/src/yara/libyara/exception.h

Source (jump to first uncovered line)
/*
Copyright (c) 2015. The YARA Authors. All Rights Reserved.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors
may be used to endorse or promote products derived from this software without
specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef YR_EXCEPTION_H
#define YR_EXCEPTION_H

#include <assert.h>
#include <yara/globals.h>

typedef struct {
  void* memfault_from;
  void* memfault_to;
  void* jump_back;
} jumpinfo;


#if _WIN32 || __CYGWIN__

#include <windows.h>

// If compiling with Microsoft's compiler use structured exception handling.

#ifdef _MSC_VER

#include <excpt.h>

static LONG CALLBACK exception_handler(PEXCEPTION_POINTERS ExceptionInfo)
{
  switch (ExceptionInfo->ExceptionRecord->ExceptionCode)
  {
  case EXCEPTION_IN_PAGE_ERROR:
  case EXCEPTION_ACCESS_VIOLATION:
    return EXCEPTION_EXECUTE_HANDLER;
  }

  return EXCEPTION_CONTINUE_SEARCH;
}

#define YR_TRYCATCH(_do_, _try_clause_, _catch_clause_)       \
  do                                                          \
  {                                                           \
    if (_do_)                                                 \
    {                                                         \
      __try                                                   \
      {                                                       \
        _try_clause_                                          \
      }                                                       \
      __except (exception_handler(GetExceptionInformation())) \
      {                                                       \
        _catch_clause_                                        \
      }                                                       \
    }                                                         \
    else                                                      \
    {                                                         \
      _try_clause_                                            \
    }                                                         \
  } while (0)

#else

// If not compiling with Microsoft's compiler use vectored exception handling.

#include <setjmp.h>

static LONG CALLBACK exception_handler(PEXCEPTION_POINTERS ExceptionInfo)
{
  jumpinfo* jump_info;

  switch (ExceptionInfo->ExceptionRecord->ExceptionCode)
  {
  case EXCEPTION_IN_PAGE_ERROR:
    jump_info =
        (jumpinfo*) yr_thread_storage_get_value(&yr_trycatch_trampoline_tls);

    if (jump_info != NULL)
    {
      void* fault_address = (void*) ExceptionInfo->ExceptionRecord->ExceptionInformation[1];
      if (jump_info->memfault_from <= fault_address && jump_info->memfault_to > fault_address)
      {
        longjmp(*(jmp_buf*)jump_info->jump_back, 1);
      }
    }
  }

  return EXCEPTION_CONTINUE_SEARCH;
}

#define YR_TRYCATCH(_do_, _try_clause_, _catch_clause_)                      \
  do                                                                         \
  {                                                                          \
    if (_do_)                                                                \
    {                                                                        \
      jumpinfo jump_info;                                                    \
      jump_info.memfault_from = 0;                                           \
      jump_info.memfault_to = 0;                                             \
      jmp_buf jb;                                                            \
      jump_info.jump_back = (void*) &jb;                                     \
      /* Store pointer to sigjmp_buf in TLS */                               \
      yr_thread_storage_set_value(&yr_trycatch_trampoline_tls, &jump_info);  \
      HANDLE exh = AddVectoredExceptionHandler(1, exception_handler);        \
      if (setjmp(jb) == 0)                                                   \
      {                                                                      \
        _try_clause_                                                         \
      }                                                                      \
      else                                                                   \
      {                                                                      \
        _catch_clause_                                                       \
      }                                                                      \
      RemoveVectoredExceptionHandler(exh);                                   \
      yr_thread_storage_set_value(&yr_trycatch_trampoline_tls, NULL);        \
    }                                                                        \
    else                                                                     \
    {                                                                        \
      _try_clause_                                                           \
    }                                                                        \
  } while (0)

#endif

#else

#if defined(__APPLE__) || defined(__linux__) || defined(_AIX)
#define CATCH_SIGSEGV 0
#define CATCH_SIGBUS 1
#elif defined(BSD)
// According to #551, older BSD versions use SIGSEGV for invalid mmap access.
// Newer versions, however, use SIGBUS (tested with FreeBSD 13.2 / OpenBSD 7.4).
// To be compatible with both, catch SIGBUS and SIGSEGV.
#define CATCH_SIGSEGV 1
#define CATCH_SIGBUS 1
#else // For unknown systems, play it safe by catching both
#define CATCH_SIGSEGV 1
#define CATCH_SIGBUS 1
#endif

