as the XSM, and
> CPU microcode into a single "unified" EFI executable.
For Arm, I would also consider to add the DTB in "unified" EFI
executable. See efi_arch_cfg_file_early() in xen/arch/arm/efi/efi-boot.h.
> The resulting EFI
> executable can be invoked directly from the UEFI Boot Manager, removing
> the need to use a separate loader like grub as well as removing
> dependencies on local filesystem access.
>
> It is inspired by systemd-boot's unified kernel technique and borrows the
> function to locate PE sections from systemd's LGPL'ed code. During EFI
> boot, Xen looks at its own loaded image to locate the PE sections for
> the configuration, kernel, etc, which are included after building xen.efi
> using objcopy to add named sections for each input file. This allows an
> administrator to update the components independently without requiring
> rebuilding xen.
>
> The unified image can also be signed by sbsigntool for verification
> by UEFI Secure Boot. If secure boot is enabled, the Xen command line
> arguments are ignored. Unlike the shim based verification, the signature
> covers the entire Xen+config+kernel+initrd unified file. This also ensures
> that properly configured platforms will measure the entire runtime into
> the TPM for unsealing secrets or remote attestation.
>
> Signed-off-by: Trammell Hudson <hudson@trmm.net>
I don't seem to be able to apply the patch using git-am:
42sh> git checkout origin/staging
42sh> git am ~/Downloads/patches/\[PATCH\]\ EFI_\ Enable\ booting\
unified\ hypervisor_kernel_initrd\ images.eml
Applying: EFI: Enable booting unified hypervisor/kernel/initrd images
error: patch failed: xen/Makefile:355
error: xen/Makefile: patch does not apply
error: patch failed: xen/arch/x86/efi/Makefile:8
error: xen/arch/x86/efi/Makefile: patch does not apply
error: patch failed: xen/common/efi/efi.h:41
error: xen/common/efi/efi.h: patch does not apply
Patch failed at 0001 EFI: Enable booting unified
hypervisor/kernel/initrd images
Use 'git am --show-current-patch' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
42sh> git am --show-current-patch | patch -p1
patching file xen/Makefile
patch: **** malformed patch at line 122: i.h;\
How did you send/generate the patch?
>
> diff --git a/xen/Makefile b/xen/Makefile
> index a87bb225dc..e4e4c6d5c1 100644
> --- a/xen/Makefile
> +++ b/xen/Makefile
> @@ -355,7 +355,7 @@ $(TARGET): delete-unfresh-files
> $(MAKE) -C tools
> $(MAKE) -f $(BASEDIR)/Rules.mk include/xen/compile.h
> [ -e include/asm ] || ln -sf asm-$(TARGET_ARCH) include/asm
> - [ -e arch/$(TARGET_ARCH)/efi ] && for f in boot.c runtime.c compat.c efi.h;\
> + [ -e arch/$(TARGET_ARCH)/efi ] && for f in boot.c pe.c runtime.c compat.c efi.h;\
> do test -r arch/$(TARGET_ARCH)/efi/$$f || \
> ln -nsf ../../../common/efi/$$f arch/$(TARGET_ARCH)/efi/; \
> done; \
> diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
> index 6527cb0bdf..483dec465d 100644
> --- a/xen/arch/arm/efi/efi-boot.h
> +++ b/xen/arch/arm/efi/efi-boot.h
> @@ -395,7 +395,7 @@ static void __init efi_arch_cfg_file_early(EFI_FILE_HANDLE dir_handle, char *sec
> blexit(L"Unable to create new FDT");
> }
>
> -static void __init efi_arch_cfg_file_late(EFI_FILE_HANDLE dir_handle, char *section)
> +static void __init efi_arch_cfg_file_late(EFI_LOADED_IMAGE * image, EFI_FILE_HANDLE dir_handle, char *section)
> {
> }
>
> diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile
> index 4b2b010a80..ae666aa14c 100644
> --- a/xen/arch/x86/efi/Makefile
> +++ b/xen/arch/x86/efi/Makefile
> @@ -8,7 +8,7 @@ cmd_objcopy_o_ihex = $(OBJCOPY) -I ihex -O binary $< $@
>
> boot.init.o: buildid.o
>
> -EFIOBJ := boot.init.o compat.o runtime.o
> +EFIOBJ := boot.init.o pe.init.o compat.o runtime.o
I believe you will need to replicate this change in
xen/arch/arm/efi/Makefile as well.
