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.g...@gmx.de>
---
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
--
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