linux-kernel - Re: [PATCH v3 17/28] x86/sgx: fix a NULL pointer

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: <op.1779qgkdwjvjmi@hhuan26-mobl.amr.corp.intel.com>
Date:   Mon, 17 Jul 2023 08:14:30 -0500
From:   "Haitao Huang" <haitao.huang@...ux.intel.com>
To:     "Jarkko Sakkinen" <jarkko@...nel.org>, dave.hansen@...ux.intel.com,
        tj@...nel.org, linux-kernel@...r.kernel.org,
        linux-sgx@...r.kernel.org, cgroups@...r.kernel.org,
        "Thomas Gleixner" <tglx@...utronix.de>,
        "Ingo Molnar" <mingo@...hat.com>, "Borislav Petkov" <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>
Cc:     kai.huang@...el.com, reinette.chatre@...el.com,
        zhiquan1.li@...el.com, kristen@...ux.intel.com, seanjc@...gle.com
Subject: Re: [PATCH v3 17/28] x86/sgx: fix a NULL pointer

On Mon, 17 Jul 2023 07:49:27 -0500, Jarkko Sakkinen <jarkko@...nel.org>  
wrote:

> On Mon Jul 17, 2023 at 12:48 PM UTC, Jarkko Sakkinen wrote:
>> On Wed Jul 12, 2023 at 11:01 PM UTC, Haitao Huang wrote:
>> > Under heavy load, the SGX EPC reclaimers (ksgxd or future EPC cgroup
>> > worker) may reclaim SECS EPC page for an enclave and set
>> > encl->secs.epc_page to NULL. But the SECS EPC page is required for  
>> EAUG
>> > in #PF handler and is used without checking for NULL and reloading.
>> >
>> > Fix this by checking if SECS is loaded before EAUG and load it if it  
>> was
>> > reclaimed.
>> >
>> > Signed-off-by: Haitao Huang <haitao.huang@...ux.intel.com>
>>
>> A bug fix should be 1/*.
>
> And a fixes tag.
>
> Or is there a bug that is momentized by the earlier patches? This patch
> feels confusing to say the least.
>

It happens in heavy reclaiming cases, just extremely rare when EPC  
accounting is not partitioned into cgroups. Will add fix tag with the  
related EDMM patch. And move this as the first patch.

Thanks
Haitao