Add support for aes256-gcm@openssh.com and aes128-gcm@openssh.com
ciphers, which are the OpenSSH implementations of AES-GCM cryptography.
It is similar to RFC5647 but has changes to the MAC protocol
negotiation. These are implemented for recent versions of OpenSSL only.
The ciphers work differently than most previous ones in two big areas:
the cipher includes its own integrated MAC, and the packet length field
in the SSH frame is left unencrypted. The code changes necessary are
gated by flags in the LIBSSH2_CRYPT_METHOD configuration structure.
These differences mean that both the first and last parts of a block
require special handling during encryption. The first part is where the
packet length field is, which must be kept out of the encryption path
but in the authenticated part (as AAD). The last part is where the
Authentication Tag is found, which is calculated and appended during
encryption or removed and validated on decryption. As encryption/
decryption is performed on each packet in a loop, one block at a time,
flags indicating when the first and last blocks are being processed are
passed down to the encryption layers.
The strict block-by-block encryption that occurs with other protocols is
inappropriate for AES-GCM, since the packet length shifts the first
encrypted byte 4 bytes into the block. Additionally, the final part of
the block must contain the AES-GCM's Authentication Tag, so it must be
presented to the lower encryption layer whole. These requirements mean
added code to consolidate blocks as they are passed down.
When AES-GCM is negotiated as the cipher, its built-in MAC is
automatically used as the SSH MAC so further MAC negotiation is not
necessary. The SSH negotiation is skipped when _libssh2_mac_override()
indicates that such a cipher is in use. The virtual MAC configuration
block mac_method_hmac_aesgcm is then used as the MAC placeholder.
This work was sponsored by Anders Borum.
Integration-patches-by: Viktor Szakats
* fix checksrc errors
* fix openssl.c warning
* fix transport.c warnings
* switch to `LIBSSH2_MIN/MAX()` from `MIN()`/`MAX()`
* fix indent
* fix libgcrypt unused warning
* fix mbedtls unused warning
* fix wincng unused warning
* fix old openssl unused variable warnings
* delete blank lines
* updates to help merging with the ETM patch
Implement picky warnings with clang in autotools. Extend picky gcc
warnings, sync them between build tools and compilers and greatly
speed up detection in CMake.
- autotools: enable clang compiler warnings with `--enable-debug`.
- autotools: enable more gcc compiler warnings with `--enable-debug`.
- autotools/cmake: sync compiler warning options between gcc and clang.
- sync compiler warning options between autotools and cmake.
- cmake: reduce option-checks to speed up the detection phase.
Bring them down to 3 (from 35). Leaving some checks to keep the
CMake logic alive and for an easy way to add new options.
clang 3.0 (2011-11-29) and gcc 2.95 (1999-07-31) now required.
- autotools logic copied from curl, with these differences:
- delete `-Wimplicit-fallthrough=4` due to a false positive.
- reduce `-Wformat-truncation=2` to `1` due to a false positive.
- simplify MinGW detection for `-Wno-pedantic-ms-format`.
- cmake: show enabled picky compiler options (like autotools).
- cmake: do compile `tests/simple.c` and `tests/ssh2.c`.
- fix new compiler warnings.
- `tests/CMakeLists.txt`: fix indentation.
Original source of autotools logic:
- a8fbdb461c/acinclude.m4
- a8fbdb461c/m4/curl-compilers.m4
Notice that the autotools implementation considers Apple clang as
legacy clang 3.7. CMake detection works more accurately, at the same
time more error-prone and difficult to update due to the sparsely
documented nature of Apple clang option evolution.
Closes#952
After recent build changes, 3rd party build that took the list of
C source to compile them as-is, stopped working as expected, due to
`blowfish.c` and crypto-backend C sources no longer expected to compile
separately but via `bcrypt_pbkdf.c` and `crypto.c`, respectively.
This patch ensures that compiling these files directly result in an
empty object instead of redundant code and duplicated symbols.
Also:
- add a compile-time error if none of the supported crypto backends
are enabled.
