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linux-next/include/linux/flex_array.h
David Rientjes b62e408c05 flex_array: convert element_nr formals to unsigned
It's problematic to allow signed element_nr's or total's to be passed as
part of the flex array API.

flex_array_alloc() allows total_nr_elements to be set to a negative
quantity, which is obviously erroneous.

flex_array_get() and flex_array_put() allows negative array indices in
dereferencing an array part, which could address memory mapped before
struct flex_array.

The fix is to convert all existing element_nr formals to be qualified as
unsigned.  Existing checks to compare it to total_nr_elements or the max
array size based on element_size need not be changed.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-26 20:06:52 -07:00

50 lines
1.2 KiB
C

#ifndef _FLEX_ARRAY_H
#define _FLEX_ARRAY_H
#include <linux/types.h>
#include <asm/page.h>
#define FLEX_ARRAY_PART_SIZE PAGE_SIZE
#define FLEX_ARRAY_BASE_SIZE PAGE_SIZE
struct flex_array_part;
/*
* This is meant to replace cases where an array-like
* structure has gotten too big to fit into kmalloc()
* and the developer is getting tempted to use
* vmalloc().
*/
struct flex_array {
union {
struct {
int element_size;
int total_nr_elements;
struct flex_array_part *parts[];
};
/*
* This little trick makes sure that
* sizeof(flex_array) == PAGE_SIZE
*/
char padding[FLEX_ARRAY_BASE_SIZE];
};
};
#define FLEX_ARRAY_INIT(size, total) { { {\
.element_size = (size), \
.total_nr_elements = (total), \
} } }
struct flex_array *flex_array_alloc(int element_size, unsigned int total,
gfp_t flags);
int flex_array_prealloc(struct flex_array *fa, unsigned int start,
unsigned int end, gfp_t flags);
void flex_array_free(struct flex_array *fa);
void flex_array_free_parts(struct flex_array *fa);
int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
gfp_t flags);
void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
#endif /* _FLEX_ARRAY_H */