linux-brain/arch/arm64/kernel/vdso
Bill Wendling 13a474c013 arm64/vdso: Discard .note.gnu.property sections in vDSO
[ Upstream commit 388708028e6937f3fc5fc19aeeb847f8970f489c ]

The arm64 assembler in binutils 2.32 and above generates a program
property note in a note section, .note.gnu.property, to encode used x86
ISAs and features. But the kernel linker script only contains a single
NOTE segment:

  PHDRS
  {
    text    PT_LOAD    FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
    dynamic PT_DYNAMIC FLAGS(4);               /* PF_R */
    note    PT_NOTE    FLAGS(4);               /* PF_R */
  }

The NOTE segment generated by the vDSO linker script is aligned to 4 bytes.
But the .note.gnu.property section must be aligned to 8 bytes on arm64.

  $ readelf -n vdso64.so

  Displaying notes found in: .note
    Owner                Data size      Description
    Linux                0x00000004     Unknown note type: (0x00000000)
     description data: 06 00 00 00
  readelf: Warning: note with invalid namesz and/or descsz found at offset 0x20
  readelf: Warning:  type: 0x78, namesize: 0x00000100, descsize: 0x756e694c, alignment: 8

Since the note.gnu.property section in the vDSO is not checked by the
dynamic linker, discard the .note.gnu.property sections in the vDSO.

Similar to commit 4caffe6a28d31 ("x86/vdso: Discard .note.gnu.property
sections in vDSO"), but for arm64.

Signed-off-by: Bill Wendling <morbo@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210423205159.830854-1-morbo@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-11 14:04:14 +02:00
..
.gitignore arm64: drop non-existing vdso-offsets.h from .gitignore 2017-03-30 19:29:30 +01:00
Makefile arm64: vdso: Add -fasynchronous-unwind-tables to cflags 2020-05-06 08:15:17 +02:00
gen_vdso_offsets.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
note.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
sigreturn.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
vdso.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
vdso.lds.S arm64/vdso: Discard .note.gnu.property sections in vDSO 2021-05-11 14:04:14 +02:00
vgettimeofday.c arm64: vdso: Substitute gettimeofday() with C implementation 2019-06-22 21:21:06 +02:00