linux-kernel - Re: [PATCH v7 3/7] mseal, system mappings: enable x86-64

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: <20250225085728-24167715-8562-45a8-86cd-0ea503e4bc73@linutronix.de>
Date: Tue, 25 Feb 2025 09:08:03 +0100
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: jeffxu@...omium.org
Cc: akpm@...ux-foundation.org, keescook@...omium.org, jannh@...gle.com, 
	torvalds@...ux-foundation.org, vbabka@...e.cz, lorenzo.stoakes@...cle.com, 
	Liam.Howlett@...cle.com, adhemerval.zanella@...aro.org, oleg@...hat.com, avagin@...il.com, 
	benjamin@...solutions.net, linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org, 
	linux-mm@...ck.org, jorgelo@...omium.org, sroettger@...gle.com, hch@....de, 
	ojeda@...nel.org, adobriyan@...il.com, johannes@...solutions.net, 
	pedro.falcato@...il.com, hca@...ux.ibm.com, willy@...radead.org, anna-maria@...utronix.de, 
	mark.rutland@....com, linus.walleij@...aro.org, Jason@...c4.com, deller@....de, 
	rdunlap@...radead.org, davem@...emloft.net, peterx@...hat.com, f.fainelli@...il.com, 
	gerg@...nel.org, dave.hansen@...ux.intel.com, mingo@...nel.org, ardb@...nel.org, 
	mhocko@...e.com, 42.hyeyoo@...il.com, peterz@...radead.org, ardb@...gle.com, 
	enh@...gle.com, rientjes@...gle.com, groeck@...omium.org, mpe@...erman.id.au, 
	aleksandr.mikhalitsyn@...onical.com, mike.rapoport@...il.com
Subject: Re: [PATCH v7 3/7] mseal, system mappings: enable x86-64

Hi Jeff,

On Mon, Feb 24, 2025 at 10:52:42PM +0000, jeffxu@...omium.org wrote:
> From: Jeff Xu <jeffxu@...omium.org>
> 
> Provide support for CONFIG_MSEAL_SYSTEM_MAPPINGS on x86-64,
> covering the vdso, vvar, vvar_vclock.
> 
> Production release testing passes on Android and Chrome OS.
> 
> Signed-off-by: Jeff Xu <jeffxu@...omium.org>
> ---
>  arch/x86/Kconfig          |  1 +
>  arch/x86/entry/vdso/vma.c | 16 ++++++++++------
>  2 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 87198d957e2f..8fa17032ca46 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -26,6 +26,7 @@ config X86_64
>  	depends on 64BIT
>  	# Options that are inherently 64-bit kernel only:
>  	select ARCH_HAS_GIGANTIC_PAGE
> +	select ARCH_HAS_MSEAL_SYSTEM_MAPPINGS
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>  	select ARCH_SUPPORTS_PER_VMA_LOCK
>  	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
> diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
> index 39e6efc1a9ca..1b1c009f20a8 100644
> --- a/arch/x86/entry/vdso/vma.c
> +++ b/arch/x86/entry/vdso/vma.c
> @@ -247,6 +247,7 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr)
>  	struct mm_struct *mm = current->mm;
>  	struct vm_area_struct *vma;
>  	unsigned long text_start;
> +	unsigned long vm_flags;
>  	int ret = 0;
>  
>  	if (mmap_write_lock_killable(mm))
> @@ -264,11 +265,12 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr)
>  	/*
>  	 * MAYWRITE to allow gdb to COW and set breakpoints
>  	 */
> +	vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC;
> +	vm_flags |= VM_SEALED_SYSMAP;
>  	vma = _install_special_mapping(mm,
>  				       text_start,
>  				       image->size,
> -				       VM_READ|VM_EXEC|
> -				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> +				       vm_flags,
>  				       &vdso_mapping);
>  
>  	if (IS_ERR(vma)) {
> @@ -276,11 +278,12 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr)
>  		goto up_fail;
>  	}
>  
> +	vm_flags = VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP|VM_PFNMAP;
> +	vm_flags |= VM_SEALED_SYSMAP;
>  	vma = _install_special_mapping(mm,
>  				       addr,
>  				       (__VVAR_PAGES - VDSO_NR_VCLOCK_PAGES) * PAGE_SIZE,
> -				       VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP|
> -				       VM_PFNMAP,
> +				       vm_flags,
>  				       &vvar_mapping);

This hunk (and the vvar mapping in the arm64 patch) will conflict with my
"Generic vDSO datapage" series.
That series is already part of the tip tree (branch timers/vdso) and scheduled
for the next merge window.

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/log/?h=timers/vdso

The conflict resolution is fairly easy:
Move the new flag logic into lib/vdso/datastore.c

Depending on the expected mainline timing for this series either mention this
somewhere for the conflict resolution by Linus or rebase your series on top of
tip/timers/vdso.

>  	if (IS_ERR(vma)) {
> @@ -289,11 +292,12 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr)
>  		goto up_fail;
>  	}
>  
> +	vm_flags = VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP|VM_PFNMAP;
> +	vm_flags |= VM_SEALED_SYSMAP;
>  	vma = _install_special_mapping(mm,
>  				       addr + (__VVAR_PAGES - VDSO_NR_VCLOCK_PAGES) * PAGE_SIZE,
>  				       VDSO_NR_VCLOCK_PAGES * PAGE_SIZE,
> -				       VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP|
> -				       VM_PFNMAP,
> +				       vm_flags,
>  				       &vvar_vclock_mapping);
>  
>  	if (IS_ERR(vma)) {
> -- 
> 2.48.1.658.g4767266eb4-goog
>