mirror of
https://src.fedoraproject.org/rpms/grub2.git
synced 2024-11-24 22:35:28 +00:00
113 lines
4.4 KiB
Diff
113 lines
4.4 KiB
Diff
From d081bd5f47235e3bfd256fd262a6f98fe8b0d0ff Mon Sep 17 00:00:00 2001
|
|
From: Laszlo Ersek <lersek@redhat.com>
|
|
Date: Wed, 23 Nov 2016 06:27:09 +0100
|
|
Subject: [PATCH 163/229] efi/chainloader: truncate overlong relocation section
|
|
|
|
The UEFI Windows 7 boot loader ("EFI/Microsoft/Boot/bootmgfw.efi", SHA1
|
|
31b410e029bba87d2068c65a80b88882f9f8ea25) has inconsistent headers.
|
|
|
|
Compare:
|
|
|
|
> The Data Directory
|
|
> ...
|
|
> Entry 5 00000000000d9000 00000574 Base Relocation Directory [.reloc]
|
|
|
|
Versus:
|
|
|
|
> Sections:
|
|
> Idx Name Size VMA LMA File off ...
|
|
> ...
|
|
> 10 .reloc 00000e22 00000000100d9000 00000000100d9000 000a1800 ...
|
|
|
|
That is, the size reported by the RelocDir entry (0x574) is smaller than
|
|
the virtual size of the .reloc section (0xe22).
|
|
|
|
Quoting the grub2 debug log for the same:
|
|
|
|
> chainloader.c:595: reloc_dir: 0xd9000 reloc_size: 0x00000574
|
|
> chainloader.c:603: reloc_base: 0x7d208000 reloc_base_end: 0x7d208573
|
|
> ...
|
|
> chainloader.c:620: Section 10 ".reloc" at 0x7d208000..0x7d208e21
|
|
> chainloader.c:661: section is not reloc section?
|
|
> chainloader.c:663: rds: 0x00001000, vs: 00000e22
|
|
> chainloader.c:664: base: 0x7d208000 end: 0x7d208e21
|
|
> chainloader.c:666: reloc_base: 0x7d208000 reloc_base_end: 0x7d208573
|
|
> chainloader.c:671: Section characteristics are 42000040
|
|
> chainloader.c:673: Section virtual size: 00000e22
|
|
> chainloader.c:675: Section raw_data size: 00001000
|
|
> chainloader.c:678: Discarding section
|
|
|
|
After hexdumping "bootmgfw.efi" and manually walking its relocation blocks
|
|
(yes, really), I determined that the (smaller) RelocDir value is correct.
|
|
The remaining area that extends up to the .reloc section size (== 0xe22 -
|
|
0x574 == 0x8ae bytes) exists as zero padding in the file.
|
|
|
|
This zero padding shouldn't be passed to relocate_coff() for parsing. In
|
|
order to cope with it, split the handling of .reloc sections into the
|
|
following branches:
|
|
|
|
- original case (equal size): original behavior (--> relocation
|
|
attempted),
|
|
|
|
- overlong .reloc section (longer than reported by RelocDir): truncate the
|
|
section to the RelocDir size for the purposes of relocate_coff(), and
|
|
attempt relocation,
|
|
|
|
- .reloc section is too short, or other checks fail: original behavior
|
|
(--> relocation not attempted).
|
|
|
|
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1347291
|
|
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
|
|
---
|
|
grub-core/loader/efi/chainloader.c | 26 +++++++++++++++++++++-----
|
|
1 file changed, 21 insertions(+), 5 deletions(-)
|
|
|
|
diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c
|
|
index d5ab21d09c3..7826e794ad9 100644
|
|
--- a/grub-core/loader/efi/chainloader.c
|
|
+++ b/grub-core/loader/efi/chainloader.c
|
|
@@ -596,7 +596,7 @@ handle_image (void *data, grub_efi_uint32_t datasize)
|
|
grub_dprintf ("chain", "reloc_base: %p reloc_base_end: %p\n",
|
|
reloc_base, reloc_base_end);
|
|
|
|
- struct grub_pe32_section_table *reloc_section = NULL;
|
|
+ struct grub_pe32_section_table *reloc_section = NULL, fake_reloc_section;
|
|
|
|
section = context.first_section;
|
|
for (i = 0; i < context.number_of_sections; i++, section++)
|
|
@@ -645,12 +645,28 @@ handle_image (void *data, grub_efi_uint32_t datasize)
|
|
* made sense, and the VA and size match RelocDir's
|
|
* versions, then we believe in this section table. */
|
|
if (section->raw_data_size && section->virtual_size &&
|
|
- base && end && reloc_base == base && reloc_base_end == end)
|
|
+ base && end && reloc_base == base)
|
|
{
|
|
- grub_dprintf ("chain", " section is relocation section\n");
|
|
- reloc_section = section;
|
|
+ if (reloc_base_end == end)
|
|
+ {
|
|
+ grub_dprintf ("chain", " section is relocation section\n");
|
|
+ reloc_section = section;
|
|
+ }
|
|
+ else if (reloc_base_end && reloc_base_end < end)
|
|
+ {
|
|
+ /* Bogus virtual size in the reloc section -- RelocDir
|
|
+ * reported a smaller Base Relocation Directory. Decrease
|
|
+ * the section's virtual size so that it equal RelocDir's
|
|
+ * idea, but only for the purposes of relocate_coff(). */
|
|
+ grub_dprintf ("chain",
|
|
+ " section is (overlong) relocation section\n");
|
|
+ grub_memcpy (&fake_reloc_section, section, sizeof *section);
|
|
+ fake_reloc_section.virtual_size -= (end - reloc_base_end);
|
|
+ reloc_section = &fake_reloc_section;
|
|
+ }
|
|
}
|
|
- else
|
|
+
|
|
+ if (!reloc_section)
|
|
{
|
|
grub_dprintf ("chain", " section is not reloc section?\n");
|
|
grub_dprintf ("chain", " rds: 0x%08x, vs: %08x\n",
|
|
--
|
|
2.15.0
|
|
|