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3396c97da9
Now that the new CMake build system is encouraging us to lay out the code like a set of libraries, it seems like a good idea to make them look more _like_ libraries, by putting things into separate modules as far as possible. This fixes several previous annoyances in which you had to link against some object in order to get a function you needed, but that object also contained other functions you didn't need which included link-time symbol references you didn't want to have to deal with. The usual offender was subsidiary supporting programs including misc.c for some innocuous function and then finding they had to deal with the requirements of buildinfo(). This big reorganisation introduces three new subdirectories called 'utils', one at the top level and one in each platform subdir. In each case, the directory contains basically the same files that were previously placed in the 'utils' build-time library, except that the ones that were extremely miscellaneous (misc.c, utils.c, uxmisc.c, winmisc.c, winmiscs.c, winutils.c) have been split up into much smaller pieces.
44 lines
1.6 KiB
C
44 lines
1.6 KiB
C
/*
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* If the OS provides it, call SetDefaultDllDirectories() to prevent
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* DLLs from being loaded from the directory containing our own
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* binary, and instead only load from system32.
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*
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* This is a protection against hijacking attacks, if someone runs
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* PuTTY directly from their web browser's download directory having
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* previously been enticed into clicking on an unwise link that
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* downloaded a malicious DLL to the same directory under one of
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* various magic names that seem to be things that standard Windows
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* DLLs delegate to.
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*
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* It shouldn't break deliberate loading of user-provided DLLs such as
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* GSSAPI providers, because those are specified by their full
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* pathname by the user-provided configuration.
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*/
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#include "putty.h"
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void dll_hijacking_protection(void)
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{
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static HMODULE kernel32_module;
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DECL_WINDOWS_FUNCTION(static, BOOL, SetDefaultDllDirectories, (DWORD));
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if (!kernel32_module) {
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kernel32_module = load_system32_dll("kernel32.dll");
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#if !HAVE_SETDEFAULTDLLDIRECTORIES
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/* For older Visual Studio, this function isn't available in
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* the header files to type-check */
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GET_WINDOWS_FUNCTION_NO_TYPECHECK(
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kernel32_module, SetDefaultDllDirectories);
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#else
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GET_WINDOWS_FUNCTION(kernel32_module, SetDefaultDllDirectories);
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#endif
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}
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if (p_SetDefaultDllDirectories) {
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/* LOAD_LIBRARY_SEARCH_SYSTEM32 and explicitly specified
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* directories only */
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p_SetDefaultDllDirectories(LOAD_LIBRARY_SEARCH_SYSTEM32 |
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LOAD_LIBRARY_SEARCH_USER_DIRS);
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}
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}
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