Messages in this thread Patch in this message | | | From | Chen Feng <> | Subject | [PATCH v2] android: binder: Sanity check at binder ioctl | Date | Tue, 19 Jan 2016 17:04:01 +0800 |
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When a process fork a child process, we should not allow the child process use the binder which opened by parent process.
But if the binder-object creater is a thread of one process who exit, the other thread can also use this binder-object normally. We can distinguish this by the member proc->tsk->mm. If the thread exit the tsk->mm will be NULL.
proc->tsk->mm != current->mm && proc->tsk->mm
So only allow the shared mm_struct to use the same binder-object and check the existence of mm_struct.
V2: Fix compile error for error commit
Signed-off-by: Chen Feng <puck.chen@hisilicon.com> Signed-off-by: Wei Dong <weidong2@hisilicon.com> Signed-off-by: Junmin Zhao <zhaojunmin@huawei.com> Reviewed-by: Zhuangluan Su <suzhuangluan@hisilicon.com> --- drivers/android/binder.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index a39e85f..279063c 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2736,6 +2736,8 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) /*pr_info("binder_ioctl: %d:%d %x %lx\n", proc->pid, current->pid, cmd, arg);*/ + if (unlikely(proc->tsk->mm != current->mm && proc->tsk->mm)) + return -EINVAL; trace_binder_ioctl(cmd, arg); -- 1.9.1
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