[PATCH 4.4 03/26] lib/cmdline.c: fix get_options() overflow while parsing ranges

Greg Kroah-Hartman
2017-06-27T12:52:31Z

From: Ilya Matveychikov <matvejchikov@gmail.com>

commit a91e0f680bcd9e10c253ae8b62462a38bd48f09f upstream.

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/2613C75C-B04D-4BFF-82A6-12F97BA0F620@gmail.com
Signed-off-by: Ilya V. Matveychikov <matvejchikov@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
lib/cmdline.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -22,14 +22,14 @@
* 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;
}
@@ -96,7 +96,7 @@ char *get_options(const char *str, int n
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;
/*