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| author | H.J. Lu <hjl.tools@gmail.com> | 2020-03-26 18:43:14 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-03-27 15:53:05 +0100 |
| commit | 4caffe6a28d3157c11cae923a40456a053c520ea (patch) | |
| tree | 587dc4dc34f68d45a04949884fd032f0764d84a4 | |
| parent | x86, vmlinux.lds: Add RUNTIME_DISCARD_EXIT to generic DISCARDS (diff) | |
| download | linux-4caffe6a28d3157c11cae923a40456a053c520ea.tar.xz linux-4caffe6a28d3157c11cae923a40456a053c520ea.zip | |
x86/vdso: Discard .note.gnu.property sections in vDSO
With the command-line option -mx86-used-note=yes which can also be
enabled at binutils build time with:
--enable-x86-used-note generate GNU x86 used ISA and feature properties
the x86 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 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 */
eh_frame_hdr 0x6474e550;
}
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 x86-64:
[hjl@gnu-skx-1 vdso]$ 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.
[ bp: Massage. ]
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200326174314.254662-1-hjl.tools@gmail.com
| -rw-r--r-- | arch/x86/entry/vdso/vdso-layout.lds.S | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S index ea7e0155c604..4d152933547d 100644 --- a/arch/x86/entry/vdso/vdso-layout.lds.S +++ b/arch/x86/entry/vdso/vdso-layout.lds.S @@ -57,6 +57,13 @@ SECTIONS *(.gnu.linkonce.b.*) } :text + /* + * Discard .note.gnu.property sections which are unused and have + * different alignment requirement from vDSO note sections. + */ + /DISCARD/ : { + *(.note.gnu.property) + } .note : { *(.note.*) } :text :note .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr |