From 5476f67dc1177a26b69fd67fbe589842f065d482 Mon Sep 17 00:00:00 2001 From: Zooko O'Whielacronx Date: Mon, 12 Sep 2011 15:23:31 -0700 Subject: [PATCH] storage: remove the storage server's "remote_cancel_lease" function We're removing this function because it is currently unused, because it is dangerous, and because the bug described in #1528 leaks the cancellation secret, which allows anyone who knows a file's storage index to abuse this function to delete shares of that file. fixes #1528 (there are two patches that are each a sufficient fix to #1528 and this is one of them) --- docs/garbage-collection.rst | 14 ++++---------- src/allmydata/interfaces.py | 15 --------------- src/allmydata/storage/server.py | 28 ---------------------------- 3 files changed, 4 insertions(+), 53 deletions(-) diff --git a/docs/garbage-collection.rst b/docs/garbage-collection.rst index 88522839..f1ae44cc 100644 --- a/docs/garbage-collection.rst +++ b/docs/garbage-collection.rst @@ -18,7 +18,7 @@ making room for other shares. Tahoe currently uses a garbage collection one or more "leases", which are managed by clients who want the file/directory to be retained. The storage server accepts each share for a pre-defined period of time, and is allowed to delete the share if all of the -leases are cancelled or allowed to expire. +leases expire. Garbage collection is not enabled by default: storage servers will not delete shares without being explicitly configured to do so. When GC is enabled, @@ -266,18 +266,12 @@ replace the previous set. The GC mechanism is also not immediate: a client which deletes a file will nevertheless be consuming extra disk space (and might be charged or otherwise held accountable for it) until the ex-file's leases finally expire on their -own. If the client is certain that they've removed their last reference to -the file, they could accelerate the GC process by cancelling their lease. The -current storage server API provides a method to cancel a lease, but the -client must be careful to coordinate with anyone else who might be -referencing the same lease (perhaps a second directory in the same virtual -drive), otherwise they might accidentally remove a lease that should have -been retained. +own. In the current release, these leases are each associated with a single "node secret" (stored in $BASEDIR/private/secret), which is used to generate -renewal- and cancel- secrets for each lease. Two nodes with different secrets -will produce separate leases, and will not be able to renew or cancel each +renewal-secrets for each lease. Two nodes with different secrets +will produce separate leases, and will not be able to renew each others' leases. Once the Accounting project is in place, leases will be scoped by a diff --git a/src/allmydata/interfaces.py b/src/allmydata/interfaces.py index 9536320d..982c8d94 100644 --- a/src/allmydata/interfaces.py +++ b/src/allmydata/interfaces.py @@ -148,21 +148,6 @@ class RIStorageServer(RemoteInterface): """ return Any() - def cancel_lease(storage_index=StorageIndex, - cancel_secret=LeaseCancelSecret): - """ - Cancel the lease on a given bucket. If this was the last lease on the - bucket, the bucket will be deleted. If there is no bucket for the - given storage_index, IndexError will be raised. - - For mutable shares, if the given cancel_secret does not match an - existing lease, IndexError will be raised with a note listing the - server-nodeids on the existing leases, so leases on migrated shares - can be renewed or cancelled. For immutable shares, IndexError - (without the note) will be raised. - """ - return Any() - def get_buckets(storage_index=StorageIndex): return DictOf(int, RIBucketReader, maxKeys=MAX_BUCKETS) diff --git a/src/allmydata/storage/server.py b/src/allmydata/storage/server.py index 48e29571..8350e813 100644 --- a/src/allmydata/storage/server.py +++ b/src/allmydata/storage/server.py @@ -345,34 +345,6 @@ class StorageServer(service.MultiService, Referenceable): if not found_buckets: raise IndexError("no such lease to renew") - def remote_cancel_lease(self, storage_index, cancel_secret): - start = time.time() - self.count("cancel") - - total_space_freed = 0 - found_buckets = False - for sf in self._iter_share_files(storage_index): - # note: if we can't find a lease on one share, we won't bother - # looking in the others. Unless something broke internally - # (perhaps we ran out of disk space while adding a lease), the - # leases on all shares will be identical. - found_buckets = True - # this raises IndexError if the lease wasn't present XXXX - total_space_freed += sf.cancel_lease(cancel_secret) - - if found_buckets: - storagedir = os.path.join(self.sharedir, - storage_index_to_dir(storage_index)) - if not os.listdir(storagedir): - os.rmdir(storagedir) - - if self.stats_provider: - self.stats_provider.count('storage_server.bytes_freed', - total_space_freed) - self.add_latency("cancel", time.time() - start) - if not found_buckets: - raise IndexError("no such storage index") - def bucket_writer_closed(self, bw, consumed_size): if self.stats_provider: self.stats_provider.count('storage_server.bytes_added', consumed_size) -- 2.37.2