#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <yara/globals.h>

static void exception_handler(int sig, siginfo_t * info, void *context)
{
  if (sig != SIGBUS && sig != SIGSEGV)
  {
    return;
  }
  jumpinfo* jump_info = (jumpinfo*) yr_thread_storage_get_value(&yr_trycatch_trampoline_tls);

  if (jump_info != NULL)
  {
    void* fault_address = (void*) info->si_addr;
    if (jump_info->memfault_from <= fault_address && jump_info->memfault_to > fault_address)
    {
      siglongjmp(*(sigjmp_buf*)jump_info->jump_back, 1);
    }
  }

  // If we're here, the signal we received didn't originate from YARA.
  // In this case, we want to invoke the original signal handler, which may handle the signal.

  // Lock the exception handler mutex to prevent simultaneous write access while we read the old signal handler
  pthread_mutex_lock(&exception_handler_mutex);
  struct sigaction old_handler;
  if (sig == SIGBUS)
    old_handler = old_sigbus_exception_handler;
  else
    old_handler = old_sigsegv_exception_handler;
  pthread_mutex_unlock(&exception_handler_mutex);

  if (old_handler.sa_flags & SA_SIGINFO)
  {
    old_handler.sa_sigaction(sig, info, context);
  }
  else if (old_handler.sa_handler == SIG_DFL)
  {
    // Old handler is the default action. To do this, set the signal handler back to default and raise the signal.
    // This is fairly volatile - since this is not an atomic operation, signals from other threads might also
    // cause the default action while we're doing this. However, the default action will typically cause a
    // process termination anyway.
    pthread_mutex_lock(&exception_handler_mutex);
    struct sigaction current_handler;
    sigaction(sig, &old_handler, &current_handler);
    raise(sig);
    sigaction(sig, &current_handler, NULL);
    pthread_mutex_unlock(&exception_handler_mutex);
  }
  else if (old_handler.sa_handler == SIG_IGN)
  {
    // SIG_IGN wants us to ignore the signal
    return;
  }
  else
  {
    old_handler.sa_handler(sig);
  }
}

// Keep debug output indentation level consistent
#if 0 == YR_DEBUG_VERBOSITY
#define YR_DEBUG_INDENT_INITIAL 0
#define YR_DEBUG_INDENT_SET(x)  ;
#else
extern YR_TLS int yr_debug_indent;
// Ugly, but unfortunately cannot use ifdef macros inside a macro
#define YR_DEBUG_INDENT_INITIAL yr_debug_indent
#define YR_DEBUG_INDENT_SET(x)  yr_debug_indent = (x);

#endif

typedef struct sigaction sa;

#define YR_TRYCATCH(_do_, _try_clause_, _catch_clause_)               \
  do                                                                  \
  {                                                                   \
    if (_do_)                                                         \
    {                                                                 \
      pthread_mutex_lock(&exception_handler_mutex);                   \
      if (exception_handler_usecount == 0)                            \
      {                                                               \
        struct sigaction act;                                         \
        /* Set exception handler for SIGSEGV / SIGBUS */              \
        act.sa_sigaction = exception_handler;                         \
        act.sa_flags = SA_SIGINFO | SA_ONSTACK;                       \
        sigfillset(&act.sa_mask);                                     \
        if (CATCH_SIGBUS)                                             \
          sigaction(SIGBUS, &act, &old_sigbus_exception_handler);     \
        if (CATCH_SIGSEGV)                                            \
          sigaction(SIGSEGV, &act, &old_sigsegv_exception_handler);   \
      }                                                               \
      exception_handler_usecount++;                                   \
      pthread_mutex_unlock(&exception_handler_mutex);                 \
      /* Save the current debug indentation level before the jump. */ \
      int yr_debug_indent_before_jump = YR_DEBUG_INDENT_INITIAL;      \
      jumpinfo ji;                                                    \
      ji.memfault_from = 0;                                           \
      ji.memfault_to = 0;                                             \
      sigjmp_buf jb;                                                  \
      ji.jump_back = (void*) &jb;                                     \
      /* Store pointer to jumpinfo in TLS */                          \
      yr_thread_storage_set_value(&yr_trycatch_trampoline_tls, &ji);  \
      if (sigsetjmp(jb, 1) == 0)                                      \
      {                                                               \
        _try_clause_                                                  \
      }                                                               \
      else                                                            \
      {                                                               \
        /* Restore debug output indentation in case of failure */     \
        YR_DEBUG_INDENT_SET(yr_debug_indent_before_jump);             \
                                                                      \
        _catch_clause_                                                \
      }                                                               \
      pthread_mutex_lock(&exception_handler_mutex);                   \
      exception_handler_usecount--;                                   \
      if (exception_handler_usecount == 0)                            \
      {                                                               \
        /* Stop capturing relevant signals */                         \
        if (CATCH_SIGBUS)                                             \
          sigaction(SIGBUS, &old_sigbus_exception_handler, NULL);     \
        if (CATCH_SIGSEGV)                                            \
          sigaction(SIGSEGV, &old_sigsegv_exception_handler, NULL);   \
      }                                                               \
      pthread_mutex_unlock(&exception_handler_mutex);                 \
      yr_thread_storage_set_value(&yr_trycatch_trampoline_tls, NULL); \
    }                                                                 \
    else                                                              \
    {                                                                 \
      _try_clause_                                                    \
    }                                                                 \
  } while (0)

