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authorH.J. Lu <hjl.tools@gmail.com>2020-03-26 20:43:14 +0300
committerBorislav Petkov <bp@suse.de>2020-03-27 17:53:05 +0300
commit4caffe6a28d3157c11cae923a40456a053c520ea (patch)
tree587dc4dc34f68d45a04949884fd032f0764d84a4
parent84d5f77fc2ee4e010c2c037750e32f06e55224b0 (diff)
downloadlinux-4caffe6a28d3157c11cae923a40456a053c520ea.tar.xz
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.S7
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