mbedtls_ssl_context contains pointers in_buf, in_hdr, in_len, ...
which point to various parts of the header of an incoming TLS or
DTLS record; similarly, there are pointers out_buf, ... for
outgoing records.
This commit adds fields in_cid and out_cid which point to where
the CID of incoming/outgoing records should reside, if present,
namely prior to where the record length resides.
Quoting https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-04:
The DTLSInnerPlaintext value is then encrypted and the CID added to
produce the final DTLSCiphertext.
struct {
ContentType special_type = tls12_cid; /* 25 */
ProtocolVersion version;
uint16 epoch;
uint48 sequence_number;
opaque cid[cid_length]; // New field
uint16 length;
opaque enc_content[DTLSCiphertext.length];
} DTLSCiphertext;
For outgoing records, out_cid is set in ssl_update_out_pointers()
based on the settings in the current outgoing transform.
For incoming records, ssl_update_in_pointers() sets in_cid as if no
CID was present, and it is the responsibility of ssl_parse_record_header()
to update the field (as well as in_len, in_msg and in_iv) when parsing
records that do contain a CID. This will be done in a subsequent commit.
Finally, the code around the invocations of ssl_decrypt_buf()
and ssl_encrypt_buf() is adapted to transfer the CID from the
input/output buffer to the CID field in the internal record
structure (which is what ssl_{encrypt/decrypt}_buf() uses).
Note that mbedtls_ssl_in_hdr_len() doesn't need change because
it infers the header length as in_iv - in_hdr, which will account
for the CID for records using such.
Using the Connection ID extension increases the maximum record expansion
because
- the real record content type is added to the plaintext
- the plaintext may be padded with an arbitrary number of
zero bytes, in order to prevent leakage of information
through package length analysis. Currently, we always
pad the plaintext in a minimal way so that its length
is a multiple of 16 Bytes.
This commit adapts the various parts of the library to account
for that additional source of record expansion.
Context:
The CID draft does not require that the length of CIDs used for incoming
records must not change in the course of a connection. Since the record
header does not contain a length field for the CID, this means that if
CIDs of varying lengths are used, the CID length must be inferred from
other aspects of the record header (such as the epoch) and/or by means
outside of the protocol, e.g. by coding its length in the CID itself.
Inferring the CID length from the record's epoch is theoretically possible
in DTLS 1.2, but it requires the information about the epoch to be present
even if the epoch is no longer used: That's because one should silently drop
records from old epochs, but not the entire datagrams to which they belong
(there might be entire flights in a single datagram, including a change of
epoch); however, in order to do so, one needs to parse the record's content
length, the position of which is only known once the CID length for the epoch
is known. In conclusion, it puts a significant burden on the implementation
to infer the CID length from the record epoch, which moreover mangles record
processing with the high-level logic of the protocol (determining which epochs
are in use in which flights, when they are changed, etc. -- this would normally
determine when we drop epochs).
Moreover, with DTLS 1.3, CIDs are no longer uniquely associated to epochs,
but every epoch may use a set of CIDs of varying lengths -- in that case,
it's even theoretically impossible to do record header parsing based on
the epoch configuration only.
We must therefore seek a way for standalone record header parsing, which
means that we must either (a) fix the CID lengths for incoming records,
or (b) allow the application-code to configure a callback to implement
an application-specific CID parsing which would somehow infer the length
of the CID from the CID itself.
Supporting multiple lengths for incoming CIDs significantly increases
complexity while, on the other hand, the restriction to a fixed CID length
for incoming CIDs (which the application controls - in contrast to the
lengths of the CIDs used when writing messages to the peer) doesn't
appear to severely limit the usefulness of the CID extension.
Therefore, the initial implementation of the CID feature will require
a fixed length for incoming CIDs, which is what this commit enforces,
in the following way:
In order to avoid a change of API in case support for variable lengths
CIDs shall be added at some point, we keep mbedtls_ssl_set_cid(), which
includes a CID length parameter, but add a new API mbedtls_ssl_conf_cid_len()
which applies to an SSL configuration, and which fixes the CID length that
any call to mbetls_ssl_set_cid() which applies to an SSL context that is bound
to the given SSL configuration must use.
