Dump stack if memwipe() check fails

diff --git a/src/libstrongswan/library.c b/src/libstrongswan/library.c
index 4dec612030e296d157f1b9c8d790daf8314e85d3..170bc9f4b83e17130a093e9019ca37a45de27e5b 100644 (file)
--- a/src/libstrongswan/library.c
+++ b/src/libstrongswan/library.c
@@ -150,13 +150,23 @@ static bool equals(char *a, char *b)
        return streq(a, b);
 }
 
+/**
+ * Number of words we write and memwipe() in memwipe check
+ */
+#define MEMWIPE_WIPE_WORDS 16
+
+/**
+ * Number of words we check stack for memwiped magic
+ */
+#define MEMWIPE_CHECK_WORDS (MEMWIPE_WIPE_WORDS * 2)
+
 /**
  * Write magic to memory, and try to clear it with memwipe()
  */
 __attribute__((noinline))
 static void do_magic(int magic, int **stack)
 {
-       int buf[32], i;
+       int buf[MEMWIPE_WIPE_WORDS], i;
 
        /* tell caller where callee stack is (but don't point to buf) */
        *stack = &i;
@@ -184,11 +194,18 @@ static bool check_memwipe()
        {       /* stack grows down */
                stackdir = -1;
        }
-       for (i = 0; i < 128; i++)
+       for (i = 0; i < MEMWIPE_CHECK_WORDS; i++)
        {
                ptr = ptr + stackdir;
                if (*ptr == magic)
                {
+                       ptr = &magic + stackdir;
+                       if (stackdir == -1)
+                       {
+                               ptr -= MEMWIPE_CHECK_WORDS;
+                       }
+                       DBG1(DBG_LIB, "memwipe() check failed: stackdir: %d %b",
+                                stackdir, ptr, (u_int)(MEMWIPE_CHECK_WORDS * sizeof(int)));
                        return FALSE;
                }
        }
@@ -268,7 +285,6 @@ bool library_init(char *settings)
 
        if (!check_memwipe())
        {
-               DBG1(DBG_LIB, "memwipe() check failed");
                return FALSE;
        }