Commit graph

2831 commits

Author SHA1 Message Date
Manuel Pégourié-Gonnard 3652e99100 Add getter function for handshake->resume
This makes the code more readable by having fewer #ifdefs all over the place.
2019-07-02 15:13:18 +02:00
Manuel Pégourié-Gonnard 33cb3e1c7e Remove cache callbacks from config on client
The session cache is only server-side. This also aligns the conditions
guarding those fields with the condition guarding the function setting them -
no need to have the fields if we can't set them.

This preserves the API and ABI in the default config as it only affects
non-default configs.
2019-07-02 15:12:29 +02:00
Manuel Pégourié-Gonnard 320eb7ac4e Expand documentation of new options a bit 2019-07-02 15:12:29 +02:00
Manuel Pégourié-Gonnard 8a0944cb99 Fix renaming oversight in documentation 2019-07-02 15:12:29 +02:00
Manuel Pégourié-Gonnard e431563269 Remove backticks in doxygen in config.h 2019-07-02 15:12:29 +02:00
Manuel Pégourié-Gonnard f130b1024a Restore config.h defaults
We want those changes only in config/baremetal.h, not in the default config.
2019-07-02 15:12:29 +02:00
Jarno Lamsa 29f2dd0a7b Address review comments 2019-07-02 15:12:29 +02:00
Jarno Lamsa 4f74f6d301 Fix check-files, check-names and check-generated-features 2019-07-02 15:12:29 +02:00
Jarno Lamsa ac57e82c7d Doxygen for new config options 2019-07-02 15:12:29 +02:00
Jarno Lamsa 59bd12bf14 Add new config MBEDTLS_SSL_SESSION_RESUMPTION
Add a new configuration option MBEDTLS_SSL_SESSION_RESUMPTION
to enable/disable the session resumption feature including
ticket and cache based session resumption.
2019-07-02 15:12:29 +02:00
Jarno Lamsa 590bf51cbb Enable MBEDTLS_SSL_SESSION_CACHE by default 2019-07-02 15:12:29 +02:00
Jarno Lamsa 7be14065e2 Add config MBEDTLS_SSL_SESSION_CACHE
Add configuration option MBEDTLS_SSL_SESSION_CACHE to control
enabling/disabling of the cache based session resumption.
2019-07-02 15:12:29 +02:00
Hanno Becker abd929c89c Merge branch 'mbedtls-2.16' into baremetal-2.16-01_07_19 2019-07-01 11:25:42 +01:00
Hanno Becker 69c303360e Don't return threading error on release()-without-acquire() calls
Previously, a call to mbedtls_x509_crt_xxx_release() would return
MBEDTLS_ERR_THREADING_MUTEX_ERROR if usage counter for the frame/PK
was 0. Now that resource counting can also be used outside of
threading support, this is no longer adequate, and this commit
changes the return code to MBEDTLS_ERR_X509_FATAL_ERROR; while
generic, this at least matches the top-level module.
2019-06-28 15:47:53 +01:00
Hanno Becker fc99a09cc4 Don't allow nested CRT acquire()-calls if MBEDTLS_X509_ALWAYS_FLUSH
Forbidding nested calls to acquire() allows to remove the reference
counting logic and hence saving some bytes of code. This is valuable
because MBEDTLS_X509_ALWAYS_FLUSH is likely to be used on constrained
systems where code-size is limited.
2019-06-28 14:48:32 +01:00
Hanno Becker a4bfaa8204 Make X.509 CRT cache reference counting unconditional
Previously, reference counting for the CRT frames and PK contexts
handed out by mbedtls_x509_crt_{frame|pk}_acquire() was implemented
only in case threading support was enabled, which leaves the door
open for a potential use-after-free should a single-threaded application
use nested calls to mbedtls_x509_crt_acquire().

