linux-kernel - Re: [PATCH] arm64/vdso: Remove --hash-style=sysv

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAFP8O3LcEZD2L6KFw-Qh5jGivtifFUzqTM=JceWKU4nJrBaBZg@mail.gmail.com>
Date: Wed, 14 Aug 2024 18:23:43 -0700
From: Fangrui Song <maskray@...gle.com>
To: Xi Ruoyao <xry111@...111.site>
Cc: Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-kselftest@...r.kernel.org
Subject: Re: [PATCH] arm64/vdso: Remove --hash-style=sysv

On Wed, Aug 14, 2024 at 12:56 PM Xi Ruoyao <xry111@...111.site> wrote:
>
> On Thu, 2024-07-18 at 10:34 -0700, Fangrui Song wrote:
> > glibc added support for .gnu.hash in 2006 and .hash has been obsoleted
> > for more than one decade in many Linux distributions.  Using
> > --hash-style=sysv might imply unaddressed issues and confuse readers.
> >
> > Just drop the option and rely on the linker default, which is likely
> > "both", or "gnu" when the distribution really wants to eliminate sysv
> > hash overhead.
> >
> > Similar to commit 6b7e26547fad ("x86/vdso: Emit a GNU hash").
> >
> > Signed-off-by: Fangrui Song <maskray@...gle.com>
>
> Hi Fangrui,
>
> If I read tools/testing/selftests/vDSO/parse_vdso.c correctly, it does
> know DT_GNU_HASH as at now.  Thus after this change the vDSO selftests
> are skipped with "Couldn't find __vdso_gettimeofday" etc if the distro
> enables --hash-style=gnu by default.
>
> So it seems we need to add DT_GNU_HASH support for parse_vdso.c to keep
> test coverage.

Hi Xi,

Perhaps the selftests file needs DT_GNU_HASH support like
https://github.com/abseil/abseil-cpp/commit/1278ee9bd9bd4916181521fac96d6fa1100e38e6


> > ---
> >  arch/arm64/kernel/vdso/Makefile   | 2 +-
> >  arch/arm64/kernel/vdso32/Makefile | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
> > index d63930c82839..d11da6461278 100644
> > --- a/arch/arm64/kernel/vdso/Makefile
> > +++ b/arch/arm64/kernel/vdso/Makefile
> > @@ -21,7 +21,7 @@ btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
> >  # potential future proofing if we end up with internal calls to the exported
> >  # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
> >  # preparation in build-time C")).
> > -ldflags-y := -shared -soname=linux-vdso.so.1 --hash-style=sysv       \
> > +ldflags-y := -shared -soname=linux-vdso.so.1 \
> >            -Bsymbolic --build-id=sha1 -n $(btildflags-y)
> >
> >  ifdef CONFIG_LD_ORPHAN_WARN
> > diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
> > index cc4508c604b2..25a2cb6317f3 100644
> > --- a/arch/arm64/kernel/vdso32/Makefile
> > +++ b/arch/arm64/kernel/vdso32/Makefile
> > @@ -98,7 +98,7 @@ VDSO_AFLAGS += -D__ASSEMBLY__
> >  # From arm vDSO Makefile
> >  VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1
> >  VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096
> > -VDSO_LDFLAGS += -shared --hash-style=sysv --build-id=sha1
> > +VDSO_LDFLAGS += -shared --build-id=sha1
> >  VDSO_LDFLAGS += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
> >
> >
>
> --
> Xi Ruoyao <xry111@...111.site>
> School of Aerospace Science and Technology, Xidian University



-- 
宋方睿