lib/cmdline.c: fix get_options() overflow while parsing ranges

When using get_options() it's possible to specify a range of numbers,
like 1-100500.  The problem is that it doesn't track array size while
calling internally to get_range() which iterates over the range and
fills the memory with numbers.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ilya V. Matveychikov <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: milabs

lib/cmdline.c

@@ -23,14 +23,14 @@
  *	the values[M, M+1, ..., N] into the ints array in get_options.
  */
 
-static int get_range(char **str, int *pint)
+static int get_range(char **str, int *pint, int n)
 {
 	int x, inc_counter, upper_range;
 
 	(*str)++;
 	upper_range = simple_strtol((*str), NULL, 0);
 	inc_counter = upper_range - *pint;
-	for (x = *pint; x < upper_range; x++)
+	for (x = *pint; n && x < upper_range; x++, n--)
 		*pint++ = x;
 	return inc_counter;
 }
@@ -97,7 +97,7 @@ char *get_options(const char *str, int nints, int *ints)
 			break;
 		if (res == 3) {
 			int range_nums;
-			range_nums = get_range((char **)&str, ints + i);
+			range_nums = get_range((char **)&str, ints + i, nints - i);
 			if (range_nums < 0)
 				break;
 			/*