- fix `libssh2_crypto_engine()` for wolfSSL and os400qc3.
Rearrange code to avoid a hard-to-find copy of crypto-backend
selection guards.
Follow-up to 4f0f4bff5a
Follow-up to ff3c774e03Closes#951
Update from:
5fec927374/scripts/checksrc.pl
- suppress these new checks:
- EQUALSNULL: 320 warnings
- NOTEQUALSZERO: 142 warnings
- TYPEDEFSTRUCT: 16 warnings
We can enabled them in the future.
- fix all other new ones.
- also fix whitespace in two `NMakefile` files.
Apply type changes to avoid casts and warnings. In most cases this
means changing to a larger type, usually `size_t` or `ssize_t`.
Change signedness in a few places.
Also introduce new variables to avoid reusing them for multiple
purposes, to avoid casts and warnings.
- add FIXME for public `libssh2_sftp_readdir_ex()` return type.
- fix `_libssh2_mbedtls_rsa_sha2_verify()` to verify if `sig_len`
is large enough.
- fix `_libssh2_dh_key_pair()` in `wincng.c` to return error if
`group_order` input is negative.
Maybe we should also reject zero?
- bump `_libssh2_random()` size type `int` -> `size_t`. Add checks
for WinCNG and OpenSSL to return error if requested more than they
support (`ULONG_MAX`, `INT_MAX` respectively).
- change `_libssh2_ntohu32()` return value `unsigned int` -> `uint32_t`.
- fix `_libssh2_mbedtls_bignum_random()` to check for a negative `top`
input.
- size down `_libssh2_wincng_key_sha_verify()` `hashlen` to match
Windows'.
- fix `session_disconnect()` to limit length of `lang_len`
(to 256 bytes).
- fix bad syntax in an `assert()`.
- add a few `const` to casts.
- `while(1)` -> `for(;;)`.
- add casts that didn't fit into #876.
- update `docs/HACKING-CRYPTO` with new sizes.
May need review for OS400QC3: /cc @monnerat @jonrumsey
See warning details in the PR's individual commits.
Cherry-picked from #846Closes#879
Most of the changes aim to silence warnings by adding casts.
An assortment of other issues, mainly compiler warnings, resolved:
- unreachable code fixed by using `goto` in
`publickey_response_success()` in `publickey.c`.
- potentially uninitialized variable in `sftp_open()`.
- MSVS-specific bogus warnings with `nid_type` in `kex.c`.
- check result of `kex_session_ecdh_curve_type()`.
- add missing function declarations.
- type changes to fit values without casts:
- `cmd_len` in `scp_recv()` and `scp_send()`: `int` -> `size_t`
- `Blowfish_expandstate()`, `Blowfish_expand0state()` loop counters:
`uint16_t` -> `int`
- `RECV_SEND_ALL()`: `int` -> `ssize_t`
- `shell_quotearg()` -> `unsigned` -> `size_t`
- `sig_len` in `_libssh2_mbedtls_rsa_sha2_sign()`:
`unsigned` -> `size_t`
- `prefs_len` in `libssh2_session_method_pref()`: `int` -> `size_t`
- `firstsec` in `_libssh2_debug_low()`: `int` -> `long`
- `method_len` in `libssh2_session_method_pref()`: `int` -> `size_t`
- simplify `_libssh2_ntohu64()`.
- fix `LIBSSH2_INT64_T_FORMAT` for MinGW.
- fix gcc warning by not using a bit field for
`burn_optimistic_kexinit`.
- fix unused variable warning in `_libssh2_cipher_crypt()` in
`libgcrypt.c`.
- fix unused variables with `HAVE_DISABLED_NONBLOCKING`.
- avoid const stripping with `BIO_new_mem_buf()` and OpenSSL 1.0.2 and
newer.
- add a missing const in `wincng.h`.
- FIXME added for public:
- `libssh2_channel_window_read_ex()` `read_avail` argument type.
- `libssh2_base64_decode()` `datalen` argument type.
- fix possible overflow in `sftp_read()`.
