| Message ID | b167fd21b86e7d728ba3a8e20be4f7e8373bc22c.1605305705.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kasan: add hardware tag-based mode for arm64 | expand |
On Fri, Nov 13, 2020 at 11:17 PM Andrey Konovalov <andreyknvl@google.com> wrote: > > From: Vincenzo Frascino <vincenzo.frascino@arm.com> > > free_reserved_area() memsets the pages belonging to a given memory area. > As that memory hasn't been allocated via page_alloc, the KASAN tags that > those pages have are 0x00. As the result the memset might result in a tag > mismatch. > > Untag the address to avoid spurious faults. > > Cc: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> > --- > Change-Id: If12b4944383575b8bbd7d971decbd7f04be6748b > --- > mm/page_alloc.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 855627e52f81..4a69fef13ac7 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -7653,6 +7653,11 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char > * alias for the memset(). > */ > direct_map_addr = page_address(page); > + /* > + * Perform a kasan-unchecked memset() since this memory > + * has not been initialized. > + */ > + direct_map_addr = kasan_reset_tag(direct_map_addr); > if ((unsigned int)poison <= 0xFF) > memset(direct_map_addr, poison, PAGE_SIZE); > > -- > 2.29.2.299.gdc1121823c-goog >
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 855627e52f81..4a69fef13ac7 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7653,6 +7653,11 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char * alias for the memset(). */ direct_map_addr = page_address(page); + /* + * Perform a kasan-unchecked memset() since this memory + * has not been initialized. + */ + direct_map_addr = kasan_reset_tag(direct_map_addr); if ((unsigned int)poison <= 0xFF) memset(direct_map_addr, poison, PAGE_SIZE);