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kernel: override access control in user_[un]block_thread()...

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when reading/writing the wait_status in userland. fixes #14067.
This commit is contained in:
Jérôme Duval 2018-04-03 22:36:33 +02:00
parent 048796e140
commit e1ceb339a0
1 changed files with 17 additions and 5 deletions
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22
src/system/kernel/thread.cpp
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@ -2965,10 +2965,13 @@ user_unblock_thread(thread_id threadID, status_t status)
InterruptsSpinLocker locker(thread->scheduler_lock);
set_ac();
if (thread->user_thread->wait_status > 0) {
thread->user_thread->wait_status = status;
clear_ac();
thread_unblock_locked(thread, status);
}
} else
clear_ac();
return B_OK;
}
@ -3626,8 +3629,13 @@ _user_block_thread(uint32 flags, bigtime_t timeout)
ThreadLocker threadLocker(thread);
// check, if already done
if (thread->user_thread->wait_status <= 0)
return thread->user_thread->wait_status;
set_ac();
if (thread->user_thread->wait_status <= 0) {
status_t status = thread->user_thread->wait_status;
clear_ac();
return status;
}
clear_ac();
// nope, so wait
thread_prepare_to_block(thread, flags, THREAD_BLOCK_TYPE_OTHER, "user");
@ -3641,11 +3649,15 @@ _user_block_thread(uint32 flags, bigtime_t timeout)
// Interruptions or timeouts can race with other threads unblocking us.
// Favor a wake-up by another thread, i.e. if someone changed the wait
// status, use that.
set_ac();
status_t oldStatus = thread->user_thread->wait_status;
if (oldStatus > 0)
if (oldStatus > 0) {
thread->user_thread->wait_status = status;
else
clear_ac();
} else {
clear_ac();
status = oldStatus;
}
threadLocker.Unlock();