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Revision 4b017e59f01097f19b938f6dc4dc2c4720701610 authored by Ard Biesheuvel on 14 October 2022, 10:25:52 UTC, committed by Ard Biesheuvel on 21 October 2022, 09:09:40 UTC 
efi: ssdt: Don't free memory if ACPI table was loaded successfully
 
Amadeusz reports KASAN use-after-free errors introduced by commit
3881ee0b1edc ("efi: avoid efivars layer when loading SSDTs from
variables"). The problem appears to be that the memory that holds the
new ACPI table is now freed unconditionally, instead of only when the
ACPI core reported a failure to load the table.

So let's fix this, by omitting the kfree() on success.

Cc: <stable@vger.kernel.org> # v6.0
Link: https://lore.kernel.org/all/a101a10a-4fbb-5fae-2e3c-76cf96ed8fbd@linux.intel.com/
Fixes: 3881ee0b1edc ("efi: avoid efivars layer when loading SSDTs from variables")
Reported-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
1 parent f57fb37
Raw File
initramfs_data.S 
/* SPDX-License-Identifier: GPL-2.0 */
/*
  initramfs_data includes the compressed binary that is the
  filesystem used for early user space.
  Note: Older versions of "as" (prior to binutils 2.11.90.0.23
  released on 2001-07-14) dit not support .incbin.
  If you are forced to use older binutils than that then the
  following trick can be applied to create the resulting binary:


  ld -m elf_i386  --format binary --oformat elf32-i386 -r \
  -T initramfs_data.scr initramfs_data.cpio.gz -o initramfs_data.o
   ld -m elf_i386  -r -o built-in.a initramfs_data.o

  For including the .init.ramfs sections, see include/asm-generic/vmlinux.lds.

  The above example is for i386 - the parameters vary from architectures.
  Eventually look up LDFLAGS_BLOB in an older version of the
  arch/$(ARCH)/Makefile to see the flags used before .incbin was introduced.

  Using .incbin has the advantage over ld that the correct flags are set
  in the ELF header, as required by certain architectures.
*/

.section .init.ramfs,"a"
__irf_start:
.incbin "usr/initramfs_inc_data"
__irf_end:
.section .init.ramfs.info,"a"
.globl __initramfs_size
__initramfs_size:
#ifdef CONFIG_64BIT
	.quad __irf_end - __irf_start
#else
	.long __irf_end - __irf_start
#endif
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