Commit graph

4324 commits

Author SHA1 Message Date
Janos Follath 28eb06df16 ECP: Catch unsupported import/export
mbedtls_ecp_read_key() module returned without an error even when
importing keys corresponding to the requested group was not
implemented.

We change this and return an error when the requested group is not
supported and make the remaining import/export functions more robust.
2019-02-26 16:48:40 +00:00
Janos Follath 7780096f3b Fix typo in ECP module 2019-02-26 16:48:40 +00:00
Hanno Becker bd5580abb1 Add further debug statements on assertion failures 2019-02-26 14:38:09 +00:00
Hanno Becker 353a6f0d50 Fix typo in documentation of ssl_parse_certificate_chain() 2019-02-26 14:38:09 +00:00
Hanno Becker 62d58ed975 Add debug output in case of assertion failure 2019-02-26 14:38:09 +00:00
Hanno Becker 6883874013 Fix typo in SSL ticket documentation 2019-02-26 14:38:09 +00:00
Hanno Becker accc5998ae Set peer CRT length only after successful allocation 2019-02-26 14:38:09 +00:00
Hanno Becker 3acc9b9042 Remove question in comment about verify flags on cli vs. server 2019-02-26 14:38:09 +00:00
Hanno Becker 6b8fbab290 Free peer CRT chain immediately after verifying it
If we don't need to store the peer's CRT chain permanently, we may
free it immediately after verifying it. Moreover, since we parse the
CRT chain in-place from the input buffer in this case, pointers from
the CRT structure remain valid after freeing the structure, and we
use that to extract the digest and pubkey from the CRT after freeing
the structure.
2019-02-26 14:38:09 +00:00
Hanno Becker 0056eab3cd Parse peer's CRT chain in-place from the input buffer 2019-02-26 14:38:09 +00:00
Hanno Becker ae553dde3a Free peer's public key as soon as it's no longer needed
On constrained devices, this saves a significant amount of RAM that
might be needed for subsequent expensive operations like ECDHE.
2019-02-26 14:38:09 +00:00
Hanno Becker b9d4479080 Correct compile-time guards for ssl_clear_peer_cert()
It is used in `mbedtls_ssl_session_free()` under
`MBEDTLS_X509_CRT_PARSE_C`, but defined only if
`MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED`.

Issue #2422 tracks the use of
`MBEDTLS_KEY_EXCHANGE__WITH_CERT_ENABLED` instead of
`MBEDTLS_X509_CRT_PARSE_C` for code and fields
related to CRT-based ciphersuites.
2019-02-26 14:38:09 +00:00
Hanno Becker e68245750a Guard mbedtls_ssl_get_peer_cert() by new compile-time option 2019-02-26 14:38:09 +00:00
Hanno Becker b6c5eca2d5 Adapt mbedtls_ssl_parse_certificate() to removal of peer_cert field 2019-02-26 14:38:09 +00:00
Hanno Becker 13c327d500 Adapt ssl_clear_peer_cert() to removal of peer_cert field 2019-02-26 14:38:09 +00:00
Hanno Becker 6d1986e6f5 Adapt mbedtls_ssl_session_copy() to removal of peer_cert field 2019-02-26 14:38:09 +00:00
Hanno Becker 94cc26dfa6 Adapt session ticket implementation to removal of peer_cert field 2019-02-26 14:38:09 +00:00
Hanno Becker 2a831a4ba7 Adapt client auth detection in ssl_parse_certificate_verify()
The server expects a CertificateVerify message only if it has
previously received a Certificate from the client.

