* [PATCH] android: binder: check result of binder_get_thread() in binder_poll()
@ 2017-05-08 20:43 Dmitry Torokhov
2017-05-08 20:46 ` John Stultz
2017-08-23 1:50 ` Greg Kroah-Hartman
0 siblings, 2 replies; 4+ messages in thread
From: Dmitry Torokhov @ 2017-05-08 20:43 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Arve Hjønnevåg, Riley Andrews, Martijn Coenen,
John Stultz, Douglas Anderson, devel, linux-kernel
If binder_get_thread() fails to give us a thread data, we should avoid
dereferencing a NULL pointer and return POLLERR instead.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
drivers/android/binder.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index aae4d8d4be36..66ed714fedd5 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3103,18 +3103,22 @@ static unsigned int binder_poll(struct file *filp,
struct poll_table_struct *wait)
{
struct binder_proc *proc = filp->private_data;
- struct binder_thread *thread = NULL;
+ struct binder_thread *thread;
int wait_for_proc_work;
binder_lock(__func__);
thread = binder_get_thread(proc);
-
- wait_for_proc_work = thread->transaction_stack == NULL &&
- list_empty(&thread->todo) && thread->return_error == BR_OK;
+ if (thread)
+ wait_for_proc_work = thread->transaction_stack == NULL &&
+ list_empty(&thread->todo) &&
+ thread->return_error == BR_OK;
binder_unlock(__func__);
+ if (!thread)
+ return POLLERR;
+
if (wait_for_proc_work) {
if (binder_has_proc_work(proc, thread))
return POLLIN;
--
2.13.0.rc1.294.g07d810a77f-goog
--
Dmitry
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] android: binder: check result of binder_get_thread() in binder_poll()
2017-05-08 20:43 [PATCH] android: binder: check result of binder_get_thread() in binder_poll() Dmitry Torokhov
@ 2017-05-08 20:46 ` John Stultz
2017-05-08 20:56 ` Doug Anderson
2017-08-23 1:50 ` Greg Kroah-Hartman
1 sibling, 1 reply; 4+ messages in thread
From: John Stultz @ 2017-05-08 20:46 UTC (permalink / raw)
To: Dmitry Torokhov
Cc: Greg Kroah-Hartman, Arve Hjønnevåg, Martijn Coenen,
Douglas Anderson, devel, lkml, Todd Kjos
On Mon, May 8, 2017 at 1:43 PM, Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
> If binder_get_thread() fails to give us a thread data, we should avoid
> dereferencing a NULL pointer and return POLLERR instead.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Pulling Todd Kjos in on this too.
-john
> ---
> drivers/android/binder.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index aae4d8d4be36..66ed714fedd5 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -3103,18 +3103,22 @@ static unsigned int binder_poll(struct file *filp,
> struct poll_table_struct *wait)
> {
> struct binder_proc *proc = filp->private_data;
> - struct binder_thread *thread = NULL;
> + struct binder_thread *thread;
> int wait_for_proc_work;
>
> binder_lock(__func__);
>
> thread = binder_get_thread(proc);
> -
> - wait_for_proc_work = thread->transaction_stack == NULL &&
> - list_empty(&thread->todo) && thread->return_error == BR_OK;
> + if (thread)
> + wait_for_proc_work = thread->transaction_stack == NULL &&
> + list_empty(&thread->todo) &&
> + thread->return_error == BR_OK;
>
> binder_unlock(__func__);
>
> + if (!thread)
> + return POLLERR;
> +
> if (wait_for_proc_work) {
> if (binder_has_proc_work(proc, thread))
> return POLLIN;
> --
> 2.13.0.rc1.294.g07d810a77f-goog
>
>
> --
> Dmitry
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] android: binder: check result of binder_get_thread() in binder_poll()
2017-05-08 20:46 ` John Stultz
@ 2017-05-08 20:56 ` Doug Anderson
0 siblings, 0 replies; 4+ messages in thread
From: Doug Anderson @ 2017-05-08 20:56 UTC (permalink / raw)
To: John Stultz
Cc: Dmitry Torokhov, Greg Kroah-Hartman, Arve Hjønnevåg,
Martijn Coenen, devel, lkml, Todd Kjos
Dmitry,
On Mon, May 8, 2017 at 1:46 PM, John Stultz <john.stultz@linaro.org> wrote:
> On Mon, May 8, 2017 at 1:43 PM, Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
>> If binder_get_thread() fails to give us a thread data, we should avoid
>> dereferencing a NULL pointer and return POLLERR instead.
>>
>> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>
> Pulling Todd Kjos in on this too.
> -john
>
>> ---
>> drivers/android/binder.c | 12 ++++++++----
>> 1 file changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
>> index aae4d8d4be36..66ed714fedd5 100644
>> --- a/drivers/android/binder.c
>> +++ b/drivers/android/binder.c
>> @@ -3103,18 +3103,22 @@ static unsigned int binder_poll(struct file *filp,
>> struct poll_table_struct *wait)
>> {
>> struct binder_proc *proc = filp->private_data;
>> - struct binder_thread *thread = NULL;
>> + struct binder_thread *thread;
>> int wait_for_proc_work;
>>
>> binder_lock(__func__);
>>
>> thread = binder_get_thread(proc);
>> -
>> - wait_for_proc_work = thread->transaction_stack == NULL &&
>> - list_empty(&thread->todo) && thread->return_error == BR_OK;
>> + if (thread)
>> + wait_for_proc_work = thread->transaction_stack == NULL &&
>> + list_empty(&thread->todo) &&
>> + thread->return_error == BR_OK;
>>
>> binder_unlock(__func__);
>>
>> + if (!thread)
>> + return POLLERR;
>> +
>> if (wait_for_proc_work) {
>> if (binder_has_proc_work(proc, thread))
>> return POLLIN;
>> --
I'm no expert on the poll function, but I agree that it's wise to
check the result of binder_get_thread() since it can return NULL.
FWIW:
Reviewed-by: Douglas Anderson <dianders@chromium.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] android: binder: check result of binder_get_thread() in binder_poll()
2017-05-08 20:43 [PATCH] android: binder: check result of binder_get_thread() in binder_poll() Dmitry Torokhov
2017-05-08 20:46 ` John Stultz
@ 2017-08-23 1:50 ` Greg Kroah-Hartman
1 sibling, 0 replies; 4+ messages in thread
From: Greg Kroah-Hartman @ 2017-08-23 1:50 UTC (permalink / raw)
To: Dmitry Torokhov
Cc: Arve Hjønnevåg, Riley Andrews, Martijn Coenen,
John Stultz, Douglas Anderson, devel, linux-kernel
On Mon, May 08, 2017 at 01:43:23PM -0700, Dmitry Torokhov wrote:
> If binder_get_thread() fails to give us a thread data, we should avoid
> dereferencing a NULL pointer and return POLLERR instead.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> ---
> drivers/android/binder.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
Doesn't apply to my tree at all :(
Please rebase and resend, thanks.
greg k-h
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-05-08 20:43 [PATCH] android: binder: check result of binder_get_thread() in binder_poll() Dmitry Torokhov
2017-05-08 20:46 ` John Stultz
2017-05-08 20:56 ` Doug Anderson
2017-08-23 1:50 ` Greg Kroah-Hartman
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