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authorDavid Rientjes <rientjes@google.com>2009-08-26 14:29:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-26 20:06:52 -0700
commitb62e408c05228f40e69bb38a48db8961cac6cd23 (patch)
tree40711bad4a60adb8f331d71574ec61e13c5a352d /lib/flex_array.c
parent8e7ee27095aee87b5db1b0061e2ceea5878a1bbd (diff)
downloadvexpress-lsk-b62e408c05228f40e69bb38a48db8961cac6cd23.tar.gz
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>
Diffstat (limited to 'lib/flex_array.c')
-rw-r--r--lib/flex_array.c24
1 files changed, 13 insertions, 11 deletions
diff --git a/lib/flex_array.c b/lib/flex_array.c
index cf4e372cae9..7baed2fc3bc 100644
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -99,7 +99,8 @@ static inline int elements_fit_in_base(struct flex_array *fa)
* capacity in the base structure. Also note that no effort is made
* to efficiently pack objects across page boundaries.
*/
-struct flex_array *flex_array_alloc(int element_size, int total, gfp_t flags)
+struct flex_array *flex_array_alloc(int element_size, unsigned int total,
+ gfp_t flags)
{
struct flex_array *ret;
int max_size = nr_base_part_ptrs() * __elements_per_part(element_size);
@@ -115,7 +116,8 @@ struct flex_array *flex_array_alloc(int element_size, int total, gfp_t flags)
return ret;
}
-static int fa_element_to_part_nr(struct flex_array *fa, int element_nr)
+static int fa_element_to_part_nr(struct flex_array *fa,
+ unsigned int element_nr)
{
return element_nr / __elements_per_part(fa->element_size);
}
@@ -143,14 +145,12 @@ void flex_array_free(struct flex_array *fa)
kfree(fa);
}
-static int fa_index_inside_part(struct flex_array *fa, int element_nr)
+static unsigned int index_inside_part(struct flex_array *fa,
+ unsigned int element_nr)
{
- return element_nr % __elements_per_part(fa->element_size);
-}
+ unsigned int part_offset;
-static int index_inside_part(struct flex_array *fa, int element_nr)
-{
- int part_offset = fa_index_inside_part(fa, element_nr);
+ part_offset = element_nr % __elements_per_part(fa->element_size);
return part_offset * fa->element_size;
}
@@ -185,7 +185,8 @@ __fa_get_part(struct flex_array *fa, int part_nr, gfp_t flags)
*
* Locking must be provided by the caller.
*/
-int flex_array_put(struct flex_array *fa, int element_nr, void *src, gfp_t flags)
+int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
+ gfp_t flags)
{
int part_nr = fa_element_to_part_nr(fa, element_nr);
struct flex_array_part *part;
@@ -217,7 +218,8 @@ int flex_array_put(struct flex_array *fa, int element_nr, void *src, gfp_t flags
*
* Locking must be provided by the caller.
*/
-int flex_array_prealloc(struct flex_array *fa, int start, int end, gfp_t flags)
+int flex_array_prealloc(struct flex_array *fa, unsigned int start,
+ unsigned int end, gfp_t flags)
{
int start_part;
int end_part;
@@ -248,7 +250,7 @@ int flex_array_prealloc(struct flex_array *fa, int start, int end, gfp_t flags)
*
* Locking must be provided by the caller.
*/
-void *flex_array_get(struct flex_array *fa, int element_nr)
+void *flex_array_get(struct flex_array *fa, unsigned int element_nr)
{
int part_nr = fa_element_to_part_nr(fa, element_nr);
struct flex_array_part *part;