Re: [PATCH 7/8] asm-generic: add KASAN instrumentation to atomic operations

[Mark Rutland <mark.rutland@arm.com>]

On Tue, Mar 28, 2017 at 06:15:44PM +0200, Dmitry Vyukov wrote:
> KASAN uses compiler instrumentation to intercept all memory accesses.
> But it does not see memory accesses done in assembly code.
> One notable user of assembly code is atomic operations. Frequently,
> for example, an atomic reference decrement is the last access to an
> object and a good candidate for a racy use-after-free.
> 
> Add manual KASAN checks to atomic operations.
> 
> Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Will Deacon <will.deacon@arm.com>,
> Cc: Andrew Morton <akpm@linux-foundation.org>,
> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
> Cc: Ingo Molnar <mingo@redhat.com>,
> Cc: kasan-dev@googlegroups.com
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Cc: x86@kernel.org

FWIW, I think that structuring the file this way will make it easier to
add the {acquire,release,relaxed} variants (as arm64 will need),
so this looks good to me.

As a heads-up, I wanted to have a go at that, but I wasn't able to apply
patch two onwards on v4.11-rc{3,4} or next-20170329. I was not able to
cleanly revert the instrumentation patches currently in next-20170329,
since other patches built atop of them.

It would be nice to see that sorted out.

Thanks,
Mark.

