* [PATCH v2] lkdtm: support llvm-objcopy
[not found] <CAKwvOdk_KmyT4yZOz8iczxeP7mYq-h5LmjzkE5yhsodupRLxEQ@mail.gmail.com>
@ 2019-05-15 18:12 ` Nick Desaulniers
2019-05-15 18:19 ` Nathan Chancellor
0 siblings, 1 reply; 5+ messages in thread
From: Nick Desaulniers @ 2019-05-15 18:12 UTC (permalink / raw)
To: gregkh
Cc: clang-built-linux, Nick Desaulniers, stable, Nathan Chancellor,
Alan Modra, Jordan Rupprect, Kees Cook, Arnd Bergmann,
linux-kernel
With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy errors:
llvm-objcopy: error: --set-section-flags=.text conflicts with
--rename-section=.text=.rodata
Rather than support setting flags then renaming sections vs renaming
then setting flags, it's simpler to just change both at the same time
via --rename-section. Adding the load flag is required for GNU objcopy
to mark .rodata Type as PROGBITS after the rename.
This can be verified with:
$ readelf -S drivers/misc/lkdtm/rodata_objcopy.o
...
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 1] .rodata PROGBITS 0000000000000000 00000040
0000000000000004 0000000000000000 A 0 0 4
...
Which shows that .text is now renamed .rodata, the alloc flag A is set,
the type is PROGBITS, and the section is not flagged as writeable W.
Cc: stable@vger.kernel.org
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=24554
Link: https://github.com/ClangBuiltLinux/linux/issues/448
Reported-by: Nathan Chancellor <nathanchance@gmail.com>
Suggested-by: Alan Modra <amodra@gmail.com>
Suggested-by: Jordan Rupprect <rupprecht@google.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes from v1 -> v2:
* add load flag, as per Kees and Alan.
* update commit message to mention reason for load flag.
* add Kees' and Alan's suggested by.
* carry Kees' Ack.
* cc stable.
drivers/misc/lkdtm/Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
index 951c984de61a..fb10eafe9bde 100644
--- a/drivers/misc/lkdtm/Makefile
+++ b/drivers/misc/lkdtm/Makefile
@@ -15,8 +15,7 @@ KCOV_INSTRUMENT_rodata.o := n
OBJCOPYFLAGS :=
OBJCOPYFLAGS_rodata_objcopy.o := \
- --set-section-flags .text=alloc,readonly \
- --rename-section .text=.rodata
+ --rename-section .text=.rodata,alloc,readonly,load
targets += rodata.o rodata_objcopy.o
$(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE
$(call if_changed,objcopy)
--
2.21.0.1020.gf2820cf01a-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] lkdtm: support llvm-objcopy
2019-05-15 18:12 ` [PATCH v2] lkdtm: support llvm-objcopy Nick Desaulniers
@ 2019-05-15 18:19 ` Nathan Chancellor
2019-05-15 18:24 ` [PATCH v3] " Nick Desaulniers
0 siblings, 1 reply; 5+ messages in thread
From: Nathan Chancellor @ 2019-05-15 18:19 UTC (permalink / raw)
To: Nick Desaulniers
Cc: gregkh, clang-built-linux, stable, Nathan Chancellor, Alan Modra,
Jordan Rupprect, Kees Cook, Arnd Bergmann, linux-kernel
On Wed, May 15, 2019 at 11:12:04AM -0700, 'Nick Desaulniers' via Clang Built Linux wrote:
> With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy errors:
> llvm-objcopy: error: --set-section-flags=.text conflicts with
> --rename-section=.text=.rodata
>
> Rather than support setting flags then renaming sections vs renaming
> then setting flags, it's simpler to just change both at the same time
> via --rename-section. Adding the load flag is required for GNU objcopy
> to mark .rodata Type as PROGBITS after the rename.
>
> This can be verified with:
> $ readelf -S drivers/misc/lkdtm/rodata_objcopy.o
> ...
> Section Headers:
> [Nr] Name Type Address Offset
> Size EntSize Flags Link Info Align
> ...
> [ 1] .rodata PROGBITS 0000000000000000 00000040
> 0000000000000004 0000000000000000 A 0 0 4
> ...
>
> Which shows that .text is now renamed .rodata, the alloc flag A is set,
> the type is PROGBITS, and the section is not flagged as writeable W.
>
> Cc: stable@vger.kernel.org
> Link: https://sourceware.org/bugzilla/show_bug.cgi?id=24554
> Link: https://github.com/ClangBuiltLinux/linux/issues/448
> Reported-by: Nathan Chancellor <nathanchance@gmail.com>
Doesn't look like this got updated. I don't want to make you send a v3
just for that though since it's purely cosmetic and adding my tag below
will ensure I get copied on any backports and such.
