commit e90bcfd520818971e6889192e0ed18c5f1deab3e
author Bogdan Caprita <caprita@google.com> Fri Aug 07 13:31:55 2015 -0700
committer Bogdan Caprita <caprita@google.com> Fri Aug 07 13:31:55 2015 -0700
tree 6aa4951268cce3dad698f612ffc5707fd4662756
parent 6069de7f4e6fd8872b06fe714af2643279227068

services/internal/binarylib: bug fix: Create call on existing binary resets ACLs

Because Create's implementation first set the ACLs and then checks if the binary
already exists, calling Create on a name corresponding to an existing binary
ends up resetting the ACLs for the binary. This gives ownership of the object to
the caller of the second Create (and overwriting any explicit ACL settings done
after the first Create). This was detected in production, where we occasionally
called "device publish" for the same binary (proxyd) twice during the same
second.

This CL swaps the ordering of operations in Create, first setting up the
directory corresponding to the new binary, and, only if it turns out that the
object is indeed new, setting the ACLs.  To prevent unauthorized access to the
object after it's created but before ACLs are set, we restrict the authorizer to
only allow Create calls against objects without permissions set on them.

Change-Id: I4788143ed739c4006e286fe36833ed0cf7a51fcf