On Thu, Aug 23, 2018 at 4:06 PM, Gustavo A. R. Silva <[email protected]> wrote: > One of the more common cases of allocation size calculations is finding > the size of a structure that has a zero-sized array at the end, along > with memory for some number of elements for that array. For example: > > struct foo { > int stuff; > void *entry[]; > }; > > instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, > GFP_KERNEL); > > Instead of leaving these open-coded and prone to type mistakes, we can > now use the new struct_size() helper: > > instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); > > Notice that, currently, there is a bug during the allocation: > > sizeof(npcm7xx_clk_data) should be sizeof(*npcm7xx_clk_data) > > Fix this bug by using struct_size() in kzalloc() > > This issue was detected with the help of Coccinelle. > > Cc: [email protected] > Signed-off-by: Gustavo A. R. Silva <[email protected]>
Reviewed-by: Kees Cook <[email protected]> -Kees > --- > drivers/clk/clk-npcm7xx.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/clk/clk-npcm7xx.c b/drivers/clk/clk-npcm7xx.c > index 740af90..c5edf8f 100644 > --- a/drivers/clk/clk-npcm7xx.c > +++ b/drivers/clk/clk-npcm7xx.c > @@ -558,8 +558,8 @@ static void __init npcm7xx_clk_init(struct device_node > *clk_np) > if (!clk_base) > goto npcm7xx_init_error; > > - npcm7xx_clk_data = kzalloc(sizeof(*npcm7xx_clk_data->hws) * > - NPCM7XX_NUM_CLOCKS + sizeof(npcm7xx_clk_data), GFP_KERNEL); > + npcm7xx_clk_data = kzalloc(struct_size(npcm7xx_clk_data, hws, > + NPCM7XX_NUM_CLOCKS), GFP_KERNEL); > if (!npcm7xx_clk_data) > goto npcm7xx_init_np_err; > > -- > 2.7.4 > -- Kees Cook Pixel Security
