From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Peter Jones Date: Fri, 25 Mar 2022 15:40:12 -0400 Subject: [PATCH] pe: add the DOS header struct and fix some bad naming. In order to properly validate a loaded kernel's support for being loaded without a writable stack or executable, we need to be able to properly parse arbitrary PE headers. Currently, pe32.h is written in such a way that the MS-DOS header that tells us where to find the PE header in the binary can't be accessed. Further, for some reason it calls the DOS MZ magic "GRUB_PE32_MAGIC". This patch adds the structure for the DOS header, renames the DOS magic define, and adds defines for the actual PE magic. Signed-off-by: Peter Jones (cherry picked from commit 955f47aa8300387eecf18b0866d21dde7720593d) (cherry picked from commit 662744c2e986cb770fe49e71e019aaf33a66272d) --- grub-core/loader/arm64/linux.c | 2 +- include/grub/efi/pe32.h | 28 ++++++++++++++++++++++++++-- 2 files changed, 27 insertions(+), 3 deletions(-) diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c index e1923cf725..24ab0f0074 100644 --- a/grub-core/loader/arm64/linux.c +++ b/grub-core/loader/arm64/linux.c @@ -57,7 +57,7 @@ grub_armxx_efi_linux_check_image (struct linux_armxx_kernel_header * lh) if (lh->magic != GRUB_LINUX_ARMXX_MAGIC_SIGNATURE) return grub_error(GRUB_ERR_BAD_OS, "invalid magic number"); - if ((lh->code0 & 0xffff) != GRUB_PE32_MAGIC) + if ((lh->code0 & 0xffff) != GRUB_DOS_MAGIC) return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, N_("plain image kernel not supported - rebuild with CONFIG_(U)EFI_STUB enabled")); diff --git a/include/grub/efi/pe32.h b/include/grub/efi/pe32.h index c03cc599f6..2241f6317b 100644 --- a/include/grub/efi/pe32.h +++ b/include/grub/efi/pe32.h @@ -45,7 +45,30 @@ #define GRUB_PE32_MSDOS_STUB_SIZE 0x80 -#define GRUB_PE32_MAGIC 0x5a4d +#define GRUB_DOS_MAGIC 0x5a4d + +struct grub_dos_header +{ + grub_uint16_t magic; + grub_uint16_t cblp; + grub_uint16_t cp; + grub_uint16_t crlc; + grub_uint16_t cparhdr; + grub_uint16_t minalloc; + grub_uint16_t maxalloc; + grub_uint16_t ss; + grub_uint16_t sp; + grub_uint16_t csum; + grub_uint16_t ip; + grub_uint16_t cs; + grub_uint16_t lfarlc; + grub_uint16_t ovno; + grub_uint16_t res0[4]; + grub_uint16_t oemid; + grub_uint16_t oeminfo; + grub_uint16_t res1[10]; + grub_uint32_t lfanew; +}; /* According to the spec, the minimal alignment is 512 bytes... But some examples (such as EFI drivers in the Intel @@ -271,7 +294,8 @@ struct grub_pe32_section_table -#define GRUB_PE32_SIGNATURE_SIZE 4 +#define GRUB_PE32_SIGNATURE_SIZE 4 +#define GRUB_PE32_SIGNATURE "PE\0\0" struct grub_pe32_header {