| Message ID | 20180823230654.GA11576@embeddedor.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | clk: npcm7xx: fix memory allocation | expand |
On Fri, Aug 24, 2018 at 2:18 AM Kees Cook <keescook@chromium.org> wrote: > > On Thu, Aug 23, 2018 at 4:06 PM, Gustavo A. R. Silva > <gustavo@embeddedor.com> 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: stable@vger.kernel.org > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > > Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Avi Fishman <avifishman70@gmail.com> > > -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
Quoting Gustavo A. R. Silva (2018-08-23 16:06:54) > 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: stable@vger.kernel.org > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > --- Applied to clk-fixes
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;
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: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/clk/clk-npcm7xx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)