While this creates a slight redundancy of parameters, it allows to
potentially add an API like mbedtls_ssl_conf_cid_len_cb() later which
could allow users to register a callback which dynamically infers the
length of a CID at record header parsing time, without changing the
rest of the API.
The function mbedtls_ssl_hdr_len() returns the length of the record
header (so far: always 13 Bytes for DTLS, and always 5 Bytes for TLS).
With the introduction of the CID extension, the lengths of record
headers depends on whether the records are incoming or outgoing,
and also on the current transform.
Preparing for this, this commit splits mbedtls_ssl_hdr_len() in two
-- so far unmodified -- functions mbedtls_ssl_in_hdr_len() and
mbedtls_ssl_out_hdr_len() and replaces the uses of mbedtls_ssl_hdr_len()
according to whether they are about incoming or outgoing records.
There is no need to change the signature of mbedtls_ssl_{in/out}_hdr_len()
in preparation for its dependency on the currently active transform,
since the SSL context is passed as an argument, and the currently
active transform is referenced from that.
This commit adds a static array `cid` to the internal structure
`mbedtls_record` representing encrypted and decrypted TLS records.
The expected evolution of state of this field is as follows:
- When handling an incoming record, the caller of `mbedtls_decrypt_buf()`
has to make sure the CID array field in `mbedtls_record` has been
properly set. Concretely, it will be copied from the CID from the record
header during record parsing.
- During decryption in `mbedtls_decrypt_buf()`, the transforms
incoming CID is compared to the CID in the `mbedtls_record`
structure representing the record to be decrypted.
- For an outgoing TLS record, the caller of `mbedtls_encrypt_buf()`
clears the CID in the `mbedtls_record` structure.
- During encryption in `mbedtls_encrypt_buf()`, the CID field in
`mbedtls_record` will be copied from the out-CID in the transform.
These will be copied from the CID fields in mbedtls_ssl_handshake_params
(outgoing CID) and mbedtls_ssl_context (incoming CID) when the transformation
is set up at the end of the handshake.
* mbedtls_ssl_context gets fields indicating whether the CID extension
should be negotiated in the next handshake, and, if yes, which CID
the user wishes the peer to use.
This information does not belong to mbedtls_ssl_handshake_params
because (a) it is configured prior to the handshake, and (b) it
applies to all subsequent handshakes.
* mbedtls_ssl_handshake_params gets fields indicating the state of CID
negotiation during the handshake. Specifically, it indicates if the
use of the CID extension has been negotiated, and if so, which CID
the peer wishes us to use for outgoing messages.
Conflicts:
* library/ssl_cli.c, library/ssl_tls.c:
Removed on the development branch. Keep them removed.
* include/psa/crypto_extra.h, library/psa_crypto_storage.c,
tests/suites/test_suite_psa_crypto.data,
tests/suites/test_suite_psa_crypto.function,
tests/suites/test_suite_psa_crypto_persistent_key.data,
tests/suites/test_suite_psa_crypto_slot_management.data,
tests/suites/test_suite_psa_crypto_slot_management.function:
Modified on the development branch only to implement the enrollment
algorithm, which has been reimplemented on the API branch.
Keep the API branch.
* origin/pr/2403: (24 commits)
crypto: Update to Mbed Crypto 8907b019e7
Create seedfile before running tests
crypto: Update to Mbed Crypto 81f9539037
ssl_cli.c : add explicit casting to unsigned char
Generating visualc files - let Mbed TLS take precedence over crypto
Add a link to the seedfile for out-of-tree cmake builds
Adjust visual studio file generation to always use the crypto submodule
all.sh: unparallelize mingw tests
all.sh - disable parallelization for shared target tests
config.pl: disable PSA_ITS_FILE and PSA_CRYPTO_STORAGE for baremetal
all.sh: unset crypto storage define in a psa full config cmake asan test
all.sh: unset FS_IO-dependent defines for tests that do not have it
curves.pl - change test script to not depend on the implementation
Export the submodule flag to sub-cmakes
Disable MBEDTLS_ECP_RESTARTABLE in full config
Export the submodule flag to sub-makes
Force the usage of crypto submodule
Fix crypto submodule usage in Makefile
Documentation rewording
Typo fixes in documentation
...
