If the C library supports these random functions, use them directly
instead of reading the /dev/urandom file. This makes life easier on
platforms that don't have /dev/urandom (like WASM).
Rely on the OS to automatically restart syscalls that were interrupted
by signals. This makes code overall more robust because we don't have
to explicitly handle EINTR everywhere ourselves.
Run clang-format over the Mosh source tree. This is a large change and
has been factored into its own commit for auditability. Reproduce it
with
find . -name \*.cc -or -name \*.h | while read f; do clang-format -i --style=file $f; done
Create .clang-format to describe the current C++ style used in Mosh.
Mark one carefully-formatted array with `// clang-format off`. Also turn
off clang-format in src/crypto/ocb_internal.cc, since it was imported
almost wholesale from another project and is written in a style
different from the rest of Mosh.
Previously, mosh used extensive -I flags and all of the mosh-local
makes it really hard to tell what the proper dependency graph is, so
instead remove the -I arguments in favvor of $(top_srcdir) and qualify
the paths wherever they are used.
tmux 3.3a has a behavior change, since reverted, that is incompatible
with this test. Unfortunately, tmux 3.3a has already made it into some
distributions, so the test has to be disabled when tmux 3.3a is encountered.
Previously, ocb_internal.cc supported different key sizes, by way of
the deprecated aes_* function family. However, in practice, mosh
always uses AES-128. In Nettle, the explicit key-size APIs are not
deprecated, so switch to AES-128 directly.
Fixes: 1202
Explicitly define the primitive AES API used by the internal OCB
implementation, and move it into its own namespace (ocb_aes). This will
ease future implementation changes.
Also make some style fixes to affected lines: Replace C-style casts
with C++-style casts, add some missing spaces in argument lists, and
remove some `inline` that the compiler will ignore.
Bug: https://github.com/mobile-shell/mosh/issues/1174
After further discussion, the Mosh maintainers have decided to stick
with the internal OCB implementation for this release. Restore support
for using OpenSSL’s AES but internal OCB. To make this commit easy to
audit, restore the code exactly, including calls to AES functions that
are deprecated in OpenSSL 3; a future commit will update ocb_internal.cc
to use EVP instead of directly calling the AES primitives.
In anticipation of future changes, preserve support for OpenSSL’s
AES-OCB, but don’t compile it in. Add
--with-crypto-library=openssl-with-openssl-ocb and
--with-crypto-library=openssl-with-internal-ocb options to configure so
that developers can easily test Mosh using OpenSSL’s AES-OCB. These
options are intended only for testing, are undocumented, and are not
subject to any API stability guarantees.
Rework configure to look for all possible cryptography libraries first
and then dispatch on --with-crypto-library as appropriate.
OpenSSL 3.0 deprecated many of the functions that ocb.cc used to
implement OCB-AES, causing a build failure when -Wdeprecated collided
with -Werror. Debian temporarily fixed this by suppressing the error
in #1191.
Since mosh 1.4 will be the next stable release of mosh, it should not
depend on deprecated functions in OpenSSL. Since version 1.1.0,
OpenSSL natively supports OCB-AES through the EVP_CIPHER API. @cgull
started early support for this in #924.
This change extends upon the previous work by @cgull in a few ways
* EVP_CipherInit_ex is called in ae_init to set up the
EVP_CIPHER_CTX. It is later called in ae_encrypt and ae_decrypt
just to load nonce (IV in OpenSSL EVP parlance), which reduces the
amount of initialization done per-packet. However, due to OpenSSL
API limitations, two copies of the EVP_CIPHER_CTX are kept: one for
encryption, and one for decryption.
* Adds missing support for an external tag, rather than just one
appended to the ciphertext
* Support for non-default-sized tags
as well as some improved error handling.
Note that this change raises the minimum OpenSSL version for Mosh to
1.1.0. OpenSSL does not provide security support for versions prior to
1.1 at this time, so this is in principle reasonable dependency. If we
want to continue to support distributions (such as RHEL7) which
continue to be supported by their vendor but use an unsupported
OpenSSL, then some future work will have to restore the ocb.cc
implementation that uses the deprecated functions.
Bugs: #1174
Split src/crypto/ocb.cc into two files – one containing the AES-OCB
implementation backed by OpenSSL, and the other containing
implementations backed by Apple Common Crypto and Nettle. This paves the
way for a new OpenSSL implementation that uses OpenSSL 1.1’s OCB support
directly, rather than one that merely uses OpenSSL to provide the
underlying block cipher.
Remove support for rijndael-alg-fst.c and compiler-provided AES
intrinsics, since they’re not in use anymore. (Mosh can still use
hardware-accelerated AES if it’s available; it just now relies
exclusively on the underlying cryptography library to accelerate AES if
possible.)
Update the build system to conditionally compile in either
ocb_openssl.cc or ocb_internal.cc, depending on which cryptography
library you pass to ./configure.
To make this commit easy to audit, ocb_openssl.cc and ocb_internal.cc
are trivially diffable against ocb.cc (now deleted). Expected diffs
consist of a copyright notice update, a preprocessor check to ensure the
appropriate cryptography implementation has been selected, and deletions
to remove code that’s no longer in use. This does mean a substantial
amount of code is duplicated between ocb_openssl.cc and ocb_internal.cc;
however, ocb_openssl.cc should be completely replaced soon, so it won’t
be an issue in the long term.
Bug: https://github.com/mobile-shell/mosh/issues/1174
This reverts commit 6321b1d9c5.
The original commit 6321b1d9c5 switched
from a malloc call of a 22400 byte buffer to a stack-allocated 22400
byte buffer, in addition to the fairly large buffers already allocated
in the functions. Some systems have fairly small stack frames, making
this 22K allocation potentially dangerous. On my stock Debian bullseye
system, I have 200809 bytes (from `getconf
_POSIX_THREAD_ATTR_STACKSIZE`); a 22400 byte buffer already represents
about 10% of the available stacksize.
Other systems, such as those with musl libc, may have either 80KiB or
128KiB [1], making this allocation represent between 18% to 28% of the
available stack space.
[1] https://wiki.musl-libc.org/functional-differences-from-glibc.html#Thread-stack-size
This commit adds the --enable-fuzzing (and --enable-asan, to make
fuzzing more useful) options and a sample fuzzer for the terminal
parser. At this time only libfuzzer is supported. Future changes to
add AFL to get more fuzzing capability should be possible with the
addition of the afl_driver.cc from Chromium.
This change adds autoconf/automake support for building all of mosh
with gcov, and generates an lcov html report. This allows seeing which
parts ofthe source tree have good test coverage, and which can be
shored up. Eventually, it would be good to hook this up to Github
Actions to be generated automatically.
Fixes#1051, mosh fails to build on case-insensitive filesystems.
XXX This isn't perfect because autoconf/automake drop several extra
files in the directory anyway.
If there are consecutive resize events in the userstream to be applied in
"serve", we should apply the last/latest one in the sequence, not the
first/earliest one.
This fixes a problem where a flurry of resize events (eg, generated
by a window manager resizing the client), can cause mosh to have an
out-of-date idea as to what the physical geometry of the window is.
