Commit graph

4208 commits

Author SHA1 Message Date
Hanno Becker
fcd9e71cdf Don't progress TLS state machine on peer CRT chain parsing error 2019-02-26 14:38:09 +00:00
Hanno Becker
77adddc9e9 Make use of macro and helper detecting whether CertRequest allowed
This commit simplifies the client-side code for outgoing CertificateVerify
messages, and server-side code for outgoing CertificateRequest messages and
incoming CertificateVerify messages, through the use of the macro

   `MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED`

indicating whether a ciphersuite allowing CertificateRequest messages
is enabled in the configuration, as well as the helper function

   `mbedtls_ssl_ciphersuite_cert_req_allowed()`

indicating whether a particular ciphersuite allows CertificateRequest
messages.

These were already used in the client-side code to simplify the
parsing functions for CertificateRequest messages.
2019-02-26 14:38:09 +00:00
Hanno Becker
28f2fcd08d Add helper function to check whether a CRT msg is expected
This commit adds a helper function `ssl_parse_certificate_coordinate()`
which checks whether a `Certificate` message is expected from the peer.

The logic is the following:
- For ciphersuites which don't use server-side CRTs, no Certificate
  message is expected (neither for the server, nor the client).
- On the server, no client certificate is expected in the following cases:
  * The server server didn't request a Certificate, which is controlled
    by the `authmode` setting.
  * A RSA-PSK suite is used; this is the only suite using server CRTs
    but not allowing client-side authentication.
2019-02-26 14:38:09 +00:00
Hanno Becker
7177a88a36 Introduce helper function to determine whether suite uses server CRT
This commit introduces a static helper function

   `mbedtls_ssl_ciphersuite_uses_srv_cert()`

which determines whether a ciphersuite may make use of server-side CRTs.

This function is in turn uses in `mbedtls_ssl_parse_certificate()` to
skip certificate parsing for ciphersuites which don't involve CRTs.

Note: Ciphersuites not using server-side CRTs don't allow client-side CRTs
either, so it is safe to guard `mbedtls_ssl_{parse/write}_certificate()`
this way.

Note: Previously, the code uses a positive check over the suites

- MBEDTLS_KEY_EXCHANGE_PSK
- MBEDTLS_KEY_EXCHANGE_DHE_PSK
- MBEDTLS_KEY_EXCHANGE_ECDHE_PSK
- MBEDTLS_KEY_EXCHANGE_ECJPAKE,

while now, it uses a negative check over `mbedtls_ssl_ciphersuite_uses_srv_cert()`,
which checks for the suites

- MBEDTLS_KEY_EXCHANGE_RSA
- MBEDTLS_KEY_EXCHANGE_RSA_PSK
- MBEDTLS_KEY_EXCHANGE_DHE_RSA
- MBEDTLS_KEY_EXCHANGE_ECDH_RSA
- MBEDTLS_KEY_EXCHANGE_ECDHE_RSA
- MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA
- MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA

This is equivalent since, together, those are all ciphersuites.
Quoting ssl_ciphersuites.h:

```
typedef enum {
    MBEDTLS_KEY_EXCHANGE_NONE = 0,
    MBEDTLS_KEY_EXCHANGE_RSA,
    MBEDTLS_KEY_EXCHANGE_DHE_RSA,
    MBEDTLS_KEY_EXCHANGE_ECDHE_RSA,
    MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA,
    MBEDTLS_KEY_EXCHANGE_PSK,
    MBEDTLS_KEY_EXCHANGE_DHE_PSK,
    MBEDTLS_KEY_EXCHANGE_RSA_PSK,
    MBEDTLS_KEY_EXCHANGE_ECDHE_PSK,
    MBEDTLS_KEY_EXCHANGE_ECDH_RSA,
    MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA,
    MBEDTLS_KEY_EXCHANGE_ECJPAKE,
} mbedtls_key_exchange_type_t;
```
2019-02-26 14:38:09 +00:00
Hanno Becker
2148993900 Use helper macro to detect whether some ciphersuite uses CRTs 2019-02-26 14:38:09 +00:00
Hanno Becker
6bdfab2ccc Unify state machine update in mbedtls_ssl_parse_certificate()
The handler `mbedtls_ssl_parse_certificate()` for incoming `Certificate`
messages contains many branches updating the handshake state. For easier
reasoning about state evolution, this commit introduces a single code-path
updating the state machine at the end of `mbedtls_ssl_parse_certificate()`.
2019-02-26 14:38:09 +00:00
Hanno Becker
7a955a043e Clear peer's CRT chain outside before parsing new one
If an attempt for session resumption fails, the `session_negotiate` structure
might be partially filled, and in particular already contain a peer certificate
structure. This certificate structure needs to be freed before parsing the
certificate sent in the `Certificate` message.

