When TLS 1.3 is negotiated on a TLS session, GNUTLS will perform
automatic rekeying of the session after 16 million records. This
is done for all algorithms except CHACHA20_POLY1305 which does
not require rekeying.
Unfortunately the rekeying breaks GNUTLS' promise that it is safe
to use a gnutls_session_t object concurrently from multiple threads
if they are exclusively calling gnutls_record_send/recv.
This patch implements a workaround for QEMU that adds a mutex lock
around any gnutls_record_send/recv call to serialize execution
within GNUTLS code. When GNUTLS calls into the push/pull functions
we can release the lock so the OS level I/O calls can at least
have some parallelism.
The big downside of this is that the actual encryption/decryption
code is fully serialized, which will halve performance of that
cipher operations if two threads are contending.
The workaround is not enabled by default, since most use of GNUTLS
in QEMU does not tickle the problem, only non-multifd migration
with a return path open is affected. Fortunately the migration
code also won't trigger the halving of performance, since only
the outbound channel diretion needs to sustain high data rates,
the inbound direction is low volume.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/qemu-devel/20250718150514.2635338-2-berrange@redhat.com
[add stub for qcrypto_tls_session_require_thread_safety; fix unused var]
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Some CA files may contain multiple intermediaries and roots of trust.
These may not fit into the hard-coded limit of 16.
Extend the validation code to allocate enough space to load all of the
certificates present in the CA file and ensure they are cleaned up.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Henry Kleynhans <hkleynhans@fb.com>
[DB: drop MAX_CERTS constant & whitespace tweaks]
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Coverity notes that in qcrypto_get_x509_cert_fingerprint() we
call gnutls_x509_crt_init() but don't check for an error return.
Add the missing check.
Coverity: CID 1593155
Fixes: 10a1d34fc0 ("crypto: Introduce x509 utils")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
When originally creating the internal crypto cipher APIs, they were
wired up to use the built-in D3DES and AES implementations, as a way
to gracefully transition to the new APIs without introducing an
immediate hard dep on any external crypto libraries for the VNC
password auth (D3DES) or the qcow2 encryption (AES).
In the 6.1.0 release we dropped the built-in D3DES impl, and also
the XTS mode for the AES impl, leaving only AES with ECB/CBC modes.
The rational was that with the system emulators, it is expected that
3rd party crypto libraries will be available.
The qcow2 LUKS impl is preferred to the legacy raw AES impl, and by
default that requires AES in XTS mode, limiting the usefulness of
the built-in cipher provider.
The built-in AES impl has known timing attacks and is only suitable
for use cases where a security boundary is already not expected to
be provided (TCG).
Providing a built-in cipher impl thus potentially misleads users,
should they configure a QEMU without any crypto library, and try
to use it with the LUKS backend, even if that requires a non-default
configuration choice.
Complete what we started in 6.1.0 and purge the remaining AES
support.
Use of either gnutls, nettle, or libcrypt is now mandatory for any
cipher support, except for TCG impls.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The correct way of calling qcrypto_tls_session_handshake() requires
calling qcrypto_tls_session_get_handshake_status() right after it so
there's no reason to have a separate method.
Refactor qcrypto_tls_session_handshake() to inform the status in its
own return value and alter the callers accordingly.
No functional change.
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
QEMU's TLS session code provides no way to call gnutls_bye() to
terminate a TLS session. Callers of qcrypto_tls_session_read() can
choose to ignore a GNUTLS_E_PREMATURE_TERMINATION error by setting the
gracefulTermination argument.
The QIOChannelTLS ignores the premature termination error whenever
shutdown() has already been issued. This was found to be not enough for
the migration code because shutdown() might not have been issued before
the connection is terminated.