So far, this was detected by looking at the `peer_cert` field
in the current session. Preparing to remove the latter, this
commit changes this to instead determine the presence of a peer
certificate by checking the new `peer_cert_digest` pointer.
2019-02-26 14:38:09 +00:00
Hanno Becker a1ab9be367 Adapt server-side signature verification to use raw public key
We must dispatch between the peer's public key stored as part of
the peer's CRT in the current session structure (situation until
now, and future behaviour if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is
enabled), and the sole public key stored in the handshake structure
(new, if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is disabled).
2019-02-26 14:38:09 +00:00
Hanno Becker a6899bb89d Adapt client-side signature verification to use raw public key
We must dispatch between the peer's public key stored as part of
the peer's CRT in the current session structure (situation until
now, and future behaviour if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is
enabled), and the sole public key stored in the handshake structure
(new, if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is disabled).
2019-02-26 14:38:09 +00:00
Hanno Becker be7f50866d Adapt ssl_get_ecdh_params_from_cert() to use raw public key
We must dispatch between the peer's public key stored as part of
the peer's CRT in the current session structure (situation until
now, and future behaviour if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is
enabled), and the sole public key stored in the handshake structure
(new, if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is disabled).
2019-02-26 14:38:09 +00:00
Hanno Becker c7d7e29b46 Adapt ssl_write_encrypted_pms() to use raw public key
We must dispatch between the peer's public key stored as part of
the peer's CRT in the current session structure (situation until
now, and future behaviour if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is
enabled), and the sole public key stored in the handshake structure
(new, if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is disabled).
2019-02-26 14:38:09 +00:00
Hanno Becker a27475335a Make a copy of peer's raw public key after verifying its CRT chain
This commit modifies `mbedtls_ssl_parse_certificate()` to store a
copy of the peer's public key after parsing and verifying the peer's
CRT chain.

So far, this leads to heavy memory duplication: We have the CRT chain
in the I/O buffer, then parse (and, thereby, copy) it to a
`mbedtls_x509_crt` structure, and then make another copy of the
peer's public key, plus the overhead from the MPI and ECP structures.

This inefficiency will soon go away to a significant extend, because:
- Another PR adds functionality to parse CRTs without taking
  ownership of the input buffers. Applying this here will allow
  parsing and verifying the peer's chain without making an additional
  raw copy. The overhead reduces to the size of `mbedtls_x509_crt`,
  the public key, and the DN structures referenced in the CRT.
- Once copyless parsing is in place and the removal of the peer CRT
  is fully implemented, we can extract the public key bounds from
  the parsed certificate and then free the entire chain before
  parsing the public key again. This means that we never store
  the parsed public key twice at the same time.
2019-02-26 14:38:09 +00:00
Hanno Becker 75173121fe Add field for peer's raw public key to TLS handshake param structure
When removing the (session-local) copy of the peer's CRT chain, we must
keep a handshake-local copy of the peer's public key, as (naturally) every
key exchange will make use of that public key at some point to verify that
the peer actually owns the corresponding private key (e.g., verify signatures
from ServerKeyExchange or CertificateVerify, or encrypt a PMS in a RSA-based
exchange, or extract static (EC)DH parameters).

This commit adds a PK context field `peer_pubkey` to the handshake parameter
structure `mbedtls_handshake_params_init()` and adapts the init and free
functions accordingly. It does not yet make actual use of the new field.
2019-02-26 14:38:09 +00:00
Hanno Becker 494dd7a6b4 Add raw public key buffer bounds to mbedtls_x509_crt struct
This commit adds an ASN.1 buffer field `pk_raw` to `mbedtls_x509_crt`
which stores the bounds of the raw public key data within an X.509 CRT.

This will be useful in subsequent commits to extract the peer's public
key from its certificate chain.
2019-02-26 14:38:09 +00:00
Hanno Becker a887d1a5b6 Remove peer CRT from cache if !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE 2019-02-26 14:38:09 +00:00
Hanno Becker c966bd16be Remove peer CRT from tickets if !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE 2019-02-26 14:38:09 +00:00
Hanno Becker c5fcbb33c0 Add peer CRT digest to session tickets
This commit changes the format of session tickets to include
the digest of the peer's CRT if MBEDTLS_SSL_KEEP_PEER_CERTIFICATE
is disabled.

