| Message ID | 20221118034250.never.999-kees@kernel.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | d662198e03bc7fb4635156ee7e8b8d325e2d8512 |
| Delegated to: | Kees Cook |
| Headers | show |
| Series | hpet: Replace one-element array with flexible-array member | expand |
On Thu, Nov 17, 2022 at 07:42:55PM -0800, Kees Cook wrote: > One-element arrays are deprecated[1] and are being replaced with > flexible array members in support of the ongoing efforts to tighten the > FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing > with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3. > > Replace one-element array with flexible-array member in struct hpet. > > This results in no differences in binary output. The use of struct hpet > is never used with sizeof() and accesses via hpet_timers array are > already done after explicit bounds checking. > > [1] https://github.com/KSPP/linux/issues/79 > > Cc: Clemens Ladisch <clemens@ladisch.de> > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > Signed-off-by: Kees Cook <keescook@chromium.org> Such a sneaky 1-element... ~.~ Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks! -- Gustavo > --- > include/linux/hpet.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/hpet.h b/include/linux/hpet.h > index 8604564b985d..21e69eaf7a36 100644 > --- a/include/linux/hpet.h > +++ b/include/linux/hpet.h > @@ -30,7 +30,7 @@ struct hpet { > unsigned long _hpet_compare; > } _u1; > u64 hpet_fsb[2]; /* FSB route */ > - } hpet_timers[1]; > + } hpet_timers[]; > }; > > #define hpet_mc _u0._hpet_mc > -- > 2.34.1 >
On Thu, Nov 17, 2022 at 09:54:04PM -0600, Gustavo A. R. Silva wrote: > On Thu, Nov 17, 2022 at 07:42:55PM -0800, Kees Cook wrote: > > One-element arrays are deprecated[1] and are being replaced with > > flexible array members in support of the ongoing efforts to tighten the > > FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing > > with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3. > > > > Replace one-element array with flexible-array member in struct hpet. > > > > This results in no differences in binary output. The use of struct hpet > > is never used with sizeof() and accesses via hpet_timers array are > > already done after explicit bounds checking. > > > > [1] https://github.com/KSPP/linux/issues/79 > > > > Cc: Clemens Ladisch <clemens@ladisch.de> > > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > > Signed-off-by: Kees Cook <keescook@chromium.org> > > Such a sneaky 1-element... ~.~ Yes! This one made my system unbootable after adding -fstrict-flex-arrays=3. :) All better now. > Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks!
diff --git a/include/linux/hpet.h b/include/linux/hpet.h index 8604564b985d..21e69eaf7a36 100644 --- a/include/linux/hpet.h +++ b/include/linux/hpet.h @@ -30,7 +30,7 @@ struct hpet { unsigned long _hpet_compare; } _u1; u64 hpet_fsb[2]; /* FSB route */ - } hpet_timers[1]; + } hpet_timers[]; }; #define hpet_mc _u0._hpet_mc
One-element arrays are deprecated[1] and are being replaced with flexible array members in support of the ongoing efforts to tighten the FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3. Replace one-element array with flexible-array member in struct hpet. This results in no differences in binary output. The use of struct hpet is never used with sizeof() and accesses via hpet_timers array are already done after explicit bounds checking. [1] https://github.com/KSPP/linux/issues/79 Cc: Clemens Ladisch <clemens@ladisch.de> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> --- include/linux/hpet.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)