Add support for calling gnutls_bye() in the tlssession layer so users
of QIOChannelTLS can clearly identify the end of a TLS session.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Replace g_strdup_printf("%s", value) -> g_strdup(value)
to avoid unnecessary string formatting.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
We're seeing periodic reports of errors like:
$ qemu-img create -f luks --object secret,data=123456,id=sec0 \
-o key-secret=sec0 luks-info.img 1M
Formatting 'luks-info.img', fmt=luks size=1048576 key-secret=sec0
qemu-img: luks-info.img: Unable to get accurate CPU usage
This error message comes from a recent attempt to workaround a
kernel bug with measuring rusage in long running processes:
commit c72cab5ad9
Author: Tiago Pasqualini <tiago.pasqualini@canonical.com>
Date: Wed Sep 4 20:52:30 2024 -0300
crypto: run qcrypto_pbkdf2_count_iters in a new thread
Unfortunately this has a subtle bug on machines which are very fast.
On the first time around the loop, the 'iterations' value is quite
small (1 << 15), and so will run quite fast. Testing has shown that
some machines can complete this benchmarking task in as little as
7 milliseconds.
Unfortunately the 'getrusage' data is not updated at the time of
the 'getrusage' call, it is done asynchronously by the scheduler.
The 7 millisecond completion time for the benchmark is short
enough that 'getrusage' sometimes reports 0 accumulated execution
time.
As a result the 'delay_ms == 0' sanity check in the above commit
is triggering non-deterministically on such machines.
The benchmarking loop intended to run multiple times, increasing
the 'iterations' value until the benchmark ran for > 500 ms, but
the sanity check doesn't allow this to happen.
To fix it, we keep a loop counter and only run the sanity check
after we've been around the loop more than 5 times. At that point
the 'iterations' value is high enough that even with infrequent
updates of 'getrusage' accounting data on fast machines, we should
see a non-zero value.
Fixes: https://lore.kernel.org/qemu-devel/ffe542bb-310c-4616-b0ca-13182f849fd1@redhat.com/
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2336437
Reported-by: Thomas Huth <thuth@redhat.com>
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20250109093746.1216300-1-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Headers in include/sysemu/ are not only related to system
*emulation*, they are also used by virtualization. Rename
as system/ which is clearer.
Files renamed manually then mechanical change using sed tool.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Lei Yang <leiyang@redhat.com>
Message-Id: <20241203172445.28576-1-philmd@linaro.org>
gcrypto has the ability to dynamically disable hash/hmac algorithms
at runtime, so QEMU must perform a runtime check.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Gcrypt does not return negative values on error, it returns non-zero
values. This caused QEMU not to detect failure to open an unsupported
hash, resulting in a later crash trying to use a NULL context.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Introduce the SM3 cryptographic hash algorithm (GB/T 32905-2016).
SM3 (GB/T 32905-2016) is a cryptographic standard issued by the
Organization of State Commercial Cryptography Administration (OSCCA)
as an authorized cryptographic algorithm for use within China.
Detect the SM3 cryptographic hash algorithm and enable the feature silently
if it is available.
Signed-off-by: cheliequan <cheliequan@inspur.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The 'loaded' property on TLS creds and secret objects was marked as
deprecated in 6.0.0. In 7.1.0 the deprecation info was moved into
the 'removed-features.rst' file, but the property was not actually
removed, just made read-only. This was a highly unusual practice,
so finish the long overdue removal job.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Fux build broken by semantic conflict with commit
8f525028bc (qapi/crypto: Rename QCryptoAFAlg to QCryptoAFAlgo).
Fixes: 90c3dc6073 (crypto/hash-afalg: Implement new hash API)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
If the user provides a pre-allocated buffer for the hash result,
we must use that rather than re-allocating a new buffer.
Reported-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
qcrypto_der_encode_octet_str_begin and _end have been unused
since they were added in
3b34ccad66 ("crypto: Support DER encodings")
Remove them.
Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The nettle 2.x series declared all the hash functions with 'int' for
the data size. Since we dropped support for anything older than 3.4
we can assume nettle is using 'size_t' and thus avoid the back compat
looping logic.
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Removes the old hash API functions in the afalg driver,
and modifies the hmac function to use the new helper functions.
Signed-off-by: Alejandro Zeise <alejandro.zeise@seagate.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[ clg: - Checkpatch fixes ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
