usbip: tools: fix atoi() on non-null terminated string

Currently the call to atoi is being passed a single char string
that is not null terminated, so there is a potential read overrun
along the stack when parsing for an integer value.  Fix this by
instead using a 2 char string that is initialized to all zeros
to ensure that a 1 char read into the string is always terminated
with a \0.

Detected by cppcheck:
"Invalid atoi() argument nr 1. A nul-terminated string is required."

Fixes: 3391ba0 ("usbip: tools: Extract generic code to be shared with vudc backend")
Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

tools/usb/usbip/libsrc/usbip_host_common.c

@@ -43,7 +43,7 @@ static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
 	int size;
 	int fd;
 	int length;
-	char status;
+	char status[2] = { 0 };
 	int value = 0;
 
 	size = snprintf(status_attr_path, sizeof(status_attr_path),
@@ -61,14 +61,14 @@ static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
 		return -1;
 	}
 
-	length = read(fd, &status, 1);
+	length = read(fd, status, 1);
 	if (length < 0) {
 		err("error reading attribute %s", status_attr_path);
 		close(fd);
 		return -1;
 	}
 
-	value = atoi(&status);
+	value = atoi(status);
 
 	return value;
 }