From: shuah <shuah@kernel.org>
To: "Liu, Changcheng" <changcheng.liu@intel.com>,
valentina.manea.m@gmail.com
Cc: linux-usb@vger.kernel.org, shuah <shuah@kernel.org>
Subject: Re: [PATCH v2] usbip: tools: fix GCC8 warning for strncpy
Date: Thu, 25 Jul 2019 08:19:19 -0600 [thread overview]
Message-ID: <2cac538b-3806-8b1f-9dce-34be9d862102@kernel.org> (raw)
In-Reply-To: <20190725132209.GA27590@jerryopenix>
On 7/25/19 7:22 AM, Liu, Changcheng wrote:
> GCC8 started emitting warning about using strncpy with number of bytes
> exactly equal destination size which could lead to non-zero terminated
> string being copied. Use "SYSFS_PATH_MAX - 1" & "SYSFS_BUS_ID_SIZE - 1"
> as number of bytes to ensure name is always zero-terminated.
>
> Signed-off-by: Changcheng Liu <changcheng.liu@aliyun.com>
> ---
> v1 -> v2:
> * Correct array tail index
> ---
> tools/usb/usbip/libsrc/usbip_common.c | 6 ++++--
> tools/usb/usbip/libsrc/usbip_device_driver.c | 6 ++++--
> 2 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
> index bb424638d75b..b8d7d480595a 100644
> --- a/tools/usb/usbip/libsrc/usbip_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_common.c
> @@ -226,8 +226,10 @@ int read_usb_device(struct udev_device *sdev, struct usbip_usb_device *udev)
> path = udev_device_get_syspath(sdev);
> name = udev_device_get_sysname(sdev);
>
> - strncpy(udev->path, path, SYSFS_PATH_MAX);
> - strncpy(udev->busid, name, SYSFS_BUS_ID_SIZE);
> + strncpy(udev->path, path, SYSFS_PATH_MAX - 1);
> + udev->path[SYSFS_PATH_MAX - 1] = '\0';
> + strncpy(udev->busid, name, SYSFS_BUS_ID_SIZE - 1);
> + udev->busid[SYSFS_BUS_ID_SIZE - 1] = '\0';
strlcpy() would be better choice here. Any reason to not use that?
>
> sscanf(name, "%u-%u", &busnum, &devnum);
> udev->busnum = busnum;
> diff --git a/tools/usb/usbip/libsrc/usbip_device_driver.c b/tools/usb/usbip/libsrc/usbip_device_driver.c
> index 5a3726eb44ab..051d7d3f443b 100644
> --- a/tools/usb/usbip/libsrc/usbip_device_driver.c
> +++ b/tools/usb/usbip/libsrc/usbip_device_driver.c
> @@ -91,7 +91,8 @@ int read_usb_vudc_device(struct udev_device *sdev, struct usbip_usb_device *dev)
> copy_descr_attr16(dev, &descr, idProduct);
> copy_descr_attr16(dev, &descr, bcdDevice);
>
> - strncpy(dev->path, path, SYSFS_PATH_MAX);
> + strncpy(dev->path, path, SYSFS_PATH_MAX - 1);
> + dev->path[SYSFS_PATH_MAX - 1] = '\0';
>
> dev->speed = USB_SPEED_UNKNOWN;
> speed = udev_device_get_sysattr_value(sdev, "current_speed");
> @@ -110,7 +111,8 @@ int read_usb_vudc_device(struct udev_device *sdev, struct usbip_usb_device *dev)
> dev->busnum = 0;
>
> name = udev_device_get_sysname(plat);
> - strncpy(dev->busid, name, SYSFS_BUS_ID_SIZE);
> + strncpy(dev->busid, name, SYSFS_BUS_ID_SIZE - 1);
> + dev->busid[SYSFS_BUS_ID_SIZE - 1] = '\0';
strlcpy() would be better choice here. Any reason to not use that?
> return 0;
> err:
> fclose(fd);
>
thanks,
-- Shuah
next prev parent reply other threads:[~2019-07-25 14:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 13:22 [PATCH v2] usbip: tools: fix GCC8 warning for strncpy Liu, Changcheng
2019-07-25 14:19 ` shuah [this message]
2019-07-25 14:44 ` Liu, Changcheng
2019-07-25 16:06 ` shuah
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