>
> $(call cc-option-add,cflags-stack-boundary,CC,-mpreferred-stack-boundary=4)
> $(EFIOBJ): CFLAGS-stack-boundary := $(cflags-stack-boundary)
[...]
> @@ -1171,8 +1221,10 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
> PrintErrMesg(L"No Loaded Image Protocol", status);
>
> efi_arch_load_addr_check(loaded_image);
> + secure = efi_secure_boot();
>
> - if ( use_cfg_file )
> + /* If UEFI Secure Boot is enabled, do not parse the command line */
> + if ( use_cfg_file && !secure )
> {
> UINTN offset = 0;
>
> @@ -1230,6 +1282,8 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
>
> PrintStr(L"Xen " __stringify(XEN_VERSION) "." __stringify(XEN_SUBVERSION)
> XEN_EXTRAVERSION " (c/s " XEN_CHANGESET ") EFI loader\r\n");
> + if ( secure )
> + PrintStr(L"UEFI Secure Boot enabled\r\n");
Xen is using softtab.
>
> efi_arch_relocate_image(0);
>
> @@ -1249,9 +1303,13 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
> /* Get the file system interface. */
> dir_handle = get_parent_handle(loaded_image, &file_name);
>
> - /* Read and parse the config file. */
> - if ( !cfg_file_name )
> + if ( read_section(loaded_image, ".config", &cfg, NULL) )
> {
> + PrintStr(L"Using unified config file\r\n");
> + }
> + else if ( !cfg_file_name )
> + {
> + /* Read and parse the config file. */
> CHAR16 *tail;
>
> while ( (tail = point_tail(file_name)) != NULL )
> @@ -1303,26 +1361,36 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
> efi_arch_cfg_file_early(dir_handle, section.s);
>
> option_str = split_string(name.s);
> - read_file(dir_handle, s2w(&name), &kernel, option_str);
> - efi_bs->FreePool(name.w);
> -
> - if ( !EFI_ERROR(efi_bs->LocateProtocol(&shim_lock_guid, NULL,
> - (void **)&shim_lock)) &&
> - (status = shim_lock->Verify(kernel.ptr, kernel.size)) != EFI_SUCCESS )
> - PrintErrMesg(L"Dom0 kernel image could not be verified", status);
>
> - name.s = get_value(&cfg, section.s, "ramdisk");
> - if ( name.s )
> + if ( !read_section(loaded_image, ".kernel", &kernel, option_str) )
> {
> - read_file(dir_handle, s2w(&name), &ramdisk, NULL);
> + read_file(dir_handle, s2w(&name), &kernel, option_str);
> efi_bs->FreePool(name.w);
> +
> + if ( !EFI_ERROR(efi_bs->LocateProtocol(&shim_lock_guid, NULL,
> + (void **)&shim_lock)) &&
> + (status = shim_lock->Verify(kernel.ptr, kernel.size)) != EFI_SUCCESS )
> + PrintErrMesg(L"Dom0 kernel image could not be verified", status);
> }
>
> - name.s = get_value(&cfg, section.s, "xsm");
> - if ( name.s )
> + if ( !read_section(loaded_image, ".ramdisk", &ramdisk, NULL) )
> {
> - read_file(dir_handle, s2w(&name), &xsm, NULL);
> - efi_bs->FreePool(name.w);
> + name.s = get_value(&cfg, section.s, "ramdisk");
> + if ( name.s )
> + {
> + read_file(dir_handle, s2w(&name), &ramdisk, NULL);
> + efi_bs->FreePool(name.w);
> + }
> + }
> +
> + if ( !read_section(loaded_image, ".xsm", &xsm, NULL) )
> + {
> + name.s = get_value(&cfg, section.s, "xsm");
> + if ( name.s )
> + {
> + read_file(dir_handle, s2w(&name), &xsm, NULL);
> + efi_bs->FreePool(name.w);
> + }
> }
AFAICT, the code to use the section or fallback to the cfg is nearly the
same for each binary. I think it would make sense to have an helper tha
check if a given section exist and look in the cfg.