Ref: 4552c73cd5
- formatting in `wincng.h`.
See warning details in the PR's individual commits.
Cherry-picked from #846Closes#876
- convert `_libssh2_explicit_zero()` to macro. This allows inlining
where supported (e.g. `SecureZeroMemory()`).
- replace `SecureZeroMemory()` (in `wincng.c`) and
`LIBSSH2_CLEAR_MEMORY`-guarded `memset()` (in `os400qc3.c`) with
`_libssh2_explicit_zero()` macro.
- delete `LIBSSH2_CLEAR_MEMORY` guards, which enables secure-zeroing
universally.
- add `LIBSSH2_NO_CLEAR_MEMORY` option to disable secure-zeroing.
- while here, delete double/triple inclusion of `misc.h`.
`libssh2_priv.h` included it already.
Closes#810
- in `hostkey.c` check the result of `libssh2_sha256_init()` and
`libssh2_sha512_init()` calls. This avoid the warning that we're
ignoring the return values.
- fix code using `int` (or `SOCKET`) for sockets. Use libssh2's
dedicated `libssh2_socket_t` and `LIBSSH2_INVALID_SOCKET` instead.
- fix compiler warnings due to `STATUS_*` macro redefinitions between
`ntstatus.h` / `winnt.h`. Solve it by manually defining the single
`STATUS` value we need from `ntstatus.h` and stop including the whole
header.
Fixes#733
- improve Windows UWP/WinRT builds by detecting it with code copied
from the curl project. Then excluding problematic libssh2 parts
according to PR by Dmitry Kostjučenko.
Fixes#734
- always use `SecureZeroMemory()` on Windows.
We can tweak this if not found or not inlined by a C compiler which
we otherwise support. Same if it causes issues with UWP apps.
Ref: https://learn.microsoft.com/en-us/previous-versions/windows/desktop/legacy/aa366877(v=vs.85)
Ref: https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/nf-wdm-rtlsecurezeromemory
- always enable `LIBSSH2_CLEAR_MEMORY` on Windows. CMake and
curl-for-win builds already did that. Delete `SecureZeroMemory()`
detection from autotools' WinCNG backend logic, that this
setting used to depend on.
TODO: Enable it for all platforms in a separate PR.
TODO: For clearing buffers in WinCNG, call `_libssh2_explicit_zero()`,
insead of a local function or explicit `SecureZeroMemory()`.
- Makefile.inc: move `os400qc3.h` to `HEADERS`. This fixes
compilation on non-unixy platforms. Recent regression.
- `libssh2.rc`: replace copyright with plain ASCII, as in curl.
Ref: curl/curl@1ca62bb
Ref: curl/curl#7765
Ref: curl/curl#7776
- CMake fixes and improvements:
- enable warnings with llvm/clang.
- enable more comprehensive warnings with gcc and llvm/clang.
Logic copied from curl:
233810bb5f/CMakeLists.txt (L131-L148)
- fix `Policy CMP0080` CMake warning by deleting that reference.
- add `ENABLE_WERROR` (default: `OFF`) option. Ported from curl.
- add `PICKY_COMPILER` (default: `ON`) option, as known from curl.
It controls both the newly added picky warnings for llvm/clang and
gcc, and also the pre-existing ones for MSVC.
- `win32/GNUmakefile` fixes and improvements:
- delete `_AMD64_` and add missing `-m64` for x64 builds under test.
- add support for `ARCH=custom`.
It disables hardcoded Intel 64-bit and Intel 32-bit options,
allowing ARM64 builds.
- add support for `LIBSSH2_RCFLAG_EXTRAS`.
To pass custom options to windres, e.g. in ARM64 builds.
- add support for `LIBSSH2_RC`. To override `windres`.
- delete support for Metrowerks C. Last released in 2004.
- `win32/libssh2_config.h`: delete unnecessary socket #includes
`src/libssh2_priv.h` includes `winsock2.h` and `ws2tcpip.h` further
down the line, triggered by `HAVE_WINSOCK2_H`.
