From e31be363df3092821bf179cf4baa076f501b8ae6 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 23 Mar 2012 09:35:05 -0700 Subject: [PATCH] x86, efi: Fix .text section overlapping image header for EFI_STUB This change modifes the PE .text section to start after the first sector of the kernel image. The header may be modified by the UEFI secure boot signing, so it is not appropriate for it to be included in one of the image sections. Since the sections are part of the secure boot hash, this modification to the .text section contents would invalidate the secure boot signed hash. Note: UEFI secure boot does hash the image header, but fields that are changed by the signing process are excluded from the hash calculation. This exclusion process is only handled for the image header, and not image sections. Luckily, we can still easily boot without the first sector by initializing a few fields in arch/x86/boot/compressed/eboot.c. Signed-off-by: Matt Fleming Link: http://lkml.kernel.org/r/1332520506-6472-3-git-send-email-jordan.l.justen@intel.com [jordan.l.justen@intel.com: set .text vma & file offset] Signed-off-by: Jordan Justen Signed-off-by: H. Peter Anvin --- arch/x86/boot/compressed/eboot.c | 14 +++++++++++--- arch/x86/boot/header.S | 2 +- arch/x86/boot/tools/build.c | 25 ++++++++++++++++++++++--- 3 files changed, 34 insertions(+), 7 deletions(-) diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index fec216f4fbc3..01cbb8707a31 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -904,11 +904,19 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table) memset(boot_params, 0x0, 0x4000); - /* Copy first two sectors to boot_params */ - memcpy(boot_params, image->image_base, 1024); - hdr = &boot_params->hdr; + /* Copy the second sector to boot_params */ + memcpy(&hdr->jump, image->image_base + 512, 512); + + /* + * Fill out some of the header fields ourselves because the + * EFI firmware loader doesn't load the first sector. + */ + hdr->root_flags = 1; + hdr->vid_mode = 0xffff; + hdr->boot_flag = 0xAA55; + /* * The EFI firmware loader could have placed the kernel image * anywhere in memory, but the kernel has various restrictions diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 4e9124b148c2..4ceb56e9a4ce 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -147,7 +147,7 @@ optional_header: # Filled in by build.c .long 0x0000 # AddressOfEntryPoint - .long 0x0000 # BaseOfCode + .long 0x0200 # BaseOfCode #ifdef CONFIG_X86_32 .long 0 # data #endif diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c index 4e9bd6bcafa6..2aeab3dc9e5f 100644 --- a/arch/x86/boot/tools/build.c +++ b/arch/x86/boot/tools/build.c @@ -202,12 +202,19 @@ int main(int argc, char ** argv) pe_header = *(unsigned int *)&buf[0x3c]; - /* Size of code */ - *(unsigned int *)&buf[pe_header + 0x1c] = file_sz; - /* Size of image */ *(unsigned int *)&buf[pe_header + 0x50] = file_sz; + /* + * Subtract the size of the first section (512 bytes) which + * includes the header and .reloc section. The remaining size + * is that of the .text section. + */ + file_sz -= 512; + + /* Size of code */ + *(unsigned int *)&buf[pe_header + 0x1c] = file_sz; + #ifdef CONFIG_X86_32 /* Address of entry point */ *(unsigned int *)&buf[pe_header + 0x28] = i; @@ -215,8 +222,14 @@ int main(int argc, char ** argv) /* .text size */ *(unsigned int *)&buf[pe_header + 0xb0] = file_sz; + /* .text vma */ + *(unsigned int *)&buf[pe_header + 0xb4] = 0x200; + /* .text size of initialised data */ *(unsigned int *)&buf[pe_header + 0xb8] = file_sz; + + /* .text file offset */ + *(unsigned int *)&buf[pe_header + 0xbc] = 0x200; #else /* * Address of entry point. startup_32 is at the beginning and @@ -228,8 +241,14 @@ int main(int argc, char ** argv) /* .text size */ *(unsigned int *)&buf[pe_header + 0xc0] = file_sz; + /* .text vma */ + *(unsigned int *)&buf[pe_header + 0xc4] = 0x200; + /* .text size of initialised data */ *(unsigned int *)&buf[pe_header + 0xc8] = file_sz; + + /* .text file offset */ + *(unsigned int *)&buf[pe_header + 0xcc] = 0x200; #endif /* CONFIG_X86_32 */ #endif /* CONFIG_EFI_STUB */ -- 2.34.1