This commit moves the code-path taking care of this from the helper
function `ssl_parse_certificate_chain()`, whose purpose should be parsing
only, to the top-level handler `mbedtls_ssl_parse_certificate()`.

The fact that we don't know the state of `ssl->session_negotiate` after
a failed attempt for session resumption is undesirable, and a separate
issue #2414 has been opened to improve on this.
2019-02-26 14:38:09 +00:00
Hanno Becker
4a55f638e2 Introduce helper to check for no-CRT notification from client
This commit introduces a server-side static helper function
`ssl_srv_check_client_no_crt_notification()`, which checks if
the message we received during the incoming certificate state
notifies the server of the lack of certificate on the client.

For SSLv3, such a notification comes as a specific alert,
while for all other TLS versions, it comes as a `Certificate`
handshake message with an empty CRT list.
2019-02-26 14:38:09 +00:00
Hanno Becker
a028c5bbd8 Introduce CRT counter to CRT chain parsing function
So far, we've used the `peer_cert` pointer to detect whether
we're parsing the first CRT, but that will soon be removed
if `MBEDTLS_SSL_KEEP_PEER_CERTIFICATE` is unset.
2019-02-26 14:38:09 +00:00
Hanno Becker
1294a0b260 Introduce helper function to clear peer CRT from session structure
This commit introduces a helper function `ssl_clear_peer_cert()`
which frees all data related to the peer's certificate from an
`mbedtls_ssl_session` structure. Currently, this is the peer's
certificate itself, while eventually, it'll be its digest only.
2019-02-26 14:38:09 +00:00
Hanno Becker
f852b1c035 Break overly long line in definition of mbedtls_ssl_get_session() 2019-02-26 14:38:09 +00:00
Hanno Becker
60848e6574 Don't reuse CRT from initial handshake during renegotiation
After mitigating the 'triple handshake attack' by checking that
the peer's end-CRT didn't change during renegotation, the current
code avoids re-parsing the CRT by moving the CRT-pointer from the
old session to the new one. While efficient, this will no longer
work once only the hash of the peer's CRT is stored beyond the
handshake.

