From: Ondrej Kozina <okozina@xxxxxxxxxx> Hi, I would like to post RFC with a set of changes for device-mapper that would enable user w/o CAP_SYS_ADMIN capability to create and manage his own devices in more or less distant future. I`ll try to be as brief as possible, so: Simple use cases: ^^^^^^^^^^^^^^^^ (1) Non-root user would be able to create dm-crypt device from USB stick (assuming the user has permission to access backing device) (2) You can create pool of storage space for virtual machines. VM managers would be able to administrate the pool w/o root permissions. Each VM would be able to create it's own device (same premise as before) Short Overview: ^^^^^^^^^^^^^^ (1) The first checkpoint that decides whether the user has an access right to submit ioctl cmds into DM driver are actually the attributes on dentry of /dev/mapper/control (through general perm., ACL, LSM checks). (2) After the DM_DEV_CREATE ioctl, new block device will receive FSUID and FSGID from the context on behalf of which we entered into kernel (3) Whenever user asks to manipulate DM device he must pass the test whether he's the owner of DM device or not (4) During the table creation process we check whether the user has right to READ/WRITE the backing device, according to table mode (there's possibly major drawback when user submits target device as major:minor couple, more on that later). For that purpose I added a new function into target_type interface - dm_security_fn. Note: It's still work in progress. I would jusk like to ask you humbly for any comments, if you may miss a few minutes. Another note: I'm prety sure that there are many bugs and many mistakes in my concept (locking, maybe even reference leaks,...) but what I'm looking for right now, is rather a proof of concept than patchset ready for upstream. With regards O. Ondrej Kozina (4): Adds support for user-submitted ioctl commands Adds support for the dentry lookup from path or major:minor couple during target security check Adds support for security checks in the linear target Adds support for security checks in the crypt target drivers/md/dm-crypt.c | 37 +++++++++++- drivers/md/dm-ioctl.c | 138 +++++++++++++++++++++++++++++++++++------ drivers/md/dm-linear.c | 49 ++++++++++++++- drivers/md/dm-sysfs.c | 30 +++++++++ drivers/md/dm-table.c | 16 +++++ drivers/md/dm-target.c | 126 +++++++++++++++++++++++++++++++++++++ drivers/md/dm.c | 86 +++++++++++++++++++++++++ drivers/md/dm.h | 14 ++++ include/linux/device-mapper.h | 3 + 9 files changed, 477 insertions(+), 22 deletions(-) -- 1.7.8.5 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel