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| author | Bruce Ashfield <bruce.ashfield@gmail.com> | 2019-09-26 10:32:26 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2019-10-01 11:19:40 +0200 |
| commit | 9e2276fa6eb39817dcc4cda415f0199fb7016b37 (patch) | |
| tree | 3d9a3ad679a0133b39c85ec96ed86ced58fc9317 | |
| parent | 54ecb8f7028c5eb3d740bb82b0f1d90f2df63c5c (diff) | |
| download | linux-9e2276fa6eb39817dcc4cda415f0199fb7016b37.tar.bz2 | |
arch/x86/boot: Use prefix map to avoid embedded paths
It was observed that the kernel embeds the absolute build path in the
x86 boot image when the __FILE__ macro is expanded.
> From https://bugzilla.yoctoproject.org/show_bug.cgi?id=13458:
If you turn on the buildpaths QA test, or try a reproducible build, you
discover that the kernel image contains build paths.
$ strings bzImage-5.0.19-yocto-standard |grep tmp/
out of pgt_buf in
/data/poky-tmp/reproducible/tmp/work-shared/qemux86-64/kernel-source/arch/x86/boot/compressed/kaslr_64.c!?
But what's this in the top-level Makefile:
$ git grep prefix-map
Makefile:KBUILD_CFLAGS += $(call
cc-option,-fmacro-prefix-map=$(srctree)/=)
So the __FILE__ shouldn't be using the full path. However
arch/x86/boot/compressed/Makefile has this:
KBUILD_CFLAGS := -m$(BITS) -O2
So that clears KBUILD_FLAGS, removing the -fmacro-prefix-map option.
Use -fmacro-prefix-map to have relative paths in the boot image too.
[ bp: Massage commit message and put the KBUILD_CFLAGS addition in
..boot/Makefile after the KBUILD_AFLAGS assignment because gas
doesn't support -fmacro-prefix-map. ]
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: George Rimar <grimar@accesssoftek.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190926093226.8568-1-ross.burton@intel.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=204333
| -rw-r--r-- | arch/x86/boot/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/Makefile | 1 |
2 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index e2839b5c246c..3e9f5544820a 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -67,6 +67,7 @@ clean-files += cpustr.h KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ +KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) GCOV_PROFILE := n UBSAN_SANITIZE := n diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 6b84afdd7538..b246f18c5857 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -38,6 +38,7 @@ KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector) KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) KBUILD_CFLAGS += $(call cc-disable-warning, gnu) KBUILD_CFLAGS += -Wno-pointer-sign +KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ GCOV_PROFILE := n |