linux-kernel - Re: [PATCH 2/2] vdso: Reject absolute relocations during build

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: <87selqp0j8.ffs@tglx>
Date: Wed, 30 Apr 2025 09:32:27 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: Jan Stancek <jstancek@...hat.com>, Thomas Weißschuh
 <thomas.weissschuh@...utronix.de>
Cc: Catalin Marinas <catalin.marinas@....com>, Will Deacon
 <will@...nel.org>, Nam Cao <namcao@...utronix.de>, Anna-Maria Behnsen
 <anna-maria@...utronix.de>, Andy Lutomirski <luto@...nel.org>, Vincenzo
 Frascino <vincenzo.frascino@....com>,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] vdso: Reject absolute relocations during build

On Tue, Apr 29 2025 at 17:17, Jan Stancek wrote:
> On Tue, Apr 29, 2025 at 2:56 PM Thomas Weißschuh
> <thomas.weissschuh@...utronix.de> wrote:
>>
>> +# Also validate that no absolute relocations are present in the object files themselves.
>>  quiet_cmd_vdso_check = VDSOCHK $@
>>        cmd_vdso_check = if $(READELF) -rW $@ | grep -v _NONE | grep -q " R_\w*_"; \
>>                        then (echo >&2 "$@: dynamic relocations are not supported"; \
>> +                            rm -f $@; /bin/false); fi && \
>> +                      if $(READELF) -rW $(filter %.o, $(real-prereqs)) | grep -q " R_\w*_ABS"; \
>> +                      then (echo >&2 "$@: absolute relocations are not supported"; \
>>                              rm -f $@; /bin/false); fi
>
> Should this check only some sections? I'm getting lot of matches on
> debuginfo related sections:

Hmm. All architecture VDSO Makefiles have -fPIC in CFLAGS except for
arm64, which only adds it in arm64/kernel/vdso32/Makefile but not in
arm64/kernel/vdso/Makefile. Confused.

Thanks,

        tglx