Messages in this thread | | | From | Ard Biesheuvel <> | Date | Wed, 28 Apr 2021 10:51:38 +0200 | Subject | Re: [PATCH] arm64/vdso: Discard .note.gnu.property sections in vDSO |
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On Wed, 28 Apr 2021 at 00:58, Kees Cook <keescook@chromium.org> wrote: > > On Fri, Apr 23, 2021 at 01:51:59PM -0700, Bill Wendling wrote: > > 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> > > Seems good to me. If we ever need the BTI markings, etc, for the vDSO, > we can revisit it then. > > Reviewed-by: Kees Cook <keescook@chromium.org> >
Acked-by: Ard Biesheuvel <ardb@kernel.org>
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