[tahoe-lafs-trac-stream] [Tahoe-LAFS] #3763: Potential issues with `PUT /v1/lease/:storage_index` in GBS protocol

[Tahoe-LAFS]

#3763: Potential issues with `PUT /v1/lease/:storage_index` in GBS protocol
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     Reporter:  itamarst  |      Owner:  exarkun
         Type:  task      |     Status:  new
     Priority:  normal    |  Milestone:  HTTP Storage Protocol
    Component:  unknown   |    Version:  n/a
   Resolution:            |   Keywords:
Launchpad Bug:            |
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Comment (by exarkun):

 Some more background related to lease cancellation:

 {{{
 commit 5476f67dc1177a26b69fd67fbe589842f065d482
 Author: Zooko O'Whielacronx <zooko at zooko.com>
 Date:   Mon Sep 12 15:23:31 2011 -0700

     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)

 commit 65de17245da26a4ce00aa7c441d6bf81464a6e65
 Author: Zooko O'Whielacronx <zooko at zooko.com>
 Date:   Mon Sep 12 15:23:24 2011 -0700

     storage: test that the storage server does *not* have a
 "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.
     ref. #1528

 commit cffc98780414760c8d5f751c5841856b3207cce3
 Author: Zooko O'Whielacronx <zooko at zooko.com>
 Date:   Mon Sep 12 15:12:01 2011 -0700

     immutable: test whether the server allows clients to read past the end
 of share data, which would allow them to learn the cancellation secret
     Also test whether the server explicitly declares that it prevents this
 problem.
     ref #1528
 }}}

 ticket:1528

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Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3763#comment:7>
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