This commit removes the code-path moving the old CRT, and instead
frees the entire peer CRT chain from the initial handshake as soon
as the 'triple handshake attack' protection has completed.
2019-02-26 14:38:09 +00:00
Jaeden Amero
86016a03a1 Merge remote-tracking branch 'origin/pr/2338' into development 2019-02-22 12:55:30 +00:00
Jaeden Amero
461bd3dcca Merge remote-tracking branch 'origin/pr/2454' into development 2019-02-22 10:32:44 +00:00
Jaeden Amero
9f47f82218 Merge remote-tracking branch 'origin/pr/2391' into development 2019-02-22 10:32:44 +00:00
Jaeden Amero
8963b0311c Merge remote-tracking branch 'origin/pr/2411' into development 2019-02-22 10:32:44 +00:00
Jaeden Amero
3497323f79 Initialize PSA Crypto operation contexts
It is now required to initialize PSA Crypto operation contexts before
calling psa_*_setup(). Otherwise, one gets a PSA_ERROR_BAD_STATE error.
2019-02-20 10:58:55 +00:00
Hanno Becker
0a94a64bbd Add debugging output to confirm that PSA was used for ECDHE 2019-02-18 16:42:02 +00:00
Hanno Becker
c14a3bb5a6 Make variable in ssl_write_client_key_exchange() more descriptive 2019-02-18 16:42:02 +00:00
Hanno Becker
4a63ed421c Implement ClientKeyExchange writing in PSA-based ECDHE suites
- Populate the ECDH private key slot with a fresh private EC key
  designated for the correct algorithm.
- Export the public part of the ECDH private key from PSA and
  reformat it to suite the format of the ClientKeyExchange message.
- Perform the PSA-based ECDH key agreement and store the result
  as the premaster secret for the connection.
2019-02-18 16:42:01 +00:00
Hanno Becker
bb89e2727f Implement ServerKeyExchange parsing for PSA-based ECDHE suites
- Reformat the server's ECDH public key to make it suitable
  for the PSA key agreement API. Currently, the key agreement
  API needs a full SubjectPublicKeyInfo structure, while the
  TLS ServerKeyExchange message only contains a ECPoint structure.
2019-02-18 16:42:01 +00:00
Jaeden Amero
6f7703df3a rsa: Enable use of zero-length null output
Enable handling of zero-length null output in PKCS1 v1.5 decryption.
Prevent undefined behavior by avoiding a memcpy() to zero-length null
output buffers.
2019-02-11 03:39:51 -05:00
Gilles Peskine
004f87b98d RSA encryption: accept input=NULL if ilen=0
In mbedtls_rsa_rsaes_oaep_encrypt and
mbedtls_rsa_rsaes_pkcs1_v15_encrypt, if the input length is 0 (which
is unusual and mostly useless, but permitted) then it is fine for the
input pointer to be NULL. Don't return an error in this case.

When `input` is NULL, `memcpy( p, input, ilen )` has undefined behavior
even if `ilen` is zero. So skip the `memcpy` call in this case.
Likewise, in `mbedtls_rsa_rsaes_oaep_decrypt`, skip the `memcpy` call if
`*olen` is zero.
2019-02-11 03:39:21 -05:00
Hanno Becker
46f34d0ac0 Fix style issue and wording 2019-02-08 14:26:41 +00:00
Hanno Becker
c1e18bdf06 Fix memory leak 2019-02-08 14:26:41 +00:00
Hanno Becker
e2734e2be4 Improve formatting of ssl_parse_certificate_chain() 2019-02-08 14:26:41 +00:00
Hanno Becker
84879e32ef Add compile-time guards around helper routine 2019-02-08 14:26:41 +00:00
Hanno Becker
def9bdc152 Don't store the peer CRT chain twice during renegotiation
Context: During a handshake, the SSL/TLS handshake logic constructs
an instance of ::mbedtls_ssl_session representing the SSL session
being established. This structure contains information such as the
session's master secret, the peer certificate, or the session ticket
issues by the server (if applicable).
During a renegotiation, the new session is constructed aside the existing
one and destroys and replaces the latter only when the renegotiation is
complete. While conceptually clear, this means that during the renegotiation,
large pieces of information such as the peer's CRT or the session ticket
exist twice in memory, even though the original versions are removed
eventually.

This commit removes the simultaneous presence of two peer CRT chains
in memory during renegotiation, in the following way:
- Unlike in the case of SessionTickets handled in the previous commit,
  we cannot simply free the peer's CRT chain from the previous handshake
  before parsing the new one, as we need to verify that the peer's end-CRT
  hasn't changed to mitigate the 'Triple Handshake Attack'.
- Instead, we perform a binary comparison of the original peer end-CRT
  with the one presented during renegotiation, and if it succeeds, we
  avoid re-parsing CRT by moving the corresponding CRT pointer from the
  old to the new session structure.
- The remaining CRTs in the peer's chain are not affected by the triple
  handshake attack protection, and for them we may employ the canonical
  approach of freeing them before parsing the remainder of the new chain.

