(SIZE_MAX) [!defined SIZE_MAX]: Define.

(error_tail): Do not loop, reallocating temporary buffer, since
the original size is big enough.  This avoids one potential size
overflow calculation.  Check for size overflow when calculating
temporary buffer size.  Free temporary buffer when done, if
it was allocated with malloc; this closes a memory leak.

diff --git a/lib/error.c b/lib/error.c
index e249942121ff5f83af7bf3a6173a3c6ab39de8d5..1c74a14febc0311b6e913b45ba005af904c22070 100644 (file)
--- a/lib/error.c
+++ b/lib/error.c
@@ -90,6 +90,10 @@ extern void __error_at_line (int status, int errnum, const char *file_name,
 char *strerror_r ();
 # endif
 
+#ifndef SIZE_MAX
+# define SIZE_MAX ((size_t) -1)
+#endif
+
 /* The calling program should define program_name and set it to the
    name of the executing program.  */
 extern char *program_name;
@@ -142,40 +146,27 @@ error_tail (int status, int errnum, const char *message, va_list args)
     {
 # define ALLOCA_LIMIT 2000
       size_t len = strlen (message) + 1;
-      wchar_t *wmessage = NULL;
+      const wchar_t *wmessage = L"out of memory";
       mbstate_t st;
       size_t res;
       const char *tmp;
+      wchar_t *wbuf = (len < ALLOCA_LIMIT
+                      ? (void *) alloca (len * sizeof *wbuf)
+                      : len <= SIZE_MAX / sizeof *wbuf
+                      ? malloc (len * sizeof *wbuf)
+                      : NULL);
 
-      do
+      if (wbuf)
        {
-         if (len < ALLOCA_LIMIT)
-           wmessage = (wchar_t *) alloca (len * sizeof (wchar_t));
-         else
-           {
-             if (wmessage != NULL && len / 2 < ALLOCA_LIMIT)
-               wmessage = NULL;
-
-             wmessage = (wchar_t *) realloc (wmessage,
-                                             len * sizeof (wchar_t));
-
-             if (wmessage == NULL)
-               {
-                 fputws_unlocked (L"out of memory\n", stderr);
-                 return;
-               }
-           }
-
          memset (&st, '\0', sizeof (st));
          tmp =message;
+         res = mbsrtowcs (wbuf, &tmp, len, &st);
+         wmessage = res == (size_t) -1 ? L"???" : wbuf;
        }
-      while ((res = mbsrtowcs (wmessage, &tmp, len, &st)) == len);
-
-      if (res == (size_t) -1)
-       /* The string cannot be converted.  */
-       wmessage = (wchar_t *) L"???";
 
       __vfwprintf (stderr, wmessage, args);
+      if (! (len < ALLOCA_LIMIT))
+       free (wbuf);
     }
   else
 #endif