> Suggested-by: Alan Modra <amodra@gmail.com>
> Suggested-by: Jordan Rupprect <rupprecht@google.com>
> Suggested-by: Kees Cook <keescook@chromium.org>
> Acked-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> Changes from v1 -> v2:
> * add load flag, as per Kees and Alan.
> * update commit message to mention reason for load flag.
> * add Kees' and Alan's suggested by.
> * carry Kees' Ack.
> * cc stable.
>
> drivers/misc/lkdtm/Makefile | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
> index 951c984de61a..fb10eafe9bde 100644
> --- a/drivers/misc/lkdtm/Makefile
> +++ b/drivers/misc/lkdtm/Makefile
> @@ -15,8 +15,7 @@ KCOV_INSTRUMENT_rodata.o := n
>
> OBJCOPYFLAGS :=
> OBJCOPYFLAGS_rodata_objcopy.o := \
> - --set-section-flags .text=alloc,readonly \
> - --rename-section .text=.rodata
> + --rename-section .text=.rodata,alloc,readonly,load
> targets += rodata.o rodata_objcopy.o
> $(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE
> $(call if_changed,objcopy)
> --
> 2.21.0.1020.gf2820cf01a-goog
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v3] lkdtm: support llvm-objcopy
2019-05-15 18:19 ` Nathan Chancellor
@ 2019-05-15 18:24 ` Nick Desaulniers
[not found] ` <20190517001002.D1A262084A@mail.kernel.org>
0 siblings, 1 reply; 5+ messages in thread
From: Nick Desaulniers @ 2019-05-15 18:24 UTC (permalink / raw)
To: gregkh
Cc: clang-built-linux, Nick Desaulniers, stable, Nathan Chancellor,
Alan Modra, Jordan Rupprect, Kees Cook, Arnd Bergmann,
linux-kernel
With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy errors:
llvm-objcopy: error: --set-section-flags=.text conflicts with
--rename-section=.text=.rodata
Rather than support setting flags then renaming sections vs renaming
then setting flags, it's simpler to just change both at the same time
via --rename-section. Adding the load flag is required for GNU objcopy
to mark .rodata Type as PROGBITS after the rename.
This can be verified with:
$ readelf -S drivers/misc/lkdtm/rodata_objcopy.o
...
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 1] .rodata PROGBITS 0000000000000000 00000040
0000000000000004 0000000000000000 A 0 0 4
...
Which shows that .text is now renamed .rodata, the alloc flag A is set,
the type is PROGBITS, and the section is not flagged as writeable W.
Cc: stable@vger.kernel.org
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=24554
Link: https://github.com/ClangBuiltLinux/linux/issues/448
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Alan Modra <amodra@gmail.com>
Suggested-by: Jordan Rupprect <rupprecht@google.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes from v2 -> v3:
* correct Nathan's email address and collect his reviewed by.
Changes from v1 -> v2:
* add load flag, as per Kees and Alan.
* update commit message to mention reason for load flag.
* add Kees' and Alan's suggested by.
* carry Kees' Ack.
* cc stable.
drivers/misc/lkdtm/Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
index 951c984de61a..fb10eafe9bde 100644
--- a/drivers/misc/lkdtm/Makefile
+++ b/drivers/misc/lkdtm/Makefile
@@ -15,8 +15,7 @@ KCOV_INSTRUMENT_rodata.o := n
OBJCOPYFLAGS :=
OBJCOPYFLAGS_rodata_objcopy.o := \
- --set-section-flags .text=alloc,readonly \
- --rename-section .text=.rodata
+ --rename-section .text=.rodata,alloc,readonly,load
targets += rodata.o rodata_objcopy.o
$(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE
$(call if_changed,objcopy)
--
2.21.0.1020.gf2820cf01a-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3] lkdtm: support llvm-objcopy
[not found] ` <20190517001002.D1A262084A@mail.kernel.org>
@ 2019-05-17 4:06 ` Nathan Chancellor
2019-05-17 4:09 ` Nathan Chancellor
0 siblings, 1 reply; 5+ messages in thread
From: Nathan Chancellor @ 2019-05-17 4:06 UTC (permalink / raw)
To: Sasha Levin; +Cc: Nick Desaulniers, gregkh, clang-built-linux, stable
On Fri, May 17, 2019 at 12:10:02AM +0000, Sasha Levin wrote:
> Hi,
>
> [This is an automated email]
>
> This commit has been processed because it contains a -stable tag.
> The stable tag indicates that it's relevant for the following trees: all
Nick, the stable tag should probably specify 4.8+ since the commit it
fixes came in during 4.8-rc1.
Cc: stable@vger.kernel.org # 4.8+
Might also help to add:
Fixes: 9a49a528dcf3 ("lkdtm: add function for testing .rodata section")
>
> The bot has tested the following trees: v5.1.2, v5.0.16, v4.19.43, v4.14.119, v4.9.176, v4.4.179, v3.18.140.
>
> v5.1.2: Build OK!
> v5.0.16: Build OK!
> v4.19.43: Build OK!