* origin/pr/2410:
Update change log
Document the default value for the maximum fragment length
Improve clarity of mbedtls_ssl_conf_max_frag_len documentation
Reword ssl_conf_max_frag_len documentation
Fix typos and miswording in the mbedtls_ssl_conf_max_frag_len documentation comment
Reword ssl_conf_max_frag_len documentation to clarify its necessity
Previously it was disabled as too experimental, which no longer holds. Also,
this option introduces new APIs, so it's not only about an internal
alternative (as the comment in config.pl used to state) - people who request a
full config should get all of the available APIs.
Adapt all.sh: now all builds with full config will also test this option, and
builds with the default config will test without it. Just to be sure, let's
have a build with full config minus this option.
Update documentation of MBEDTLS_USE_PSA_CRYPTO to reflect the status of the
new APIs it enables in Mbed TLS and why they're still opt-in.
Also enable it in scripts/config.pl full, as well as two storage options that
were only blacklisted from full config because they depended on
MBEDTLS_PSA_CRYPTO_C.
Don't use "safe buffer size", because this it's somewhat misleading to
make it about safety: a buffer size that's too small will lead to a
runtime error, not to undefined behavior.
Convert the description of PSA_ALG_TLS12_PRF and
PSA_ALG_TLS12_PSK_TO_MS to the key derivation API that takes one input
at a time rather than the old {secret,salt,label} interface.
Define a new input category "seed".
PSA_KEY_ATTRIBUTES_INIT and psa_key_attributes_init weren't declared
in the API document, only defined in our implementation, but they are
referenced in the API document.
Resolve conflicts by performing the following operations:
- Reject changes to files removed during the creation of Mbed Crypto
from Mbed TLS.
- Reject the addition of certificates that would not be used by any
tests, including rejecting the addition of Makefile rules to
generate these certificates.
- Reject changes to error.c referencing modules that are not part of
Mbed Crypto.
* origin/development: (80 commits)
Style fix
Fix test data
Update test data
Add some negative test cases
Fix minor issues
Add ChangeLog entry about listing all SAN
Remove unneeded whitespaces
Fix mingw CI failures
Initialize psa_crypto in ssl test
Check that SAN is not malformed when parsing
Documentation fixes
Fix ChangeLog entry
Fix missing tls version test failures
Fix typo
Fix ChangeLog entry location
Add changeLog entry
Add test for export keys functionality
Add function to retrieve the tls_prf type
Add tests for the public tls_prf API
Add public API for tls_prf
...
* origin/pr/2530: (27 commits)
Style fix
Fix test data
Update test data
Add some negative test cases
Fix minor issues
Add ChangeLog entry about listing all SAN
Check that SAN is not malformed when parsing
Documentation fixes
Fix ChangeLog entry
Fail in case critical crt policy not supported
Update SAN parsing documentation
change the type of hardware_module_name member
Change mbedtls_x509_subject_alternative_name
Add length checking in certificate policy parsing
Rephrase x509_crt extension member description
Rephrase changeLog entries
Remove redundant memset()
Propogate error when parsing SubjectAltNames
Tidy up style in x509_info_subject_alt_name
Print unparseable SubjectAlternativeNames
...
* origin/pr/2538:
Remove unneeded whitespaces
Fix mingw CI failures
Initialize psa_crypto in ssl test
Fix missing tls version test failures
Fix typo
Fix ChangeLog entry location
Add changeLog entry
Add test for export keys functionality
Add function to retrieve the tls_prf type
Add tests for the public tls_prf API
Add public API for tls_prf
Add eap-tls key derivation in the examples.
