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| author | Mike Snitzer <snitzer@redhat.com> | 2014-10-04 18:55:32 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-10-04 18:55:32 +0200 |
| commit | b277da0a8a594308e17881f4926879bd5fca2a2d (patch) | |
| tree | 1af7df6ade218a4b246dd43a0771701a672c6cb8 /drivers/block/null_blk.c | |
| parent | Merge branch 'stable/for-jens-3.18' of git://git.kernel.org/pub/scm/linux/ker... (diff) | |
| download | linux-b277da0a8a594308e17881f4926879bd5fca2a2d.tar.xz linux-b277da0a8a594308e17881f4926879bd5fca2a2d.zip | |
block: disable entropy contributions for nonrot devices
Clear QUEUE_FLAG_ADD_RANDOM in all block drivers that set
QUEUE_FLAG_NONROT.
Historically, all block devices have automatically made entropy
contributions. But as previously stated in commit e2e1a148 ("block: add
sysfs knob for turning off disk entropy contributions"):
- On SSD disks, the completion times aren't as random as they
are for rotational drives. So it's questionable whether they
should contribute to the random pool in the first place.
- Calling add_disk_randomness() has a lot of overhead.
There are more reliable sources for randomness than non-rotational block
devices. From a security perspective it is better to err on the side of
caution than to allow entropy contributions from unreliable "random"
sources.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/block/null_blk.c')
| -rw-r--r-- | drivers/block/null_blk.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index a3b042c4d448..b0d94b6973ab 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -507,6 +507,7 @@ static int null_add_dev(void) nullb->q->queuedata = nullb; queue_flag_set_unlocked(QUEUE_FLAG_NONROT, nullb->q); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, nullb->q); disk = nullb->disk = alloc_disk_node(1, home_node); if (!disk) |