Since Mbed TLS itself does not use such nested calls, it might be
preferred long-term to forbid nesting of acquire calls on the API
level, and hence get rid of reference counting in the interest of
code-size benefits. However, this can be considered as an optimization
of X.509 on demand parsing, and for now this commit introduces
reference counting unconditionally to have a safe version of
on demand parsing to build further optimizations upon.
2019-06-28 14:48:32 +01:00
Hanno Becker b653aa3d16 Don't mention pk_sign() in the context of public-key contexts 2019-06-28 14:48:32 +01:00
Hanno Becker d92078fc55 Fix copy pasta in x509_crt.h 2019-06-28 14:48:31 +01:00
Hanno Becker 608de6a50d Reference copy-less versions of X.509 CRT frame/PK getters 2019-06-28 14:48:31 +01:00
Hanno Becker 2656bfe9b0 [FIXUP] Fix typo in declaration of mbedtls_x509_memcasecmp() 2019-06-25 10:41:34 +01:00
Hanno Becker 60785d113b Remove unused variable warning in on-demand X.509 parsing 2019-06-25 09:11:11 +01:00
Hanno Becker 2ba9fbdfe9 Allow multiple concurrent readers for X.509 CRT frame and PK context
Previously, only one thread could access the parsing cache of an X.509 CRT
at a time. Firstly, this leads to significant performance penalties on
systems running many concurrent threads which share CRT structures --
for example, server threads sharing an SSL configuration containing the
server CRT. Secondly, the locking should be logically unnecessary, because
the threads are supposed to access the CRT frame and PK in a read-only,
or at least thread-safe manner.

This commit modifies the X.509 CRT cache implementation by allowing an
arbitrary number of concurrent readers, locking only the path of setting
up and clearing the cache.
2019-06-25 09:10:57 +01:00
Hanno Becker 4b70e12dde Document mbedtls_x509_crt_pk_{acquire/release}()
In contrast to mbedtls_x509_crt_frame_acquire(), the public key context
returned by mbedtls_x509_crt_pk_acquire() cannot be marked `const` because
the caller must be able to use it e.g. for mbedtls_pk_sign() and
mbedtls_pk_verify(), which don't have `const` input parameters.

Instead, return a non-`const` context, but explicitly state that callers
must use that context in a thread-safe way.
2019-06-25 09:10:57 +01:00
Hanno Becker b8670fcab3 Document mbedtls_x509_crt_frame_{acquire/release}() 2019-06-25 09:10:57 +01:00
Hanno Becker 5f268b3cf6 Don't allow change of CRT frame returned by x509_crt_frame_acquire() 2019-06-25 09:10:57 +01:00
Hanno Becker 9219f9e7b8 Fix yet another occasions of 'setup' vs. 'set up' typo in x509_crt.h 2019-06-25 09:10:57 +01:00
Hanno Becker a4dfc0d73d Move X.509 CRT cache handling functions to x509_internal.h 2019-06-25 09:10:57 +01:00
Hanno Becker 3c3d5c5836 Fix spacing in declaration of mbedtls_asn1_get_sequence_of() 2019-06-25 09:10:57 +01:00
Hanno Becker c0dab627ce Fix typo 'setup' -> 'set up' throughout x509_crt.h 2019-06-25 09:10:57 +01:00
Hanno Becker fd5c185ed6 Use uint16_t to store key usage field in X.509 CRT
Also, reorder the fields to avoid padding, thereby reducing the size of
mbedtls_x509_crt_frame by 2 Bytes.
2019-06-25 09:10:57 +01:00
Hanno Becker 00d390338d Move internal mbedtls_x509_crt_cache to x509_internal.h
We cannot move it to x509_crt.c because there are some static inline
function definitions in x509_crt.h which access members of
mbedtls_x509_crt_cache.
2019-06-25 09:10:57 +01:00
Hanno Becker f332a97e1b Add ASN.1 API to free linked list representation of ASN.1 sequences 2019-06-25 09:10:57 +01:00
Hanno Becker f6bc8886c7 Move declarations of internal X.509 functions to separate header
This makes it easier to distinguish public from internal functions;
for us, for users, and for automated API compatibility checkers.
2019-06-25 09:10:57 +01:00
Hanno Becker 76428359b3 Move existence check for pk/frame to mbedtls_x509_crt_provide_xxx() 2019-06-25 09:07:16 +01:00
Hanno Becker bc685199d9 Implement MBEDTLS_X509_ALWAYS_FLUSH 2019-06-25 09:07:16 +01:00
Hanno Becker ffcd8c39a4 Introduce compile-time option to always flush X.509 CRT caches
This commit introduces a compile-time option MBEDTLS_X509_ALWAYS_FLUSH
which controls whether releasing of CRT frames or public key contexts
associated to X.509 CRTs (or, in the future, other cached parsed X.509
structures) should lead to freeing those structures immediately.

Enabling this alongside of the MBEDTLS_X509_ON_DEMAND_PARSING leads
to significant reduction of the average RAM consumption of Mbed TLS.

