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UPSTREAM: kasan, mm, arm64: tag non slab memory allocated via pagealloc

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(Upstream commit 2813b9c0296259fb11e75c839bab2d958ba4f96c).

Tag-based KASAN doesn't check memory accesses through pointers tagged with
0xff.  When page_address is used to get pointer to memory that corresponds
to some page, the tag of the resulting pointer gets set to 0xff, even
though the allocated memory might have been tagged differently.

For slab pages it's impossible to recover the correct tag to return from
page_address, since the page might contain multiple slab objects tagged
with different values, and we can't know in advance which one of them is
going to get accessed.  For non slab pages however, we can recover the tag
in page_address, since the whole page was marked with the same tag.

This patch adds tagging to non slab memory allocated with pagealloc.  To
set the tag of the pointer returned from page_address, the tag gets stored
to page->flags when the memory gets allocated.

Link: http://lkml.kernel.org/r/d758ddcef46a5abc9970182b9137e2fbee202a2c.1544099024.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Bug: 128674696
Change-Id: I500bdf42462fee0ee14495a6be51815e7e44460f
This commit is contained in:
Andrey Konovalov
2018-12-28 00:30:57 -08:00
committed by Alistair Delva
parent fd535b3748
commit be21fa3044
7 changed files with 72 additions and 4 deletions
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29
include/linux/mm.h
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@@ -804,6 +804,7 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
#define NODES_PGOFF (SECTIONS_PGOFF - NODES_WIDTH)
#define ZONES_PGOFF (NODES_PGOFF - ZONES_WIDTH)
#define LAST_CPUPID_PGOFF (ZONES_PGOFF - LAST_CPUPID_WIDTH)
#define KASAN_TAG_PGOFF (LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH)
/*
* Define the bit shifts to access each section. For non-existent
@@ -814,6 +815,7 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
#define NODES_PGSHIFT (NODES_PGOFF * (NODES_WIDTH != 0))
#define ZONES_PGSHIFT (ZONES_PGOFF * (ZONES_WIDTH != 0))
#define LAST_CPUPID_PGSHIFT (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
#define KASAN_TAG_PGSHIFT (KASAN_TAG_PGOFF * (KASAN_TAG_WIDTH != 0))
/* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
#ifdef NODE_NOT_IN_PAGE_FLAGS
@@ -836,6 +838,7 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
#define NODES_MASK ((1UL << NODES_WIDTH) - 1)
#define SECTIONS_MASK ((1UL << SECTIONS_WIDTH) - 1)
#define LAST_CPUPID_MASK ((1UL << LAST_CPUPID_SHIFT) - 1)
#define KASAN_TAG_MASK ((1UL << KASAN_TAG_WIDTH) - 1)
#define ZONEID_MASK ((1UL << ZONEID_SHIFT) - 1)
static inline enum zone_type page_zonenum(const struct page *page)
@@ -1094,6 +1097,32 @@ static inline bool cpupid_match_pid(struct task_struct *task, int cpupid)
}
#endif /* CONFIG_NUMA_BALANCING */
#ifdef CONFIG_KASAN_SW_TAGS
static inline u8 page_kasan_tag(const struct page *page)
{
return (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK;
}
static inline void page_kasan_tag_set(struct page *page, u8 tag)
{
page->flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT);
page->flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT;
}
static inline void page_kasan_tag_reset(struct page *page)
{
page_kasan_tag_set(page, 0xff);
}
#else
static inline u8 page_kasan_tag(const struct page *page)
{
return 0xff;
}
static inline void page_kasan_tag_set(struct page *page, u8 tag) { }
static inline void page_kasan_tag_reset(struct page *page) { }
#endif
static inline struct zone *page_zone(const struct page *page)
{
return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];