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x86/boot: Split off PE/COFF .data section

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[ Commit 34951f3c28 upstream ]

Describe the code and data of the decompressor binary using separate
.text and .data PE/COFF sections, so that we will be able to map them
using restricted permissions once we increase the section and file
alignment sufficiently. This avoids the need for memory mappings that
are writable and executable at the same time, which is something that
is best avoided for security reasons.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230915171623.655440-17-ardb@google.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ard Biesheuvel
2024-04-19 10:11:21 +02:00
committed by Greg Kroah-Hartman
parent 43b1920588
commit 581f5d5e02
2 changed files with 16 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/x86/boot/Makefile
+1 -1
View File
@@ -91,7 +91,7 @@ $(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE
SETUP_OBJS = $(addprefix $(obj)/,$(setup-y))
sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi.._stub_entry\|efi\(32\)\?_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|_edata\|z_.*\)$$/\#define ZO_\2 0x\1/p'
sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi.._stub_entry\|efi\(32\)\?_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|_e\?data\|z_.*\)$$/\#define ZO_\2 0x\1/p'
quiet_cmd_zoffset = ZOFFSET $@
cmd_zoffset = $(NM) $< | sed -n $(sed-zoffset) > $@
arch/x86/boot/header.S
+15 -4
View File
@@ -74,9 +74,9 @@ optional_header:
.byte 0x02 # MajorLinkerVersion
.byte 0x14 # MinorLinkerVersion
.long setup_size + ZO__end - 0x200 # SizeOfCode
.long ZO__data # SizeOfCode
.long 0 # SizeOfInitializedData
.long ZO__end - ZO__data # SizeOfInitializedData
.long 0 # SizeOfUninitializedData
.long setup_size + ZO_efi_pe_entry # AddressOfEntryPoint
@@ -177,9 +177,9 @@ section_table:
.byte 0
.byte 0
.byte 0
.long ZO__end
.long ZO__data
.long setup_size
.long ZO__edata # Size of initialized data
.long ZO__data # Size of initialized data
# on disk
.long setup_size
.long 0 # PointerToRelocations
@@ -190,6 +190,17 @@ section_table:
IMAGE_SCN_MEM_READ | \
IMAGE_SCN_MEM_EXECUTE # Characteristics
.ascii ".data\0\0\0"
.long ZO__end - ZO__data # VirtualSize
.long setup_size + ZO__data # VirtualAddress
.long ZO__edata - ZO__data # SizeOfRawData
.long setup_size + ZO__data # PointerToRawData
.long 0, 0, 0
.long IMAGE_SCN_CNT_INITIALIZED_DATA | \
IMAGE_SCN_MEM_READ | \
IMAGE_SCN_MEM_WRITE # Characteristics
.set section_count, (. - section_table) / 40
#endif /* CONFIG_EFI_STUB */