ublk: enforce ublks_max only for unprivileged devices

Browse source

[ Upstream commit 80bdfbb354 ]

Commit 403ebc8778 ("ublk_drv: add module parameter of ublks_max for
limiting max allowed ublk dev"), claimed ublks_max was added to prevent
a DoS situation with an untrusted user creating too many ublk devices.
If that's the case, ublks_max should only restrict the number of
unprivileged ublk devices in the system. Enforce the limit only for
unprivileged ublk devices, and rename variables accordingly. Leave the
external-facing parameter name unchanged, since changing it may break
systems which use it (but still update its documentation to reflect its
new meaning).

As a result of this change, in a system where there are only normal
(non-unprivileged) devices, the maximum number of such devices is
increased to 1 << MINORBITS, or 1048576. That ought to be enough for
anyone, right?

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250228-ublks_max-v1-1-04b7379190c0@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Uday Shankar 2025-02-28 21:31:48 -07:00 • committed by Greg Kroah-Hartman

parent c4f025a58e

commit af73c8fd73

1 changed files with 27 additions and 15 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

42

drivers/block/ublk_drv.c

View file