>
> /*
> @@ -1358,7 +1426,7 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
> }
> }
>
> - efi_arch_cfg_file_late(dir_handle, section.s);
> + efi_arch_cfg_file_late(loaded_image, dir_handle, section.s);
>
> efi_bs->FreePages(cfg.addr, PFN_UP(cfg.size));
> cfg.addr = 0;
> diff --git a/xen/common/efi/efi.h b/xen/common/efi/efi.h
> index 2e38d05f3d..d3018f81a1 100644
> --- a/xen/common/efi/efi.h
> +++ b/xen/common/efi/efi.h
> @@ -41,3 +41,6 @@ extern UINT64 efi_apple_properties_addr;
> extern UINTN efi_apple_properties_len;
>
> const CHAR16 *wmemchr(const CHAR16 *s, CHAR16 c, UINTN n);
> +
> +const void * pe_find_section(const UINT8 * image_base, const size_t image_size,
> + const char * section_name, UINTN * size_out);
> diff --git a/xen/common/efi/pe.c b/xen/common/efi/pe.c
> new file mode 100644
> index 0000000000..3440d82598
> --- /dev/null
> +++ b/xen/common/efi/pe.c
> @@ -0,0 +1,181 @@
> +/*
> + * xen/common/efi/pe.c
> + *
> + * PE executable header parser.
> + *
> + * Derived from https://github.com/systemd/systemd/blob/master/src/boot/efi/pe.c
I would suggest to mention the commit ID of the baseline.
> + *
> + * Copyright (C) 2015 Kay Sievers <kay@vrfy.org>
> + * Copyright (C) 2020 Trammell Hudson <hudson@trmm.net>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU Lesser General Public License as published by
> + * the Free Software Foundation; either version 2.1 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + */
> +
> +/*
> + * The "Unified" kernel image can be generated by adding additional
> + * sections to the Xen EFI executable with objcopy, similar to how
> + * systemd-boot uses the stub to add them to the Linux kernel:
> + *
> + * https://wiki.archlinux.org/index.php/systemd-boot#Preparing_a_unified_kernel_image
> + *
> + * The sections for the xen configuration file, the dom0 kernel, dom0 initrd,
> + * XSM and CPU microcode should be added after the Xen `.pad` section, the
> + * ending address of which can be located with:
> + *
> + * objdump -h xen.efi \
> + * | perl -ane '/\.pad/ && printf "0x%016x\n", hex($F[2]) + hex($F[3])'
> + *
> + * All the additional sections are optional and the order does not
> + * matter. The addresses do not need to be contiguous, although
> + * they should not be overlapping.
> + *
> + * objcopy \
> + * --add-section .config=xen.cfg \
> + * --change-section-vma .config=0xffff82d041000000
> + * --add-section .ucode=ucode.bin \
> + * --change-section-vma .ucode=0xffff82d041010000 \
> + * --add-section .xsm=xsm.cfg \
> + * --change-section-vma .xsm=0xffff82d041080000 \
> + * --add-section .kernel=vmlinux \
> + * --change-section-vma .kernel=0xffff82d041100000 \
> + * --add-section .ramdisk=initrd.img \
> + * --change-section-vma .initrd=0xffff82d042000000 \
> + * xen.efi \
> + * xen.unified.efi
> + *
> + * The unified executable can be signed with sbsigntool to make
> + * it usable with UEFI secure boot:
> + *
> + * sbsign \
> + * --key signing.key \
> + * --cert cert.pem \
> + * --output xen.signed.efi \
> + * xen.unified.efi
> + */
> +
> +#include "efi.h"
> +
> +struct DosFileHeader {
> + UINT8 Magic[2];
> + UINT16 LastSize;
> + UINT16 nBlocks;
> + UINT16 nReloc;
> + UINT16 HdrSize;
> + UINT16 MinAlloc;
> + UINT16 MaxAlloc;
> + UINT16 ss;
> + UINT16 sp;
> + UINT16 Checksum;
> + UINT16 ip;
> + UINT16 cs;
> + UINT16 RelocPos;
> + UINT16 nOverlay;
> + UINT16 reserved[4];
> + UINT16 OEMId;
