Because `keylen` is unsigned the subtraction results in an integer
underflow if the key length is < 11 bytes.
This is only a problem when verifying signatures with a public key (for
private keys the plugin enforces a minimum modulus length) and to do so
we usually only use trusted keys. However, the x509 plugin actually
calls issued_by() on a parsed certificate to check if it is self-signed,
which is the reason this issue was found by OSS-Fuzz in the first place.
So, unfortunately, this can be triggered by sending an invalid client
cert to a peer.
Fixes: 5955db5b12 ("gmp: Don't parse PKCS1 v1.5 RSA signatures to verify them")
Fixes: CVE-2018-17540
Instead we generate the expected signature encoding and compare it to the
decrypted value.
Due to the lenient nature of the previous parsing code (minimum padding
length was not enforced, the algorithmIdentifier/OID parser accepts arbitrary
data after OIDs and in the parameters field etc.) it was susceptible to
Daniel Bleichenbacher's low-exponent attack (from 2006!), which allowed
forging signatures for keys that use low public exponents (i.e. e=3).
Since the public exponent is usually set to 0x10001 (65537) since quite a
while, the flaws in the previous code should not have had that much of a
practical impact in recent years.
Fixes: CVE-2018-16151, CVE-2018-16152
This also changes how unknown/corrupted memory is handled in the free()
and realloc() hooks in general.
Incorporates changes provided by Thomas Egerer who ran into a similar
issue.
Due to the mangled C++ function names it's tricky to be more specific. The
"leaked" allocations are from a static hashtable containing EC groups.
There is another leak caused by the locking allocator singleton
(triggered by the first function that uses it, usually initialization of
a cipher, but could be a hasher in other test runners), but we can avoid
that with a Botan config option.
Simplifies public key loading and this way unencrypted PKCS#8-encoded
keys can be loaded directly without pkcs8 plugin (code for encrypted
keys could probably later be added, if necessary).
It also simplifies the implementation of private_key_t::get_public_key()
a lot.
Without OID we can't generate an algorithmIdentifier when loading the
key again. And older versions of OpenSSL insist on a public key when
e.g. converting a key to PKCS#8.
Simply unwrapping the ECPrivateKey structure avoids log messages when
parsing other keys in the KEY_ANY case.
Support MD5 in the Botan plugin if supported by Botan.
MD5 is required for RADIUS and obviously EAP-MD5,
and also for non-PKCS#8 encoded, encrypted private keys.
Botan only allows RSA generating keys >= 1,024 bits, which makes
the RSA test suite fail. It is questionable whether it makes
sense to test 768 bit RSA keys anymore. They are too weak
from today's perspective anyway.
This requires config changes if filelog is used with a path that
contains dots. This path must now be defined in the `path` setting of an
arbitrarily named subsection of `filelog`. Without that change the
whole strongswan.conf file will fail to load, which some users might
not notice immediately.
Tobias Brunner