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-rw-r--r--include/linux/slab.h1
-rw-r--r--mm/slab.c13
-rw-r--r--mm/util.c21
3 files changed, 23 insertions, 12 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 488446289cab..49d1247cd6d9 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -106,6 +106,7 @@ int kmem_cache_shrink(struct kmem_cache *);
void kmem_cache_free(struct kmem_cache *, void *);
unsigned int kmem_cache_size(struct kmem_cache *);
const char *kmem_cache_name(struct kmem_cache *);
+int kern_ptr_validate(const void *ptr, unsigned long size);
int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
/*
diff --git a/mm/slab.c b/mm/slab.c
index a9f325b28bed..bac0f4fcc216 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3602,21 +3602,10 @@ EXPORT_SYMBOL(kmem_cache_alloc_notrace);
*/
int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr)
{
- unsigned long addr = (unsigned long)ptr;
- unsigned long min_addr = PAGE_OFFSET;
- unsigned long align_mask = BYTES_PER_WORD - 1;
unsigned long size = cachep->buffer_size;
struct page *page;
- if (unlikely(addr < min_addr))
- goto out;
- if (unlikely(addr > (unsigned long)high_memory - size))
- goto out;
- if (unlikely(addr & align_mask))
- goto out;
- if (unlikely(!kern_addr_valid(addr)))
- goto out;
- if (unlikely(!kern_addr_valid(addr + size - 1)))
+ if (unlikely(!kern_ptr_validate(ptr, size)))
goto out;
page = virt_to_page(ptr);
if (unlikely(!PageSlab(page)))
diff --git a/mm/util.c b/mm/util.c
index 834db7be240f..f5712e8964be 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -186,6 +186,27 @@ void kzfree(const void *p)
}
EXPORT_SYMBOL(kzfree);
+int kern_ptr_validate(const void *ptr, unsigned long size)
+{
+ unsigned long addr = (unsigned long)ptr;
+ unsigned long min_addr = PAGE_OFFSET;
+ unsigned long align_mask = sizeof(void *) - 1;
+
+ if (unlikely(addr < min_addr))
+ goto out;
+ if (unlikely(addr > (unsigned long)high_memory - size))
+ goto out;
+ if (unlikely(addr & align_mask))
+ goto out;
+ if (unlikely(!kern_addr_valid(addr)))
+ goto out;
+ if (unlikely(!kern_addr_valid(addr + size - 1)))
+ goto out;
+ return 1;
+out:
+ return 0;
+}
+
/*
* strndup_user - duplicate an existing string from user space
* @s: The string to duplicate