linux-kernel - Re: [PATCH v6 22/41] mm/mmap: Add shadow stack pages to memory accounting

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: <6ccc8d30-336a-12af-1179-5dc4eca3048d@redhat.com>
Date:   Mon, 20 Feb 2023 13:58:38 +0100
From:   David Hildenbrand <david@...hat.com>
To:     Rick Edgecombe <rick.p.edgecombe@...el.com>, x86@...nel.org,
        "H . Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-mm@...ck.org,
        linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
        Arnd Bergmann <arnd@...db.de>,
        Andy Lutomirski <luto@...nel.org>,
        Balbir Singh <bsingharora@...il.com>,
        Borislav Petkov <bp@...en8.de>,
        Cyrill Gorcunov <gorcunov@...il.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Eugene Syromiatnikov <esyr@...hat.com>,
        Florian Weimer <fweimer@...hat.com>,
        "H . J . Lu" <hjl.tools@...il.com>, Jann Horn <jannh@...gle.com>,
        Jonathan Corbet <corbet@....net>,
        Kees Cook <keescook@...omium.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Nadav Amit <nadav.amit@...il.com>,
        Oleg Nesterov <oleg@...hat.com>, Pavel Machek <pavel@....cz>,
        Peter Zijlstra <peterz@...radead.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        Weijiang Yang <weijiang.yang@...el.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        John Allen <john.allen@....com>, kcc@...gle.com,
        eranian@...gle.com, rppt@...nel.org, jamorris@...ux.microsoft.com,
        dethoma@...rosoft.com, akpm@...ux-foundation.org,
        Andrew.Cooper3@...rix.com, christina.schimpe@...el.com,
        debug@...osinc.com
Cc:     Yu-cheng Yu <yu-cheng.yu@...el.com>
Subject: Re: [PATCH v6 22/41] mm/mmap: Add shadow stack pages to memory
 accounting

On 18.02.23 22:14, Rick Edgecombe wrote:
> From: Yu-cheng Yu <yu-cheng.yu@...el.com>
> 
> The x86 Control-flow Enforcement Technology (CET) feature includes a new
> type of memory called shadow stack. This shadow stack memory has some
> unusual properties, which requires some core mm changes to function
> properly.
> 
> Account shadow stack pages to stack memory.
> 
> Reviewed-by: Kees Cook <keescook@...omium.org>
> Tested-by: Pengfei Xu <pengfei.xu@...el.com>
> Tested-by: John Allen <john.allen@....com>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@...el.com>
> Co-developed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
> Cc: Kees Cook <keescook@...omium.org>
> 
> ---
> v3:
>   - Remove unneeded VM_SHADOW_STACK check in accountable_mapping()
>     (Kirill)
> 
> v2:
>   - Remove is_shadow_stack_mapping() and just change it to directly bitwise
>     and VM_SHADOW_STACK.
> 
> Yu-cheng v26:
>   - Remove redundant #ifdef CONFIG_MMU.
> 
> Yu-cheng v25:
>   - Remove #ifdef CONFIG_ARCH_HAS_SHADOW_STACK for is_shadow_stack_mapping().
> ---
>   mm/mmap.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 425a9349e610..9f85596cce31 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -3290,6 +3290,8 @@ void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages)
>   		mm->exec_vm += npages;
>   	else if (is_stack_mapping(flags))
>   		mm->stack_vm += npages;
> +	else if (flags & VM_SHADOW_STACK)
> +		mm->stack_vm += npages;

Why not modify is_stack_mapping() ?

-- 
Thanks,

David / dhildenb