diff mbox series

[v2,2/2] kasan, slub: reset tag when printing address

Message ID 20210804082230.10837-3-Kuan-Ying.Lee@mediatek.com (mailing list archive)
State New
Headers show
Series kasan: reset tag when accessing invalid data | expand

Commit Message

Kuan-Ying Lee Aug. 4, 2021, 8:22 a.m. UTC
The address still includes the tags when it is printed.
With hardware tag-based kasan enabled, we will get a
false positive KASAN issue when we access metadata.

Reset the tag before we access the metadata.

Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing metadata")
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Suggested-by: Marco Elver <elver@google.com>
---
 mm/slub.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Marco Elver Aug. 4, 2021, 8:41 a.m. UTC | #1
On Wed, 4 Aug 2021 at 10:23, Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> wrote:
>
> The address still includes the tags when it is printed.
> With hardware tag-based kasan enabled, we will get a
> false positive KASAN issue when we access metadata.
>
> Reset the tag before we access the metadata.
>
> Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing metadata")
> Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
> Suggested-by: Marco Elver <elver@google.com>

Note, in this case Suggested-by is inappropriate, because I did not
suggest the change in any way (you already had it in v1). I just
commented on the fact that it's missing a Fixes so stable can pick it
up and some clarification.

Reviewed-by: Marco Elver <elver@google.com>

> ---
>  mm/slub.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index b6c5205252eb..f77d8cd79ef7 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -576,8 +576,8 @@ static void print_section(char *level, char *text, u8 *addr,
>                           unsigned int length)
>  {
>         metadata_access_enable();
> -       print_hex_dump(level, kasan_reset_tag(text), DUMP_PREFIX_ADDRESS,
> -                       16, 1, addr, length, 1);
> +       print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
> +                       16, 1, kasan_reset_tag((void *)addr), length, 1);
>         metadata_access_disable();
>  }
>
> --
> 2.18.0
Kuan-Ying Lee Aug. 4, 2021, 8:59 a.m. UTC | #2
On Wed, 2021-08-04 at 10:41 +0200, Marco Elver wrote:
> On Wed, 4 Aug 2021 at 10:23, Kuan-Ying Lee <
> Kuan-Ying.Lee@mediatek.com> wrote:
> > 
> > The address still includes the tags when it is printed.
> > With hardware tag-based kasan enabled, we will get a
> > false positive KASAN issue when we access metadata.
> > 
> > Reset the tag before we access the metadata.
> > 
> > Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing
> > metadata")
> > Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
> > Suggested-by: Marco Elver <elver@google.com>
> 
> Note, in this case Suggested-by is inappropriate, because I did not
> suggest the change in any way (you already had it in v1). I just
> commented on the fact that it's missing a Fixes so stable can pick it
> up and some clarification.
> 
> Reviewed-by: Marco Elver <elver@google.com>

Got it.
I will remove it on v3.
Thanks.

> 
> > ---
> >  mm/slub.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/mm/slub.c b/mm/slub.c
> > index b6c5205252eb..f77d8cd79ef7 100644
> > --- a/mm/slub.c
> > +++ b/mm/slub.c
> > @@ -576,8 +576,8 @@ static void print_section(char *level, char
> > *text, u8 *addr,
> >                           unsigned int length)
> >  {
> >         metadata_access_enable();
> > -       print_hex_dump(level, kasan_reset_tag(text),
> > DUMP_PREFIX_ADDRESS,
> > -                       16, 1, addr, length, 1);
> > +       print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
> > +                       16, 1, kasan_reset_tag((void *)addr),
> > length, 1);
> >         metadata_access_disable();
> >  }
> > 
> > --
> > 2.18.0
diff mbox series

Patch

diff --git a/mm/slub.c b/mm/slub.c
index b6c5205252eb..f77d8cd79ef7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -576,8 +576,8 @@  static void print_section(char *level, char *text, u8 *addr,
 			  unsigned int length)
 {
 	metadata_access_enable();
-	print_hex_dump(level, kasan_reset_tag(text), DUMP_PREFIX_ADDRESS,
-			16, 1, addr, length, 1);
+	print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
+			16, 1, kasan_reset_tag((void *)addr), length, 1);
 	metadata_access_disable();
 }