Add ChangeLog entry
Add an extra key export function
Have the temporary buffer allocated dynamically
Zeroize secret data in the exit point
Add a single exit point in key derivation function
generate_key is a more classical name. The longer name was only
introduced to avoid confusion with getting a key from a generator,
which is key derivation, but we no longer use the generator
terminology so this reason no longer applies.
perl -i -pe 's/psa_generate_random_key/psa_generate_key/g' $(git ls-files)
“Tampering detected” was misleading because in the real world it can
also arise due to a software bug. “Corruption detected” is neutral and
more precisely reflects what can trigger the error.
perl -i -pe 's/PSA_ERROR_TAMPERING_DETECTED/PSA_ERROR_CORRUPTION_DETECTED/gi' $(git ls-files)
Move DSA-related key types and algorithms to the
implementation-specific header file. Not that we actually implement
DSA, but with domain parameters, we should be able to.
Parametrize finite-field Diffie-Hellman key types with a DH group
identifier, in the same way elliptic curve keys are parametrized with
an EC curve identifier.
Define the DH groups from the TLS registry (these are the groups from
RFC 7919).
Replicate the macro definitions and the metadata tests from elliptic
curve identifiers to DH group identifiers.
Define PSA_DH_GROUP_CUSTOM as an implementation-specific extension for
which domain parameters are used to specify the group.
Move psa_get_key_domain_parameters() and
psa_set_key_domain_parameters() out of the official API and declare
them to be implementation-specific extensions.
Expand the documentation of psa_set_key_domain_parameters() a bit to
explain how domain parameters are used.
Remove all mentions of domain parameters from the documentation of API
functions. This leaves DH and DSA effectively unusable.
Generators are mostly about key derivation (currently: only about key
derivation). "Generator" is not a commonly used term in cryptography.
So favor "derivation" as terminology.
This commit updates the function descriptions.
Generators are mostly about key derivation (currently: only about key
derivation). "Generator" is not a commonly used term in cryptography.
So favor "derivation" as terminology. Call a generator a key
derivation operation structure, since it behaves like other multipart
operation structures. Furthermore, the function names are not fully
consistent.
In this commit, I rename the functions to consistently have the prefix
"psa_key_derivation_". I used the following command:
perl -i -pe '%t = (
psa_crypto_generator_t => "psa_key_derivation_operation_t",
psa_crypto_generator_init => "psa_key_derivation_init",
psa_key_derivation_setup => "psa_key_derivation_setup",
psa_key_derivation_input_key => "psa_key_derivation_input_key",
psa_key_derivation_input_bytes => "psa_key_derivation_input_bytes",
psa_key_agreement => "psa_key_derivation_key_agreement",
psa_set_generator_capacity => "psa_key_derivation_set_capacity",
psa_get_generator_capacity => "psa_key_derivation_get_capacity",
psa_generator_read => "psa_key_derivation_output_bytes",
psa_generate_derived_key => "psa_key_derivation_output_key",
psa_generator_abort => "psa_key_derivation_abort",
PSA_CRYPTO_GENERATOR_INIT => "PSA_KEY_DERIVATION_OPERATION_INIT",
PSA_GENERATOR_UNBRIDLED_CAPACITY => "PSA_KEY_DERIVATION_UNLIMITED_CAPACITY",
); s/\b(@{[join("|", keys %t)]})\b/$t{$1}/ge' $(git ls-files)
In psa_import_key, change the order of parameters to pass
the pointer where the newly created handle will be stored last.
This is consistent with most other library functions that put inputs
before outputs.
In psa_generate_derived_key, change the order of parameters to pass
the pointer where the newly created handle will be stored last.
This is consistent with most other library functions that put inputs
before outputs.
Use individual setters for the id and lifetime fields of an attribute
structure, like the other attributes.
This commit updates the specification and adds an implementation of
the new setters.
Add an additional function `mbedtls_ssl_export_keys_ext_t()`
for exporting key, that adds additional information such as
the used `tls_prf` and the random bytes.