This commit does not yet remove the peer CRT itself.
2019-02-26 14:38:09 +00:00
Hanno Becker 3dad311ef0 Parse and verify peer CRT chain in local variable
`mbedtls_ssl_parse_certificate()` parses the peer's certificate chain
directly into the `peer_cert` field of the `mbedtls_ssl_session`
structure being established. To allow to optionally remove this field
from the session structure, this commit changes this to parse the peer's
chain into a local variable instead first, which can then either be freed
after CRT verification - in case the chain should not be stored - or
mapped to the `peer_cert` if it should be kept. For now, only the latter
is implemented.
2019-02-26 14:38:09 +00:00
Hanno Becker 177475a3aa Mitigate triple handshake attack by comparing digests only
This paves the way for the removal of the peer CRT chain from
`mbedtls_ssl_session`.
2019-02-26 14:38:09 +00:00
Hanno Becker 6bbd94c4eb Compute digest of peer's end-CRT in mbedtls_ssl_parse_certificate() 2019-02-26 14:38:09 +00:00
Hanno Becker 9198ad1101 Extend mbedtls_ssl_session by buffer holding peer CRT digest 2019-02-26 14:38:09 +00:00
Hanno Becker 8d84fd83ff Update version_features.c 2019-02-26 14:38:09 +00:00
Hanno Becker 8273df8383 Re-classify errors on missing peer CRT
mbedtls_ssl_parse_certificate() will fail if a ciphersuite requires
a certificate, but none is provided. While it is sensible to double-
check this, failure should be reported as an internal error and not
as an unexpected message.
2019-02-26 14:38:09 +00:00
Hanno Becker 0329f75a93 Increase robustness and documentation of ticket implementation 2019-02-26 14:38:09 +00:00
Hanno Becker aee8717877 Simplify session cache implementation via mbedtls_ssl_session_copy() 2019-02-26 14:38:09 +00:00
Hanno Becker 52055ae91f Give ssl_session_copy() external linkage
A subsequent commit will need this function in the session ticket
and session cache implementations. As the latter are server-side,
this commit also removes the MBEDTLS_SSL_CLI_C guard.

For now, the function is declared in ssl_internal.h and hence not
part of the public API.
2019-02-26 14:38:09 +00:00
Hanno Becker c7bd780e02 Allow passing any X.509 CRT chain to ssl_parse_certificate_chain()
This commit modifies the helper `ssl_parse_certificate_chain()` to
accep any target X.509 CRT chain instead of hardcoding it to
`session_negotiate->peer_cert`. This increases modularity and paves
the way towards removing `mbedtls_ssl_session::peer_cert`.
2019-02-26 14:38:09 +00:00
Hanno Becker 6863619a2f Introduce helper function for peer CRT chain verification 2019-02-26 14:38:09 +00:00
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
Janos Follath ffbd7e8ff3 Improve mbedtls_ecp_point_read_binary tests
Renamed the tests because they are explicitly testing Curve25519 and
nothing else. Improved test coverage, test documentation and extended
in-code documentation with a specific reference to the standard as well.
2019-02-25 11:49:54 +00:00
Janos Follath 7caf8e452f Add Montgomery points to ecp_point_write_binary
The library is able to perform computations and cryptographic schemes on
curves with x coordinate ladder representation. Here we add the
capability to export such points.
2019-02-22 15:42:18 +00:00
Janos Follath ab0f71a22a ECDH: Add test vectors for Curve25519
The test vectors added are published in RFC 7748.
2019-02-22 15:42:03 +00:00
Janos Follath e344d0f6fc Add little endian export to Bignum
The function `mbedtls_mpi_write_binary()` writes big endian byte order,
but we need to be able to write little endian in some caseses. (For
example when handling keys corresponding to Montgomery curves.)

