This is mostly for the non-mmap case as with mmap available, access to the
unmapped memory isn't easily possible (e.g. opening the same area with
MAP_ANONYMOUS | MAP_UNINITIALIZED is usually prevented by the missing
CONFIG_MMAP_ALLOW_UNINITIALIZED option in most kernels).
Using the workaround with the EVP interface, which we use to derive shared
keys since 74e02ff5e6 ("openssl: Mainly use EVP interface for ECDH"),
would actually require us to register the OIDs of these curves as NID.
Otherwise, the two EC_GROUPs used by private and public key objects
are not considered the same and the key derivation fails.
Since the curves are supported by OpenSSL since 1.0.2 it's probably rare to
find a version without them nowadays. One exception is the old BoringSSL
version we still use on Android, which defines the NIDs but not the curve
data. However, that version also lacks support to register OIDs as NIDs,
so the only option to support these groups there would be to got back to not
using the EVP interface, which isn't in anyone's interest. If there really
is a need for them there, we could probably patch BoringSSL or use OpenSSL.
If there are many CHILD_SAs, the time between initiating the new IKE_SA
and checking it in might be longer (depending on what else is going on
in the daemon) than the retransmission timeout and no retransmits might
be sent afterwards for this SA (it will just linger around dead).
Calling initiate() last should avoid that (we do this similarly for MBB
reauthentication).
If we are using make-before-break reauthentication, this could lead to
duplicates as the new IKE_SA wouldn't be able to delete the previous
one if it was replaced by a rekeying.
If we initiated a make-before-break reauthentication and the peer
concurrently deletes the IKE_SA (e.g. because it uses break-before-make
reauthentication), we would create a duplicate IKE_SA (the condition forces
a recreation of all existing CHILD_SAs because reestablish() is also called
to complete a break-before-make reauthentication).
Previously, only the tpm plugin initialized the library, so in order
to use a TPM 2.0 (a required TCTI library is loaded via init), it was
necessary to load it even if none of its actual features were used.
OpenSSL enforces a minimum of 14 bytes (112 bits) on the key size when
used in FIPS-mode (as required by SP 800-131A). So by using an empty
string, instantiation always failed. 32 bytes (256 bits) should be safe
for now.
Closesstrongswan/strongswan#557
This is required when targeting Android 11 (API 30) in order to see all
packages, which we use to allow selecting apps ex-/included from VPN
profiles and for the EAP-TNC use case.
As suggested by the Android docs, we use a global thread pool and handler
to avoid recreating them repeatedly. Four threads should be more than
enough as we only use this to load CA certificates when the app starts
initially and to load user certs when editing a profile.
This will be mandatory for new apps in August and for existing apps
in November. However, several classes like AsyncTask are now deprecated
so this needs some work to avoid warnings and problems in the future.
Tobias Brunner