From: "tip-bot2 for H.J. Lu" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: "H.J. Lu" <hjl.tools@gmail.com>, Borislav Petkov <bp@suse.de>,
Kees Cook <keescook@chromium.org>, x86 <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [tip: x86/build] x86/vdso: Discard .note.gnu.property sections in vDSO
Date: Fri, 27 Mar 2020 17:27:25 -0000 [thread overview]
Message-ID: <158533004544.28353.7775118937296827800.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200326174314.254662-1-hjl.tools@gmail.com>
The following commit has been merged into the x86/build branch of tip:
Commit-ID: 4caffe6a28d3157c11cae923a40456a053c520ea
Gitweb: https://git.kernel.org/tip/4caffe6a28d3157c11cae923a40456a053c520ea
Author: H.J. Lu <hjl.tools@gmail.com>
AuthorDate: Thu, 26 Mar 2020 10:43:14 -07:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Fri, 27 Mar 2020 15:53:05 +01:00
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
---
arch/x86/entry/vdso/vdso-layout.lds.S | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index ea7e015..4d15293 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
prev parent reply other threads:[~2020-03-27 17:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 17:43 [PATCH] x86: Discard .note.gnu.property sections in vDSO H.J. Lu
2020-03-27 10:44 ` Borislav Petkov
2020-03-27 12:07 ` H.J. Lu
2020-03-27 17:27 ` tip-bot2 for H.J. Lu [this message]
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