A string written by the user may not be zero terminated. sscanf may read memory beyond the buffer if no zero byte is found. For testing build with CONFIG_USB_CHIPIDEA=y, CONFIG_USB_CHIPIDEA_DEBUG=y. Version 2: Use '\0' for char constant. Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx> --- drivers/usb/chipidea/debug.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/usb/chipidea/debug.c b/drivers/usb/chipidea/debug.c index dfb05ed..ef08af3 100644 --- a/drivers/usb/chipidea/debug.c +++ b/drivers/usb/chipidea/debug.c @@ -88,9 +88,13 @@ static ssize_t ci_port_test_write(struct file *file, const char __user *ubuf, char buf[32]; int ret; - if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count))) + count = min_t(size_t, sizeof(buf) - 1, count); + if (copy_from_user(buf, ubuf, count)) return -EFAULT; + /* sscanf requires a zero terminated string */ + buf[count] = '\0'; + if (sscanf(buf, "%u", &mode) != 1) return -EINVAL; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
