On Wed, Jun 17, 2020 at 01:08:44PM -0700, Nathan Chancellor wrote:
> On Mon, Jun 01, 2020 at 04:25:32AM -0700, Sargun Dhillon wrote:
> > [...]
> > static long seccomp_notify_recv(struct seccomp_filter *filter,
> > void __user *buf)
> > {
> > - struct seccomp_knotif *knotif = NULL, *cur;
> > + struct seccomp_knotif *knotif, *cur;
> > struct seccomp_notif unotif;
> > ssize_t ret;
> >
>
> I don't know that this should have been removed, clang now warns:
>
> kernel/seccomp.c:1063:2: warning: variable 'knotif' is used uninitialized
> whenever 'for' loop exits because its condition is false
> [-Wsometimes-uninitialized]
> list_for_each_entry(cur, &filter->notif->notifications, list) {
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/list.h:602:7: note: expanded from macro 'list_for_each_entry'
> &pos->member != (head); \
> ^~~~~~~~~~~~~~~~~~~~~~
> kernel/seccomp.c:1075:7: note: uninitialized use occurs here
> if (!knotif) {
> ^~~~~~
> kernel/seccomp.c:1063:2: note: remove the condition if it is always true
> list_for_each_entry(cur, &filter->notif->notifications, list) {
> ^
> include/linux/list.h:602:7: note: expanded from macro 'list_for_each_entry'
> &pos->member != (head); \
> ^
> kernel/seccomp.c:1045:31: note: initialize the variable 'knotif' to silence
> this warning
> struct seccomp_knotif *knotif, *cur;
> ^
> = NULL
> 1 warning generated.
Eek; yes, thank you! I've folded the fix into Sargun's patch.
--
Kees Cook
