On Mon, Feb 24, 2025 at 10:52:45PM +0000, jeffxu@xxxxxxxxxxxx wrote:
> From: Jeff Xu <jeffxu@xxxxxxxxxxxx>
>
> Provide support to mseal the uprobe mapping.
>
> Unlike other system mappings, the uprobe mapping is not
> established during program startup. However, its lifetime is the same
> as the process's lifetime. It could be sealed from creation.
>
I thought we agreed not to enable this for uprobes for now? What testing
have you done to ensure this is functional?
I mean is this literally _all_ uprobe mappings now being sealed?
I'd really like some more assurances on this one. And what are you
mitigating by sealing these? I get VDSO (kinda) but uprobes?
You really need to provide more justification here.
> Signed-off-by: Jeff Xu <jeffxu@xxxxxxxxxxxx>
> ---
> kernel/events/uprobes.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index 2ca797cbe465..8dcdfa0d306b 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -1662,6 +1662,7 @@ static const struct vm_special_mapping xol_mapping = {
> static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
> {
> struct vm_area_struct *vma;
> + unsigned long vm_flags;
> int ret;
>
> if (mmap_write_lock_killable(mm))
> @@ -1682,8 +1683,10 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
> }
> }
>
> + vm_flags = VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO;
> + vm_flags |= VM_SEALED_SYSMAP;
> vma = _install_special_mapping(mm, area->vaddr, PAGE_SIZE,
> - VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO,
> + vm_flags,
> &xol_mapping);
> if (IS_ERR(vma)) {
> ret = PTR_ERR(vma);
> --
> 2.48.1.658.g4767266eb4-goog
>
