This commit deprecates the `EncodeError::always_bug` function with a
`From<EncodeError> for Bug` trait, which is a more semantically correct
way to perform this action.
Previously, if somebody wrote this code, an attacker could easily
use it to cause an OOM panic:
```
let n = r.take_u64();
let items: Vec<Foo> = r.extract_n(n as usize)?;
```
The first line of defense here is not to write protocols like that:
we don't actually _have_ any 32-bit counters in our protocol
AFAICT.
The second line of defense is to pre-check `n` for reasonableness
before calling `extract_n`.
Here we add a third line of defense: whereas previously we would do
`Vec::with_capacity(n)` in `extract_n`, we now allocate an initial
capacity of `min(n, r.remaining())`. This ensures that the size of
the allocation can't exceed the remaining length of the message,
which (for our cell types at least) should prevent it from
overflowing or running OOM.
Actually, to avoid making a breaking change, I'm deprecating
BadMessage and creating a new InvalidMessage variant that takes a
Cow. This way I don't need to track every crate that re-exposes
tor_bytes::Error and call this a breaking change in those.
Making this change will allow tor_bytes errors to be much more
helpful.
This warning kind of snuck up on us! (See #748) For now, let's
disable it. (I've cleaned it up in a couple of examples, since
those are meant to be more idiomatic and user-facing.)
Closes#748.
In addition to the usual "You named that method wrong!" errors, we
have a new rustdoc error that complains about bogus "HTML tags" that
are actually unquoted usage of types like `Result<Foo>`.
The feature we want is `#[doc = include_str!("README.md")]`, which is
stable since 1.54 and our MSRV is now 1.56.
This commit is precisely the result of the following Perl rune:
perl -i~ -0777 -pe 's{(^//!(?!.*\@\@).*\n)+}{#![doc = include_str!("../README.md")]\n}m' crates/*/src/lib.rs
This Writer is a simple wrapper around `Vec<u8>` that makes sure
that its contents are cleared whenever they are dropped _or
reallocated_.
The reallocation is the important part here: without that, we risk
not zeroizing the first allocation of the buffer.
This comprises four renames:
```
write_onto -> write_onto_infallible
write_into -> write_into_infallible
write -> write_infallible
writer_and_consume -> write_and_consume_infallible.
```
The rest of this branch will be concerned with replacing these
`_infallible` methods with ones that return a `Result`. This is
part of #513.
Since there is currently only one error type that can occur when
encoding, it doesn't make sense to use the full Error type here.
This split will help us downstream, as we no longer need to
categorize tor_bytes::Error as "an error in encoding or decoding".
I considered renaming Error to DecodeError, but that had pretty huge
downstream effects, and didn't seem to be worth it.
Ian Jackson
Emil Engler
Nick Mathewson
Ian Jackson
trinity-1686a
eta
Samanta Navarro