On Wed, Sep 29, 2021 at 11:43:39AM -0700, Neeraj Singh wrote:
It seems to me that one problem is that the new "primary" objdir code doesn't
disable ref updates since the GIT_QUARANTINE_ENVIRONMENT setting isn't set.
If we fix that we should be forbidding ref updates.
I've included a path that fixes my test case. This is on top of:
https://lore.kernel.org/git/CANQDOddqwVtWfC4eEP3fJB4sUiszGX8bLqoEVLcMf=v+jzx19g@mail.gmail.com/ (local)
Ah, right, I forgot we had that "forbid ref updates in quarantine" magic
(despite being the one who added it).
I do think this improves the safety, but things are still a bit more
dangerous because we're handling it all in a single process, which sees
both the quarantine and non-quarantine states. I wrote more details in
this reply a few minutes ago:
https://lore.kernel.org/git/YVVmssXlaFM6yD5W@coredump.intra.peff.net/ (local)
(sorry, it's long; search for the paragraph starting with "Whereas doing
it in-process").
When creating a subprocess with a temporary ODB, we set the
GIT_QUARANTINE_ENVIRONMENT env var to tell child Git processes not
to update refs, since the tmp-objdir may go away.
Introduce a similar mechanism for in-process temporary ODBs when
we call tmp_objdir_replace_primary_odb.
Peff's test case was invoking ref updates via the cachetextconv
setting. That particular code silently does nothing when a ref
update is forbidden
Oh good. I was worried that it would generate ugly errors, rather than
silently skipping the update.
quoted hunk ↗ jump to hunk
@@ -2126,7 +2146,7 @@ int ref_transaction_prepare(struct ref_transaction *transaction,
break;
}
- if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
+ if (getenv(GIT_QUARANTINE_ENVIRONMENT) || !ref_updates_are_enabled()) {
strbuf_addstr(err,
_("ref updates forbidden inside quarantine environment"));
return -1;
I think the overall goal of this patch makes sense, but this
conditional, along with tmp-objdir reaching out to the refs code, feels
funny. Should we perhaps have a single:
int tmp_objdir_is_primary(struct repository *r)
{
if (the_tmp_objdir &&
!strcmp(the_tmp_objdir->path.buf, r->objects->odb->path))
return 1; /* our temporary is the primary */
if (getenv(GIT_QUARANTINE_PATH))
return 1; /* our caller put us in quarantine */
return 0;
}
Then it's all nicely abstracted and the ref code does not have to know
the details of GIT_QUARANTINE_PATH in the first place.
If you do got that route, the strcmp() might need to be a little more
careful about whether r->objects can be NULL (I didn't check).
Alternatively, I kind of wonder if "struct object_directory" should just
have a flag that says "is_temporary".
-Peff