[v16,04/16] mm: untag user pointers in do_pages_move
diff mbox series

Message ID e410843d00a4ecd7e525a7a949e605ffc6c394c4.1559580831.git.andreyknvl@google.com
State New
Headers show
Series
  • arm64: untag user pointers passed to the kernel
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Commit Message

Andrey Konovalov June 3, 2019, 4:55 p.m. UTC
This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

do_pages_move() is used in the implementation of the move_pages syscall.

Untag user pointers in this function.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/migrate.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Kees Cook June 8, 2019, 3:49 a.m. UTC | #1
On Mon, Jun 03, 2019 at 06:55:06PM +0200, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> do_pages_move() is used in the implementation of the move_pages syscall.
> 
> Untag user pointers in this function.
> 
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  mm/migrate.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/migrate.c b/mm/migrate.c
> index f2ecc2855a12..3930bb6fa656 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1617,6 +1617,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>  		if (get_user(node, nodes + i))
>  			goto out_flush;
>  		addr = (unsigned long)p;
> +		addr = untagged_addr(addr);
>  
>  		err = -ENODEV;
>  		if (node < 0 || node >= MAX_NUMNODES)
> -- 
> 2.22.0.rc1.311.g5d7573a151-goog
>
Khalid Aziz June 11, 2019, 8:18 p.m. UTC | #2
On 6/3/19 10:55 AM, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> do_pages_move() is used in the implementation of the move_pages syscall.
> 
> Untag user pointers in this function.
> 
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---
>  mm/migrate.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/migrate.c b/mm/migrate.c
> index f2ecc2855a12..3930bb6fa656 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1617,6 +1617,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>  		if (get_user(node, nodes + i))
>  			goto out_flush;
>  		addr = (unsigned long)p;
> +		addr = untagged_addr(addr);

Why not just "addr = (unsigned long)untagged_addr(p);"

--
Khalid
Andrey Konovalov June 12, 2019, 11:08 a.m. UTC | #3
On Tue, Jun 11, 2019 at 10:18 PM Khalid Aziz <khalid.aziz@oracle.com> wrote:
>
> On 6/3/19 10:55 AM, Andrey Konovalov wrote:
> > This patch is a part of a series that extends arm64 kernel ABI to allow to
> > pass tagged user pointers (with the top byte set to something else other
> > than 0x00) as syscall arguments.
> >
> > do_pages_move() is used in the implementation of the move_pages syscall.
> >
> > Untag user pointers in this function.
> >
> > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> > ---
> >  mm/migrate.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/mm/migrate.c b/mm/migrate.c
> > index f2ecc2855a12..3930bb6fa656 100644
> > --- a/mm/migrate.c
> > +++ b/mm/migrate.c
> > @@ -1617,6 +1617,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
> >               if (get_user(node, nodes + i))
> >                       goto out_flush;
> >               addr = (unsigned long)p;
> > +             addr = untagged_addr(addr);
>
> Why not just "addr = (unsigned long)untagged_addr(p);"

Will do in the next version. I think I'll also merge this commit into
the "untag user pointers passed to memory syscalls" one.

>
> --
> Khalid
>

Patch
diff mbox series

diff --git a/mm/migrate.c b/mm/migrate.c
index f2ecc2855a12..3930bb6fa656 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1617,6 +1617,7 @@  static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
 		if (get_user(node, nodes + i))
 			goto out_flush;
 		addr = (unsigned long)p;
+		addr = untagged_addr(addr);
 
 		err = -ENODEV;
 		if (node < 0 || node >= MAX_NUMNODES)