efi_loader: sections with zero VirtualSize

In a section header VirtualSize may be zero. This is for instance seen in
the .sbat section of shim. In this case use SizeOfRawData as section size.

Fixes: 9d30a941cc ("efi_loader: don't load beyond VirtualSize")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Asherah Connor <ashe@kivikakk.ee>
This commit is contained in:
Heinrich Schuchardt 2021-08-29 11:52:44 +02:00 committed by Heinrich Schuchardt
parent d6136c63ca
commit 1ea133acd6

View file

@ -800,6 +800,23 @@ efi_status_t efi_check_pe(void *buffer, size_t size, void **nt_header)
return EFI_SUCCESS;
}
/**
* section_size() - determine size of section
*
* The size of a section in memory if normally given by VirtualSize.
* If VirtualSize is not provided, use SizeOfRawData.
*
* @sec: section header
* Return: size of section in memory
*/
static u32 section_size(IMAGE_SECTION_HEADER *sec)
{
if (sec->Misc.VirtualSize)
return sec->Misc.VirtualSize;
else
return sec->SizeOfRawData;
}
/**
* efi_load_pe() - relocate EFI binary
*
@ -869,8 +886,9 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
/* Calculate upper virtual address boundary */
for (i = num_sections - 1; i >= 0; i--) {
IMAGE_SECTION_HEADER *sec = &sections[i];
virt_size = max_t(unsigned long, virt_size,
sec->VirtualAddress + sec->Misc.VirtualSize);
sec->VirtualAddress + section_size(sec));
}
/* Read 32/64bit specific header bits */
@ -931,11 +949,16 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
/* Load sections into RAM */
for (i = num_sections - 1; i >= 0; i--) {
IMAGE_SECTION_HEADER *sec = &sections[i];
u32 copy_size = section_size(sec);
if (copy_size > sec->SizeOfRawData) {
copy_size = sec->SizeOfRawData;
memset(efi_reloc + sec->VirtualAddress, 0,
sec->Misc.VirtualSize);
}
memcpy(efi_reloc + sec->VirtualAddress,
efi + sec->PointerToRawData,
min(sec->Misc.VirtualSize, sec->SizeOfRawData));
copy_size);
}
/* Run through relocations */