From: Dave Hansen <dave.hansen@linux.intel.com>
To: Thomas Garnier <thgarnie@google.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@suse.de>,
Andy Lutomirski <luto@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Kees Cook <keescook@chromium.org>,
Stephen Smalley <sds@tycho.nsa.gov>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Jonathan Corbet <corbet@lwn.net>,
Matt Fleming <matt@codeblueprint.co.uk>,
Toshi Kani <toshi.kani@hpe.com>,
Alexander Kuleshov <kuleshovmail@gmail.com>,
Alexander Popov <alpopov@ptsecurity.com>,
Joerg Roedel <jroedel@suse.de>, Dave Young <dyoung@redhat.com>,
Baoquan He <bhe@redhat.com>, Mark Salter <msalter@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, gthelen@google.com,
kernel-hardening@lists.openwall.com
Subject: [kernel-hardening] Re: [PATCH v2 2/4] x86, boot: PUD VA support for physical mapping (x86_64)
Date: Mon, 2 May 2016 14:58:01 -0700 [thread overview]
Message-ID: <5727CD69.7040901@linux.intel.com> (raw)
In-Reply-To: <1462225276-106993-3-git-send-email-thgarnie@google.com>
On 05/02/2016 02:41 PM, Thomas Garnier wrote:
> Minor change that allows early boot physical mapping of PUD level virtual
> addresses. This change prepares usage of different virtual addresses for
> KASLR memory randomization. It has no impact on default usage.
...
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 89d9747..6adfbce 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -526,10 +526,10 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
> {
> unsigned long pages = 0, next;
> unsigned long last_map_addr = end;
> - int i = pud_index(addr);
> + int i = pud_index((unsigned long)__va(addr));
>
> for (; i < PTRS_PER_PUD; i++, addr = next) {
> - pud_t *pud = pud_page + pud_index(addr);
> + pud_t *pud = pud_page + pud_index((unsigned long)__va(addr));
> pmd_t *pmd;
> pgprot_t prot = PAGE_KERNEL;
pud_index() is supposed to take a virtual address. We were passing a
physical address in here, and it all just worked because PAGE_OFFSET is
PUD-aligned. Now that you are moving PAGE_OFFSET around a bit and not
PUD-aligning it, this breaks. Right?
Could you spell this out a bit more the changelog?
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@linux.intel.com>
To: Thomas Garnier <thgarnie@google.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@suse.de>,
Andy Lutomirski <luto@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Kees Cook <keescook@chromium.org>,
Stephen Smalley <sds@tycho.nsa.gov>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Jonathan Corbet <corbet@lwn.net>,
Matt Fleming <matt@codeblueprint.co.uk>,
Toshi Kani <toshi.kani@hpe.com>,
Alexander Kuleshov <kuleshovmail@gmail.com>,
Alexander Popov <alpopov@ptsecurity.com>,
Joerg Roedel <jroedel@suse.de>, Dave Young <dyoung@redhat.com>,
Baoquan He <bhe@redhat.com>, Mark Salter <msalter@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, gthelen@google.com,
kernel-hardening@lists.openwall.com
Subject: Re: [PATCH v2 2/4] x86, boot: PUD VA support for physical mapping (x86_64)
Date: Mon, 2 May 2016 14:58:01 -0700 [thread overview]
Message-ID: <5727CD69.7040901@linux.intel.com> (raw)
In-Reply-To: <1462225276-106993-3-git-send-email-thgarnie@google.com>
On 05/02/2016 02:41 PM, Thomas Garnier wrote:
> Minor change that allows early boot physical mapping of PUD level virtual
> addresses. This change prepares usage of different virtual addresses for
> KASLR memory randomization. It has no impact on default usage.
...
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 89d9747..6adfbce 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -526,10 +526,10 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
> {
> unsigned long pages = 0, next;
> unsigned long last_map_addr = end;
> - int i = pud_index(addr);
> + int i = pud_index((unsigned long)__va(addr));
>
> for (; i < PTRS_PER_PUD; i++, addr = next) {
> - pud_t *pud = pud_page + pud_index(addr);
> + pud_t *pud = pud_page + pud_index((unsigned long)__va(addr));
> pmd_t *pmd;
> pgprot_t prot = PAGE_KERNEL;
pud_index() is supposed to take a virtual address. We were passing a
physical address in here, and it all just worked because PAGE_OFFSET is
PUD-aligned. Now that you are moving PAGE_OFFSET around a bit and not
PUD-aligning it, this breaks. Right?
Could you spell this out a bit more the changelog?
next prev parent reply other threads:[~2016-05-02 21:58 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-02 21:41 [kernel-hardening] [PATCH v2 0/4] x86, boot: KASLR memory implementation Thomas Garnier
2016-05-02 21:41 ` Thomas Garnier
2016-05-02 21:41 ` [kernel-hardening] [PATCH v2 1/4] x86, boot: Refactor KASLR entropy functions Thomas Garnier
2016-05-02 21:41 ` Thomas Garnier
2016-05-02 21:41 ` [kernel-hardening] [PATCH v2 2/4] x86, boot: PUD VA support for physical mapping (x86_64) Thomas Garnier
2016-05-02 21:41 ` Thomas Garnier
2016-05-02 21:58 ` Dave Hansen [this message]
2016-05-02 21:58 ` Dave Hansen
2016-05-03 10:05 ` [kernel-hardening] " Baoquan He
2016-05-03 10:05 ` Baoquan He
2016-05-03 15:08 ` [kernel-hardening] " Dave Hansen
2016-05-03 15:08 ` Dave Hansen
2016-05-03 15:46 ` [kernel-hardening] " Thomas Garnier
2016-05-03 15:46 ` Thomas Garnier
2016-05-02 21:41 ` [kernel-hardening] [PATCH v2 3/4] x86, boot: Implement ASLR for kernel memory sections (x86_64) Thomas Garnier
2016-05-02 21:41 ` Thomas Garnier
2016-05-02 22:00 ` [kernel-hardening] " Dave Hansen
2016-05-02 22:00 ` Dave Hansen
2016-05-03 19:16 ` [kernel-hardening] " Thomas Garnier
2016-05-03 19:16 ` Thomas Garnier
2016-05-02 21:41 ` [kernel-hardening] [PATCH v2 4/4] x86, boot: Memory hotplug support for KASLR memory randomization Thomas Garnier
2016-05-02 21:41 ` Thomas Garnier
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