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.