The option is enabled by default to reduce the permanent RAM overhead of
MBEDTLS_X509_ON_DEMAND_PARSING in case the latter is *disabled* (default).
(Note that there is very little performance penalty enabling
MBEDTLS_X509_ALWAYS_FLUSH in case MBEDTLS_X509_ON_DEMAND_PARSING is disabled,
because hardly any parsing needs to be done to setup a CRT frame / PK context
from the legacy `mbedtls_x509_crt` structure.)
2019-06-25 09:07:16 +01:00
Hanno Becker c6d1c3ed1c Remove frame/pk parameter from mbedtls_x509_crt_xxx_release() 2019-06-25 09:07:16 +01:00
Hanno Becker 1e11f217d4 Solely use raw X.509 name data references including SEQUENCE header
So far, the CRT frame structure `mbedtls_x509_crt_frame` used
as `issuer_raw` and `subject_raw` the _content_ of the ASN.1
name structure for issuer resp. subject. This was in contrast
to the fields `issuer_raw` and `subject_raw` from the legacy
`mbedtls_x509_crt` structure, and caused some information
duplication by having both variants `xxx_no_hdr` and `xxx_with_hdr`
in `mbedtls_x509_crt` and `mbedtls_x509_crt_frame`.

This commit removes this mismatch by solely using the legacy
form of `issuer_raw` and `subject_raw`, i.e. those _including_
the ASN.1 name header.
2019-06-25 09:07:16 +01:00
Hanno Becker 4e021c8f50 Remove raw SubjectAltNames and ExtKeyUsage from legacy CRT struct 2019-06-25 09:07:16 +01:00
Hanno Becker 2bcc7640f8 Give x509_{sequence|name}_free() external linkage
With the introduction of `mbedtls_x509_crt_get_{issuer|name}()`,
users need an easy way of freeing the dynamic name structures these
functions return.

To that end, this commit renames `x509_{sequence|name}_free()`
to `mbedtls_x509_{sequence|name}_free()` and gives them external linkage.
2019-06-25 09:06:26 +01:00
Hanno Becker ab6c8ea8bc Add public API to query SubjectAltNames and ExtKeyUsage extensions 2019-06-25 09:06:26 +01:00
Hanno Becker 63e6998dd7 Add public API to query subject and issuer from CRT
The legacy `mbedtls_x509_crt` contains fields `issuer/subject`
which are dynamically allocated linked list presentations of the
CRTs issuer and subject names, respectively.

The new CRT frame structure `mbedtls_x509_crt_frame`, however,
only provides pointers to the raw ASN.1 buffers for the issuer
and subject, for reasons of memory usage.

For convenience to users that previously used the `issuer`/`subject`
fields of `mbedtls_x509_crt`, this commit adds two public API functions
`mbedtls_x509_crt_get_subject()` and `mbedtls_x509_crt_get_issuer()`
which allow to request the legacy linked list presentation of the
CRTs subject / issuer names.

Similar to `mbedtls_x509_crt_get_pk()`, the returned names are owned
by the user, and must be freed through a call to `mbedtls_x509_name_free()`.
2019-06-25 09:06:26 +01:00
Hanno Becker 823efad6e8 Add public API to query for CRT frame and PK
This commit unconditionally adds two convenience API functions:
- mbedtls_x509_crt_get_frame()
- mbedtls_x509_crt_get_pk()
which allow users to extract a CRT frame or PK context
from a certificate.

The difference with the existing acquire/release API for frame and PK
contexts is that in contrast to the latter, the structures returned by
the new API are owned by the user (and, in case of the PK context, need
to be freed by him). This makes the API easier to use, but comes at the
cost of additional memory overhead.
2019-06-25 09:06:26 +01:00
Hanno Becker 180f7bf60b Add compile-time option to remove legacy CRT fields 2019-06-25 09:06:26 +01:00
Hanno Becker b6c39fca5c Add parsing cache to mbedtls_x509_crt
This commit replaces the dummy implementation of the CRT acquire/release
framework by a cache-based implementation which remembers frame and PK
associated to a CRT across multiple `acquire/release` pairs.
2019-06-25 09:06:26 +01:00
Hanno Becker 343fec08ad Add version of MBEDTLS_X509_SAFE_SNPRINTF supporting cleanup section
This will be needed in debugging functions that maintain heap
allocated state, and which hence needs to be freed in case an
`snprintf()` call fails.
2019-06-25 09:06:26 +01:00
Hanno Becker 21f5567571 Introduce X.509 CRT frame structure
This commit restructures the parsing of X.509 CRTs in the following way:

First, it introduces a 'frame' structure `mbedtls_x509_crt_frame`, which
contains pointers to some structured fields of a CRT as well as copies of
primitive fields. For example, there's a pointer-length pair delimiting the raw
public key data in the CRT, but there's a C-uint8 to store the CRT version
(not a pointer-length pair delimiting the ASN.1 structure holding the version).

