Don't decrement an unsigned zero value below zero.

In fact, don't waste time incrementing the pointer or decrementing the
count until we know that we're going to go through another trip through
the loop.  (This isn't a PDP-11 and probably isn't a VAX or 68k, so *p++
isn't going to be done by an addressing mode.)

This should fix an undefined-behavior warning.

diff --git a/print-isakmp.c b/print-isakmp.c
index ba12f912d0998205b8cb578f2f84d9887d1c10f4..af7e7b654f0f860802d318ee46c3048d44260173 100644 (file)
--- a/print-isakmp.c
+++ b/print-isakmp.c
@@ -741,9 +741,11 @@ static const char *etypestr[] = {
 static int
 iszero(const u_char *p, size_t l)
 {
-       while (l--) {
-               if (*p++)
+       while (l != 0) {
+               if (*p)
                        return 0;
+               p++;
+               l--;
        }
        return 1;
 }