usb: chipidea: debug: avoid out of bound read

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.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
This commit is contained in:
Heinrich Schuchardt 2015-04-28 19:30:47 +02:00 коммит произвёл Peter Chen
Родитель 0d3bba0287
Коммит bd5fb0aec3
1 изменённых файлов: 5 добавлений и 1 удалений

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@ -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;