microdesc_free_() called get_microdesc_cache(), which had the fun
side-effect of potentially reloading the whole cache from disk.
Replace it with a variant that doesn't.
One pain point in evolving the Tor design and implementing has been
adding code that makes clients reject directory documents that they
previously would have accepted, if those descriptors actually exist.
When this happened, the clients would get the document, reject it,
and then decide to try downloading it again, ad infinitum. This
problem becomes particularly obnoxious with authorities, since if
some authorities accept a descriptor that others don't, the ones
that don't accept it would go crazy trying to re-fetch it over and
over. (See for example ticket #9286.)
This patch tries to solve this problem by tracking, if a descriptor
isn't parseable, what its digest was, and whether it is invalid
because of some flaw that applies to the portion containing the
digest. (This excludes RSA signature problems: RSA signatures
aren't included in the digest. This means that a directory
authority can still put another directory authority into a loop by
mentioning a descriptor, and then serving that descriptor with an
invalid RSA signatures. But that would also make the misbehaving
directory authority get DoSed by the server it's attacking, so it's
not much of an issue.)
We already have a mechanism to mark something undownloadable with
downloadstatus_mark_impossible(); we use that here for
microdescriptors, extrainfos, and router descriptors.
Unit tests to follow in another patch.
Closes ticket #11243.
We're calling mallocfn() and reallocfn() in the HT_GENERATE macro
with the result of a product. But that makes any sane analyzer
worry about overflow.
This patch keeps HT_GENERATE having its old semantics, since we
aren't the only project using ht.h. Instead, define a HT_GENERATE2
that takes a reallocarrayfn.
I've made an exception for cases where I'm sure that users can't
influence the inputs. This is likely to cause a slowdown somewhere,
but it's safer to siphash everything and *then* look for cases to
optimize.
This patch doesn't actually get us any _benefit_ from siphash yet,
since we don't really randomize the key at any point.
The 'body' field of a microdesc_t holds a strdup()'d value if the
microdesc's saved_location field is SAVED_IN_JOURNAL or
SAVED_NOWHERE, and holds a pointer to the middle of an mmap if the
microdesc is SAVED_IN_CACHE. But we weren't setting that field
until a while after we parsed the microdescriptor, which left an
interval where microdesc_free() would try to free() the middle of
the mmap().
This patch also includes a regression test.
This is a fix for #10409; bugfix on 0.2.2.6-alpha.
It's conceivable (but probably impossible given our code) that lseek
could return -1 on an error; when that happens, we don't want off to
become -1.
Fixes CID 1035124.
This is a reprise of the fix in bdff7e3299d78; 6905c1f6 reintroduced
that bug. Briefly: windows doesn't seem to like deleting a mapped
file. I tried adding the PROT_SHARED_DELETE flag to the createfile
all, but that didn't actually fix this issue. Fortunately, the unit
test I added in 4f4fc63fea should
prevent us from making this particular screw-up again.
This patch also tries to limit the crash potential of a failure to
write by a little bit, although it could do a better job of retaining
microdescriptor bodies.
Fix for bug 8822, bugfix on 0.2.4.12-alpha.
This bug affects hosts where time_t is unsigned, which AFAICT does
not include anything we currently support. (It _does_ include
OpenVMS, about a month of BSD4.2's history[1], and a lot of the 1970s.)
There are probably more bugs when time_t is unsigned. This one was
[1] http://mail-index.netbsd.org/tech-userlevel/1998/06/04/0000.html
This time, I'm checking whether our calculated offset matches our
real offset, in each case, as we go along. I don't think this is
the bug, but it can't hurt to check.
Now as we move into a future where most bridges can handle microdescs
we will generally find ourselves using them, rather than holding back
just because one of our bridges doesn't use them.
Here we try to handle curve25519 onion keys from generating them,
loading and storing them, publishing them in our descriptors, putting
them in microdescriptors, and so on.
This commit is untested and probably buggy like whoa
We want to be saying fast_mem{cmp,eq,neq} when we're doing a
comparison that's allowed to exit early, or tor_mem{cmp,eq,neq} when
we need a data-invariant timing. Direct use of memcmp tends to imply
that we haven't thought about the issue.
