writing: put type into repoobj metadata
reading: check wanted type against type we got
repoobj metadata is encrypted and authenticated.
repoobj data is encrypted and authenticated, also (separately).
encryption and decryption of both metadata and data get the
same "chunk ID" as AAD, so both are "bound" to that (same) ID.
a repo-side attacker can neither see cleartext metadata/data,
nor successfully tamper with it (AEAD decryption would fail).
also, a repo-side attacker could not replace a repoobj A with a
differently typed repoobj B without borg noticing:
- the metadata/data is cryptographically bound to its ID.
authentication/decryption would fail on mismatch.
- the type check would fail.
thus, the problem (see CVEs in changelog) solved in borg 1 by the
manifest and archive TAMs is now already solved by the type check.
remove a lot of complexity from the code that was just there to
support legacy borg versions < 1.0.9 which did not TAM authenticate
the manifest.
since then, borg writes TAM authentication to the manifest,
even if the repo is unencrypted.
if the repo is unencrypted, it did not check the somehow pointless
authentication that was generated without any secret, but
if we add that fake TAM, we can also verify the fake TAM.
if somebody explicitly switches off all crypto, they can not
expect authentication.
for everybody else, borg now always generates the TAM and also
verifies it.
check --archives: add --newer/--older/--newest/--oldest, fixes#7062
Options accept a timespan, like Nd for N days or Nm for N months.
Use these to do date-based matching on archives and only check some of them,
like: borg check --archives --newer=1m --newest=7d
Author: Michael Deyaso <mdeyaso@fusioniq.io>
borg < 2:
obj = encrypted(compressed(data))
borg 2:
obj = enc_meta_len32 + encrypted(msgpacked(meta)) + encrypted(compressed(data))
handle compr / decompr in repoobj
move the assert_id call from decrypt to RepoObj.parse
also:
- for AEADKeyBase, add a dummy assert_id (not needed here)
- only test assert_id for other if not AEADKeyBase instance
- remove test_getting_wrong_chunk. assert_id is called elsewhere
and is not needed any more anyway with the new AEAD crypto.
- only give manifest (includes key, repo, repo_objs)
- only return manifest from Manifest.load (includes key, repo, repo_objs)
Thomas Waldmann