#endif

#endif

Coverage Report

Created: 2025-07-11 06:08

Line	Count	Source (jump to first uncovered line)
1		/*
2		Copyright (c) 2015. The YARA Authors. All Rights Reserved.
3
4		Redistribution and use in source and binary forms, with or without modification,
5		are permitted provided that the following conditions are met:
6
7		1. Redistributions of source code must retain the above copyright notice, this
8		list of conditions and the following disclaimer.
9
10		2. Redistributions in binary form must reproduce the above copyright notice,
11		this list of conditions and the following disclaimer in the documentation and/or
12		other materials provided with the distribution.
13
14		3. Neither the name of the copyright holder nor the names of its contributors
15		may be used to endorse or promote products derived from this software without
16		specific prior written permission.
17
18		THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
19		ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20		WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21		DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
22		ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23		(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24		LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
25		ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26		(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
27		SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28		*/
29
30		#ifndef YR_EXCEPTION_H
31		#define YR_EXCEPTION_H
32
33		#include <assert.h>
34		#include <yara/globals.h>
35
36		typedef struct {
37		void* memfault_from;
38		void* memfault_to;
39		void* jump_back;
40		} jumpinfo;
41
42
43		#if _WIN32 \|\| __CYGWIN__
44
45		#include <windows.h>
46
47		// If compiling with Microsoft's compiler use structured exception handling.
48
49		#ifdef _MSC_VER
50
51		#include <excpt.h>
52
53		static LONG CALLBACK exception_handler(PEXCEPTION_POINTERS ExceptionInfo)
54		{
55		switch (ExceptionInfo->ExceptionRecord->ExceptionCode)
56		{
57		case EXCEPTION_IN_PAGE_ERROR:
58		case EXCEPTION_ACCESS_VIOLATION:
59		return EXCEPTION_EXECUTE_HANDLER;
60		}
61
62		return EXCEPTION_CONTINUE_SEARCH;
63		}
64
65		#define YR_TRYCATCH(_do_, _try_clause_, _catch_clause_) \
66		do \
67		{ \
68		if (_do_) \
69		{ \
70		__try \
71		{ \
72		_try_clause_ \
73		} \
74		__except (exception_handler(GetExceptionInformation())) \
75		{ \
76		_catch_clause_ \
77		} \
78		} \
79		else \
80		{ \
81		_try_clause_ \
82		} \
83		} while (0)
84
85		#else
86
87		// If not compiling with Microsoft's compiler use vectored exception handling.
88
89		#include <setjmp.h>
90
91		static LONG CALLBACK exception_handler(PEXCEPTION_POINTERS ExceptionInfo)
92		{
93		jumpinfo* jump_info;
94
95		switch (ExceptionInfo->ExceptionRecord->ExceptionCode)
96		{
97		case EXCEPTION_IN_PAGE_ERROR:
98		jump_info =
99		(jumpinfo*) yr_thread_storage_get_value(&yr_trycatch_trampoline_tls);
100
101		if (jump_info != NULL)
102		{
103		void* fault_address = (void*) ExceptionInfo->ExceptionRecord->ExceptionInformation[1];
104		if (jump_info->memfault_from <= fault_address && jump_info->memfault_to > fault_address)
