From: Joe Perches <joe@perches.com>
To: glider@google.com, tkjos@google.com, keescook@chromium.org,
gregkh@linuxfoundation.org, arve@android.com, mingo@redhat.com
Cc: dvyukov@google.com, jannh@google.com, devel@driverdev.osuosl.org,
peterz@infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] binder: do not initialize locals passed to copy_from_user()
Date: Mon, 02 Mar 2020 05:09:58 -0800 [thread overview]
Message-ID: <0eaac427354844a4fcfb0d9843cf3024c6af21df.camel@perches.com> (raw)
In-Reply-To: <20200302130430.201037-2-glider@google.com>
On Mon, 2020-03-02 at 14:04 +0100, glider@google.com wrote:
> Certain copy_from_user() invocations in binder.c are known to
> unconditionally initialize locals before their first use, like e.g. in
> the following case:
[]
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
[]
> @@ -3788,7 +3788,7 @@ static int binder_thread_write(struct binder_proc *proc,
>
> case BC_TRANSACTION_SG:
> case BC_REPLY_SG: {
> - struct binder_transaction_data_sg tr;
> + struct binder_transaction_data_sg tr __no_initialize;
>
> if (copy_from_user(&tr, ptr, sizeof(tr)))
I fail to see any value in marking tr with __no_initialize
when it's immediately written to by copy_from_user.
> return -EFAULT;
> @@ -3799,7 +3799,7 @@ static int binder_thread_write(struct binder_proc *proc,
> }
> case BC_TRANSACTION:
> case BC_REPLY: {
> - struct binder_transaction_data tr;
> + struct binder_transaction_data tr __no_initialize;
>
> if (copy_from_user(&tr, ptr, sizeof(tr)))
etc...
next prev parent reply other threads:[~2020-03-02 13:11 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-02 13:04 [PATCH v2 1/3] compiler.h: define __no_initialize glider
2020-03-02 13:04 ` [PATCH v2 2/3] binder: do not initialize locals passed to copy_from_user() glider
2020-03-02 13:09 ` Joe Perches [this message]
2020-03-02 13:25 ` Alexander Potapenko
2020-03-02 13:52 ` Dan Carpenter
2020-03-02 13:58 ` Joe Perches
2020-03-02 18:17 ` Alexander Potapenko
2020-03-02 18:31 ` Jann Horn
2020-03-05 9:03 ` Rasmus Villemoes
2020-03-05 12:45 ` Jann Horn
2020-03-06 2:29 ` Al Viro
2020-03-02 18:50 ` Joe Perches
2020-03-03 9:14 ` Alexander Potapenko
2020-03-03 9:38 ` Dan Carpenter
2020-03-03 13:56 ` Joe Perches
2020-03-03 14:15 ` Dan Carpenter
2020-03-04 18:13 ` Kees Cook
2020-03-05 8:07 ` Dan Carpenter
2020-03-05 8:26 ` Kees Cook
2020-03-05 8:33 ` Alexander Potapenko
2020-03-02 17:38 ` Greg KH
2020-03-02 18:28 ` Alexander Potapenko
2020-03-02 13:04 ` [PATCH v2 3/3] sched/wait: avoid double initialization in ___wait_event() glider
2020-03-02 16:56 ` Todd Kjos
2020-03-02 18:03 ` Alexander Potapenko
2020-03-02 18:39 ` Greg Kroah-Hartman
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