patch 9.0.2109: [security]: overflow in nv_z_get_count

Problem:  [security]: overflow in nv_z_get_count
Solution: break out, if count is too large

When getting the count for a normal z command, it may overflow for large
counts given. So verify, that we can safely store the result in a long.

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/normal.c

@@ -2562,7 +2562,14 @@ nv_z_get_count(cmdarg_T *cap, int *nchar_arg)
 	if (nchar == K_DEL || nchar == K_KDEL)
 	    n /= 10;
 	else if (VIM_ISDIGIT(nchar))
+	{
+	    if (n > LONG_MAX / 10)
+	    {
+		clearopbeep(cap->oap);
+		break;
+	    }
 	    n = n * 10 + (nchar - '0');
+	}
 	else if (nchar == CAR)
 	{
 #ifdef FEAT_GUI

src/testdir/test_normal.vim

@@ -4159,4 +4159,9 @@ func Test_normal33_g_cmd_nonblank()
   bw!
 endfunc
 
+func Test_normal34_zet_large()
+  " shouldn't cause overflow
+  norm! z9765405999999999999
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2109,
 /**/
     2108,
 /**/