The previous sample for creating a ~/.borg-passphrase file creates it first and then chmod's it to 400 permissions. That's probably fine in practice, but means there's a tiny window where the passphrase file is sitting with default permissions (likely world readable, depending on the system umask).
It seems safer to first change the umask to remove all group & world bits (0077) _before_ creating the file. To be polite and avoid messing with the user's previous umask, we do this in a subshell. (Note that umask 0077 leads to a mode of 600 rather than the previous 400, because removing the owner write bit doesn't seem to buy much since the owner can just chmod the file anyway.)
export-tar: just msgpack and b64encode all item metadata and
put that into a BORG specific PAX header.
this is *additional* to the standard tar metadata.
import-tar: when detecting the BORG specific PAX header, just get
all metadata from there (and ignore the standard tar
metadata).
--tar-format=GNU|PAX (default: GNU)
changed the tests which use GNU tar cli tool to use --tar-format=GNU
explicitly, so they don't break in case we change the default.
atime timestamp is only present in output if the archive item has it
(which is not the case by default, needs "borg create --atime ...").
if LZ4/ZSTD.decompress gets called with a memoryview idata, keep
it until after the super().decompress(idata) call, so we save one
copy operation just to remove the 2 bytes long compression type
header.
attic is borg's parent project, but it stalled in 2015 and was not updated since then.
guess we can assume that most attic users have meanwhile noticed this and already
converted their repos to borg.
if some did not yet, they are advised to use borg < 1.3 to do that ASAP.
note: borg can still DETECT an attic repo by recognizing its ATTIC_MAGIC value
and then gives exactly that advice.
Code gets simpler if we always only use the (shorter) header_fmt.
That format ALWAYS applies, to all tags borg writes.
If the tag unpacked from there indicates that there is also a chunkid
to read (like for PUT and DEL), we can decide that inside _read and
then read the chunkid from the fd.
olen is assigned by OpenSSL, but the compiler can't know that and generates these warnings:
warning: src/borg/crypto/low_level.pyx:271:22: local variable 'olen' referenced before assignment
warning: src/borg/crypto/low_level.pyx:274:22: local variable 'olen' referenced before assignment
warning: src/borg/crypto/low_level.pyx:314:22: local variable 'olen' referenced before assignment
warning: src/borg/crypto/low_level.pyx:317:22: local variable 'olen' referenced before assignment
warning: src/borg/crypto/low_level.pyx:514:22: local variable 'olen' referenced before assignment
warning: src/borg/crypto/low_level.pyx:517:22: local variable 'olen' referenced before assignment
warning: src/borg/crypto/low_level.pyx:566:22: local variable 'olen' referenced before assignment
warning: src/borg/crypto/low_level.pyx:572:22: local variable 'olen' referenced before assignment
added it for all classes there, so the caller just give it.
for the legacy AES-CTR based classes, the given aad is completely ignored.
this is to stay compatible with repo data of borg < 1.3.
for the new AEAD based classes:
encrypt: the aad is fed into the auth tag computation
decrypt: same. decrypt will fail on auth tag mismatch.
we already have .decrypt(id, data, ...).
i changed .encrypt(chunk) to .encrypt(id, data).
the old borg crypto won't really need or use the id,
but the new AEAD crypto will authenticate the id in future.
