On 09/13/2017 03:45 PM, Milan Broz wrote: > If a crypt mapping uses optional sector_size feature, additional > restrictions to mapped device segment size must be applied in constructor, > otherwise the device activation will fail later.
Hi, we had some discussion with Mikulas if this check should be better in generic DM code. I think that for this case it is not a good idea - dm-crypt can increase encryption sector size during load (it is stupid to do, but I see no reason why to block it). And then only constructor of the target itself know what is possible and what should be rejected. Anyway, there is a short reproducer what this patch solves: Create simple mapping with 4096 encryption sector: # dmsetup create test --table "0 8 crypt cipher_null - 0 /dev/sdb 0 1 sector_size:4096" Now load new unaligned-length table (this should fail!) # dmsetup load test --table "0 9 crypt cipher_null - 0 /dev/sdb 0 1 sector_size:4096" Inactive table is apparently accepted: # dmsetup table --inactive test: 0 9 crypt cipher_null 0 0 8:16 0 1 sector_size:4096 And now, resume fails, keeping the device in suspended state afterward: # dmsetup resume test device-mapper: resume ioctl on test failed: Invalid argument Command failed kernel: device-mapper: table: 254:0: len=9 not aligned to h/w logical block size 4096 of sdb # dmsetup info -c Name Maj Min Stat Open Targ Event UUID test 254 0 L-sw 0 1 0 With the patch applied, the load step correctly fails: # dmsetup load test --table "0 9 crypt cipher_null - 0 /dev/sdb 0 1 sector_size:4096" device-mapper: reload ioctl on test failed: Invalid argument kernel: device-mapper: table: 254:0: crypt: Device size is not multiple of sector_size feature Please consider this for 4.14 (and stable 4.12+ perhaps). Thanks, Milan > > Signed-off-by: Milan Broz <[email protected]> > --- > drivers/md/dm-crypt.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c > index 54aef8ed97db..488ecd0b1bd0 100644 > --- a/drivers/md/dm-crypt.c > +++ b/drivers/md/dm-crypt.c > @@ -2584,6 +2584,10 @@ static int crypt_ctr_optional(struct dm_target *ti, > unsigned int argc, char **ar > ti->error = "Invalid feature value for > sector_size"; > return -EINVAL; > } > + if (ti->len & ((cc->sector_size >> SECTOR_SHIFT) - 1)) { > + ti->error = "Device size is not multiple of > sector_size feature"; > + return -EINVAL; > + } > cc->sector_shift = __ffs(cc->sector_size) - > SECTOR_SHIFT; > } else if (!strcasecmp(opt_string, "iv_large_sectors")) > set_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags); > -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