1) Fix typo in `mbedtls_x509_parse_subject_alt_name()` documentation.
2) Add a not in `mbedtls_x509_parse_subject_alt_name()` documentation,
stating that the lifetime of the target structure is restricted
by the lifetime ofthe parsed certificate.
Make `mbedtls_x509_subject_alternative_name` to be a single item
rather than a list. Adapt the subject alternative name parsing function,
to receive a signle `mbedtls_x509_buf` item from the subject_alt_names
sequence of the certificate.
The documentation for some new structures and members was only a C style
comment and wasn't picked up by doxygen. This commit adds the missing
asterisks.
Define a range of key identifiers for use by the application
(0..2^30-1), a range for use by implementations (2^30..2^31), and a
range that is reserved for future use (2^31..2^32-1).
Change the scope of key identifiers to be global, rather than
per lifetime. As a result, you now need to specify the lifetime of a
key only when creating it.
Declare algorithms for ChaCha20 and ChaCha20-Poly1305, and a
corresponding (common) key type.
Don't declare Poly1305 as a separate algorithm because it's a one-time
authenticator, not a MAC, so the API isn't suitable for it (no way to
use a nonce).
New macros PSA_AEAD_UPDATE_OUTPUT_SIZE, PSA_AEAD_FINISH_OUTPUT_SIZE
and PSA_AEAD_VERIFY_OUTPUT_SIZE to determine the output buffer sizes
for psa_aead_update(), psa_aead_finish() and psa_aead_verify().
Like psa_aead_finish(), psa_aead_verify() needs to produce output from
the last partial block of input if psa_aead_update() cannot produce
output byte by byte.
In psa_import_key and psa_copy_key, some information comes from the
key data (input buffer or source key) rather than from the attributes:
key size for import, key size and type and domain parameters for copy.
If an unused attribute is nonzero in the attribute structure, check
that it matches the correct value. This protects against application
errors.
* origin/pr/1633: (26 commits)
Fix uninitialized variable access in debug output of record enc/dec
Adapt PSA code to ssl_transform changes
Ensure non-NULL key buffer when building SSL test transforms
Catch errors while building SSL test transforms
Use mbedtls_{calloc|free}() in SSL unit test suite
Improve documentation of mbedtls_record
Adapt record length value after encryption
Alternative between send/recv transform in SSL record test suite
Fix memory leak on failure in test_suite_ssl
Rename ssl_decrypt_buf() to mbedtls_ssl_decrypt_buf() in comment
Add record encryption/decryption tests for ARIA to SSL test suite
Improve documentation of mbedtls_ssl_transform
Double check that record expansion is as expected during decryption
Move debugging output after record decryption
Add encryption/decryption tests for small records
Add tests for record encryption/decryption
Reduce size of `ssl_transform` if no MAC ciphersuite is enabled
Remove code from `ssl_derive_keys` if relevant modes are not enabled
Provide standalone version of `ssl_decrypt_buf`
Provide standalone version of `ssl_encrypt_buf`
...
Resolve merge conflicts by performing the following actions:
- Reject changes to deleted files.
- Reject changes to generate_errors.pl and generate_visualc_files.pl.
Don't add an 'include-crypto' option which would attempt to use the
non-existent crypto submodule.
- list-identifiers.sh had the `--internal` option added to it, which
lists identifiers only in internal headers. Add PSA-specific internal
headers to list-identifiers.sh.
* origin/development: (40 commits)
Document the scripts behaviour further
Use check_output instead of Popen
all.sh: Require i686-w64-mingw32-gcc version >= 6
generate_visualc_files.pl: add mbedtls source shadowing by crypto
generate_errors.pl: refactor and simplify the code
Start unused variable with underscore
Correct documentation
generate_errors.pl: typo fix
revert changes to generate_features.pl and generate_query_config.pl
Check that the report directory is a directory
Use namespaces instead of full classes
Fix pylint issues
Don't put abi dumps in subfolders
Add verbose switch to silence all output except the final report
Fetch the remote crypto branch, rather than cloning it
Prefix internal functions with underscore
Add RepoVersion class to make handling of many arguments easier
Reduce indentation levels
Improve documentation
Use optional arguments for setting repositories
...