Setting up a frame from a raw CRT buffer does not require any memory outside
of the frame structure itself; it's just attaches a 'template' to the buffer
that allows to inspect the structured parts of the CRT afterwards.

Note that the frame structure does not correspond to a particular ASN.1
structure; for example, it contains pointers to delimit the three parts
of a CRT (TBS, SignatureAlgorithm, Signature), but also pointers to the
fields of the TBS, and pointers into the Extensions substructure of the TBS.

Further, the commit introduces an internal function `x509_crt_parse_frame()`
which sets up a frame from a raw CRT buffer, as well as several small helper
functions which help setting up the more complex structures (Subject, Issuer, PK)
from the frame.

These functions are then put to use to rewrite the existing parsing function
`mbedtls_x509_crt_parse_der_core()` by setting up a CRT frame from the input
buffer, residing on the stack, and afterwards copying the respective fields
to the actual `mbedtls_x509_crt` structure and performing the deeper parsing
through the various helper functions.
2019-06-25 09:06:26 +01:00
Hanno Becker 6b37812a45 Add next_merged field to X.509 name comparison abort callback 2019-06-25 09:06:26 +01:00
Hanno Becker b59d3f1692 Add single function to parse ASN.1 AlgorithmIdentifier to x509.c 2019-06-25 09:06:26 +01:00
Hanno Becker b3def1d341 Move length check into mbedtls_x509_memcasecmp()
At every occasion where we're using `mbedtls_x509_memcasecmp()` we're
checking that the two buffer lengths coincide before making the call.

This commit saves a few bytes of code by moving this length check
to `mbedtls_x509_memcasecmp()`.
2019-06-25 09:06:26 +01:00
Hanno Becker 8730610ae0 Introduce ASN.1 API for traversing ASN.1 SEQUENCEs
This commit adds a new function `mbedtls_asn1_traverse_sequence_of()`
which traverses an ASN.1 SEQUENCE and calls a user-provided callback
for each entry.

It allows to put the following constraints on the tags allowed
in the SEQUENCE:
- A tag mask and mandatory tag value w.r.t. that mask.
  A non-matching tag leads to an MBEDTLS_ERR_ASN1_UNEXPECTED_TAG error.
  For example, it the mask if 0xFF, this means that only
  a single tag will be allowed in the SEQUENCE.
- A tag mask and optional tag value w.r.t. that mask.
  A non-matching tag is silently ignored.

The main use for this flexibility is the traversal of the
`SubjectAlternativeNames` extension, where some parts of the
tag are fixed but some are flexible to indicate which type
of name the entry describes.
2019-06-25 09:06:26 +01:00
Hanno Becker ded167e18c Add raw buffer holding SubjectAlternativeName ext to CRT structure
This is analogous to a previous commit for the `ExtendedKeyUsage`
extension: We aim at not using dynamically allocated linked lists
to represent the components of the `SubjectAlternativeName` extension,
but to traverse the raw ASN.1 data when needed.

This commit adds a field to `mbedtls_x509_crt` containing the raw
ASN.1 buffer bounds of the `SubjectAlternativeNames` extension.
2019-06-25 09:06:26 +01:00
Hanno Becker e1956af057 Check for extended key usage by traversing raw extension data
This commit re-implements `mbedtls_x509_crt_check_extended_key_usage()`
to not use the dynamically allocated linked list presentation of the
`ExtendedKeyUsage` but to search for the required usage by traversing
the raw ASN.1 data.
2019-06-25 09:06:26 +01:00
Hanno Becker 7ec9c368f1 Add buffer holding raw ExtKeyUsage extension data to CRT struct
The previous commits replace the use of dynamically allocated linked lists
for X.509 name inspection. This commit is the first in a series which attempts
the same for the `ExtendedKeyUsage` extension. So far, when a CRT is parsed,
the extension is traversed and converted into a dynamically allocated linked
list, which is then search through whenever the usage of a CRT needs to be
checked through `mbedtls_x509_check_extended_key_usage()`.

