LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Kees Cook <keescook@chromium.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@suse.de>,
	Catalin Marinas <catalin.marinas@arm.com>,
	clang-built-linux@googlegroups.com,
	"H.J. Lu" <hjl.tools@gmail.com>,
	James Morse <james.morse@arm.com>,
	linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Russell King <linux@armlinux.org.uk>,
	linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
	Mark Rutland <mark.rutland@arm.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Peter Collingbourne <pcc@google.com>,
	Will Deacon <will@kernel.org>,
	x86@kernel.org
Subject: Re: [PATCH 1/9] scripts/link-vmlinux.sh: Delay orphan handling warnings until final link
Date: Sun, 22 Mar 2020 09:00:22 -0700
Message-ID: <202003220859.E54327D98C@keescook> (raw)
In-Reply-To: <1584868418.o62lxee8k1.astroid@bobo.none>

On Sun, Mar 22, 2020 at 07:16:29PM +1000, Nicholas Piggin wrote:
> Kees Cook's on March 21, 2020 4:24 am:
> > On Fri, Mar 20, 2020 at 12:47:54PM +1000, Nicholas Piggin wrote:
> >> Kees Cook's on February 28, 2020 10:22 am:
> >> > Right now, powerpc adds "--orphan-handling=warn" to LD_FLAGS_vmlinux
> >> > to detect when there are unexpected sections getting added to the kernel
> >> > image. There is no need to report these warnings more than once, so it
> >> > can be removed until the final link stage.
> >> > 
> >> > This helps pave the way for other architectures to enable this, with the
> >> > end goal of enabling this warning by default for vmlinux for all
> >> > architectures.
> >> > 
> >> > Signed-off-by: Kees Cook <keescook@chromium.org>
> >> > ---
> >> >  scripts/link-vmlinux.sh | 6 ++++++
> >> >  1 file changed, 6 insertions(+)
> >> > 
> >> > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
> >> > index 1919c311c149..416968fea685 100755
> >> > --- a/scripts/link-vmlinux.sh
> >> > +++ b/scripts/link-vmlinux.sh
> >> > @@ -255,6 +255,11 @@ info GEN modules.builtin
> >> >  tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |
> >> >  	tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin
> >> >  
> >> > +
> >> > +# Do not warn about orphan sections until the final link stage.
> >> > +saved_LDFLAGS_vmlinux="${LDFLAGS_vmlinux}"
> >> > +LDFLAGS_vmlinux="$(echo "${LDFLAGS_vmlinux}" | sed -E 's/ --orphan-handling=warn( |$)/ /g')"
> >> > +
> >> >  btf_vmlinux_bin_o=""
> >> >  if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
> >> >  	if gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then
> >> > @@ -306,6 +311,7 @@ if [ -n "${CONFIG_KALLSYMS}" ]; then
> >> >  	fi
> >> >  fi
> >> >  
> >> > +LDFLAGS_vmlinux="${saved_LDFLAGS_vmlinux}"
> >> >  vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
> >> >  
> >> >  if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
> >> 
> >> That's ugly. Why not just enable it for all archs?
> > 
> > It is ugly; I agree.
> > 
> > I can try to do this for all architectures, but I worry there are a
> > bunch I can't test. But I guess it would stand out. ;)
> 
> It's only warn, so it doesn't break their builds (unless there's a 
> linker error on warn option I don't know about?). We had a powerpc bug 
> that would have been caught with it as well, so it's not a bad idea to
> get everyone using it.

Well, it's bad form to add warnings to a build. I am expected to fix any
warnings before I enable a warning flag.

> I would just do it. Doesn't take much to fix.

I will do my best on the archs I can't test. :)

-- 
Kees Cook

  reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-28  0:22 [PATCH 0/9] Enable orphan section warning Kees Cook
2020-02-28  0:22 ` [PATCH 1/9] scripts/link-vmlinux.sh: Delay orphan handling warnings until final link Kees Cook
2020-03-20  2:47   ` Nicholas Piggin
2020-03-20 18:24     ` Kees Cook
2020-03-22  9:16       ` Nicholas Piggin
2020-03-22 16:00         ` Kees Cook [this message]
2020-02-28  0:22 ` [PATCH 2/9] vmlinux.lds.h: Add .gnu.version* to DISCARDS Kees Cook
2020-02-28  0:22 ` [PATCH 3/9] x86/build: Warn on orphan section placement Kees Cook
2020-02-28  0:22 ` [PATCH 4/9] x86/boot: " Kees Cook
2020-02-28  0:22 ` [PATCH 5/9] Add RUNTIME_DISCARD_EXIT to generic DISCARDS Kees Cook
2020-02-28  0:22 ` [PATCH 6/9] arm64/build: Use common DISCARDS in linker script Kees Cook
2020-03-17 21:52   ` Will Deacon
2020-02-28  0:22 ` [PATCH 7/9] arm64/build: Warn on orphan section placement Kees Cook
2020-03-17 21:56   ` Will Deacon
2020-03-17 23:01     ` Kees Cook
2020-03-17 23:10       ` Nick Desaulniers
2020-02-28  0:22 ` [PATCH 8/9] arm/build: " Kees Cook
2020-02-28  0:22 ` [PATCH 9/9] arm/boot: " Kees Cook
2020-02-28  6:51 ` [PATCH 0/9] Enable orphan section warning Sedat Dilek
2020-03-03  4:32   ` Kees Cook
2020-04-02 16:20 ` Sedat Dilek
2020-04-02 17:26   ` Kees Cook
2020-04-05 11:15     ` Sedat Dilek

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=202003220859.E54327D98C@keescook \
    --to=keescook@chromium.org \
    --cc=arnd@arndb.de \
    --cc=bp@suse.de \
    --cc=catalin.marinas@arm.com \
    --cc=clang-built-linux@googlegroups.com \
    --cc=hjl.tools@gmail.com \
    --cc=james.morse@arm.com \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@armlinux.org.uk \
    --cc=mark.rutland@arm.com \
    --cc=masahiroy@kernel.org \
    --cc=npiggin@gmail.com \
    --cc=pcc@google.com \
    --cc=will@kernel.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git