105		{
106		longjmp((jmp_buf)jump_info->jump_back, 1);
107		}
108		}
109		}
110
111		return EXCEPTION_CONTINUE_SEARCH;
112		}
113
114		#define YR_TRYCATCH(_do_, _try_clause_, _catch_clause_) \
115		do \
116		{ \
117		if (_do_) \
118		{ \
119		jumpinfo jump_info; \
120		jump_info.memfault_from = 0; \
121		jump_info.memfault_to = 0; \
122		jmp_buf jb; \
123		jump_info.jump_back = (void*) &jb; \
124		/* Store pointer to sigjmp_buf in TLS */ \
125		yr_thread_storage_set_value(&yr_trycatch_trampoline_tls, &jump_info); \
126		HANDLE exh = AddVectoredExceptionHandler(1, exception_handler); \
127		if (setjmp(jb) == 0) \
128		{ \
129		_try_clause_ \
130		} \
131		else \
132		{ \
133		_catch_clause_ \
134		} \
135		RemoveVectoredExceptionHandler(exh); \
136		yr_thread_storage_set_value(&yr_trycatch_trampoline_tls, NULL); \
137		} \
138		else \
139		{ \
140		_try_clause_ \
141		} \
142		} while (0)
143
144		#endif
145
146		#else
147
148		#if defined(__APPLE__) \|\| defined(__linux__) \|\| defined(_AIX)
149	0	#define CATCH_SIGSEGV 0
150	0	#define CATCH_SIGBUS 1
151		#elif defined(BSD)
152		// According to #551, older BSD versions use SIGSEGV for invalid mmap access.
153		// Newer versions, however, use SIGBUS (tested with FreeBSD 13.2 / OpenBSD 7.4).
154		// To be compatible with both, catch SIGBUS and SIGSEGV.
155		#define CATCH_SIGSEGV 1
156		#define CATCH_SIGBUS 1
157		#else // For unknown systems, play it safe by catching both
158		#define CATCH_SIGSEGV 1
159		#define CATCH_SIGBUS 1
160		#endif
161
162		#include <pthread.h>
163		#include <setjmp.h>
164		#include <signal.h>
165		#include <yara/globals.h>
166
167		static void exception_handler(int sig, siginfo_t * info, void *context)
168	0	{
169	0	if (sig != SIGBUS && sig != SIGSEGV)
170	0	{
171	0	return;
172	0	}
173	0	jumpinfo* jump_info = (jumpinfo*) yr_thread_storage_get_value(&yr_trycatch_trampoline_tls);
174
175	0	if (jump_info != NULL)
176	0	{
177	0	void* fault_address = (void*) info->si_addr;
178	0	if (jump_info->memfault_from <= fault_address && jump_info->memfault_to > fault_address)
179	0	{
180	0	siglongjmp((sigjmp_buf)jump_info->jump_back, 1);
181	0	}
182	0	}
183
184		// If we're here, the signal we received didn't originate from YARA.
185		// In this case, we want to invoke the original signal handler, which may handle the signal.
186
187		// Lock the exception handler mutex to prevent simultaneous write access while we read the old signal handler
188	0	pthread_mutex_lock(&exception_handler_mutex);
189	0	struct sigaction old_handler;
190	0	if (sig == SIGBUS)
191	0	old_handler = old_sigbus_exception_handler;
192	0	else
193	0	old_handler = old_sigsegv_exception_handler;
194	0	pthread_mutex_unlock(&exception_handler_mutex);
195
196	0	if (old_handler.sa_flags & SA_SIGINFO)
197	0	{
198	0	old_handler.sa_sigaction(sig, info, context);
199	0	}
200	0	else if (old_handler.sa_handler == SIG_DFL)
201	0	{
202		// Old handler is the default action. To do this, set the signal handler back to default and raise the signal.
203		// This is fairly volatile - since this is not an atomic operation, signals from other threads might also
