| Message ID | 20200925163008.39727-2-william.gray@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [SRU,F/B,CVE-2020-25284,v2,1/1] rbd: require global CAP_SYS_ADMIN for mapping and unmapping | expand |
This patch was applied in the following patchset:
Focal update: v5.4.66 upstream stable release
https://bugs.launchpad.net/bugs/1896824
Thanks!
Ian
On 2020-09-25 12:30:07 , William Breathitt Gray wrote:
> From: Ilya Dryomov <idryomov@gmail.com>
>
> It turns out that currently we rely only on sysfs attribute
> permissions:
>
> $ ll /sys/bus/rbd/{add*,remove*}
> --w------- 1 root root 4096 Sep 3 20:37 /sys/bus/rbd/add
> --w------- 1 root root 4096 Sep 3 20:37 /sys/bus/rbd/add_single_major
> --w------- 1 root root 4096 Sep 3 20:37 /sys/bus/rbd/remove
> --w------- 1 root root 4096 Sep 3 20:38 /sys/bus/rbd/remove_single_major
>
> This means that images can be mapped and unmapped (i.e. block devices
> can be created and deleted) by a UID 0 process even after it drops all
> privileges or by any process with CAP_DAC_OVERRIDE in its user namespace
> as long as UID 0 is mapped into that user namespace.
>
> Be consistent with other virtual block devices (loop, nbd, dm, md, etc)
> and require CAP_SYS_ADMIN in the initial user namespace for mapping and
> unmapping, and also for dumping the configuration string and refreshing
> the image header.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
>
> CVE-2020-25284
>
> (cherry-picked from commit f44d04e696feaf13d192d942c4f14ad2e117065a)
> Signed-off-by: William Breathitt Gray <william.gray@canonical.com>
> ---
> drivers/block/rbd.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 274beda31c35..bf2f0373a3b2 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -5280,6 +5280,9 @@ static ssize_t rbd_config_info_show(struct device *dev,
> {
> struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
>
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> return sprintf(buf, "%s\n", rbd_dev->config_info);
> }
>
> @@ -5391,6 +5394,9 @@ static ssize_t rbd_image_refresh(struct device *dev,
> struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
> int ret;
>
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> ret = rbd_dev_refresh(rbd_dev);
> if (ret)
> return ret;
> @@ -7059,6 +7065,9 @@ static ssize_t do_rbd_add(struct bus_type *bus,
> struct rbd_client *rbdc;
> int rc;
>
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> if (!try_module_get(THIS_MODULE))
> return -ENODEV;
>
> @@ -7208,6 +7217,9 @@ static ssize_t do_rbd_remove(struct bus_type *bus,
> bool force = false;
> int ret;
>
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> dev_id = -1;
> opt_buf[0] = '\0';
> sscanf(buf, "%d %5s", &dev_id, opt_buf);
> --
> 2.25.1
>
>
> --
> kernel-team mailing list
> kernel-team@lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 274beda31c35..bf2f0373a3b2 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -5280,6 +5280,9 @@ static ssize_t rbd_config_info_show(struct device *dev, { struct rbd_device *rbd_dev = dev_to_rbd_dev(dev); + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + return sprintf(buf, "%s\n", rbd_dev->config_info); } @@ -5391,6 +5394,9 @@ static ssize_t rbd_image_refresh(struct device *dev, struct rbd_device *rbd_dev = dev_to_rbd_dev(dev); int ret; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + ret = rbd_dev_refresh(rbd_dev); if (ret) return ret; @@ -7059,6 +7065,9 @@ static ssize_t do_rbd_add(struct bus_type *bus, struct rbd_client *rbdc; int rc; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (!try_module_get(THIS_MODULE)) return -ENODEV; @@ -7208,6 +7217,9 @@ static ssize_t do_rbd_remove(struct bus_type *bus, bool force = false; int ret; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + dev_id = -1; opt_buf[0] = '\0'; sscanf(buf, "%d %5s", &dev_id, opt_buf);