There was a guarantee that psa_get_key_attributes() does not require a
subsequent psa_reset_key_attributes() to free resources as long as the
key was created with attributes having this property. This requirement
was hard to pin down because if a key is created with default
parameters, there are cases where it is difficult to ensure that the
domain parameters will be reported without allocating memory. So
remove this guarantee. Now the only case psa_reset_key_attributes() is
not required is if the attribute structure has only been modified with
certain specific setters.
Read extra data from the domain parameters in the attribute structure
instead of taking an argument on the function call.
Implement this for RSA key generation, where the public exponent can
be set as a domain parameter.
Add tests that generate RSA keys with various public exponents.
Change psa_get_domain_parameters() and psa_set_domain_parameters() to
access a psa_key_attributes_t structure rather than a key handle.
In psa_get_key_attributes(), treat the RSA public exponent as a domain
parameter and read it out. This is in preparation for removing the
`extra` parameter of psa_generate_key() and setting the RSA public
exponent for key generation via domain parameters.
In this commit, the default public exponent 65537 is not treated
specially, which allows us to verify that test code that should be
calling psa_reset_key_attributes() after retrieving the attributes of
an RSA key is doing so properly (if it wasn't, there would be a memory
leak), even if the test data happens to use an RSA key with the
default public exponent.
Instead of passing a separate parameter for the key size to
psa_generate_key and psa_generator_import_key, set it through the
attributes, like the key type and other metadata.
This commit adds tests exercising mutually inverse pairs of
record encryption and decryption transformations for the various
transformation types allowed in TLS: Stream, CBC, and AEAD.
The hash contexts `ssl_transform->md_ctx_{enc/dec}` are not used if
only AEAD ciphersuites are enabled. This commit removes them from the
`ssl_transform` struct in this case, saving a few bytes.
Analogous to the previous commit, but concerning the record decryption
routine `ssl_decrypt_buf`.
An important change regards the checking of CBC padding:
Prior to this commit, the CBC padding check always read 256 bytes at
the end of the internal record buffer, almost always going past the
boundaries of the record under consideration. In order to stay within
the bounds of the given record, this commit changes this behavior by
always reading the last min(256, plaintext_len) bytes of the record
plaintext buffer and taking into consideration the last `padlen` of
these for the padding check. With this change, the memory access
pattern and runtime of the padding check is entirely determined by
the size of the encrypted record, in particular not giving away
any information on the validity of the padding.
The following depicts the different behaviors:
1) Previous CBC padding check
1.a) Claimed padding length <= plaintext length
+----------------------------------------+----+
| Record plaintext buffer | | PL |
+----------------------------------------+----+
\__ PL __/
+------------------------------------...
| read for padding check ...
+------------------------------------...
|
contents discarded
from here
1.b) Claimed padding length > plaintext length
+----------------------------------------+----+
| Record plaintext buffer | PL |
+----------------------------------------+----+
+-------------------------...
| read for padding check ...
+-------------------------...
|
contents discarded
from here
2) New CBC padding check
+----------------------------------------+----+
| Record plaintext buffer | | PL |
+----------------------------------------+----+
\__ PL __/
+---------------------------------------+
| read for padding check |
+---------------------------------------+
|
contents discarded
until here
The previous version of the record encryption function
`ssl_encrypt_buf` takes the entire SSL context as an argument,
while intuitively, it should only depend on the current security
parameters and the record buffer.
Analyzing the exact dependencies, it turned out that in addition
to the currently active `ssl_transform` instance and the record
information, the encryption function needs access to
- the negotiated protocol version, and
- the status of the encrypt-then-MAC extension.
This commit moves these two fields into `ssl_transform` and
changes the signature of `ssl_encrypt_buf` to only use an instance
of `ssl_transform` and an instance of the new `ssl_record` type.
