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mutable.py: reject shares with different k/N than we expect. Quick fix for #312: avoids data corruption but has availability problems.

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Brian Warner 2008-02-13 13:34:20 -07:00
parent 871e7756f7
commit 8c8bcb6d53
1 changed files with 20 additions and 0 deletions
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20
src/allmydata/mutable.py
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@ -410,6 +410,9 @@ class Retrieve:
self._valid_versions[verinfo] = (prefix, DictOfSets()) self._valid_versions[verinfo] = (prefix, DictOfSets())
# and make a note of the other parameters we've just learned # and make a note of the other parameters we've just learned
# NOTE: Retrieve needs to be refactored to put k,N in the verinfo
# along with seqnum/etc, to make sure we don't co-mingle shares
# from differently-encoded versions of the same file.
if self._required_shares is None: if self._required_shares is None:
self._required_shares = k self._required_shares = k
self._node._populate_required_shares(k) self._node._populate_required_shares(k)
@ -417,6 +420,23 @@ class Retrieve:
self._total_shares = N self._total_shares = N
self._node._populate_total_shares(N) self._node._populate_total_shares(N)
# reject shares that don't match our narrow-minded ideas of what
# encoding we're going to use. This addresses the immediate needs of
# ticket #312, by turning the data corruption into unavailability. To
# get back the availability (i.e. make sure that one weird-encoding
# share that happens to come back first doesn't make us ignore the
# rest of the shares), we need to implement the refactoring mentioned
# above.
if k != self._required_shares:
raise CorruptShareError(peerid, shnum,
"share has k=%d, we want k=%d" %
(k, self._required_shares))
if N != self._total_shares:
raise CorruptShareError(peerid, shnum,
"share has N=%d, we want N=%d" %
(N, self._total_shares))
# we've already seen this pair, and checked the signature so we # we've already seen this pair, and checked the signature so we
# know it's a valid candidate. Accumulate the share info, if # know it's a valid candidate. Accumulate the share info, if
# there's enough data present. If not, raise NeedMoreDataError, # there's enough data present. If not, raise NeedMoreDataError,