`mswsock.h` does not seem to be necessary anymore.
Double-including these (before `windows.h`) caused compiler failures
when building against BoringSSL and warnings with LibreSSL. We could
work this around by passing `-DNOCRYPT`. Deleting the duplicates
fixes these issues.
Timeline:
2013: c910cd382d deleted `mswsock.h` from `src/libssh2_priv.h`
2008: 8c43bc52b1 added `winsock2.h` and `ws2tcpip.h` to `src/libssh2_priv.h`
2005: dc4bb1af96 added the now deleted #includes
- delete or replace `LIBSSH2_WIN32` with `WIN32`.
- replace hand-rolled `HAVE_WINDOWS_H` macro with `WIN32`. Also delete
its detections/definitions.
- delete unused `LIBSSH2_DARWIN` macro.
- delete unused `writev()` Windows implementation
There is no reference to `writev()` since 2007-02-02, commit
9d55db6501.
- fix a bunch of MSVC / llvm/clang / gcc compiler warnings:
- `warning C4100: '...': unreferenced formal parameter`
- using value of undefined PP macro `LIBSSH2DEBUG`
- missing void from function definition
- `if()` block missing in non-debug builds
- unreferenced variable in non-debug builds
- `warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]`
in `_libssh2_debug()`
- `warning C4295: 'ciphertext' : array is too small to include a terminating null character`
- `warning C4706: assignment within conditional expression`
- `warning C4996: 'inet_addr': Use inet_pton() or InetPton() instead or
define _WINSOCK_DEPRECATED_NO_WARNINGS to disable deprecated API warnings`
By suppressning it. Would be best to use inet_pton() as suggested.
On Windows this needs Vista though.
- `warning C4152: nonstandard extension, function/data pointer conversion in expression`
(silenced locally)
- `warning C4068: unknown pragma`
Ref: https://ci.appveyor.com/project/libssh2org/libssh2/builds/46354480/job/j7d0m34qgq8rag5wCloses#808
Make libssh2 compile cleanly with mbedTLS 3.x and later.
This patch makes use of `MBEDTLS_PRIVATE()`, which is not the
recommended, future-proof way to access mbedTLS data structures. This
method may break with a minor upgrade, according to the authors. This
is also the method used by libcurl.
Also:
- Fix a potentially uninitialized variable in
`libssh2_mbedtls_rsa_sha2_sign()`. This happened in an error path,
resulting in an unnecessary mbedTLS API call, with an uninitialized
`md_type`.
- Bump mbedTLS version used in CI tests to 3.2.1.
Fixes#751
Notes:
* Host Key RSA 256/512 support #536
* Client side key hash upgrading for RFC 8332
* Support for server-sig-algs, ext-info-c server messages
* Customizing preferred server-sig-algs via the preference LIBSSH2_METHOD_SIGN_ALGO
Credit: Anders Borum, Will Cosgrove
Files:
mbedtls.c, mbedtls.h, .travis.yml
Notes:
This PR adds support for ECDSA for both key exchange and host key algorithms.
The following elliptic curves are supported:
256-bit curve defined by FIPS 186-4 and SEC1
384-bit curve defined by FIPS 186-4 and SEC1
521-bit curve defined by FIPS 186-4 and SEC1
Credit:
Sebastián Katzer
Use checksrc.pl from the curl project, with (for now)
suppressed long line warnings and indentation set to
4 spaces. Fixes are whitespace for the most part.
Warning count went down from 2704 to 12.
Also fix codespell typos, two non-ANSI C89 comments
and a stray tab in include/libssh2.h.
Ref: https://github.com/libssh2/libssh2/pull/235
Not all backends feature the low level API needed to compute a Diffie-Hellman
secret, but some of them directly implement Diffie-Hellman support with opaque
private data. The later approach is now generalized and backends are
responsible for all Diffie Hellman computations.
As a side effect, procedures/macros _libssh2_bn_rand and _libssh2_bn_mod_exp
are no longer needed outside the backends.