204		// cause the default action while we're doing this. However, the default action will typically cause a
205		// process termination anyway.
206	0	pthread_mutex_lock(&exception_handler_mutex);
207	0	struct sigaction current_handler;
208	0	sigaction(sig, &old_handler, &current_handler);
209	0	raise(sig);
210	0	sigaction(sig, &current_handler, NULL);
211	0	pthread_mutex_unlock(&exception_handler_mutex);
212	0	}
213	0	else if (old_handler.sa_handler == SIG_IGN)
214	0	{
215		// SIG_IGN wants us to ignore the signal
216	0	return;
217	0	}
218	0	else
219	0	{
220	0	old_handler.sa_handler(sig);
221	0	}
222	0	} Unexecuted instantiation: scanner.c:exception_handler Unexecuted instantiation: elf.c:exception_handler
223
224		// Keep debug output indentation level consistent
225		#if 0 == YR_DEBUG_VERBOSITY
226	0	#define YR_DEBUG_INDENT_INITIAL 0
227	0	#define YR_DEBUG_INDENT_SET(x) ;
228		#else
229		extern YR_TLS int yr_debug_indent;
230		// Ugly, but unfortunately cannot use ifdef macros inside a macro
231		#define YR_DEBUG_INDENT_INITIAL yr_debug_indent
232		#define YR_DEBUG_INDENT_SET(x) yr_debug_indent = (x);
233
234		#endif
235
236		typedef struct sigaction sa;
237
238		#define YR_TRYCATCH(_do_, _try_clause_, _catch_clause_) \
239	8.54k	do \
240	8.54k	{ \
241	8.54k	if (_do_) \
242	8.54k	{ \
243	0	pthread_mutex_lock(&exception_handler_mutex); \
244	0	if (exception_handler_usecount == 0) \
245	0	{ \
246	0	struct sigaction act; \
247	0	/* Set exception handler for SIGSEGV / SIGBUS */ \
248	0	act.sa_sigaction = exception_handler; \
249	0	act.sa_flags = SA_SIGINFO \| SA_ONSTACK; \
250	0	sigfillset(&act.sa_mask); \
251	0	if (CATCH_SIGBUS) \
252	0	sigaction(SIGBUS, &act, &old_sigbus_exception_handler); \
253	0	if (CATCH_SIGSEGV) \
254	0	sigaction(SIGSEGV, &act, &old_sigsegv_exception_handler); \
255	0	} \
256	0	exception_handler_usecount++; \
257	0	pthread_mutex_unlock(&exception_handler_mutex); \
258	0	/* Save the current debug indentation level before the jump. */ \
259	0	int yr_debug_indent_before_jump = YR_DEBUG_INDENT_INITIAL; \
260	0	jumpinfo ji; \
261	0	ji.memfault_from = 0; \
262	0	ji.memfault_to = 0; \
263	0	sigjmp_buf jb; \
264	0	ji.jump_back = (void*) &jb; \
265	0	/* Store pointer to jumpinfo in TLS */ \
266	0	yr_thread_storage_set_value(&yr_trycatch_trampoline_tls, &ji); \
267	0	if (sigsetjmp(jb, 1) == 0) \
268	0	{ \
269	0	_try_clause_ \
270	0	} \
271	0	else \
272	0	{ \
273	0	/* Restore debug output indentation in case of failure */ \
274	0	YR_DEBUG_INDENT_SET(yr_debug_indent_before_jump); \
275	0	\
276	0	_catch_clause_ \
277	0	} \
278	0	pthread_mutex_lock(&exception_handler_mutex); \
279	0	exception_handler_usecount--; \
280	0	if (exception_handler_usecount == 0) \
281	0	{ \
282	0	/* Stop capturing relevant signals */ \
283	0	if (CATCH_SIGBUS) \
284	0	sigaction(SIGBUS, &old_sigbus_exception_handler, NULL); \
285	0	if (CATCH_SIGSEGV) \
286	0	sigaction(SIGSEGV, &old_sigsegv_exception_handler, NULL); \
287	0	} \
288	0	pthread_mutex_unlock(&exception_handler_mutex); \
289	0	yr_thread_storage_set_value(&yr_trycatch_trampoline_tls, NULL); \
290	0	} \
291	8.54k	else \
292	8.54k	{ \
293	47.0k	_try_clause_ \
294	8.54k	} \
295	8.54k	} while (0)
296
297		#endif
298
299		#endif