proc: Use new infrastructure to fix deadlocks in execve
This changes lock_trace to use the new exec_update_mutex instead of cred_guard_mutex. This fixes possible deadlocks when the trace is accessing /proc/$pid/stack for instance. This should be safe, as the credentials are only used for reading, and task->mm is updated on execve under the new exec_update_mutex. Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>alistair/sensors
parent
454e3126cb
commit
2db9dbf71b
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@ -405,11 +405,11 @@ print0:
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static int lock_trace(struct task_struct *task)
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static int lock_trace(struct task_struct *task)
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{
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{
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int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
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int err = mutex_lock_killable(&task->signal->exec_update_mutex);
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if (err)
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if (err)
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return err;
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return err;
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if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
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if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
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mutex_unlock(&task->signal->cred_guard_mutex);
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mutex_unlock(&task->signal->exec_update_mutex);
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return -EPERM;
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return -EPERM;
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}
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}
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return 0;
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return 0;
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@ -417,7 +417,7 @@ static int lock_trace(struct task_struct *task)
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static void unlock_trace(struct task_struct *task)
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static void unlock_trace(struct task_struct *task)
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{
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{
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mutex_unlock(&task->signal->cred_guard_mutex);
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mutex_unlock(&task->signal->exec_update_mutex);
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}
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}
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#ifdef CONFIG_STACKTRACE
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#ifdef CONFIG_STACKTRACE
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