[PATCH v2 0/1] add mseal to /proc/pid/smaps

[PATCH v2 0/1] add mseal to /proc/pid/smaps

[jeffxu]

From: Jeff Xu <jeffxu@chromium.org>

Add mseal information in /proc/pid/smaps to indicate the VMA is sealed.

I appreicate Adhemerval Zanella Netto to bring this to my attention. [1]

[1] https://public-inbox.org/libc-alpha/743ac2ce-817b-42ef-a0a1-7edf9a85d8e5@linaro.org/#t

History:

v2:
update from Jann Horn's comments:
- change 'sp' to 'sl'
- change 'sealed page' to 'sealed'
- move VM_SEALED define after VM_ALLOW_ANY_UNCACHED

v1:
https://lore.kernel.org/lkml/20240614182327.752156-1-jeffxu@google.com/

Jeff Xu (1):
  /proc/pid/smaps: add mseal info for vma

 Documentation/filesystems/proc.rst | 1 +
 fs/proc/task_mmu.c                 | 3 +++
 include/linux/mm.h                 | 5 +++++
 mm/internal.h                      | 5 -----
 4 files changed, 9 insertions(+), 5 deletions(-)

-- 
2.45.2.627.g7a2c4fd464-goog

[PATCH v2 1/1] /proc/pid/smaps: add mseal info for vma

[jeffxu]

From: Jeff Xu <jeffxu@chromium.org>

Add sl in /proc/pid/smaps to indicate vma is sealed

Signed-off-by: Jeff Xu <jeffxu@chromium.org>
---
 Documentation/filesystems/proc.rst | 1 +
 fs/proc/task_mmu.c                 | 3 +++
 include/linux/mm.h                 | 5 +++++
 mm/internal.h                      | 5 -----
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 7c3a565ffbef..82d142de3461 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -571,6 +571,7 @@ encoded manner. The codes are the following:
     um    userfaultfd missing tracking
     uw    userfaultfd wr-protect tracking
     ss    shadow stack page
+    sl    sealed
     ==    =======================================
 
 Note that there is no guarantee that every flag and associated mnemonic will
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6ed1f56b32b4..93fb2c61b154 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -711,6 +711,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
 #ifdef CONFIG_X86_USER_SHADOW_STACK
 		[ilog2(VM_SHADOW_STACK)] = "ss",
+#endif
+#ifdef CONFIG_64BIT
+		[ilog2(VM_SEALED)] = "sl",
 #endif
 	};
 	size_t i;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 587d34879865..84c4cc7354b4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -406,6 +406,11 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_ALLOW_ANY_UNCACHED		VM_NONE
 #endif
 
+#ifdef CONFIG_64BIT
+/* VM is sealed, in vm_flags */
+#define VM_SEALED	_BITUL(63)
+#endif
+
 /* Bits set in the VMA until the stack is in its final location */
 #define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEQ_READ | VM_STACK_EARLY)
 
diff --git a/mm/internal.h b/mm/internal.h
index fd68c43664d5..72f7c110d563 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1509,11 +1509,6 @@ void __meminit __init_single_page(struct page *page, unsigned long pfn,
 unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg,
 			  int priority);
 
-#ifdef CONFIG_64BIT
-/* VM is sealed, in vm_flags */
-#define VM_SEALED	_BITUL(63)
-#endif
-
 #ifdef CONFIG_64BIT
 static inline int can_do_mseal(unsigned long flags)
 {
-- 
2.45.2.627.g7a2c4fd464-goog

Re: [PATCH v2 1/1] /proc/pid/smaps: add mseal info for vma

[Andrew Morton]

On Fri, 14 Jun 2024 23:20:14 +0000 jeffxu@chromium.org wrote:

> From: Jeff Xu <jeffxu@chromium.org>
> 
> Add sl in /proc/pid/smaps to indicate vma is sealed
> 
> ...
>
> --- a/Documentation/filesystems/proc.rst
> +++ b/Documentation/filesystems/proc.rst
> @@ -571,6 +571,7 @@ encoded manner. The codes are the following:
>      um    userfaultfd missing tracking
>      uw    userfaultfd wr-protect tracking
>      ss    shadow stack page
> +    sl    sealed
>      ==    =======================================

I'll queue this for 6.10-rcX as a fix for 8be7258aad44 ("mseal: add
mseal syscall").

Re: [PATCH v2 1/1] /proc/pid/smaps: add mseal info for vma

[David Hildenbrand]

On 15.06.24 01:20, jeffxu@chromium.org wrote:
> From: Jeff Xu <jeffxu@chromium.org>
> 
> Add sl in /proc/pid/smaps to indicate vma is sealed
> 
> Signed-off-by: Jeff Xu <jeffxu@chromium.org>
> ---

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb