1 //===-- sanitizer_win_dll_thunk.h -----------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 // This header provide helper macros to delegate calls to the shared runtime
9 // that lives in the main executable. It should be included to dll_thunks that
10 // will be linked to the dlls, when the sanitizer is a static library included
11 // in the main executable.
12 //===----------------------------------------------------------------------===//
13 #ifndef SANITIZER_WIN_DLL_THUNK_H
14 #define SANITIZER_WIN_DLL_THUNK_H
15 #include "sanitizer_internal_defs.h"
16 
17 namespace __sanitizer {
18 uptr dllThunkGetRealAddrOrDie(const char *name);
19 
20 int dllThunkIntercept(const char* main_function, uptr dll_function);
21 
22 int dllThunkInterceptWhenPossible(const char* main_function,
23     const char* default_function, uptr dll_function);
24 }
25 
26 extern "C" int __dll_thunk_init();
27 
28 // ----------------- Function interception helper macros -------------------- //
29 // Override dll_function with main_function from main executable.
30 #define INTERCEPT_OR_DIE(main_function, dll_function)                          \
31   static int intercept_##dll_function() {                                      \
32     return __sanitizer::dllThunkIntercept(main_function, (__sanitizer::uptr)   \
33         dll_function);                                                         \
34   }                                                                            \
35   __pragma(section(".DLLTH$M", long, read))                                    \
36   __declspec(allocate(".DLLTH$M")) int (*__dll_thunk_##dll_function)() =       \
37     intercept_##dll_function;
38 
39 // Try to override dll_function with main_function from main executable.
40 // If main_function is not present, override dll_function with default_function.
41 #define INTERCEPT_WHEN_POSSIBLE(main_function, default_function, dll_function) \
42   static int intercept_##dll_function() {                                      \
43     return __sanitizer::dllThunkInterceptWhenPossible(main_function,           \
44         default_function, (__sanitizer::uptr)dll_function);                    \
45   }                                                                            \
46   __pragma(section(".DLLTH$M", long, read))                                    \
47   __declspec(allocate(".DLLTH$M")) int (*__dll_thunk_##dll_function)() =       \
48     intercept_##dll_function;
49 
50 // -------------------- Function interception macros ------------------------ //
51 // Special case of hooks -- ASan own interface functions.  Those are only called
52 // after __asan_init, thus an empty implementation is sufficient.
53 #define INTERCEPT_SANITIZER_FUNCTION(name)                                     \
54   extern "C" __declspec(noinline) void name() {                                \
55     volatile int prevent_icf = (__LINE__ << 8) ^ __COUNTER__;                  \
56     static const char function_name[] = #name;                                 \
57     for (const char* ptr = &function_name[0]; *ptr; ++ptr)                     \
58       prevent_icf ^= *ptr;                                                     \
59     (void)prevent_icf;                                                         \
60     __debugbreak();                                                            \
61   }                                                                            \
62   INTERCEPT_OR_DIE(#name, name)
63 
64 // Special case of hooks -- Weak functions, could be redefined in the main
65 // executable, but that is not necessary, so we shouldn't die if we can not find
66 // a reference. Instead, when the function is not present in the main executable
67 // we consider the default impl provided by asan library.
68 #define INTERCEPT_SANITIZER_WEAK_FUNCTION(name)                                \
69   extern "C" __declspec(noinline) void name() {                                \
70     volatile int prevent_icf = (__LINE__ << 8) ^ __COUNTER__;                  \
71     static const char function_name[] = #name;                                 \
72     for (const char* ptr = &function_name[0]; *ptr; ++ptr)                     \
73       prevent_icf ^= *ptr;                                                     \
74     (void)prevent_icf;                                                         \
75     __debugbreak();                                                            \
76   }                                                                            \
77   INTERCEPT_WHEN_POSSIBLE(#name, STRINGIFY(WEAK_EXPORT_NAME(name)), name)
78 
79 // We can't define our own version of strlen etc. because that would lead to
80 // link-time or even type mismatch errors.  Instead, we can declare a function
81 // just to be able to get its address.  Me may miss the first few calls to the
82 // functions since it can be called before __dll_thunk_init, but that would lead
83 // to false negatives in the startup code before user's global initializers,
84 // which isn't a big deal.
85 #define INTERCEPT_LIBRARY_FUNCTION(name)                                       \
86   extern "C" void name();                                                      \
87   INTERCEPT_OR_DIE(WRAPPER_NAME(name), name)
88 
89 // Use these macros for functions that could be called before __dll_thunk_init()
90 // is executed and don't lead to errors if defined (free, malloc, etc).
91 #define INTERCEPT_WRAP_V_V(name)                                               \
92   extern "C" void name() {                                                     \
93     typedef decltype(name) *fntype;                                            \
94     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
95     fn();                                                                      \
96   }                                                                            \
97   INTERCEPT_OR_DIE(#name, name);
98 
99 #define INTERCEPT_WRAP_V_W(name)                                               \
100   extern "C" void name(void *arg) {                                            \
101     typedef decltype(name) *fntype;                                            \
102     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
103     fn(arg);                                                                   \
104   }                                                                            \
105   INTERCEPT_OR_DIE(#name, name);
106 
107 #define INTERCEPT_WRAP_V_WW(name)                                              \
108   extern "C" void name(void *arg1, void *arg2) {                               \
109     typedef decltype(name) *fntype;                                            \
110     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
111     fn(arg1, arg2);                                                            \
112   }                                                                            \
113   INTERCEPT_OR_DIE(#name, name);
114 
115 #define INTERCEPT_WRAP_V_WWW(name)                                             \
116   extern "C" void name(void *arg1, void *arg2, void *arg3) {                   \
117     typedef decltype(name) *fntype;                                            \
118     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
119     fn(arg1, arg2, arg3);                                                      \
120   }                                                                            \
121   INTERCEPT_OR_DIE(#name, name);
122 
123 #define INTERCEPT_WRAP_W_V(name)                                               \
124   extern "C" void *name() {                                                    \
125     typedef decltype(name) *fntype;                                            \
126     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
127     return fn();                                                               \
128   }                                                                            \
129   INTERCEPT_OR_DIE(#name, name);
130 
131 #define INTERCEPT_WRAP_W_W(name)                                               \
132   extern "C" void *name(void *arg) {                                           \
133     typedef decltype(name) *fntype;                                            \
134     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
135     return fn(arg);                                                            \
136   }                                                                            \
137   INTERCEPT_OR_DIE(#name, name);
138 
139 #define INTERCEPT_WRAP_W_WW(name)                                              \
140   extern "C" void *name(void *arg1, void *arg2) {                              \
141     typedef decltype(name) *fntype;                                            \
142     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
143     return fn(arg1, arg2);                                                     \
144   }                                                                            \
145   INTERCEPT_OR_DIE(#name, name);
146 
147 #define INTERCEPT_WRAP_W_WWW(name)                                             \
148   extern "C" void *name(void *arg1, void *arg2, void *arg3) {                  \
149     typedef decltype(name) *fntype;                                            \
150     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
151     return fn(arg1, arg2, arg3);                                               \
152   }                                                                            \
153   INTERCEPT_OR_DIE(#name, name);
154 
155 #define INTERCEPT_WRAP_W_WWWW(name)                                            \
156   extern "C" void *name(void *arg1, void *arg2, void *arg3, void *arg4) {      \
157     typedef decltype(name) *fntype;                                            \
158     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
159     return fn(arg1, arg2, arg3, arg4);                                         \
160   }                                                                            \
161   INTERCEPT_OR_DIE(#name, name);
162 
163 #define INTERCEPT_WRAP_W_WWWWW(name)                                           \
164   extern "C" void *name(void *arg1, void *arg2, void *arg3, void *arg4,        \
165                         void *arg5) {                                          \
166     typedef decltype(name) *fntype;                                            \
167     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
168     return fn(arg1, arg2, arg3, arg4, arg5);                                   \
169   }                                                                            \
170   INTERCEPT_OR_DIE(#name, name);
171 
172 #define INTERCEPT_WRAP_W_WWWWWW(name)                                          \
173   extern "C" void *name(void *arg1, void *arg2, void *arg3, void *arg4,        \
174                         void *arg5, void *arg6) {                              \
175     typedef decltype(name) *fntype;                                            \
176     static fntype fn = (fntype)__sanitizer::dllThunkGetRealAddrOrDie(#name);   \
177     return fn(arg1, arg2, arg3, arg4, arg5, arg6);                             \
178   }                                                                            \
179   INTERCEPT_OR_DIE(#name, name);
180 
181 #endif // SANITIZER_WIN_DLL_THUNK_H
182