Re: [RFC PATCH v1 1/1] exec: seal system mappings

[Randy Dunlap <rdunlap@infradead.org>]

Hi Jeff,

On 10/4/24 9:31 AM, jeffxu@chromium.org wrote:
> From: Jeff Xu <jeffxu@chromium.org>
> 
> Seal vdso, vvar, sigpage, uprobes and vsyscall.
> 

> 
> Signed-off-by: Jeff Xu <jeffxu@chromium.org>
> ---
>  .../admin-guide/kernel-parameters.txt         |  9 ++++
>  arch/x86/entry/vsyscall/vsyscall_64.c         |  9 +++-
>  fs/exec.c                                     | 53 +++++++++++++++++++
>  include/linux/fs.h                            |  1 +
>  mm/mmap.c                                     |  1 +
>  security/Kconfig                              | 26 +++++++++
>  6 files changed, 97 insertions(+), 2 deletions(-)
> 


> diff --git a/security/Kconfig b/security/Kconfig
> index 28e685f53bd1..e289fbb5d676 100644
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -51,6 +51,32 @@ config PROC_MEM_NO_FORCE
>  
>  endchoice
>  
> +choice
> +	prompt "Seal system mappings"
> +	default SEAL_SYSTEM_MAPPINGS_NEVER
> +	help
> +	  Seal system mappings such as vdso, vvar, sigpage, uprobes and
> +	  vsyscall.
> +	  Note: kernel command line exec.seal_system_mappings overwrite this.

	                                                      overwrites

> +
> +config SEAL_SYSTEM_MAPPINGS_NEVER
> +	bool "Traditional behavior - not sealed"
> +	help
> +	  Do not seal system mappings.
> +	  This is default.
> +
> +config SEAL_SYSTEM_MAPPINGS_ALWAYS
> +	bool "Always seal system mappings"
> +	depends on 64BIT
> +	depends on !CHECKPOINT_RESTORE
> +	help
> +	  Seal system mappings such as vdso, vvar, sigpage, uprobes and
> +	  vsyscall.
> +	  Note: CHECKPOINT_RESTORE might relocate vdso mapping during restore,
> +	  and remap will fail if the mapping is sealed, therefore
> +	  !CHECKPOINT_RESTORE is added as dependency.
> +endchoice
> +
>  config SECURITY
>  	bool "Enable different security models"
>  	depends on SYSFS

-- 
~Randy