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| author |   Ilya Dryomov <idryomov@gmail.com> | 2020-09-03 13:24:11 +0200 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2020-09-07 13:14:30 +0200 |
| commit | f44d04e696feaf13d192d942c4f14ad2e117065a (patch) | |
| tree | ff70ce2d10b87bccdd6f7bad906d91beb262b2d5 /drivers/block | |
| parent | Linux 5.9-rc4 (diff) | |
| download | linux-dev-f44d04e696feaf13d192d942c4f14ad2e117065a.tar.xz linux-dev-f44d04e696feaf13d192d942c4f14ad2e117065a.zip | |
rbd: require global CAP_SYS_ADMIN for mapping and unmapping
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>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/rbd.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 011539039693..e77eaab5cf23 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -5120,6 +5120,9 @@ 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); } @@ -5231,6 +5234,9 @@ 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; @@ -7209,6 +7218,9 @@ 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); |