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mingkuang
42 lines
1.3 KiB
C++
42 lines
1.3 KiB
C++
//
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// printf_count_output.cpp
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// Defines the functions that control the enable state of %n.
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//
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#include <corecrt_internal_stdio.h>
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static UINT_PTR enable_percent_n = 0;
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// Enables or disables the %n format specifier for the printf family of functions.
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// Note the use of the __security_cookie: if the static variable was set to a
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// known value, an attacker could potentially modify that value and then provide
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// a malicious %n specifier. The cookie is or'ed with 1 becuase a cookie with a
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// value of zero is possible.
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#if WindowsTargetPlatformMinVersion < WindowsTargetPlatformWindows10_10240
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extern "C" int __cdecl _set_printf_count_output(int const value)
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{
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int const old = (enable_percent_n == (__security_cookie | 1));
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enable_percent_n = (value ? (__security_cookie | 1) : 0);
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return old;
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}
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_LCRT_DEFINE_IAT_SYMBOL(_set_printf_count_output);
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#endif
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// Tests whether the %n format specifier for the printf family of functions is
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// enabled.
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#if WindowsTargetPlatformMinVersion < WindowsTargetPlatformWindows10_10240
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extern "C" int __cdecl _get_printf_count_output()
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{
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return enable_percent_n == (__security_cookie | 1);
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}
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_LCRT_DEFINE_IAT_SYMBOL(_get_printf_count_output);
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#endif |