> + UINT16 OEMInfo;
> + UINT16 reserved2[10];
> + UINT32 ExeHeader;
> +} __attribute__((packed));
> +
> +#define PE_HEADER_MACHINE_ARM64 0xaa64
> +#define PE_HEADER_MACHINE_X64 0x8664
> +#define PE_HEADER_MACHINE_I386 0x014c
> +
> +struct PeFileHeader {
> + UINT16 Machine;
> + UINT16 NumberOfSections;
> + UINT32 TimeDateStamp;
> + UINT32 PointerToSymbolTable;
> + UINT32 NumberOfSymbols;
> + UINT16 SizeOfOptionalHeader;
> + UINT16 Characteristics;
> +} __attribute__((packed));
> +
> +struct PeHeader {
> + UINT8 Magic[4];
> + struct PeFileHeader FileHeader;
> +} __attribute__((packed));
> +
> +struct PeSectionHeader {
> + UINT8 Name[8];
> + UINT32 VirtualSize;
> + UINT32 VirtualAddress;
> + UINT32 SizeOfRawData;
> + UINT32 PointerToRawData;
> + UINT32 PointerToRelocations;
> + UINT32 PointerToLinenumbers;
> + UINT16 NumberOfRelocations;
> + UINT16 NumberOfLinenumbers;
> + UINT32 Characteristics;
> +} __attribute__((packed));
> +
> +const void * __init pe_find_section(const CHAR8 * image, const UINTN image_size,
> + const char * section_name, UINTN * size_out)
> +{
> + const struct DosFileHeader * dos = (const void*) image;
> + const struct PeHeader * pe;
> + const struct PeSectionHeader * sect;
> + const UINTN name_len = strlen(section_name);
> + UINTN offset = 0;
> +
> + if ( name_len > sizeof(sect->Name) )
> + return NULL;
> +
> + if ( image_size < sizeof(*dos) )
> + return NULL;
> + if ( memcmp(dos->Magic, "MZ", 2) != 0 )
> + return NULL;
> +
> + offset = dos->ExeHeader;
> + pe = (const void *) &image[offset];
> +
> + offset += sizeof(*pe);
> + if ( image_size < offset)
> + return NULL;
> +
> + if ( memcmp(pe->Magic, "PE\0\0", 4) != 0 )
> + return NULL;
> +
> + /* PE32+ Subsystem type */
> +#if defined(__ARM__)
> + if (pe->FileHeader.Machine != PE_HEADER_MACHINE_ARM64)
> + return NULL;
> +#elif defined(__x86_64__)
> + if (pe->FileHeader.Machine != PE_HEADER_MACHINE_X64)
> + return NULL;
> +#else
> + /* unknown architecture */
> + return NULL;
> +#endif
> +
> + offset += pe->FileHeader.SizeOfOptionalHeader;
> +
> + for (UINTN i = 0 ; i < pe->FileHeader.NumberOfSections ; i++)
> + {
> + sect = (const void *) &image[offset];
> + if ( image_size < offset + sizeof(*sect) )
> + return NULL;
> +
> + if ( memcmp(sect->Name, section_name, name_len) != 0
> + || image_size < sect->VirtualSize + sect->VirtualAddress )
> + {
> + offset += sizeof(*sect);
> + continue;
> + }
> +
> + if ( size_out )
> + *size_out = sect->VirtualSize;
> +
> + return &image[sect->VirtualAddress];
> + }
> +
> + return NULL;
> +}
>
>
Cheers,
--
Julien Grall
On Friday, September 4, 2020 1:58 PM, Julien Grall <julien@xen.org> wrote: > On 28/08/2020 12:51, Trammell Hudson wrote: > > This patch adds support for bundling the xen.efi hypervisor, the xen.cfg > > configuration file, the Linux kernel and initrd, as well as the XSM, and > > CPU microcode into a single "unified" EFI executable. > > For Arm, I would also consider to add the DTB in "unified" EFI > executable. See efi_arch_cfg_file_early() in xen/arch/arm/efi/efi-boot.h. Excellent point. The DTB is critical as well. I'll add that to the patch on Xen's gitlab. x86 has a similar call in efi_arch-cfg_file_early() to load the CPU microcode from the unified image, if it exists. > [...] > I don't seem to be able to apply the patch using git-am: You might try this one instead -- it has been based on the latest staging tree and has had a few rounds of style guide issues as well as the commit id for the systemd-boot code. https://gitlab.com/xen-project/xen/-/merge_requests/4 -- Trammell