Used `echo xx | tac -rs ..` to transform the test data to little endian.
2019-02-22 15:41:31 +00:00
Janos Follath 171a7efd02 Add mbedtls_ecp_read_key
The private keys used in ECDH differ in the case of Weierstrass and
Montgomery curves. They have different constraints, the former is based
on big endian, the latter little endian byte order. The fundamental
approach is different too:
- Weierstrass keys have to be in the right interval, otherwise they are
  rejected.
- Any byte array of the right size is a valid Montgomery key and it
  needs to be masked before interpreting it as a number.

Historically it was sufficient to use mbedtls_mpi_read_binary() to read
private keys, but as a preparation to improve support for Montgomery
curves we add mbedtls_ecp_read_key() to enable uniform treatment of EC
keys.

For the masking the `mbedtls_mpi_set_bit()` function is used. This is
suboptimal but seems to provide the best trade-off at this time.
Alternatives considered:
- Making a copy of the input buffer (less efficient)
- removing the `const` constraint from the input buffer (breaks the api
and makes it less user friendly)
- applying the mask directly to the limbs (violates the api between the
modules and creates and unwanted dependency)
2019-02-22 15:39:03 +00:00
Janos Follath 59b813c7be Add Montgomery points to ecp_point_read_binary
The library is able to perform computations and cryptographic schemes on
curves with x coordinate ladder representation. Here we add the
capability to import such points.
2019-02-22 15:38:46 +00:00
Janos Follath a778a94b7d Add little endian import to Bignum
The function `mbedtls_mpi_read_binary()` expects big endian byte order,
but we need to be able to read from little endian in some caseses. (For
example when handling keys corresponding to Montgomery curves.)

Used `echo xx | tac -rs .. | tr [a-z] [A-Z]` to transform the test data
to little endian and `echo "ibase=16;xx" | bc` to convert to decimal.
2019-02-22 15:38:32 +00:00
Jaeden Amero 86016a03a1 Merge remote-tracking branch 'origin/pr/2338' into development 2019-02-22 12:55:30 +00:00
Gilles Peskine 3081629de4 Fix mbedtls_ecdh_get_params with new ECDH context
The new check for matching groups in mbedtls_ecdh_get_params only worked
with legacy ECDH contexts. Make it work with the new context format.
2019-02-22 13:04:23 +01:00
Gilles Peskine 43f564f29d Define MBEDTLS_ECDH_LEGACY_CONTEXT in config.h
Define MBEDTLS_ECDH_LEGACY_CONTEXT in config.h instead of hard-coding
this in ecdh.h so that its absence can be tested. Document it as
experimental so that we reserve the right to change it in the future.
2019-02-22 13:04:20 +01:00
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
Gilles Peskine 0b1b71d712 Fix ecdh_get_params with mismatching group
If mbedtls_ecdh_get_params is called with keys belonging to
different groups, make it return an error the second time, rather than
silently interpret the first key as being on the second curve.

This makes the non-regression test added by the previous commit pass.
2019-02-22 10:21:46 +01:00
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
k-stachowiak 28cb6fbd47 Unbump version to 0.0.0 2019-02-18 12:01:03 +01:00
Ron Eldor 3467dcf452 Use certificates from data_files and refer them
Use the server certificate from `data_files` folder, for formality,
and refer to the source, for easier reproduction.
2019-02-12 15:30:26 +02:00
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
Hanno Becker 23cfea01e8 Improve documentation of mbedtls_mpi_write_string() 2019-02-04 09:45:07 +00:00
Hanno Becker c983c81a23 Fix 1-byte buffer overflow in mbedtls_mpi_write_string()
This can only occur for negative numbers. Fixes #2404.
2019-02-01 16:41:30 +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
Peter Kolbus e6bcad3f79 Fix DEADCODE in mbedtls_mpi_exp_mod()
In mbedtls_mpi_exp_mod(), the limit check on wsize is never true when
MBEDTLS_MPI_WINDOW_SIZE is at least 6. Wrap in a preprocessor guard
to remove the dead code and resolve a Coverity finding from the
DEADCODE checker.

Change-Id: Ice7739031a9e8249283a04de11150565b613ae89
2019-01-31 19:37:51 -06:00
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