[PATCH] efi_loader: sections with zero VirtualSize
Heinrich Schuchardt
heinrich.schuchardt at canonical.com
Sun Aug 29 13:13:08 CEST 2021
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: 9d30a941cce5 ("efi_loader: don't load beyond VirtualSize")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
---
lib/efi_loader/efi_image_loader.c | 31 +++++++++++++++++++++++++++----
1 file changed, 27 insertions(+), 4 deletions(-)
diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
index a0eb63fceb..838e3a7f02 100644
--- a/lib/efi_loader/efi_image_loader.c
+++ b/lib/efi_loader/efi_image_loader.c
@@ -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 = §ions[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 = §ions[i];
- memset(efi_reloc + sec->VirtualAddress, 0,
- sec->Misc.VirtualSize);
+ 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 */
--
2.30.2
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