No C++ exceptions from cpu probe functions. See GH #920

3 files changed, 11 insertions, 30 deletions

diff --git a/src/lib/utils/os_utils.cpp b/src/lib/utils/os_utils.cpp
index fc401c3c1..fe45ad82f 100644
--- a/src/lib/utils/os_utils.cpp
+++ b/src/lib/utils/os_utils.cpp
@@ -360,26 +360,17 @@ int OS::run_cpu_instruction_probe(std::function<int ()> probe_fn)
    if(rc != 0)
       throw Exception("run_cpu_instruction_probe sigaction failed");
 
-   try
-      {
-      rc = ::sigsetjmp(g_sigill_jmp_buf, /*save sigs*/1);
+   rc = ::sigsetjmp(g_sigill_jmp_buf, /*save sigs*/1);
 
-      if(rc == 0)
-         {
-         // first call to sigsetjmp
-         probe_result = probe_fn();
-         }
-      else if(rc == 1)
-         {
-         // non-local return from siglongjmp in signal handler: return error
-         probe_result = -1;
-         }
-      else
-         throw Exception("run_cpu_instruction_probe unexpected sigsetjmp return value");
+   if(rc == 0)
+      {
+      // first call to sigsetjmp
+      probe_result = probe_fn();
       }
-   catch(...)
+   else if(rc == 1)
       {
-      probe_result = -2;
+      // non-local return from siglongjmp in signal handler: return error
+      probe_result = -1;
       }
 
    // Restore old SIGILL handler, if any
@@ -392,14 +383,7 @@ int OS::run_cpu_instruction_probe(std::function<int ()> probe_fn)
    // Windows SEH
    __try
       {
-      try
-         {
-         probe_result = probe_fn();
-         }
-      catch(...)
-         {
-         probe_result = -2;
-         }
+      probe_result = probe_fn();
       }
    __except(::GetExceptionCode() == EXCEPTION_ILLEGAL_INSTRUCTION ?
             EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH)
diff --git a/src/lib/utils/os_utils.h b/src/lib/utils/os_utils.h
index a1693bcc5..cae1192f1 100644
--- a/src/lib/utils/os_utils.h
+++ b/src/lib/utils/os_utils.h
@@ -98,9 +98,10 @@ void free_locked_pages(void* ptr, size_t length);
 * thread safe. It should only be called in a single-threaded context
 * (ie, at static init time).
 *
+* If probe_fn throws an exception the result is undefined.
+*
 * Return codes:
 * -1 illegal instruction detected
-* -2 exception thrown
 */
 int BOTAN_DLL run_cpu_instruction_probe(std::function<int ()> probe_fn);
 
diff --git a/src/tests/test_os_utils.cpp b/src/tests/test_os_utils.cpp
index 58858a4c2..d779f41de 100644
--- a/src/tests/test_os_utils.cpp
+++ b/src/tests/test_os_utils.cpp
@@ -146,10 +146,6 @@ class OS_Utils_Tests : public Test
 
          result.confirm("Correct result returned by working probe fn", run_rc == 5);
 
-         std::function<int ()> throw_fn = []() -> int { throw 3.14159; return 5; };
-         const int throw_rc = Botan::OS::run_cpu_instruction_probe(throw_fn);
-         result.confirm("Error return if probe function threw exception", throw_rc < 0);
-
          std::function<int ()> crash_probe;
 
 #if defined(BOTAN_TARGET_COMPILER_IS_MSVC)