4.17-stable review patch. If anyone has any objections, please let me know.
------------------ From: Daniel Rosenberg <[email protected]> commit 717adfdaf14704fd3ec7fa2c04520c0723247eac upstream. If our length is greater than the size of the buffer, we overflow the buffer Cc: [email protected] Signed-off-by: Daniel Rosenberg <[email protected]> Reviewed-by: Benjamin Tissoires <[email protected]> Signed-off-by: Jiri Kosina <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/hid/hid-debug.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -1154,6 +1154,8 @@ copy_rest: goto out; if (list->tail > list->head) { len = list->tail - list->head; + if (len > count) + len = count; if (copy_to_user(buffer + ret, &list->hid_debug_buf[list->head], len)) { ret = -EFAULT; @@ -1163,6 +1165,8 @@ copy_rest: list->head += len; } else { len = HID_DEBUG_BUFSIZE - list->head; + if (len > count) + len = count; if (copy_to_user(buffer, &list->hid_debug_buf[list->head], len)) { ret = -EFAULT; @@ -1170,7 +1174,9 @@ copy_rest: } list->head = 0; ret += len; - goto copy_rest; + count -= len; + if (count > 0) + goto copy_rest; } }
