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authorIlya Dryomov <idryomov@gmail.com>2020-09-03 13:24:11 +0200
committerIlya Dryomov <idryomov@gmail.com>2020-09-07 13:14:30 +0200
commitf44d04e696feaf13d192d942c4f14ad2e117065a (patch)
treeff70ce2d10b87bccdd6f7bad906d91beb262b2d5 /drivers/block/rbd.c
parentf4d51dffc6c01a9e94650d95ce0104964f8ae822 (diff)
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/rbd.c')
-rw-r--r--drivers/block/rbd.c12
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);