From 0c1f3193b1cdd21e7182f97dc9bca7d284d18a15 Mon Sep 17 00:00:00 2001 From: John Keeping Date: Wed, 12 May 2021 12:14:21 +0100 Subject: [PATCH 1/3] dm verity: fix require_signatures module_param permissions The third parameter of module_param() is permissions for the sysfs node but it looks like it is being used as the initial value of the parameter here. In fact, false here equates to omitting the file from sysfs and does not affect the value of require_signatures. Making the parameter writable is not simple because going from false->true is fine but it should not be possible to remove the requirement to verify a signature. But it can be useful to inspect the value of this parameter from userspace, so change the permissions to make a read-only file in sysfs. Signed-off-by: John Keeping Signed-off-by: Mike Snitzer --- drivers/md/dm-verity-verify-sig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-verity-verify-sig.c b/drivers/md/dm-verity-verify-sig.c index 29385dc470d5..db61a1f43ae9 100644 --- a/drivers/md/dm-verity-verify-sig.c +++ b/drivers/md/dm-verity-verify-sig.c @@ -15,7 +15,7 @@ #define DM_VERITY_VERIFY_ERR(s) DM_VERITY_ROOT_HASH_VERIFICATION " " s static bool require_signatures; -module_param(require_signatures, bool, false); +module_param(require_signatures, bool, 0444); MODULE_PARM_DESC(require_signatures, "Verify the roothash of dm-verity hash tree"); From f16dba5dc6f094041ab8c356e1e3a48ee0e3c8cd Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Tue, 25 May 2021 13:16:21 -0400 Subject: [PATCH 2/3] dm snapshot: revert "fix a crash when an origin has no snapshots" Commit 7ee06ddc4038f936b0d4459d37a7d4d844fb03db ("dm snapshot: fix a crash when an origin has no snapshots") introduced a regression in snapshot merging - causing the lvm2 test lvcreate-cache-snapshot.sh got stuck in an infinite loop. Even though commit 7ee06ddc4038f936b0d4459d37a7d4d844fb03db was marked for stable@ the stable team was notified to _not_ backport it. Fixes: 7ee06ddc4038 ("dm snapshot: fix a crash when an origin has no snapshots") Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- drivers/md/dm-snap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index b8e4d31124ea..75e59294ef77 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -855,11 +855,12 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new) static uint32_t __minimum_chunk_size(struct origin *o) { struct dm_snapshot *snap; - unsigned chunk_size = rounddown_pow_of_two(UINT_MAX); + unsigned chunk_size = 0; if (o) list_for_each_entry(snap, &o->snapshots, list) - chunk_size = min(chunk_size, snap->store->chunk_size); + chunk_size = min_not_zero(chunk_size, + snap->store->chunk_size); return (uint32_t) chunk_size; } From 7e768532b2396bcb7fbf6f82384b85c0f1d2f197 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Tue, 25 May 2021 13:17:19 -0400 Subject: [PATCH 3/3] dm snapshot: properly fix a crash when an origin has no snapshots If an origin target has no snapshots, o->split_boundary is set to 0. This causes BUG_ON(sectors <= 0) in block/bio.c:bio_split(). Fix this by initializing chunk_size, and in turn split_boundary, to rounddown_pow_of_two(UINT_MAX) -- the largest power of two that fits into "unsigned" type. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer --- drivers/md/dm-snap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 75e59294ef77..751ec5ea1dbb 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -855,7 +855,7 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new) static uint32_t __minimum_chunk_size(struct origin *o) { struct dm_snapshot *snap; - unsigned chunk_size = 0; + unsigned chunk_size = rounddown_pow_of_two(UINT_MAX); if (o) list_for_each_entry(snap, &o->snapshots, list)