kasan: save alloc stack traces for mempool

Update kasan_mempool_unpoison_object to properly poison the redzone and
save alloc strack traces for kmalloc and slab pools.

As a part of this change, split out and use a unpoison_slab_object helper
function from __kasan_slab_alloc.

[nathan@kernel.org: mark unpoison_slab_object() as static]
Link: https://lkml.kernel.org/r/20231221180042.104694-1-andrey.konovalov@linux.dev
Link: https://lkml.kernel.org/r/05ad235da8347cfe14d496d01b2aaf074b4f607c.1703024586.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index e636a00e26bac13853b03a709961c7b39e980f0b..7392c5d89b920a1bd63f34e27b2d677b51b72cf1 100644 (file)
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -303,9 +303,10 @@ void __kasan_mempool_unpoison_object(void *ptr, size_t size, unsigned long ip);
  * mempool).
  *
  * This function unpoisons a slab allocation that was previously poisoned via
- * kasan_mempool_poison_object() without initializing its memory. For the
- * tag-based modes, this function does not assign a new tag to the allocation
- * and instead restores the original tags based on the pointer value.
+ * kasan_mempool_poison_object() and saves an alloc stack trace for it without
+ * initializing the allocation's memory. For the tag-based modes, this function
+ * does not assign a new tag to the allocation and instead restores the
+ * original tags based on the pointer value.
  *
  * This function operates on all slab allocations including large kmalloc
  * allocations (the ones returned by kmalloc_large() or by kmalloc() with the

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 962805bf5f621736a61f4d2dbeae98e0a84dc6be..bf16c2dfa8e7168f217e15ff5bf7cd57e7d5c3b9 100644 (file)
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -277,6 +277,20 @@ void __kasan_kfree_large(void *ptr, unsigned long ip)
        /* The object will be poisoned by kasan_poison_pages(). */
 }
 
+static inline void unpoison_slab_object(struct kmem_cache *cache, void *object,
+                                       gfp_t flags, bool init)
+{
+       /*
+        * Unpoison the whole object. For kmalloc() allocations,
+        * poison_kmalloc_redzone() will do precise poisoning.
+        */
+       kasan_unpoison(object, cache->object_size, init);
+
+       /* Save alloc info (if possible) for non-kmalloc() allocations. */
+       if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache))
+               kasan_save_alloc_info(cache, object, flags);
+}
+
 void * __must_check __kasan_slab_alloc(struct kmem_cache *cache,
                                        void *object, gfp_t flags, bool init)
 {
@@ -299,15 +313,8 @@ void * __must_check __kasan_slab_alloc(struct kmem_cache *cache,
        tag = assign_tag(cache, object, false);
        tagged_object = set_tag(object, tag);
 
-       /*
-        * Unpoison the whole object.
-        * For kmalloc() allocations, kasan_kmalloc() will do precise poisoning.
-        */
-       kasan_unpoison(tagged_object, cache->object_size, init);
-
-       /* Save alloc info (if possible) for non-kmalloc() allocations. */
-       if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache))
-               kasan_save_alloc_info(cache, tagged_object, flags);
+       /* Unpoison the object and save alloc info for non-kmalloc() allocations. */
+       unpoison_slab_object(cache, tagged_object, flags, init);
 
        return tagged_object;
 }
@@ -482,7 +489,30 @@ bool __kasan_mempool_poison_object(void *ptr, unsigned long ip)
 
 void __kasan_mempool_unpoison_object(void *ptr, size_t size, unsigned long ip)
 {
-       kasan_unpoison(ptr, size, false);
+       struct slab *slab;
+       gfp_t flags = 0; /* Might be executing under a lock. */
+
+       if (is_kfence_address(kasan_reset_tag(ptr)))
+               return;
+
+       slab = virt_to_slab(ptr);
+
+       /*
+        * This function can be called for large kmalloc allocation that get
+        * their memory from page_alloc.
+        */
+       if (unlikely(!slab)) {
+               kasan_unpoison(ptr, size, false);
+               poison_kmalloc_large_redzone(ptr, size, flags);
+               return;
+       }
+
+       /* Unpoison the object and save alloc info for non-kmalloc() allocations. */
+       unpoison_slab_object(slab->slab_cache, ptr, size, flags);
+
+       /* Poison the redzone and save alloc info for kmalloc() allocations. */
+       if (is_kmalloc_cache(slab->slab_cache))
+               poison_kmalloc_redzone(slab->slab_cache, ptr, size, flags);
 }
 
 bool __kasan_check_byte(const void *address, unsigned long ip)