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

[Jeff Xu]

On Mon, Oct 7, 2024 at 4:42 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
> Hi Jeff,
>
> On 10/4/24 9:31 AM, jeffxu@xxxxxxxxxxxx wrote:
> > From: Jeff Xu <jeffxu@xxxxxxxxxxxx>
> >
> > Seal vdso, vvar, sigpage, uprobes and vsyscall.
> >
>
> >
> > Signed-off-by: Jeff Xu <jeffxu@xxxxxxxxxxxx>
> > ---
> >  .../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
fixed.
Thanks

>
> > +
> > +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