As a first step, this commit introduces a raw buffer holding the bounds
of the `ExtendedKeyUsage` extension to the `mbedtls_x509_crt` structure.
2019-06-25 09:06:26 +01:00
Hanno Becker 67284cce00 Add abort condition callback to mbedtls_x509_name_cmp_raw()
There are three operations that need to be performed on an X.509 name:
1 Initial traversal to check well-formedness of the ASN.1 structure.
2 Comparison between two X.509 name sequences.
3 Checking whether an X.509 name matches a client's ServerName request.

Each of these tasks involves traversing the nested ASN.1 structure,
In the interest of saving code, we aim to provide a single function
which can perform all of the above tasks.

The existing comparison function is already suitable not only for task 2,
but also for 1: One can simply pass two equal ASN.1 name buffers, in which
case the function will succeed if and only if that buffer is a well-formed
ASN.1 name.

This commit further adds a callback to `mbedtls_x509_name_cmp_raw()` which
is called after each successful step in the simultaneous name traversal and
comparison; it may perform any operation on the current name and potentially
signal that the comparison should be aborted.

With that, task 3 can be implemented by passing equal names and a callback
which aborts as soon as it finds the desired name component.
2019-06-25 09:06:26 +01:00
Hanno Becker 7dee12a38c Make use of raw comparison function in CRT verification
This commit replaces the previous calls to `mbedtls_x509_name_cmp()`
during CRT verification (to match child and parent, to check whether
a CRT is self-issued, and to match CRLs and CAs) by calls to the new
`mbedtls_x509_name_cmp_raw()` using the raw ASN.1 data; it passes the
raw buffers introduced in the last commits.

The previous name comparison function mbedtls_x509_name_cmp() is now
both unused and unneeded, and is removed.
2019-06-25 09:06:26 +01:00
Hanno Becker f8a42862b7 Add buffers with raw issuer/subject data to CRT structure 2019-06-25 09:06:26 +01:00
Hanno Becker a632e3638c Add buffer with raw issuer data to CRL structure
To make use of the X.509 name comparison function based on raw
ASN.1 data that was introduced in the previous commit, this commit
adds an ASN.1 buffer field `issuer_raw_no_hdr` to `mbedtls_x509_crl`
which delimits the raw contents of the CRLs `Issuer` field.

The previous field `issuer_raw` isn't suitable for that because
it includes the ASN.1 header.
2019-06-25 09:06:26 +01:00
Hanno Becker a3a2ca1333 Provide X.509 name comparison based on raw ASN.1 data
This commit provides a new function `mbedtls_x509_name_cmp_raw()`
to x509.c for comparing to X.509 names by traversing the raw ASN.1
data (as opposed to using the dynamically allocated linked list
of `mbedtls_x509_name` structures). It has external linkage because
it will be needed in `x509_crt` and `x509_crl`, but is marked
internal and hence not part of the public API.
2019-06-25 09:06:26 +01:00
Hanno Becker 88de342c95 Move x509_name_cmp() from x509_crt.c to x509.c
This is to prepare a subsequent rewrite of `x509_name_cmp()` in terms
of the X.509 name traversal helper `x509_set_sequence_iterate()`
from `x509.c`.
2019-06-25 09:06:26 +01:00
Hanno Becker 83cd8676fa Remove sig_oid parameter from mbedtls_x509_sig_alg_gets()
The function `mbedtls_x509_sig_alg_gets()` previously needed the
raw ASN.1 OID string even though it is implicit in the PK and MD
parameters.

This commit modifies `mbedtls_x509_sig_alg_gets()` to infer the OID
and remove it from the parameters.

This will be needed for the new X.509 CRT structure which will
likely not store the signature OID.

Care has to be taken to handle the case of RSASSA-PSS correctly,
where the hash algorithm in the OID list is set to MBEDTLS_MD_NONE
because it's only determined by the algorithm parameters.
2019-06-25 09:06:26 +01:00
Hanno Becker b40dc58a83 Introduce a helper macro to check for ASN.1 string tags
This commit introduces a macro `MBEDTLS_ASN1_IS_STRING_TAG`
that can be used to check if an ASN.1 tag is among the list
of string tags:
- MBEDTLS_ASN1_BMP_STRING
- MBEDTLS_ASN1_UTF8_STRING
- MBEDTLS_ASN1_T61_STRING
- MBEDTLS_ASN1_IA5_STRING
- MBEDTLS_ASN1_UNIVERSAL_STRING
- MBEDTLS_ASN1_PRINTABLE_STRING
- MBEDTLS_ASN1_BIT_STRING
2019-06-25 09:00:25 +01:00
Hanno Becker 7f376f4ece Allow compile-time configuration of DTLS anti replay
Introduce MBEDTLS_SSL_CONF_ANTI_REPLAY to allow configuring
the use/nonuse of DTLS anti replay protection at compile-time.

