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[kernel] Update kernel binary's header structure

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The kernel's file header has not been verified for a long time. This
change returns file verification to the bootloader to make sure the ELF
loaded in position 0 is actually the kernel.
This commit is contained in:
Justin C. Miller
2021-05-28 14:44:13 -07:00
parent 910fde3b2c
commit 9fbbd8b954
6 changed files with 78 additions and 17 deletions
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24
src/boot/loader.cpp
View File

@@ -113,5 +113,29 @@ load_program(
program.entrypoint = header->entrypoint;
}
void
verify_kernel_header(
init::program &program,
uefi::boot_services *bs)
{
status_line status(L"Verifying kernel header");
const init::header *header =
reinterpret_cast<const init::header *>(program.sections[0].phys_addr);
if (header->magic != init::header_magic)
error::raise(uefi::status::load_error, L"Bad kernel magic number");
if (header->length < sizeof(init::header))
error::raise(uefi::status::load_error, L"Bad kernel header length");
if (header->version < init::min_header_version)
error::raise(uefi::status::unsupported, L"Kernel header version not supported");
console::print(L" Loaded kernel vserion: %d.%d.%d %lx\r\n",
header->version_major, header->version_minor, header->version_patch,
header->version_gitsha);
}
} // namespace loader
} // namespace boot

8
src/boot/loader.h
View File

@@ -38,5 +38,13 @@ load_program(
buffer data,
uefi::boot_services *bs);
/// Verify that a loaded ELF has the j6 kernel header
/// \arg program The program to check for a header
/// \arg bs Boot services
void
verify_kernel_header(
kernel::init::program &program,
uefi::boot_services *bs);
} // namespace loader
} // namespace boot

11
src/boot/main.cpp
View File

@@ -134,8 +134,8 @@ uefi_preboot(uefi::handle image, uefi::system_table *st)
init::args *args =
allocate_args_structure(bs, max_modules, max_programs);
args->magic = init::magic;
args->version = init::version;
args->magic = init::args_magic;
args->version = init::args_version;
args->runtime_services = rs;
args->acpi_table = hw::find_acpi_table(st);
paging::allocate_tables(args, bs);
@@ -154,6 +154,9 @@ uefi_preboot(uefi::handle image, uefi::system_table *st)
loader::load_program(program, desc.name, buf, bs);
}
// First program *must* be the kernel
loader::verify_kernel_header(args->programs[0], bs);
return args;
}
@@ -196,8 +199,8 @@ efi_main(uefi::handle image, uefi::system_table *st)
memory::fix_frame_blocks(args);
kernel::entrypoint kentry =
reinterpret_cast<kernel::entrypoint>(kernel.entrypoint);
init::entrypoint kentry =
reinterpret_cast<init::entrypoint>(kernel.entrypoint);
status.next();
hw::setup_control_regs();