2019-07-08 22:45:15

by Marco Elver

[permalink] [raw]
Subject: [PATCH v5 0/5] Add object validation in ksize()

This version fixes several build issues --
Reported-by: kbuild test robot <[email protected]>

Previous version here:
http://lkml.kernel.org/r/[email protected]

Marco Elver (5):
mm/kasan: Introduce __kasan_check_{read,write}
mm/kasan: Change kasan_check_{read,write} to return boolean
lib/test_kasan: Add test for double-kzfree detection
mm/slab: Refactor common ksize KASAN logic into slab_common.c
mm/kasan: Add object validation in ksize()

include/linux/kasan-checks.h | 43 +++++++++++++++++++++++++++------
include/linux/kasan.h | 7 ++++--
include/linux/slab.h | 1 +
lib/test_kasan.c | 17 +++++++++++++
mm/kasan/common.c | 14 +++++------
mm/kasan/generic.c | 13 +++++-----
mm/kasan/kasan.h | 10 +++++++-
mm/kasan/tags.c | 12 ++++++----
mm/slab.c | 28 +++++-----------------
mm/slab_common.c | 46 ++++++++++++++++++++++++++++++++++++
mm/slob.c | 4 ++--
mm/slub.c | 14 ++---------
12 files changed, 144 insertions(+), 65 deletions(-)

--
2.22.0.410.gd8fdbe21b5-goog


2019-07-08 22:45:19

by Marco Elver

[permalink] [raw]
Subject: [PATCH v5 2/5] mm/kasan: Change kasan_check_{read,write} to return boolean

This changes {,__}kasan_check_{read,write} functions to return a boolean
denoting if the access was valid or not.

Signed-off-by: Marco Elver <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
v5:
* Rebase on top of v5 of preceding patch.
* Include types.h for bool.

v3:
* Fix Formatting and split introduction of __kasan_check_* and returning
bool into 2 patches.
---
include/linux/kasan-checks.h | 30 ++++++++++++++++++++----------
mm/kasan/common.c | 8 ++++----
mm/kasan/generic.c | 13 +++++++------
mm/kasan/kasan.h | 10 +++++++++-
mm/kasan/tags.c | 12 +++++++-----
5 files changed, 47 insertions(+), 26 deletions(-)

diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h
index 221f05fbddd7..ac6aba632f2d 100644
--- a/include/linux/kasan-checks.h
+++ b/include/linux/kasan-checks.h
@@ -2,19 +2,25 @@
#ifndef _LINUX_KASAN_CHECKS_H
#define _LINUX_KASAN_CHECKS_H

+#include <linux/types.h>
+
/*
* __kasan_check_*: Always available when KASAN is enabled. This may be used
* even in compilation units that selectively disable KASAN, but must use KASAN
* to validate access to an address. Never use these in header files!
*/
#ifdef CONFIG_KASAN
-void __kasan_check_read(const volatile void *p, unsigned int size);
-void __kasan_check_write(const volatile void *p, unsigned int size);
+bool __kasan_check_read(const volatile void *p, unsigned int size);
+bool __kasan_check_write(const volatile void *p, unsigned int size);
#else
-static inline void __kasan_check_read(const volatile void *p, unsigned int size)
-{ }
-static inline void __kasan_check_write(const volatile void *p, unsigned int size)
-{ }
+static inline bool __kasan_check_read(const volatile void *p, unsigned int size)
+{
+ return true;
+}
+static inline bool __kasan_check_write(const volatile void *p, unsigned int size)
+{
+ return true;
+}
#endif

/*
@@ -25,10 +31,14 @@ static inline void __kasan_check_write(const volatile void *p, unsigned int size
#define kasan_check_read __kasan_check_read
#define kasan_check_write __kasan_check_write
#else
-static inline void kasan_check_read(const volatile void *p, unsigned int size)
-{ }
-static inline void kasan_check_write(const volatile void *p, unsigned int size)
-{ }
+static inline bool kasan_check_read(const volatile void *p, unsigned int size)
+{
+ return true;
+}
+static inline bool kasan_check_write(const volatile void *p, unsigned int size)
+{
+ return true;
+}
#endif

