I was reading about a recent security issue with both EMC and VMWare:
https://arstechnica.com/information-technology/2018/01/emc-vmware-security-bugs-throw-gasoline-on-cloud-security-fire/
It's a classic path traversal problem, and that made me think more about our
handling of this in libostree. Fortunately of course, not being new to
this rodeo, long ago I *did* consider path traversal. Inside the pull
code, we call `ot_util_filename_validate()`. Also, `fsck` does this too.
I have further followups here, but let's add some test cases for this. I crafted
a repository with a `../` in a dirtree object by patching libostree to inject
it, and that's included as a tarball.
This patch covers the two cases where we do already have checks; pulling
via HTTP, and in `fsck`.
Closes: #1412
Approved by: jlebon
A while ago I did `truncate -s 0 /path/to/repo/00/123.commit`, and expected a
checksum error, but I actually got a validation error due to us loading the
commit into a variant and trying to parse out the parent checksum, etc.
I first started by changing the `load_and_fsck_one_object()` function to
checksum before loading, but the problem is that we do a traverse of all objects
first. Fixing this is going to require an `OSTREE_REPO_COMMIT_TRAVER_FLAG_FSCK`
or something.
In the meantime at least though, let's add a public API to fsck a single object
which *does* checksum cleanly before parsing the object, and change the `fsck`
command to use it.
We then change the fsck binary to do this while iterating over the refs
and finding the commit object. This way we'll at least get a checksum
first for commit objects, even if not dirtree/dirmeta.
Closes: #1364
Approved by: jlebon
I noticed in the static deltas tests, there were some tests that
should have been under `-o pipefail` to ensure we properly propagate
errors.
There were a few places where we were referencing undefined variables.
Overall, this is clearly a good idea IMO.
Colin Walters