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 6321b1d9.

The original commit 6321b1d9 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 a fuzzer for more of the terminal pipeline, adding
coverage for the input and output portions of the terminal
framebuffer.

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.

Signed-off-by: Wolfgang E. Sanyer <WolfgangESanyer@gmail.com>

Signed-off-by: Wolfgang E. Sanyer <WolfgangSanyer@Google.com>

Signed-off-by: Wolfgang E. Sanyer <WolfgangSanyer@Google.com>

Add tmux and alacritty to title_term_types

Use CLOCK_MONOTONIC_RAW when available

Don't sometimes hang just after launching ssh

sshd has a bug in which the sometimes it may get stuck trying to read from the client
even though the child process has already exited. This is visible at
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/serverloop.c?annotate=1.226 line 274:
once the child is waited on, `child_terminated` is reset to 0, which causes it to use an infinite timeout 
in the select there.

This workaround causes mosh to disconnect from the server, thereby allowing sshd finish.

Resolves #1130

.gitignore: add autogenerated files

fixed the irc channel link in README

This makes the resulting error from mosh-server visible in ordinary usage.

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.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

The uninitialized variable warning from T x; broke the test if the
user passed CXXFLAGS='-O2 -Wall -Werror'.  (Users shouldn’t do that;
our own --enable-compile-warnings=error option was unaffected.)

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

These tests only define HAVE_* macros that we never check.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

As of commit dd941df1

, we no longer
build any plain C, except within AM_PROG_AR.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Change the openssl-devel package to libssl-devel.  Cygwin still has an
"obsolete" (essentially virtual) package for openssl-devel, but it
doesn't seem to work properly on Appveyor's Cygwin install.

Protobuf >= 3.6.0 requires C++11, which I added support for last year.
But when I did that, I requested strict ANSI C++ compatibility, which
causes Cygwin/newlib's libc feature test macros to be set to disable
(at least) POSIX.1 extensions.  Let the Autoconf macro use its default
instead (prefer GNU/extended C++, accept anything).

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Statically linking mosh-server with glibc isn’t a great idea for
various reasons (nsswitch modules, locale format incompatibilities).
But we can provide most of the benefits of static linking by allowing
specific library dependencies to be linked statically using -Bstatic
and -Bdynamic.  The full set is enabled by

    ./configure --enable-static-libraries

which is equivalent to

    ./configure --enable-static-libstdc++ --enable-static-libgcc \
      --enable-static-utempter --enable-static-zlib --enable-static-curses \
      --enable-static-crypto --enable-static-protobuf

and results in binaries whose only runtime library dependencies are
provided with libc:

    $ ldd src/frontend/mosh-server
            linux-vdso.so.1 (0x00007ffe0b377000)
            libutil.so.1 => /lib/x86_64-linux-gnu/libutil.so.1 (0x00007fa0d9970000)
            libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fa0d97e3000)
            libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fa0d97c2000)
            libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fa0d95d8000)
            /lib64/ld-linux-x86-64.so.2 (0x00007fa0d9f6a000)

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

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.