#endif
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 6bada42cc152..2277b82902d8 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -87,15 +87,15 @@ void kasan_disable_current(void)
current->kasan_depth--;
}

-void __kasan_check_read(const volatile void *p, unsigned int size)
+bool __kasan_check_read(const volatile void *p, unsigned int size)
{
- check_memory_region((unsigned long)p, size, false, _RET_IP_);
+ return check_memory_region((unsigned long)p, size, false, _RET_IP_);
}
EXPORT_SYMBOL(__kasan_check_read);

-void __kasan_check_write(const volatile void *p, unsigned int size)
+bool __kasan_check_write(const volatile void *p, unsigned int size)
{
- check_memory_region((unsigned long)p, size, true, _RET_IP_);
+ return check_memory_region((unsigned long)p, size, true, _RET_IP_);
}
EXPORT_SYMBOL(__kasan_check_write);

diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 504c79363a34..616f9dd82d12 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -166,29 +166,30 @@ static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
return memory_is_poisoned_n(addr, size);
}

-static __always_inline void check_memory_region_inline(unsigned long addr,
+static __always_inline bool check_memory_region_inline(unsigned long addr,
size_t size, bool write,
unsigned long ret_ip)
{
if (unlikely(size == 0))
- return;
+ return true;

if (unlikely((void *)addr <
kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
kasan_report(addr, size, write, ret_ip);
- return;
+ return false;
}

if (likely(!memory_is_poisoned(addr, size)))
- return;
+ return true;

kasan_report(addr, size, write, ret_ip);
+ return false;
}

-void check_memory_region(unsigned long addr, size_t size, bool write,
+bool check_memory_region(unsigned long addr, size_t size, bool write,
unsigned long ret_ip)
{
- check_memory_region_inline(addr, size, write, ret_ip);
+ return check_memory_region_inline(addr, size, write, ret_ip);
}

void kasan_cache_shrink(struct kmem_cache *cache)
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 3ce956efa0cb..e62ea45d02e3 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -123,7 +123,15 @@ static inline bool addr_has_shadow(const void *addr)

void kasan_poison_shadow(const void *address, size_t size, u8 value);

-void check_memory_region(unsigned long addr, size_t size, bool write,
+/**
+ * check_memory_region - Check memory region, and report if invalid access.
+ * @addr: the accessed address
+ * @size: the accessed size
+ * @write: true if access is a write access
+ * @ret_ip: return address
+ * @return: true if access was valid, false if invalid
+ */
+bool check_memory_region(unsigned long addr, size_t size, bool write,
unsigned long ret_ip);

void *find_first_bad_addr(void *addr, size_t size);
diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
index 63fca3172659..0e987c9ca052 100644
--- a/mm/kasan/tags.c
+++ b/mm/kasan/tags.c
@@ -76,7 +76,7 @@ void *kasan_reset_tag(const void *addr)
return reset_tag(addr);
}

-void check_memory_region(unsigned long addr, size_t size, bool write,
+bool check_memory_region(unsigned long addr, size_t size, bool write,
unsigned long ret_ip)
{
u8 tag;
@@ -84,7 +84,7 @@ void check_memory_region(unsigned long addr, size_t size, bool write,
void *untagged_addr;

if (unlikely(size == 0))
- return;
+ return true;

tag = get_tag((const void *)addr);

@@ -106,22 +106,24 @@ void check_memory_region(unsigned long addr, size_t size, bool write,
* set to KASAN_TAG_KERNEL (0xFF)).
*/
if (tag == KASAN_TAG_KERNEL)
- return;
+ return true;

untagged_addr = reset_tag((const void *)addr);
if (unlikely(untagged_addr <
kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
kasan_report(addr, size, write, ret_ip);
- return;
+ return false;
}
shadow_first = kasan_mem_to_shadow(untagged_addr);
shadow_last = kasan_mem_to_shadow(untagged_addr + size - 1);
for (shadow = shadow_first; shadow <= shadow_last; shadow++) {
if (*shadow != tag) {
kasan_report(addr, size, write, ret_ip);
- return;
+ return false;
}
}
+
+ return true;
}

#define DEFINE_HWASAN_LOAD_STORE(size) \
--
2.22.0.410.gd8fdbe21b5-goog

2019-07-08 22:45:19

by Marco Elver

[permalink] [raw]
Subject: [PATCH v5 1/5] mm/kasan: Introduce __kasan_check_{read,write}

This introduces __kasan_check_{read,write}. __kasan_check functions may
be used from anywhere, even compilation units that disable
instrumentation selectively.

