On Tue, Apr 11, 2023 at 12:39:06PM -0600, Gustavo A. R. Silva wrote: > [You don't often get email from gustavo@xxxxxxxxxxxxxx. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > On 4/7/23 01:23, Simon Horman wrote: > > On Thu, Apr 06, 2023 at 08:32:12AM -0600, Gustavo A. R. Silva wrote: > > > Zero-length arrays are deprecated [1] and have to be replaced by C99 > > > flexible-array members. > > > > > > This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines > > > on memcpy() and help to make progress towards globally enabling > > > -fstrict-flex-arrays=3 [2] > > > > > > Link: https://github.com/KSPP/linux/issues/78 [1] > > > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [2] > > > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > > > > Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx> > > Thanks :) > > > > > > --- > > > drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h > > > index a5e6ee4daf92..9bf4b4199ee3 100644 > > > --- a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h > > > +++ b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h > > > @@ -127,7 +127,7 @@ struct mt76_connac2_mcu_rxd { > > > u8 rsv1[2]; > > > u8 s2d_index; > > > > > > - u8 tlv[0]; > > > + u8 tlv[]; > > > }; > > > > > > struct mt76_connac2_patch_hdr { > > > > Curiously -fstrict-flex-arrays=3 didn't flag this one in my environment, > > Ubuntu Lunar. > > Yep; that's why I didn't include any warning message in the changelog text > this time. > > And the reason for that is that tlv is not being indexed anywhere in the > code. However, it's being used in the pointer arithmetic operation below: > > drivers/net/wireless/mediatek/mt76/mt7921/mcu.c: > 164 rxd = (struct mt76_connac2_mcu_rxd *)skb->data; > 165 grant = (struct mt7921_roc_grant_tlv *)(rxd->tlv + 4); > > > which means that it can be considered as an array of size greater than zero > at some point. Hence, it should be transformed into a C99 flexible array. Understood, thanks for the explanation. > > gcc-13 --version > > gcc-13 (Ubuntu 13-20230320-1ubuntu1) 13.0.1 20230320 (experimental) [master r13-6759-g5194ad1958c] > > Copyright (C) 2023 Free Software Foundation, Inc. > > This is free software; see the source for copying conditions. There is NO > > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. > > > > I did, however, notice some other problems reported by gcc-13 with > > -fstrict-flex-arrays=3 in drivers/net/wireless/mediatek/mt76 > > when run against net-next wireless. I've listed them in diff format below. > > > > Are these on your radar too? > > Yep; those are being addressed here: > > https://lore.kernel.org/linux-hardening/ZBTUB%2FkJYQxq%2F6Cj@work/ Thanks, I had forgotten about that.