> ---
>  include/asm-generic/atomic-instrumented.h | 76 +++++++++++++++++++++++++++++--
>  1 file changed, 72 insertions(+), 4 deletions(-)
> 
> diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h
> index fd483115d4c6..7f8eb761f896 100644
> --- a/include/asm-generic/atomic-instrumented.h
> +++ b/include/asm-generic/atomic-instrumented.h
> @@ -1,44 +1,54 @@
>  #ifndef _LINUX_ATOMIC_INSTRUMENTED_H
>  #define _LINUX_ATOMIC_INSTRUMENTED_H
>  
> +#include <linux/kasan-checks.h>
> +
>  static __always_inline int atomic_read(const atomic_t *v)
>  {
> +	kasan_check_read(v, sizeof(*v));
>  	return arch_atomic_read(v);
>  }
>  
>  static __always_inline long long atomic64_read(const atomic64_t *v)
>  {
> +	kasan_check_read(v, sizeof(*v));
>  	return arch_atomic64_read(v);
>  }
>  
>  static __always_inline void atomic_set(atomic_t *v, int i)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic_set(v, i);
>  }
>  
>  static __always_inline void atomic64_set(atomic64_t *v, long long i)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic64_set(v, i);
>  }
>  
>  static __always_inline int atomic_xchg(atomic_t *v, int i)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_xchg(v, i);
>  }
>  
>  static __always_inline long long atomic64_xchg(atomic64_t *v, long long i)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_xchg(v, i);
>  }
>  
>  static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_cmpxchg(v, old, new);
>  }
>  
>  static __always_inline long long atomic64_cmpxchg(atomic64_t *v, long long old,
>  						  long long new)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_cmpxchg(v, old, new);
>  }
>  
> @@ -46,6 +56,8 @@ static __always_inline long long atomic64_cmpxchg(atomic64_t *v, long long old,
>  #define atomic_try_cmpxchg atomic_try_cmpxchg
>  static __always_inline bool atomic_try_cmpxchg(atomic_t *v, int *old, int new)
>  {
> +	kasan_check_write(v, sizeof(*v));
> +	kasan_check_read(old, sizeof(*old));
>  	return arch_atomic_try_cmpxchg(v, old, new);
>  }
>  #endif
> @@ -55,12 +67,15 @@ static __always_inline bool atomic_try_cmpxchg(atomic_t *v, int *old, int new)
>  static __always_inline bool atomic64_try_cmpxchg(atomic64_t *v, long long *old,
>  						 long long new)
>  {
> +	kasan_check_write(v, sizeof(*v));
> +	kasan_check_read(old, sizeof(*old));
>  	return arch_atomic64_try_cmpxchg(v, old, new);
>  }
>  #endif
>  
>  static __always_inline int __atomic_add_unless(atomic_t *v, int a, int u)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return __arch_atomic_add_unless(v, a, u);
>  }
>  
> @@ -68,242 +83,295 @@ static __always_inline int __atomic_add_unless(atomic_t *v, int a, int u)
>  static __always_inline bool atomic64_add_unless(atomic64_t *v, long long a,
>  						long long u)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_add_unless(v, a, u);
>  }
>  
>  static __always_inline void atomic_inc(atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic_inc(v);
>  }
>  
>  static __always_inline void atomic64_inc(atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic64_inc(v);
>  }
>  
>  static __always_inline void atomic_dec(atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic_dec(v);
>  }
>  
>  static __always_inline void atomic64_dec(atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic64_dec(v);
>  }
>  
>  static __always_inline void atomic_add(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic_add(i, v);
>  }
>  
>  static __always_inline void atomic64_add(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic64_add(i, v);
>  }
>  
>  static __always_inline void atomic_sub(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic_sub(i, v);
>  }
>  
>  static __always_inline void atomic64_sub(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic64_sub(i, v);
>  }
>  
>  static __always_inline void atomic_and(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic_and(i, v);
>  }
>  
>  static __always_inline void atomic64_and(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic64_and(i, v);
>  }
>  
>  static __always_inline void atomic_or(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic_or(i, v);
>  }
>  
>  static __always_inline void atomic64_or(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic64_or(i, v);
>  }
>  
>  static __always_inline void atomic_xor(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic_xor(i, v);
>  }
>  
>  static __always_inline void atomic64_xor(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	arch_atomic64_xor(i, v);
>  }
>  
>  static __always_inline int atomic_inc_return(atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_inc_return(v);
>  }
>  
>  static __always_inline long long atomic64_inc_return(atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_inc_return(v);
>  }
>  
>  static __always_inline int atomic_dec_return(atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_dec_return(v);
>  }
>  
>  static __always_inline long long atomic64_dec_return(atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_dec_return(v);
>  }
>  
>  static __always_inline long long atomic64_inc_not_zero(atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_inc_not_zero(v);
>  }
>  
>  static __always_inline long long atomic64_dec_if_positive(atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_dec_if_positive(v);
>  }
>  
>  static __always_inline bool atomic_dec_and_test(atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_dec_and_test(v);
>  }
>  
>  static __always_inline bool atomic64_dec_and_test(atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_dec_and_test(v);
>  }
>  
>  static __always_inline bool atomic_inc_and_test(atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_inc_and_test(v);
>  }
>  
>  static __always_inline bool atomic64_inc_and_test(atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_inc_and_test(v);
>  }
>  
>  static __always_inline int atomic_add_return(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_add_return(i, v);
>  }
>  
>  static __always_inline long long atomic64_add_return(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_add_return(i, v);
>  }
>  
>  static __always_inline int atomic_sub_return(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_sub_return(i, v);
>  }
>  
>  static __always_inline long long atomic64_sub_return(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_sub_return(i, v);
>  }
>  
>  static __always_inline int atomic_fetch_add(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_fetch_add(i, v);
>  }
>  
>  static __always_inline long long atomic64_fetch_add(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_fetch_add(i, v);
>  }
>  
>  static __always_inline int atomic_fetch_sub(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_fetch_sub(i, v);
>  }
>  
>  static __always_inline long long atomic64_fetch_sub(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_fetch_sub(i, v);
>  }
>  
>  static __always_inline int atomic_fetch_and(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_fetch_and(i, v);
>  }
>  
>  static __always_inline long long atomic64_fetch_and(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_fetch_and(i, v);
>  }
>  
>  static __always_inline int atomic_fetch_or(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_fetch_or(i, v);
>  }
>  
>  static __always_inline long long atomic64_fetch_or(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_fetch_or(i, v);
>  }
>  
>  static __always_inline int atomic_fetch_xor(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_fetch_xor(i, v);
>  }
>  
>  static __always_inline long long atomic64_fetch_xor(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_fetch_xor(i, v);
>  }
>  
>  static __always_inline bool atomic_sub_and_test(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_sub_and_test(i, v);
>  }
>  
>  static __always_inline bool atomic64_sub_and_test(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_sub_and_test(i, v);
>  }
>  
>  static __always_inline bool atomic_add_negative(int i, atomic_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic_add_negative(i, v);
>  }
>  
>  static __always_inline bool atomic64_add_negative(long long i, atomic64_t *v)
>  {
> +	kasan_check_write(v, sizeof(*v));
>  	return arch_atomic64_add_negative(i, v);
>  }
>  
>  #define cmpxchg(ptr, old, new)				\
>  ({							\
> +	__typeof__(ptr) ___ptr = (ptr);			\
> +	kasan_check_write(___ptr, sizeof(*___ptr));	\
>  	arch_cmpxchg((ptr), (old), (new));		\
>  })
>  
>  #define sync_cmpxchg(ptr, old, new)			\
>  ({							\
> -	arch_sync_cmpxchg((ptr), (old), (new));		\
> +	__typeof__(ptr) ___ptr = (ptr);			\
> +	kasan_check_write(___ptr, sizeof(*___ptr));	\
> +	arch_sync_cmpxchg(___ptr, (old), (new));	\
>  })
>  
>  #define cmpxchg_local(ptr, old, new)			\
>  ({							\
> -	arch_cmpxchg_local((ptr), (old), (new));	\
> +	__typeof__(ptr) ____ptr = (ptr);		\
> +	kasan_check_write(____ptr, sizeof(*____ptr));	\
> +	arch_cmpxchg_local(____ptr, (old), (new));	\
>  })
>  
>  #define cmpxchg64(ptr, old, new)			\
>  ({							\
> -	arch_cmpxchg64((ptr), (old), (new));		\
> +	__typeof__(ptr) ____ptr = (ptr);		\
> +	kasan_check_write(____ptr, sizeof(*____ptr));	\
> +	arch_cmpxchg64(____ptr, (old), (new));		\
>  })
>  
>  #define cmpxchg64_local(ptr, old, new)			\
>  ({							\
> -	arch_cmpxchg64_local((ptr), (old), (new));	\
> +	__typeof__(ptr) ____ptr = (ptr);		\
> +	kasan_check_write(____ptr, sizeof(*____ptr));	\
> +	arch_cmpxchg64_local(____ptr, (old), (new));	\
>  })
>  
>  #define cmpxchg_double(p1, p2, o1, o2, n1, n2)				\
> -- 
> 2.12.2.564.g063fe858b8-goog
> 

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