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| author | David Rientjes <rientjes@google.com> | 2009-08-26 14:29:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-08-26 20:06:52 -0700 |
| commit | b62e408c05228f40e69bb38a48db8961cac6cd23 (patch) | |
| tree | 40711bad4a60adb8f331d71574ec61e13c5a352d /lib | |
| parent | 8e7ee27095aee87b5db1b0061e2ceea5878a1bbd (diff) | |
| download | lwn-b62e408c05228f40e69bb38a48db8961cac6cd23.tar.gz lwn-b62e408c05228f40e69bb38a48db8961cac6cd23.zip | |
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')
| -rw-r--r-- | lib/flex_array.c | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/lib/flex_array.c b/lib/flex_array.c index cf4e372cae90..7baed2fc3bc8 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; |