This change eliminates the need for the __KASAN_INTERNAL definition.

Signed-off-by: Marco Elver <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
v5:
* Use #define for kasan_check_* in the __SANITIZE_ADDRESS__ case, as the
inline functions conflict with the __no_sanitize_address attribute.
Reported-by: kbuild test robot <[email protected]>

v3:
* Fix Formatting and split introduction of __kasan_check_* and returning
bool into 2 patches.
---
include/linux/kasan-checks.h | 25 ++++++++++++++++++++++---
mm/kasan/common.c | 10 ++++------
2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h
index a61dc075e2ce..221f05fbddd7 100644
--- a/include/linux/kasan-checks.h
+++ b/include/linux/kasan-checks.h
@@ -2,9 +2,28 @@
#ifndef _LINUX_KASAN_CHECKS_H
#define _LINUX_KASAN_CHECKS_H

-#if defined(__SANITIZE_ADDRESS__) || defined(__KASAN_INTERNAL)
-void kasan_check_read(const volatile void *p, unsigned int size);
-void kasan_check_write(const volatile void *p, unsigned int size);
+/*
+ * __kasan_check_*: Always available when KASAN is enabled. This may be used
+ * even in compilation units that selectively disable KASAN, but must use KASAN
+ * to validate access to an address. Never use these in header files!
+ */
+#ifdef CONFIG_KASAN
+void __kasan_check_read(const volatile void *p, unsigned int size);
+void __kasan_check_write(const volatile void *p, unsigned int size);
+#else
+static inline void __kasan_check_read(const volatile void *p, unsigned int size)
+{ }
+static inline void __kasan_check_write(const volatile void *p, unsigned int size)
+{ }
+#endif
+
+/*
+ * kasan_check_*: Only available when the particular compilation unit has KASAN
+ * instrumentation enabled. May be used in header files.
+ */
+#ifdef __SANITIZE_ADDRESS__
+#define kasan_check_read __kasan_check_read
+#define kasan_check_write __kasan_check_write
#else
static inline void kasan_check_read(const volatile void *p, unsigned int size)
{ }
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 242fdc01aaa9..6bada42cc152 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -14,8 +14,6 @@
*
*/

-#define __KASAN_INTERNAL
-
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/init.h>
@@ -89,17 +87,17 @@ void kasan_disable_current(void)
current->kasan_depth--;
}

-void kasan_check_read(const volatile void *p, unsigned int size)
+void __kasan_check_read(const volatile void *p, unsigned int size)
{
check_memory_region((unsigned long)p, size, false, _RET_IP_);
}
-EXPORT_SYMBOL(kasan_check_read);
+EXPORT_SYMBOL(__kasan_check_read);

-void kasan_check_write(const volatile void *p, unsigned int size)
+void __kasan_check_write(const volatile void *p, unsigned int size)
{
check_memory_region((unsigned long)p, size, true, _RET_IP_);
}
-EXPORT_SYMBOL(kasan_check_write);
+EXPORT_SYMBOL(__kasan_check_write);

#undef memset
void *memset(void *addr, int c, size_t len)
--
2.22.0.410.gd8fdbe21b5-goog

2019-07-10 18:38:29

by Andrey Ryabinin

[permalink] [raw]
Subject: Re: [PATCH v5 0/5] Add object validation in ksize()



On 7/8/19 8:07 PM, Marco Elver wrote:
> This version fixes several build issues --
> Reported-by: kbuild test robot <[email protected]>
>
> Previous version here:
> http://lkml.kernel.org/r/[email protected]
>
> Marco Elver (5):
> mm/kasan: Introduce __kasan_check_{read,write}
> mm/kasan: Change kasan_check_{read,write} to return boolean
> lib/test_kasan: Add test for double-kzfree detection
> mm/slab: Refactor common ksize KASAN logic into slab_common.c
> mm/kasan: Add object validation in ksize()
>

Reviewed-by: Andrey Ryabinin <[email protected]>