> v4.14.119: Failed to apply! Possible dependencies:
> 039a1c42058d ("lkdtm: Relocate code to subdirectory")
However, it will still need a manual backport because of the lack of
this commit. I've attached the current patch backported for reference,
the git am flags '-3 -p4 --directory=drivers/misc' help get it proper
then the conflict is rather easy to resolve.
Thanks,
Nathan
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3] lkdtm: support llvm-objcopy
2019-05-17 4:06 ` Nathan Chancellor
@ 2019-05-17 4:09 ` Nathan Chancellor
0 siblings, 0 replies; 5+ messages in thread
From: Nathan Chancellor @ 2019-05-17 4:09 UTC (permalink / raw)
To: Sasha Levin; +Cc: Nick Desaulniers, gregkh, clang-built-linux, stable
[-- Attachment #1: Type: text/plain, Size: 1223 bytes --]
On Thu, May 16, 2019 at 09:06:13PM -0700, Nathan Chancellor wrote:
> On Fri, May 17, 2019 at 12:10:02AM +0000, Sasha Levin wrote:
> > Hi,
> >
> > [This is an automated email]
> >
> > This commit has been processed because it contains a -stable tag.
> > The stable tag indicates that it's relevant for the following trees: all
>
> Nick, the stable tag should probably specify 4.8+ since the commit it
> fixes came in during 4.8-rc1.
>
> Cc: stable@vger.kernel.org # 4.8+
>
> Might also help to add:
>
> Fixes: 9a49a528dcf3 ("lkdtm: add function for testing .rodata section")
>
> >
> > The bot has tested the following trees: v5.1.2, v5.0.16, v4.19.43, v4.14.119, v4.9.176, v4.4.179, v3.18.140.
> >
> > v5.1.2: Build OK!
> > v5.0.16: Build OK!
> > v4.19.43: Build OK!
> > v4.14.119: Failed to apply! Possible dependencies:
> > 039a1c42058d ("lkdtm: Relocate code to subdirectory")
>
> However, it will still need a manual backport because of the lack of
> this commit. I've attached the current patch backported for reference,
Would help if I actually did this... :^)
> the git am flags '-3 -p4 --directory=drivers/misc' help get it proper
> then the conflict is rather easy to resolve.
>
> Thanks,
> Nathan
[-- Attachment #2: 0001-lkdtm-support-llvm-objcopy.patch --]
[-- Type: text/plain, Size: 2363 bytes --]
From 10c0a74a8d92669b91b66efe6b72550fc24e8e7d Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Wed, 15 May 2019 11:24:41 -0700
Subject: [PATCH] lkdtm: support llvm-objcopy
With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy errors:
llvm-objcopy: error: --set-section-flags=.text conflicts with
--rename-section=.text=.rodata
Rather than support setting flags then renaming sections vs renaming
then setting flags, it's simpler to just change both at the same time
via --rename-section. Adding the load flag is required for GNU objcopy
to mark .rodata Type as PROGBITS after the rename.
This can be verified with:
$ readelf -S drivers/misc/lkdtm/rodata_objcopy.o
...
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 1] .rodata PROGBITS 0000000000000000 00000040
0000000000000004 0000000000000000 A 0 0 4
...
Which shows that .text is now renamed .rodata, the alloc flag A is set,
the type is PROGBITS, and the section is not flagged as writeable W.
Cc: stable@vger.kernel.org
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=24554
Link: https://github.com/ClangBuiltLinux/linux/issues/448
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Alan Modra <amodra@gmail.com>
Suggested-by: Jordan Rupprect <rupprecht@google.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
drivers/misc/Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index c3c8624f4d95..805835c2b99b 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -70,8 +70,7 @@ KCOV_INSTRUMENT_lkdtm_rodata.o := n
OBJCOPYFLAGS :=
OBJCOPYFLAGS_lkdtm_rodata_objcopy.o := \
- --set-section-flags .text=alloc,readonly \
- --rename-section .text=.rodata
+ --rename-section .text=.rodata,alloc,readonly,load
targets += lkdtm_rodata.o lkdtm_rodata_objcopy.o
$(obj)/lkdtm_rodata_objcopy.o: $(obj)/lkdtm_rodata.o FORCE
$(call if_changed,objcopy)
--
2.22.0.rc0
^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-05-17 4:09 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <CAKwvOdk_KmyT4yZOz8iczxeP7mYq-h5LmjzkE5yhsodupRLxEQ@mail.gmail.com>
2019-05-15 18:12 ` [PATCH v2] lkdtm: support llvm-objcopy Nick Desaulniers
2019-05-15 18:19 ` Nathan Chancellor
2019-05-15 18:24 ` [PATCH v3] " Nick Desaulniers
[not found] ` <20190517001002.D1A262084A@mail.kernel.org>
2019-05-17 4:06 ` Nathan Chancellor
2019-05-17 4:09 ` Nathan Chancellor
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