[PATCH v13 22/25] kasan: add __must_check annotations to kasan hooks

From: Andrey Konovalov <andreyknvl@google.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Christoph Lameter <cl@linux.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Dave Martin <dave.martin@arm.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Ingo Molnar <mingo@kernel.org>,
	Paul Lawrence <paullawrence@google.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Arnd Bergmann <arnd@arndb.de>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kate Stewart <kstewart@linuxfoundation.org>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	kasan-dev@googlegroups.com, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-sparse@vger.kernel.org, linux-mm@kvack.org,
	linux-kbuild@vger.kernel.org
Cc: Vishwath Mohan <vishwath@google.com>,
	Chintan Pandya <cpandya@codeaurora.org>,
	Jacob Bramley <Jacob.Bramley@arm.com>,
	Jann Horn <jannh@google.com>,
	Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	Lee Smith <Lee.Smith@arm.com>, Kostya Serebryany <kcc@google.com>,
	Mark Brand <markbrand@google.com>,
	Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
	Evgeniy Stepanov <eugenis@google.com>
Subject: [PATCH v13 22/25] kasan: add __must_check annotations to kasan hooks
Date: Thu,  6 Dec 2018 13:24:40 +0100	[thread overview]
Message-ID: <03b269c5e453945f724bfca3159d4e1333a8fb1c.1544099024.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1544099024.git.andreyknvl@google.com>

This patch adds __must_check annotations to kasan hooks that return a
pointer to make sure that a tagged pointer always gets propagated.

Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 include/linux/kasan.h | 16 ++++++++++------
 mm/kasan/common.c     | 15 +++++++++------
 2 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 8da7b7a4397a..b40ea104dd36 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -49,16 +49,20 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
 void kasan_poison_slab(struct page *page);
 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
 void kasan_poison_object_data(struct kmem_cache *cache, void *object);
-void *kasan_init_slab_obj(struct kmem_cache *cache, const void *object);
+void * __must_check kasan_init_slab_obj(struct kmem_cache *cache,
+					const void *object);
 
-void *kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags);
+void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
+						gfp_t flags);
 void kasan_kfree_large(void *ptr, unsigned long ip);
 void kasan_poison_kfree(void *ptr, unsigned long ip);
-void *kasan_kmalloc(struct kmem_cache *s, const void *object, size_t size,
-		  gfp_t flags);
-void *kasan_krealloc(const void *object, size_t new_size, gfp_t flags);
+void * __must_check kasan_kmalloc(struct kmem_cache *s, const void *object,
+					size_t size, gfp_t flags);
+void * __must_check kasan_krealloc(const void *object, size_t new_size,
+					gfp_t flags);
 
-void *kasan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags);
+void * __must_check kasan_slab_alloc(struct kmem_cache *s, void *object,
+					gfp_t flags);
 bool kasan_slab_free(struct kmem_cache *s, void *object, unsigned long ip);
 
 struct kasan_cache {
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 195ca385cf7a..1144e741feb6 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -373,7 +373,8 @@ static u8 assign_tag(struct kmem_cache *cache, const void *object, bool new)
 #endif
 }
 
-void *kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
+void * __must_check kasan_init_slab_obj(struct kmem_cache *cache,
+						const void *object)
 {
 	struct kasan_alloc_meta *alloc_info;
 
@@ -389,7 +390,8 @@ void *kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
 	return (void *)object;
 }
 
-void *kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
+void * __must_check kasan_slab_alloc(struct kmem_cache *cache, void *object,
+					gfp_t flags)
 {
 	return kasan_kmalloc(cache, object, cache->object_size, flags);
 }
@@ -449,8 +451,8 @@ bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip)
 	return __kasan_slab_free(cache, object, ip, true);
 }
 
-void *kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
-		   gfp_t flags)
+void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object,
+					size_t size, gfp_t flags)
 {
 	unsigned long redzone_start;
 	unsigned long redzone_end;
@@ -482,7 +484,8 @@ void *kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
 }
 EXPORT_SYMBOL(kasan_kmalloc);
 
-void *kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
+void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
+						gfp_t flags)
 {
 	struct page *page;
 	unsigned long redzone_start;
@@ -506,7 +509,7 @@ void *kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
 	return (void *)ptr;
 }
 
-void *kasan_krealloc(const void *object, size_t size, gfp_t flags)
+void * __must_check kasan_krealloc(const void *object, size_t size, gfp_t flags)
 {
 	struct page *page;
 
-- 
2.20.0.rc1.387.gf8505762e3-goog


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