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# Control number of allowed entropy calls.
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import sys
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from array import array
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from contextlib import contextmanager
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ALLOWED_ENTROPY_CALLS = array("b", [0])
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IN_REQUEST_CONTEXT = False
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def in_request_context():
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    return IN_REQUEST_CONTEXT
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def _set_in_request_context():
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    global IN_REQUEST_CONTEXT
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    IN_REQUEST_CONTEXT = True
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def should_allow_entropy_call():
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    """This helps us raise Python errors rather than fatal errors in some cases.
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    It doesn't really matter that much since we're not likely to recover from
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    these anyways but it feels better.
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    """
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    # Allow if we've either entered request context or if we've temporarily
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    # enabled entropy.
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    return IN_REQUEST_CONTEXT or is_bad_entropy_enabled()
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def raise_unless_entropy_allowed():
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    if not should_allow_entropy_call():
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        EIO = 29
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        raise OSError(EIO, "Cannot get entropy outside of request context")
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def get_bad_entropy_flag():
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    # simpleRunPython reads out stderr. We put the address there so we can fish
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    # it out... We could use ctypes instead of array but ctypes weighs an extra
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    # 100kb compared to array.
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    print(ALLOWED_ENTROPY_CALLS.buffer_info()[0], file=sys.stderr)
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def is_bad_entropy_enabled():
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    """This is used in entropy_patches.py to let calls to disabled functions
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    through if we are allowing bad entropy
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    """
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    return ALLOWED_ENTROPY_CALLS[0] > 0
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@contextmanager
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def allow_bad_entropy_calls(n):
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    old_allowed_entropy_calls = ALLOWED_ENTROPY_CALLS[0]
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    ALLOWED_ENTROPY_CALLS[0] = n
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    yield
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    if ALLOWED_ENTROPY_CALLS[0] > 0:
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        raise RuntimeError(
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            f"{ALLOWED_ENTROPY_CALLS[0]} unexpected leftover getentropy calls "
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        )
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    ALLOWED_ENTROPY_CALLS[0] = old_allowed_entropy_calls