| Message ID | 20240128112722.4334-1-erick.archer@gmx.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | ae1d892d518af5c092f2b1f8e6921996c6a95cb3 |
| Headers | show |
| Series | [v2] bus: mhi: ep: Use kcalloc() instead of kzalloc() | expand |
On Sun, Jan 28, 2024 at 12:27:22PM +0100, Erick Archer wrote: > This is an effort to get rid of all multiplications from allocation > functions in order to prevent integer overflows [1]. > > Here the multiplication is obviously safe because the "event_rings" > member never can have a value greater than 255 (8 bits). This member > is set twice using always FIELD_GET: > > mhi_cntrl->event_rings = FIELD_GET(MHICFG_NER_MASK, regval); > mhi_cntrl->event_rings = FIELD_GET(MHICFG_NER_MASK, regval); > > And the MHICFG_NER_MASK macro defines the 8 bits mask that guarantees > a maximum value of 255. > > However, using kcalloc() is more appropriate [1] and improves > readability. This patch has no effect on runtime behavior. > > Link: https://github.com/KSPP/linux/issues/162 [1] > Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] > Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> > Signed-off-by: Erick Archer <erick.archer@gmx.com> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> - Mani > --- > Changes in v2: > - Add more info in the commit message to better explain the change. > (Dan Carpenter) > - Add the "Reviewed-by:" tag. > > Previous versions: > v1 - https://lore.kernel.org/linux-hardening/20240120152518.13006-1-erick.archer@gmx.com/ > --- > drivers/bus/mhi/ep/main.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c > index 65fc1d738bec..8d7a4102bdb7 100644 > --- a/drivers/bus/mhi/ep/main.c > +++ b/drivers/bus/mhi/ep/main.c > @@ -1149,8 +1149,9 @@ int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl) > mhi_ep_mmio_mask_interrupts(mhi_cntrl); > mhi_ep_mmio_init(mhi_cntrl); > > - mhi_cntrl->mhi_event = kzalloc(mhi_cntrl->event_rings * (sizeof(*mhi_cntrl->mhi_event)), > - GFP_KERNEL); > + mhi_cntrl->mhi_event = kcalloc(mhi_cntrl->event_rings, > + sizeof(*mhi_cntrl->mhi_event), > + GFP_KERNEL); > if (!mhi_cntrl->mhi_event) > return -ENOMEM; > > -- > 2.25.1 >
On 1/28/24 5:27 AM, Erick Archer wrote: > This is an effort to get rid of all multiplications from allocation > functions in order to prevent integer overflows [1]. > > Here the multiplication is obviously safe because the "event_rings" > member never can have a value greater than 255 (8 bits). This member > is set twice using always FIELD_GET: > > mhi_cntrl->event_rings = FIELD_GET(MHICFG_NER_MASK, regval); > mhi_cntrl->event_rings = FIELD_GET(MHICFG_NER_MASK, regval); > > And the MHICFG_NER_MASK macro defines the 8 bits mask that guarantees > a maximum value of 255. > > However, using kcalloc() is more appropriate [1] and improves > readability. This patch has no effect on runtime behavior. > > Link: https://github.com/KSPP/linux/issues/162 [1] > Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] > Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> > Signed-off-by: Erick Archer <erick.archer@gmx.com> > --- > Changes in v2: > - Add more info in the commit message to better explain the change. > (Dan Carpenter) > - Add the "Reviewed-by:" tag. Looks good. Reviewed-by: Alex Elder <elder@linaro.org> > > Previous versions: > v1 - https://lore.kernel.org/linux-hardening/20240120152518.13006-1-erick.archer@gmx.com/ > --- > drivers/bus/mhi/ep/main.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c > index 65fc1d738bec..8d7a4102bdb7 100644 > --- a/drivers/bus/mhi/ep/main.c > +++ b/drivers/bus/mhi/ep/main.c > @@ -1149,8 +1149,9 @@ int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl) > mhi_ep_mmio_mask_interrupts(mhi_cntrl); > mhi_ep_mmio_init(mhi_cntrl); > > - mhi_cntrl->mhi_event = kzalloc(mhi_cntrl->event_rings * (sizeof(*mhi_cntrl->mhi_event)), > - GFP_KERNEL); > + mhi_cntrl->mhi_event = kcalloc(mhi_cntrl->event_rings, > + sizeof(*mhi_cntrl->mhi_event), > + GFP_KERNEL); > if (!mhi_cntrl->mhi_event) > return -ENOMEM; > > -- > 2.25.1 >
On Sun, Jan 28, 2024 at 12:27:22PM +0100, Erick Archer wrote: > This is an effort to get rid of all multiplications from allocation > functions in order to prevent integer overflows [1]. > > Here the multiplication is obviously safe because the "event_rings" > member never can have a value greater than 255 (8 bits). This member > is set twice using always FIELD_GET: > > mhi_cntrl->event_rings = FIELD_GET(MHICFG_NER_MASK, regval); > mhi_cntrl->event_rings = FIELD_GET(MHICFG_NER_MASK, regval); > > And the MHICFG_NER_MASK macro defines the 8 bits mask that guarantees > a maximum value of 255. > > However, using kcalloc() is more appropriate [1] and improves > readability. This patch has no effect on runtime behavior. > > Link: https://github.com/KSPP/linux/issues/162 [1] > Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] > Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> > Signed-off-by: Erick Archer <erick.archer@gmx.com> Applied to mhi-next! - Mani > --- > Changes in v2: > - Add more info in the commit message to better explain the change. > (Dan Carpenter) > - Add the "Reviewed-by:" tag. > > Previous versions: > v1 - https://lore.kernel.org/linux-hardening/20240120152518.13006-1-erick.archer@gmx.com/ > --- > drivers/bus/mhi/ep/main.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c > index 65fc1d738bec..8d7a4102bdb7 100644 > --- a/drivers/bus/mhi/ep/main.c > +++ b/drivers/bus/mhi/ep/main.c > @@ -1149,8 +1149,9 @@ int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl) > mhi_ep_mmio_mask_interrupts(mhi_cntrl); > mhi_ep_mmio_init(mhi_cntrl); > > - mhi_cntrl->mhi_event = kzalloc(mhi_cntrl->event_rings * (sizeof(*mhi_cntrl->mhi_event)), > - GFP_KERNEL); > + mhi_cntrl->mhi_event = kcalloc(mhi_cntrl->event_rings, > + sizeof(*mhi_cntrl->mhi_event), > + GFP_KERNEL); > if (!mhi_cntrl->mhi_event) > return -ENOMEM; > > -- > 2.25.1 >
diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c index 65fc1d738bec..8d7a4102bdb7 100644 --- a/drivers/bus/mhi/ep/main.c +++ b/drivers/bus/mhi/ep/main.c @@ -1149,8 +1149,9 @@ int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl) mhi_ep_mmio_mask_interrupts(mhi_cntrl); mhi_ep_mmio_init(mhi_cntrl); - mhi_cntrl->mhi_event = kzalloc(mhi_cntrl->event_rings * (sizeof(*mhi_cntrl->mhi_event)), - GFP_KERNEL); + mhi_cntrl->mhi_event = kcalloc(mhi_cntrl->event_rings, + sizeof(*mhi_cntrl->mhi_event), + GFP_KERNEL); if (!mhi_cntrl->mhi_event) return -ENOMEM;