On Friday, September 4, 2020 2:05 PM, Trammell Hudson <hudson@trmm.net> wrote: > On Friday, September 4, 2020 1:58 PM, Julien Grall julien@xen.org wrote: > > On 28/08/2020 12:51, Trammell Hudson wrote: > > > This patch adds support for bundling the xen.efi hypervisor, the xen.cfg > > > configuration file, the Linux kernel and initrd, as well as the XSM, and > > > CPU microcode into a single "unified" EFI executable. > > > > For Arm, I would also consider to add the DTB in "unified" EFI > > executable. See efi_arch_cfg_file_early() in xen/arch/arm/efi/efi-boot.h. > > Excellent point. The DTB is critical as well. I'll add that to > the patch on Xen's gitlab. Here is an untested patch for loading DTB from unified image: https://gitlab.com/xen-project/xen/-/merge_requests/4/diffs?commit_id=e55336e11cc6a7ce77f0bf8ce3aa0712c7017e8b -- trammell
On 04/09/2020 19:18, Trammell Hudson wrote: > On Friday, September 4, 2020 2:05 PM, Trammell Hudson <hudson@trmm.net> wrote: > >> On Friday, September 4, 2020 1:58 PM, Julien Grall julien@xen.org wrote: >>> On 28/08/2020 12:51, Trammell Hudson wrote: >>>> This patch adds support for bundling the xen.efi hypervisor, the xen.cfg >>>> configuration file, the Linux kernel and initrd, as well as the XSM, and >>>> CPU microcode into a single "unified" EFI executable. >>> >>> For Arm, I would also consider to add the DTB in "unified" EFI >>> executable. See efi_arch_cfg_file_early() in xen/arch/arm/efi/efi-boot.h. >> >> Excellent point. The DTB is critical as well. I'll add that to >> the patch on Xen's gitlab. > > Here is an untested patch for loading DTB from unified image: > > https://gitlab.com/xen-project/xen/-/merge_requests/4/diffs?commit_id=e55336e11cc6a7ce77f0bf8ce3aa0712c7017e8b Thanks! I will directly try to the v3 of this series. Cheers, -- Julien Grall
Hi, On 28/08/2020 12:51, Trammell Hudson wrote: > + /* PE32+ Subsystem type */ > +#if defined(__ARM__) Shouldn't this be defined(__aarch64__) ? > + if (pe->FileHeader.Machine != PE_HEADER_MACHINE_ARM64) > + return NULL; > +#elif defined(__x86_64__) > + if (pe->FileHeader.Machine != PE_HEADER_MACHINE_X64) > + return NULL; > +#else > + /* unknown architecture */ > + return NULL; > +#endif Cheers, -- Julien Grall
On Friday, September 4, 2020 5:29 AM, Julien Grall <julien@xen.org> wrote: > On 28/08/2020 12:51, Trammell Hudson wrote: > > > - /* PE32+ Subsystem type */ > > +#if defined(ARM) > > > > Shouldn't this be defined(aarch64) ? To be honest I'm not sure and don't have a way to check if this code works on ARM. Does an Xen EFI build on ARM even use the PE32+ format? -- Trammell
Hi Trammell, On 04/09/2020 11:06, Trammell Hudson wrote: > On Friday, September 4, 2020 5:29 AM, Julien Grall <julien@xen.org> wrote: > >> On 28/08/2020 12:51, Trammell Hudson wrote: >> >>> - /* PE32+ Subsystem type */ >>> +#if defined(ARM) >>> >> >> Shouldn't this be defined(aarch64) ? > > To be honest I'm not sure and don't have a way to check if > this code works on ARM. The code looks generic enough. I will give a try to build it. > Does an Xen EFI build on ARM even > use the PE32+ format? So far, we only support EFI and AArch64. This is built using PE32+ format. Looking at the rest of the UEFI code, we are using CONFIG_ARM. But I think, in this particular instance, we want to use CONFIG_ARM_64. Cheers, -- Julien Grall
