linux/arch/arm64/kernel/vdso
Bill Wendling 388708028e arm64/vdso: Discard .note.gnu.property sections in vDSO
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 4caffe6a28 ("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>
2021-04-30 18:25:39 +01:00
..
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
gen_vdso_offsets.sh arm64: Support running gen_vdso_offsets.sh with BSD userland. 2021-01-20 12:23:27 +00:00
Makefile clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
note.S arm64: vdso: Annotate for BTI 2020-05-07 17:53:20 +01:00
sigreturn.S arm64: vdso: Disable dwarf unwinding through the sigreturn trampoline 2020-06-23 14:47:03 +01:00
vdso.lds.S arm64/vdso: Discard .note.gnu.property sections in vDSO 2021-04-30 18:25:39 +01:00
vgettimeofday.c arm64: vdso: Include common headers in the vdso library 2020-03-21 15:24:01 +01:00