Путеводитель по Руководству Linux

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   git-fetch    ( 1 )

скачать объекты и ссылки из другого репозитория (Download objects and refs from another repository)

Безопасность (Security)

The fetch and push protocols are not designed to prevent one side
       from stealing data from the other repository that was not
       intended to be shared. If you have private data that you need to
       protect from a malicious peer, your best option is to store it in
       another repository. This applies to both clients and servers. In
       particular, namespaces on a server are not effective for read
       access control; you should only grant read access to a namespace
       to clients that you would trust with read access to the entire
       repository.

The known attack vectors are as follows:

1. The victim sends "have" lines advertising the IDs of objects it has that are not explicitly intended to be shared but can be used to optimize the transfer if the peer also has them. The attacker chooses an object ID X to steal and sends a ref to X, but isn't required to send the content of X because the victim already has it. Now the victim believes that the attacker has X, and it sends the content of X back to the attacker later. (This attack is most straightforward for a client to perform on a server, by creating a ref to X in the namespace the client has access to and then fetching it. The most likely way for a server to perform it on a client is to "merge" X into a public branch and hope that the user does additional work on this branch and pushes it back to the server without noticing the merge.)

2. As in #1, the attacker chooses an object ID X to steal. The victim sends an object Y that the attacker already has, and the attacker falsely claims to have X and not Y, so the victim sends Y as a delta against X. The delta reveals regions of X that are similar to Y to the attacker.