From: Kees Cook <keescook@chromium.org>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Sargun Dhillon <sargun@sargun.me>,
containers@lists.linux-foundation.org, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk,
christian.brauner@ubuntu.com, cyphar@cyphar.com,
jannh@google.com, jeffv@google.com, palmer@google.com,
rsesek@google.com, tycho@tycho.ws,
Matt Denton <mpdenton@google.com>
Subject: Re: [PATCH v3] seccomp: Add find_notification helper
Date: Wed, 17 Jun 2020 14:22:15 -0700 [thread overview]
Message-ID: <202006171420.C8007EDCD8@keescook> (raw)
In-Reply-To: <20200617200844.GA12976@Ryzen-9-3900X.localdomain>
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
next prev parent reply other threads:[~2020-06-17 21:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-01 11:25 [PATCH v3] seccomp: Add find_notification helper Sargun Dhillon
2020-06-01 18:26 ` Kees Cook
2020-06-17 20:08 ` Nathan Chancellor
2020-06-17 21:22 ` Kees Cook [this message]
2020-06-18 5:44 ` Sargun Dhillon
2020-06-18 6:04 ` Nathan Chancellor
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