Note that this commit intends to not change any observable behavior
of the stack. In particular:
- The peer's CRT chain is still verified during renegotiation.
- The tail of the peer's CRT chain may change during renegotiation.
2019-02-08 14:26:41 +00:00
Hanno Becker
b2964cbe14 SSL/TLS client: Remove old session ticket on renegotiation
Context: During a handshake, the SSL/TLS handshake logic constructs
an instance of ::mbedtls_ssl_session representing the SSL session
being established. This structure contains information such as the
session's master secret, the peer certificate, or the session ticket
issues by the server (if applicable).

During a renegotiation, the new session is constructed aside the existing
one and destroys and replaces the latter only when the renegotiation is
complete. While conceptually clear, this means that during the renegotiation,
large pieces of information such as the peer's CRT or the session ticket
exist twice in memory, even though the original versions are removed
eventually.

This commit starts removing this memory inefficiency by freeing the old
session's SessionTicket before the one for the new session is allocated.
2019-02-08 14:26:41 +00:00
Hanno Becker
1a65dcd44f Add a new X.509 API call for copy-less parsing of CRTs
Context:
The existing API `mbedtls_x509_parse_crt_der()` for parsing DER
encoded X.509 CRTs unconditionally makes creates a copy of the
input buffer in RAM. While this comes at the benefit of easy use,
-- specifically: allowing the user to free or re-use the input
buffer right after the call -- it creates a significant memory
overhead, as the CRT is duplicated in memory (at least temporarily).
This might not be tolerable a resource constrained device.

As a remedy, this commit adds a new X.509 API call

   `mbedtls_x509_parse_crt_der_nocopy()`

which has the same signature as `mbedtls_x509_parse_crt_der()`
and almost the same semantics, with one difference: The input
buffer must persist and be unmodified for the lifetime of the
established instance of `mbedtls_x509_crt`, that is, until
`mbedtls_x509_crt_free()` is called.
2019-02-08 14:24:58 +00:00
Jaeden Amero
fb236739da Revert "Forbid passing NULL input buffers to RSA encryption routines"
Resolve incompatibilties in the RSA module where changes made for
parameter validation prevent Mbed Crypto from working. Mbed Crypto
depends on being able to pass zero-length buffers that are NULL to RSA
encryption functions.

This reverts commit 2f660d047d.
2019-02-08 08:43:31 -05:00
Andrzej Kurek
3c2b15d31e Update version_features file 2019-02-08 02:38:45 -05:00
Andrzej Kurek
8a2e97c2df Merge development-psa commit 80b5662 into development-psa-merged branch
Adjust crypto submodule version to use new, forked crypto version accordingly.
2019-02-05 06:02:51 -05:00
Andrzej Kurek
d142856846 cipher: remove unnecessary precondition
Already checked by parameter validation macros
2019-02-05 05:11:03 -05:00
Andrzej Kurek
efed323698 pk: restructure precondition check 2019-02-05 05:09:05 -05:00
Jaeden Amero
80b566267f Merge remote-tracking branch 'origin/pr/2386' into development-psa 2019-02-04 16:42:23 +00:00
Jaeden Amero
d18b264eaf Merge remote-tracking branch 'origin/pr/2382' into development-psa 2019-02-04 16:41:46 +00:00
Jaeden Amero
65408c5f92 Merge remote-tracking branch 'origin/pr/2355' into development-psa 2019-02-04 16:41:12 +00:00
Andrzej Kurek
de5a007316 Merge development commit f352f7 into development-psa 2019-02-01 07:03:03 -05:00
Hanno Becker
65935d90c9 Add missing include to library/pkwrite.c 2019-02-01 11:55:03 +00:00
Hanno Becker
493c171a1c Adapt mbedtls_pk_write_pubkey_der() to the new PSA public key format
Context: There are two public key writing functions in Mbed TLS. First,
mbedtls_pk_write_pubkey(), which exports a public key in the form of a
SubjectPublicKey structure containing the raw keying material
(for example, EC point coordinates for an EC public key, without
reference to the underlying curve). Secondly, mbedtls_pk_write_pubkey_der(),
which exports a public key in the form of a SubjectPublicKeyInfo structure,
wrapping the SubjectPublicKey structure by additional information
identifying the type of public key (and for ECC, e.g., it'd also contain
the ECC group identifier). The implementation of mbedtls_pk_write_pubkey_der()
calls mbedtls_pk_write_pubkey() first and then adds the corresponding
algorithm identifier wrapper.

