[OpenMP][Tool] Fix buffer overflow in ompt-multiplex.h

[protze.joachim]

Summary

The code failed to allocate memory for the terminating 0-byte.

Reported by: @ronlieb

[ronlieb]

thanks for the quick response, lgtm.

[ronlieb]

LGTM, please commit

openmp/tools/multiplex/ompt-multiplex.h

 #endif
 #include <dlfcn.h>
 #include <execinfo.h>
 #include <inttypes.h>
 #include <omp-tools.h>
 #include <omp.h>
 #include <stdio.h>
 #include <string.h>
+#include <errno.h>
 
 static ompt_set_callback_t ompt_multiplex_set_callback;
 static ompt_get_task_info_t ompt_multiplex_get_task_info;
 static ompt_get_thread_data_t ompt_multiplex_get_thread_data;
 static ompt_get_parallel_info_t ompt_multiplex_get_parallel_info;
 
 // contains name of the environment var in which the tool path is specified
 #ifndef CLIENT_TOOL_LIBRARIES_VAR
ompt_start_tool_result_t *ompt_start_tool(unsigned int omp_version,
   // try loading client tool
   ompt_multiplex_client_fns = NULL;
   ompt_start_tool_result_t *(*client_start_tool)(unsigned int, const char *) =
       NULL;
 
   const char *tool_libs = getenv(CLIENT_TOOL_LIBRARIES_VAR);
   if (tool_libs) {
     // copy environement variable
-    char *tool_libs_buffer = (char *)malloc(sizeof(char) * strlen(tool_libs));
+    char *tool_libs_buffer = strdup(tool_libs);
     if (!tool_libs_buffer) {
-      printf("malloc Error\n");
+      printf("strdup Error (%i)\n", errno);
       exit(-1);
     }
-    strcpy(tool_libs_buffer, tool_libs);
 
     int progress = 0;
     while (progress < strlen(tool_libs)) {
       int tmp_progress = progress;
       while (tmp_progress < strlen(tool_libs) &&
              tool_libs_buffer[tmp_progress] != ':')
         tmp_progress++;
       if (tmp_progress < strlen(tool_libs))