Impact on code-size, measured with
> ./scripts/baremetal.sh --rom --gcc --armc5 --armc6

|  | GCC | ARMC5 | ARMC6 |
| --- | --- | --- | --- |
| `libmbedtls.a` before | 23559 | 24089 | 27921 |
| `libmbedtls.a` after  | 23511 | 24049 | 27903 |
| gain in Bytes | 48 | 40 | 18 |
2019-06-25 08:43:31 +01:00
Hanno Becker ab1ce76682 Mention possibility of hardcoding SSL config in ssl.h 2019-06-25 08:42:20 +01:00
Hanno Becker f765ce617f Remove ExtendedMS configuration API if hardcoded at compile-time
If the ExtendedMasterSecret extension is configured at compile-time
by setting MBEDTLS_SSL_CONF_EXTENDED_MASTER_SECRET and/or
MBEDTLS_SSL_CONF_ENFORCE_EXTENDED_MASTER_SECRET, the runtime
configuration APIs mbedtls_ssl_conf_extended_master_secret()
and mbedtls_ssl_conf_extended_master_secret_enforce() must
either be removed or modified to take no effect (or at most
check that the runtime value matches the hardcoded one, but
that would undermine the code-size benefits the hardcoding
is supposed to bring in the first place).

Previously, the API was kept but modified to have no effect.
While convenient for us because we don't have to adapt example
applications, this comes at the danger of users calling the runtime
configuration API, forgetting that the respective fields are
potentially already hardcoded at compile-time - and hence silently
using a configuration they don't intend to use.

This commit changes the approach to removing the configuration
API in case the respective field is hardcoded at compile-time,
and exemplifies it in the only case implemented so far, namely
the configuration of the ExtendedMasterSecret extension.

It adapts ssl_client2 and ssl_server2 by omitting the call to
the corresponding API if MBEDTLS_SSL_CONF_XXX are defined and
removing the command line parameters for the runtime configuration
of the ExtendedMasterSecret extension.
2019-06-25 08:42:20 +01:00
Hanno Becker 57e72c750c Move getter functions for SSL configuration to ssl_internal.h 2019-06-25 08:42:20 +01:00
Hanno Becker 4c4a2e1a0b Don't break func'def after linkage type, fixing check-names.sh 2019-06-25 08:42:20 +01:00
Hanno Becker 1ab322bb51 Remove extended_ms field from HS param if ExtendedMS enforced 2019-06-25 08:42:20 +01:00
Hanno Becker a49ec56f51 Introduce getter function for extended_ms field in HS struct 2019-06-25 08:42:20 +01:00
Hanno Becker 3010d55a3b Introduce helper macro indicating if use of ExtendedMS is enforced 2019-06-25 08:42:20 +01:00
Hanno Becker aabbb582eb Exemplify harcoding SSL config at compile-time in example of ExtMS
This commit is the first in a series demonstrating how code-size
can be reduced by hardcoding parts of the SSL configuration at
compile-time, focusing on the example of the configuration of
the ExtendedMasterSecret extension.

The flexibility of an SSL configuration defined a runtime vs.
compile-time is necessary for the use of Mbed TLS as a
dynamically linked library, but is undesirable in constrained
environments because it introduces the following overhead:
- Definition of SSL configuration API (code-size overhead)
  (and on the application-side: The API needs to be called)
- Additional fields in the SSL configuration (RAM overhead,
  and potentially code-size overhead if structures grow
  beyond immediate-offset bounds).
- Dereferencing is needed to obtain configuration settings.
- Code contains branches and potentially additional structure
  fields to distinguish between different configurations.

Considering the example of the ExtendedMasterSecret extension,
this instantiates as follows:
- mbedtls_ssl_conf_extended_master_secret() and
  mbedtls_ssl_conf_extended_master_secret_enforced()
  are introduced to configure the ExtendedMasterSecret extension.
- mbedtls_ssl_config contains bitflags `extended_ms` and
  `enforce_extended_master_secret` reflecting the runtime
  configuration of the ExtendedMasterSecret extension.
- Whenever we need to access these fields, we need a chain
  of dereferences `ssl->conf->extended_ms`.
- Determining whether Client/Server should write the
  ExtendedMasterSecret extension needs a branch
  depending on `extended_ms`, and the state of the
  ExtendedMasterSecret negotiation needs to be stored in a new
  handshake-local variable mbedtls_ssl_handshake_params::extended_ms.
  Finally (that's the point of ExtendedMasterSecret) key derivation
  depends on this handshake-local state of ExtendedMasterSecret.