Both of these functions need to be provided for PSA-based opaque PK contexts,
based on PSA's public key export function.

Previously, PSA used the SubjectPublicKeyInfo structure as its export format,
so mbedtls_pk_write_pubkey_der() could be easily implemented, while
mbedtls_pk_write_pubkey() would need to trim the output of the PSA export.

The previous implementation of mbedtls_pk_write_pubkey() is not quite right
because it calls PSA export doesn't do any trimming, hence exporting the large
SubjectPublicKeyInfo structure instead of the small SubjectPublicKey.
mbedtls_pk_write_pubkey_der(), in turn, immediately returns after calling
mbedtls_pk_write_pubkey(), hence also returning the SubjectPublicKeyInfo
structure, which is correct.

By now, the PSA public key export format has changed to the smaller
SubjectPublicKey structure. This means that, now, mbedtls_pk_write_pubkey()
can be implemented by just calling the PSA export, and that
mbedtls_pk_write_pubkey_der() needs to add the algorithm information around
it, just as in the other types of PK contexts. While not correct for the
old format, the existing code for mbedtls_pk_write_pubkey() is therefore
correct for the new PSA public key format, and needs no change apart from
the missing pointer shift in the last commit.

The implementation of mbedtls_pk_write_pubkey_der() needs a special code
path for PSA-based opaque PK contexts, as the PK context only contains
the PSA key handle, and the PSA API needs to be used to extract the
underlying EC curve to be able to write the AlgorithmParameter structure
that's part of the SubjectPublicKeyInfo structure.

That's what this commit does, (hopefully) making both
mbedtls_pk_write_pubkey() and mbedtls_pk_write_pubkey_der() export
the correctly formatted public key based on the new PSA public key format.
2019-02-01 10:25:25 +00:00
Hanno Becker
4fb8db23b9 Update pointer in PSA-based mbedtls_pk_write_pubkey() 2019-02-01 09:57:20 +00:00
Andrzej Kurek
f093a3dc61 Use ecdh_setup instead of ecp_group_load
Align files with development to ensure the same state of repositories.
2019-02-01 02:50:36 -05:00
Andrzej Kurek
c470b6b021 Merge development commit 8e76332 into development-psa
Additional changes to temporarily enable running tests:
ssl_srv.c and test_suite_ecdh use mbedtls_ecp_group_load instead of
mbedtls_ecdh_setup
test_suite_ctr_drbg uses mbedtls_ctr_drbg_update instead of 
mbedtls_ctr_drbg_update_ret
2019-01-31 08:20:20 -05:00
Jaeden Amero
f352f75f6b Merge remote-tracking branch 'origin/pr/2332' into development 2019-01-30 15:53:00 +00:00
Jaeden Amero
91af329a55 Merge remote-tracking branch 'origin/pr/2214' into development 2019-01-30 15:08:25 +00:00
Jaeden Amero
14eca249f1 Merge remote-tracking branch 'origin/pr/2213' into development 2019-01-30 15:01:20 +00:00
Jaeden Amero
dac9f45e5a Merge remote-tracking branch 'origin/pr/1551' into development 2019-01-30 13:24:55 +00:00
Jaeden Amero
e6e2686cf8 Merge remote-tracking branch 'origin/pr/2055' into development
Resolve conflicts in ctr_drbg.c where zeroization had been added upon
exit.
2019-01-30 13:23:03 +00:00
Jaeden Amero
730ecdf3b1 Merge remote-tracking branch 'origin/pr/2371' into development 2019-01-30 13:15:40 +00:00