linux-kernel - Re: [PATCH v2 25/43] powerpc/32: Replace ASM exception exit by C exception exit from ppc64

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: <0296d1bc-b37e-43c8-06cf-00ec458fb74e@csgroup.eu>
Date:   Thu, 11 Mar 2021 20:39:04 +0100
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>, npiggin@...il.com
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v2 25/43] powerpc/32: Replace ASM exception exit by C
 exception exit from ppc64



Le 11/03/2021 à 14:46, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@...roup.eu> writes:
>> This patch replaces the PPC32 ASM exception exit by C exception exit.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
>> ---
>>   arch/powerpc/kernel/entry_32.S  | 481 +++++++++-----------------------
>>   arch/powerpc/kernel/interrupt.c |   4 +
>>   2 files changed, 132 insertions(+), 353 deletions(-)
> 
> Bisect points to this breaking qemu mac99 for me, with pmac32_defconfig.
> 
> I haven't had time to dig any deeper sorry.

Embarrasing ...

I don't get this problem on the 8xx (nohash/32) or the 83xx (book3s/32).
I don't get this problem with qemu mac99 when using my klibc-based initramfs.

I managed to reproduce it with the rootfs.cpio that I got some time ago from linuxppc github Wiki.

I'll investigate it tomorrow.

Thanks
Christophe


> 
> cheers
> 
> 
> Freeing unused kernel memory: 1132K
> This architecture does not have kernel memory protection.
> Run /init as init process
> init[1]: User access of kernel address (fffffd20) - exploit attempt? (uid: 0)
> init[1]: segfault (11) at fffffd20 nip b7e78638 lr b7e845e4 code 1 in ld-2.27.so[b7e6b000+22000]
> init[1]: code: 92010080 92210084 92410088 92810090 92a10094 92c10098 930100a0 932100a4
> init[1]: code: 934100a8 936100ac 93a100b4 91810074 <7d41496e> 39400000 3b810017 579c0036
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x00ERROR: Error: saw oops/warning etc. while expecting
> 00000b
> CPU: 0 PID: 1 Comm: init Not tainted 5.12.0-rc2+ #1
> Call Trace:
> [f1019d80] [c004f1ec] panic+0x138/0x328 (unreliable)
> [f1019de0] [c0051c8c] do_exit+0x880/0x8f4
> [f1019e30] [c0052bdc] do_group_exit+0x40/0xa4
> [f1019e50] [c0060d04] get_signal+0x1e8/0x834
> [f1019eb0] [c000b624] do_notify_resume+0xc8/0x314
> [f1019f10] [c0010da8] interrupt_exit_user_prepare+0xa4/0xdc
> [f1019f30] [c0018228] interrupt_return+0x14/0x14c
> --- interrupt: 300 at 0xb7e78638
> NIP:  b7e78638 LR: b7e845e4 CTR: c01ea2d8
> REGS: f1019f40 TRAP: 0300   Not tainted  (5.12.0-rc2+)
> MSR:  0000d032 <EE,PR,ME,IR,DR,RI>  CR: 28004422  XER: 20000000
> DAR: fffffd20 DSISR: 42000000
> GPR00: b7e845e4 bf951440 00000000 bf951460 00000000 bf951718 fefefeff 7f7f7f7f
> GPR08: bf9516b0 406ae8e0 b7eac1d4 00000000 0a12247b 00000000 b7e8a0d0 b7e78554
> GPR16: bf951730 bf9516f0 b7eaaf40 bf9516f0 00000001 b7eaa688 10002178 bf951460
> GPR24: 00000000 00000000 b7eac200 100cff38 bf9516f0 10002179 b7e845e4 bf951440
> NIP [b7e78638] 0xb7e78638
> LR [b7e845e4] 0xb7e845e4
> --- interrupt: 300
> Rebooting in 180 seconds..
>