All this is unnecessary if it is known at compile-time that the
ExtendedMasterSecret extension is used and enforced:
- No API calls are necessary because the configuration is fixed
  at compile-time.
- No SSL config fields are necessary because there are corresponding
  compile-time constants instead.
- Accordingly, no dereferences for field accesses are necessary,
  and these accesses can instead be replaced by the corresponding
  compile-time constants.
- Branches can be eliminated at compile-time because the compiler
  knows the configuration. Also, specifically for the ExtendedMasterSecret
  extension, the field `extended_ms` in the handshake structure
  is unnecessary, because we can fail immediately during the Hello-
  stage of the handshake if the ExtendedMasterSecret extension
  is not negotiated; accordingly, the non-ExtendedMS code-path
  can be eliminated from the key derivation logic.

A way needs to be found to allow fixing parts of the SSL configuration
at compile-time which removes this overhead in case it is used,
while at the same time maintaining readability and backwards
compatibility.

This commit proposes the following approach:

From the user perspective, for aspect of the SSL configuration
mbedtls_ssl_config that should be configurable at compile-time,
introduce a compile-time option MBEDTLS_SSL_CONF_FIELD_NAME.
If this option is not defined, the field is kept and configurable
at runtime as usual. If the option is defined, the field is logically
forced to the value of the option at compile time.

Internally, read-access to fields in the SSL configuration which are
configurable at compile-time gets replaced by new `static inline` getter
functions which evaluate to the corresponding field access or to the
constant MBEDTLS_SSL_CONF_FIELD_NAME, depending on whether the latter
is defined or not.

Write-access to fields which are configurable at compile-time needs
to be removed: Specifically, the corresponding API itself either
needs to be removed or replaced by a stub function without effect.
This commit takes the latter approach, which has the benefit of
not requiring any change on the example applications, but introducing
the risk of mismatching API calls and compile-time configuration,
in case a user doesn't correctly keep track of which parts of the
configuration have been fixed at compile-time, and which haven't.
Write-access for the purpose of setting defaults is simply omitted.
2019-06-25 08:42:20 +01:00
Jaeden Amero 5ecbd14fdd Merge remote-tracking branch 'origin/pr/2701' into mbedtls-2.16
* origin/pr/2701:
  Add all.sh component that exercises invalid_param checks
  Remove mbedtls_param_failed from programs
  Make it easier to define MBEDTLS_PARAM_FAILED as assert
  Make test suites compatible with #include <assert.h>
  Pass -m32 to the linker as well
2019-06-21 16:00:06 +01:00
Jaeden Amero 096bccf204 Merge remote-tracking branch 'origin/pr/2450' into mbedtls-2.16
* origin/pr/2450:
  Fix #2370, minor typos and spelling mistakes
2019-06-21 15:59:29 +01:00
Hanno Becker 5882dd0856 Remove CRT digest from SSL session if !RENEGO + !KEEP_PEER_CERT
If `MBEDTLS_SSL_KEEP_PEER_CERTIFICATE` is not set, `mbedtls_ssl_session`
contains the digest of the peer's certificate for the sole purpose of
detecting a CRT change on renegotiation. Hence, it is not needed if
renegotiation is disabled.

This commit removes the `peer_cert_digest` fields (and friends) from
`mbedtls_ssl_session` if
   `!MBEDTLS_SSL_KEEP_PEER_CERTIFICATE + !MBEDTLS_SSL_RENEGOTIATION`,
which is a sensible configuration for constrained devices.