The `ssl_context` instance is *solely* kept for the debugging macros
which need an SSL context instance.
The benefit of the change is twofold:
1) It avoids the need of the MPS to deal with instances of
`ssl_context`. The MPS should only work with records and
opaque security parameters, which is what the change in
this commit makes progress towards.
2) It significantly eases testing of the encryption function:
independent of any SSL context, the encryption function can
be passed some record buffer to encrypt alongside some arbitrary
choice of parameters, and e.g. be checked to not overflow the
provided memory.
This commit adds a structure `mbedtls_record` whose instances
represent (D)TLS records. This structure will be used in the
subsequent adaptions of the record encryption and decryption
routines `ssl_decrypt_buf` and `ssl_encrypt_buf`, which currently
take the entire SSL context as input, but should only use the
record to be acted on as well as the record transformation to use.
The macro constant `MBEDTLS_SSL_MAC_ADD` defined in `ssl_internal.h`
defines an upper bound for the amount of space needed for the record
authentication tag. Its definition distinguishes between the
presence of an ARC4 or CBC ciphersuite suite, in which case the maximum
size of an enabled SHA digest is used; otherwise, `MBEDTLS_SSL_MAC_ADD`
is set to 16 to accomodate AEAD authentication tags.
This assignment has a flaw in the situation where confidentiality is
not needed and the NULL cipher is in use. In this case, the
authentication tag also uses a SHA digest, but the definition of
`MBEDTLS_SSL_MAC_ADD` doesn't guarantee enough space.
The present commit fixes this by distinguishing between the presence
of *some* ciphersuite using a MAC, including those using a NULL cipher.
For that, the previously internal macro `SSL_SOME_MODES_USE_MAC` from
`ssl_tls.c` is renamed and moved to the public macro
`MBEDTLS_SOME_MODES_USE_MAC` defined in `ssl_internal.h`.
Prior to this commit, the security parameter struct `ssl_transform`
contained a `ciphersuite_info` field pointing to the information
structure for the negotiated ciphersuite. However, the only
information extracted from that structure that was used in the core
encryption and decryption functions `ssl_encrypt_buf`/`ssl_decrypt_buf`
was the authentication tag length in case of an AEAD cipher.
The present commit removes the `ciphersuite_info` field from the
`ssl_transform` structure and adds an explicit `taglen` field
for AEAD authentication tag length.
This is in accordance with the principle that the `ssl_transform`
structure should contain the raw parameters needed for the record
encryption and decryption functions to work, but not the higher-level
information that gave rise to them. For example, the `ssl_transform`
structure implicitly contains the encryption/decryption keys within
their cipher contexts, but it doesn't contain the SSL master or
premaster secrets. Likewise, it contains an explicit `maclen`, while
the status of the 'Truncated HMAC' extension -- which determines the
value of `maclen` when the `ssl_transform` structure is created in
`ssl_derive_keys` -- is not contained in `ssl_transform`.
The `ciphersuite_info` pointer was used in other places outside
the encryption/decryption functions during the handshake, and for
these functions to work, this commit adds a `ciphersuite_info` pointer
field to the handshake-local `ssl_handshake_params` structure.
The `ssl_transform` security parameter structure contains opaque
cipher contexts for use by the record encryption/decryption functions
`ssl_decrypt_buf`/`ssl_encrypt_buf`, while the underlying key material
is configured once in `ssl_derive_keys` and is not explicitly dealt with
anymore afterwards. In particular, the key length is not needed
explicitly by the encryption/decryption functions but is nonetheless
stored in an explicit yet superfluous `keylen` field in `ssl_transform`.
This commit removes this field.
Previously, GCM required enabling either AES or Camellia. However, we
also support using GCM with ARIA and without other ciphers. Enable
configurations with only ARIA enabled to use GCM.
Make maintaining config files easier by removing any explicit
ciphersuite lists. These explicit lists are prone to being incomplete as
TLS defines more and more ciphersuites. Rather than try to play catch
up, let's refer to sets of ciphersuites with declarative language.
