From: Krzysztof Opasiak <k.opasiak@samsung.com>
To: Jonathan Dieter <jdieter@lesbg.com>, linux-kernel@vger.kernel.org
Cc: Valentina Manea <valentina.manea.m@gmail.com>,
Shuah Khan <shuah@kernel.org>,
Peter Senna Tschudin <peter.senna@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"open list:USB OVER IP DRIVER" <linux-usb@vger.kernel.org>
Subject: Re: [PATCH 1/2] Fix format overflows
Date: Tue, 21 Feb 2017 07:12:27 +0100 [thread overview]
Message-ID: <ff9e6f1a-0590-449a-11b4-bc521b4b7953@samsung.com> (raw)
In-Reply-To: <20170220205129.18194-1-jdieter@lesbg.com>
Hi,
W dniu 2017-02-20 o 21:51, Jonathan Dieter pisze:
> The usbip userspace tools call sprintf()/snprintf() and don't check for
> the return value which can lead the paths to overflow, truncating the
> final file in the path.
>
> More urgently, GCC 7 now warns that these aren't checked with
> -Wformat-overflow, and with -Werror enabled in configure.ac, that makes
> these tools unbuildable.
>
> This patch fixes these problems by replacing sprintf() with snprintf() in
> one place and adding checks for the return value of snprintf().
>
> Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
> Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
> ---
> tools/usb/usbip/libsrc/usbip_common.c | 8 +++++++-
> tools/usb/usbip/libsrc/usbip_host_common.c | 25 ++++++++++++++++++++-----
> 2 files changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
> index ac73710..fc875ee 100644
> --- a/tools/usb/usbip/libsrc/usbip_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_common.c
> @@ -215,9 +215,15 @@ int read_usb_interface(struct usbip_usb_device *udev, int i,
> struct usbip_usb_interface *uinf)
> {
> char busid[SYSFS_BUS_ID_SIZE];
> + int size;
> struct udev_device *sif;
>
> - sprintf(busid, "%s:%d.%d", udev->busid, udev->bConfigurationValue, i);
> + size = snprintf(busid, SYSFS_BUS_ID_SIZE, "%s:%d.%d",
why not sizeof(busid)?
> + udev->busid, udev->bConfigurationValue, i);
> + if (size >= SYSFS_BUS_ID_SIZE) {
As above.
> + err("busid length %i >= SYSFS_BUS_ID_SIZE", size);
> + return -1;
> + }
>
> sif = udev_device_new_from_subsystem_sysname(udev_context, "usb", busid);
> if (!sif) {
> diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
> index 9d41522..690cd49 100644
> --- a/tools/usb/usbip/libsrc/usbip_host_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_host_common.c
> @@ -40,13 +40,19 @@ struct udev *udev_context;
> static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
> {
> char status_attr_path[SYSFS_PATH_MAX];
> + int size;
> int fd;
> int length;
> char status;
> int value = 0;
>
> - snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
> - udev->path);
> + size = snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
The same here.
> + udev->path);
> + if (size >= SYSFS_PATH_MAX) {
> + err("usbip_status path length %i >= SYSFS_PATH_MAX", size);
> + return -1;
> + }
> +
>
> fd = open(status_attr_path, O_RDONLY);
> if (fd < 0) {
> @@ -218,6 +224,7 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
> {
> char attr_name[] = "usbip_sockfd";
> char sockfd_attr_path[SYSFS_PATH_MAX];
> + int size;
> char sockfd_buff[30];
> int ret;
>
> @@ -237,10 +244,18 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
> }
>
> /* only the first interface is true */
> - snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
> - edev->udev.path, attr_name);
> + size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
> + edev->udev.path, attr_name);
> + if (size >= SYSFS_PATH_MAX) {
hmmm this should be sizeof(sockfd_attr_path) not SYSFS_PATH_MAX
> + err("exported device path length %i >= SYSFS_PATH_MAX", size);
> + return -1;
> + }
>
> - snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
> + size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
> + if (size >= 30) {
Please don't hardcode such values in if. use sizeof() like one line above
> + err("socket length %i >= 30", size);
> + return -1;
> + }
>
> ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
> strlen(sockfd_buff));
>
Best regards,
--
Krzysztof Opasiak
Samsung R&D Institute Poland
Samsung Electronics
next prev parent reply other threads:[~2017-02-21 6:13 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20170220205937epcas3p4e334a658cf4d67f4a7d5a4ae7ce10afc@epcas3p4.samsung.com>
2017-02-20 20:51 ` [PATCH 1/2] Fix format overflows Jonathan Dieter
2017-02-20 20:51 ` [PATCH 2/2] Fix implicit fallthrough warning Jonathan Dieter
2017-02-21 6:12 ` Krzysztof Opasiak [this message]
2017-02-21 6:48 ` [PATCH 1/2] Fix format overflows Jonathan Dieter
2017-02-21 17:50 ` Jonathan Dieter
2017-02-21 17:57 ` [PATCH v2 1/2] usbip: Fix-format-overflow Jonathan Dieter
2017-02-21 17:57 ` [PATCH v2 2/2] usbip: Fix implicit fallthrough warning Jonathan Dieter
2017-02-22 5:49 ` [PATCH v2 1/2] usbip: Fix-format-overflow Krzysztof Opasiak
2017-02-22 18:14 ` Jonathan Dieter
2017-02-22 18:17 ` [PATCH v3 " Jonathan Dieter
2017-02-22 18:18 ` [PATCH v3 2/2] usbip: Fix implicit fallthrough warning Jonathan Dieter
2017-02-27 8:31 ` [PATCH v4 1/2] usbip: Fix-format-overflow Jonathan Dieter
2017-02-27 8:31 ` [PATCH v4 2/2] usbip: Fix implicit fallthrough warning Jonathan Dieter
2017-03-16 7:47 ` [PATCH v4 1/2] usbip: Fix-format-overflow Jonathan Dieter
2017-03-16 15:04 ` Shuah Khan
2017-03-17 1:37 ` Greg Kroah-Hartman
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