Apart from straightforward replacements of
   `if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)`
by
   `if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) && \
        defined(MBEDTLS_SSL_RENEGOTIATION)`,
there's one notable change: On the server-side, the CertificateVerify
parsing function is a no-op if the client hasn't sent a certificate.
So far, this was determined by either looking at the peer CRT or the
peer CRT digest in the SSL session structure (depending on the setting
of `MBEDTLS_SSL_KEEP_PEER_CERTIFICATE`), which now no longer works if
`MBEDTLS_SSL_KEEP_PEER_CERTIFICATE` is unset. Instead, this function
now checks whether the temporary copy of the peer's public key within
the handshake structure is initialized or not (which is also a
beneficial simplification in its own right, because the pubkey is
all the function needs anyway).
2019-06-19 16:56:51 +01:00
Hanno Becker d972f005bf Use consistent error messages in check_config.h 2019-06-19 14:59:42 +01:00
Hanno Becker 2984bd2543 Add config sanity check for !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE 2019-06-19 14:59:41 +01:00
Hanno Becker 24bc570814 Improve documentation of mbedtls_ssl_get_peer_cert() 2019-06-19 10:26:50 +01:00
Hanno Becker 3ed64578d2 Improve documentation of MBEDTLS_SSL_KEEP_PEER_CERTIFICATE 2019-06-19 10:26:50 +01:00
Hanno Becker dd689316d1 Fix indentation of Doxygen comment in ssl_internal.h 2019-06-19 10:26:50 +01:00
Hanno Becker e669770b52 Remove misleading and redundant guard around restartable ECC field
`MBEDTLS_SSL__ECP_RESTARTABLE` is only defined if
`MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED` is set, which
requires `MBEDTLS_X509_PARSE_C` to be set (this is checked
in `check_config.`). The additional `MBEDTLS_X509_PARSE_C`
guard around the `ecrs_peer_cert` field is therefore not
necessary; moreover, it's misleading, because it hasn't
been used consistently throughout the code.
2019-06-19 10:26:50 +01:00
Hanno Becker 3bf8cdf2f8 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.
2019-06-19 10:25:01 +01:00
Hanno Becker 32c530ece2 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.
2019-06-19 10:25:01 +01:00
Hanno Becker 2e6d34761f Remove peer CRT from mbedtls_ssl_session if !KEEP_PEER_CERT 2019-06-19 10:25:01 +01:00
Hanno Becker e4aeb76a2c 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.
2019-06-19 10:25:01 +01:00
Hanno Becker 9fb6e2e203 Extend mbedtls_ssl_session by buffer holding peer CRT digest 2019-06-19 10:25:01 +01:00
Hanno Becker b90f655a78 Add configuration option to remove peer CRT after handshake 2019-06-19 10:25:01 +01:00
Hanno Becker 869144b3e9 Improve documentation of mbedtls_ssl_get_peer_cert() 2019-06-19 10:25:01 +01:00
Hanno Becker 58fccf2f62 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.
2019-06-19 10:25:01 +01:00
Hanno Becker 5097cba93c 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;
```
2019-06-19 10:25:01 +01:00
Simon Butcher 7400e8fb36 Merge remote-tracking branch 'origin/pr/591' into baremetal 2019-06-18 17:36:45 +01:00
Simon Butcher f2ef573f2b Merge remote-tracking branch 'origin/pr/598' into baremetal 2019-06-18 15:00:02 +01:00
Simon Butcher f1ff74574d Merge remote-tracking branch 'origin/pr/597' into baremetal 2019-06-18 14:58:37 +01:00
Jaeden Amero d81c11b8ab Merge remote-tracking branch 'origin/pr/2687' into mbedtls-2.16
* origin/pr/2687:
  Update library to 2.16.2
2019-06-18 14:23:28 +01:00
Hanno Becker c6043f2b75 Address review comments 2019-06-18 11:05:44 +01:00
Hanno Becker 02a2193f60 Rename MBEDTLS_X509_INFO to !MBEDTLS_X509_REMOVE_INFO 2019-06-18 11:05:44 +01:00
Peter Kolbus dc470ae8af Reduce code size when mbedtls_x509_*_info() unused
Introduce MBEDTLS_X509_INFO to indicate the availability of the
mbedtls_x509_*_info() function and closely related APIs. When this is
not defined, also omit name and description from
mbedtls_oid_descriptor_t, and omit OID arrays, macros, and types that
are entirely unused. This saves several KB of code space.

Change-Id: I056312613379890e0d70e1d08c34171287c0aa17
2019-06-18 11:05:37 +01:00
Manuel Pégourié-Gonnard 889bbc70b6 Fix unreachable code warnings with armc5
Some TLS-only code paths were not protected by an #ifdef and while some
compiler are happy to just silently remove them, armc5 complains:

Warning:  #111-D: statement is unreachable

Let's make armc5 happy.
2019-06-18 10:56:09 +02:00
Manuel Pégourié-Gonnard c84511fb1f Add check for undocumented positive option 2019-06-18 10:32:25 +02:00
Manuel Pégourié-Gonnard 41efa2109e Improve documentation of PROTO_NO_TLS 2019-06-18 10:28:52 +02:00
Manuel Pégourié-Gonnard 7667afd4fc Clarify documentation of mbedtls_ssl_context_load() 2019-06-18 10:09:27 +02:00