On 04.09.2020 19:35, Julien Grall wrote: > On 04/09/2020 11:06, Trammell Hudson wrote: >> On Friday, September 4, 2020 5:29 AM, Julien Grall <julien@xen.org> wrote: >> >>> On 28/08/2020 12:51, Trammell Hudson wrote: >>> >>>> - /* PE32+ Subsystem type */ >>>> +#if defined(ARM) >>>> >>> >>> Shouldn't this be defined(aarch64) ? >> >> To be honest I'm not sure and don't have a way to check if >> this code works on ARM. > > The code looks generic enough. I will give a try to build it. > >> Does an Xen EFI build on ARM even >> use the PE32+ format? > > So far, we only support EFI and AArch64. This is built using PE32+ format. But this gets done by some custom means iirc, not by linking to that format? (I'm not certain whether this matters here, so I'm sorry for the noise if it doesn't.) Jan
On 07/09/2020 08:11, Jan Beulich wrote: > On 04.09.2020 19:35, Julien Grall wrote: >> On 04/09/2020 11:06, Trammell Hudson wrote: >>> On Friday, September 4, 2020 5:29 AM, Julien Grall <julien@xen.org> wrote: >>> >>>> On 28/08/2020 12:51, Trammell Hudson wrote: >>>> >>>>> - /* PE32+ Subsystem type */ >>>>> +#if defined(ARM) >>>>> >>>> >>>> Shouldn't this be defined(aarch64) ? >>> >>> To be honest I'm not sure and don't have a way to check if >>> this code works on ARM. >> >> The code looks generic enough. I will give a try to build it. >> >>> Does an Xen EFI build on ARM even >>> use the PE32+ format? >> >> So far, we only support EFI and AArch64. This is built using PE32+ format. > > But this gets done by some custom means iirc, not by linking to that > format? (I'm not certain whether this matters here, so I'm sorry for > the noise if it doesn't.) The header is written manually in .S but the final binary is looking like a PE32+: 42sh> file xen/xen xen/xen: MS-DOS executable, MZ for MS-DOS As you asked the question, you must be concerned with this approach. Can you outline what could be the issue? Cheers, -- Julien Grall
On 07.09.2020 20:07, Julien Grall wrote: > > > On 07/09/2020 08:11, Jan Beulich wrote: >> On 04.09.2020 19:35, Julien Grall wrote: >>> On 04/09/2020 11:06, Trammell Hudson wrote: >>>> On Friday, September 4, 2020 5:29 AM, Julien Grall <julien@xen.org> wrote: >>>> >>>>> On 28/08/2020 12:51, Trammell Hudson wrote: >>>>> >>>>>> - /* PE32+ Subsystem type */ >>>>>> +#if defined(ARM) >>>>>> >>>>> >>>>> Shouldn't this be defined(aarch64) ? >>>> >>>> To be honest I'm not sure and don't have a way to check if >>>> this code works on ARM. >>> >>> The code looks generic enough. I will give a try to build it. >>> >>>> Does an Xen EFI build on ARM even >>>> use the PE32+ format? >>> >>> So far, we only support EFI and AArch64. This is built using PE32+ format. >> >> But this gets done by some custom means iirc, not by linking to that >> format? (I'm not certain whether this matters here, so I'm sorry for >> the noise if it doesn't.) > > The header is written manually in .S but the final binary is looking > like a PE32+: > > 42sh> file xen/xen > > xen/xen: MS-DOS executable, MZ for MS-DOS > > As you asked the question, you must be concerned with this approach. Can > you outline what could be the issue? My thinking merely is: If it's not linked "normally", maybe there are further odd things? I have no specific concern. Jan
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