Commit graph

2719 commits

Author SHA1 Message Date
Jarno Lamsa 20095afc58 Changes according to review comments 2019-06-11 17:16:58 +03:00
Manuel Pégourié-Gonnard 8794a4290d Clarify a few more comments and documentation 2019-06-11 10:04:57 +02:00
Jarno Lamsa 18b9a491e1 Disable the enforce flag by default 2019-06-10 15:23:29 +03:00
Jarno Lamsa d9382f85e7 Add definitions for enforce flag values 2019-06-10 10:27:14 +03:00
Jarno Lamsa 95f752e679 Fix typo 2019-06-10 10:15:49 +03:00
Jarno Lamsa 7a5e2bec75 Create a new flag for enforcing the extended master secret
If the flag is enabled, drop the connection if peer doesn't support
extended master secret extension.
2019-06-10 10:13:03 +03:00
Manuel Pégourié-Gonnard c6d9e3a28f Clarify documentation of MBEDTLS_SSL_PROTO_TLS 2019-06-07 11:07:53 +02:00
Jaeden Amero c30740368b Merge remote-tracking branch 'origin/pr/2657' into mbedtls-2.16
* origin/pr/2657:
  Create link to include/mbedtls only when testing is enabled
2019-06-06 14:18:59 +01:00
Manuel Pégourié-Gonnard 25838b795f Introduce tools for transport-specific code
And use those tools in a few places. For now the purpose is just to validate
those tools before using them in all occurrences of transport-specific code.

The effect of these changes was measured with the following script:

```
set -eu

build() {
    printf "\n$1\n"
    CC=arm-none-eabi-gcc CFLAGS='-Werror -Os -march=armv6-m -mthumb' \
        AR=arm-none-eabi-ar LD=arm-none-eabi-ld make clean lib >/dev/null
    arm-none-eabi-size -t library/libmbedtls.a
}

git checkout -- include/mbedtls/config.h
scripts/config.pl unset MBEDTLS_NET_C
scripts/config.pl unset MBEDTLS_TIMING_C
scripts/config.pl unset MBEDTLS_FS_IO
scripts/config.pl unset MBEDTLS_ENTROPY_NV_SEED
scripts/config.pl set MBEDTLS_NO_PLATFORM_ENTROPY
build "both"

scripts/config.pl unset MBEDTLS_SSL_PROTO_TLS
build "DTLS-only"

scripts/config.pl set MBEDTLS_SSL_PROTO_TLS
scripts/config.pl unset MBEDTLS_SSL_PROTO_DTLS
scripts/config.pl unset MBEDTLS_SSL_DTLS_HELLO_VERIFY
scripts/config.pl unset MBEDTLS_SSL_DTLS_ANTI_REPLAY
scripts/config.pl unset MBEDTLS_SSL_DTLS_BADMAC_LIMIT
scripts/config.pl unset MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE
build "TLS-only"

git checkout -- include/mbedtls/config.h
```

The output of the script is as follows:

```
both
   text    data     bss     dec     hex filename
   1820       0       4    1824     720 debug.o (ex library/libmbedtls.a)
      0       0       0       0       0 net_sockets.o (ex library/libmbedtls.a)
    548       0       0     548     224 ssl_cache.o (ex library/libmbedtls.a)
  11155       0     596   11751    2de7 ssl_ciphersuites.o (ex library/libmbedtls.a)
  17160       0       0   17160    4308 ssl_cli.o (ex library/libmbedtls.a)
    460       0       0     460     1cc ssl_cookie.o (ex library/libmbedtls.a)
  17637       0       0   17637    44e5 ssl_srv.o (ex library/libmbedtls.a)
    800       0       0     800     320 ssl_ticket.o (ex library/libmbedtls.a)
  39322      60       0   39382    99d6 ssl_tls.o (ex library/libmbedtls.a)
  88902      60     600   89562   15dda (TOTALS)

DTLS-only
   text    data     bss     dec     hex filename
   1820       0       4    1824     720 debug.o (ex library/libmbedtls.a)
      0       0       0       0       0 net_sockets.o (ex library/libmbedtls.a)
    548       0       0     548     224 ssl_cache.o (ex library/libmbedtls.a)
  11155       0     596   11751    2de7 ssl_ciphersuites.o (ex library/libmbedtls.a)
  17072       0       0   17072    42b0 ssl_cli.o (ex library/libmbedtls.a)
    460       0       0     460     1cc ssl_cookie.o (ex library/libmbedtls.a)
  17565       0       0   17565    449d ssl_srv.o (ex library/libmbedtls.a)
    800       0       0     800     320 ssl_ticket.o (ex library/libmbedtls.a)
  38953      60       0   39013    9865 ssl_tls.o (ex library/libmbedtls.a)
  88373      60     600   89033   15bc9 (TOTALS)

TLS-only
   text    data     bss     dec     hex filename
   1820       0       4    1824     720 debug.o (ex library/libmbedtls.a)
      0       0       0       0       0 net_sockets.o (ex library/libmbedtls.a)
    548       0       0     548     224 ssl_cache.o (ex library/libmbedtls.a)
  11155       0     596   11751    2de7 ssl_ciphersuites.o (ex library/libmbedtls.a)
  14916       0       0   14916    3a44 ssl_cli.o (ex library/libmbedtls.a)
    460       0       0     460     1cc ssl_cookie.o (ex library/libmbedtls.a)
  15852       0       0   15852    3dec ssl_srv.o (ex library/libmbedtls.a)
    800       0       0     800     320 ssl_ticket.o (ex library/libmbedtls.a)
  27623      60       0   27683    6c23 ssl_tls.o (ex library/libmbedtls.a)
  73174      60     600   73834   1206a (TOTALS)
```

It can be seen that a DTLS-only build is now starting to be a bit smaller than
a dual-mode build, which is the purpose of the new build option.
2019-06-06 13:02:14 +02:00
Manuel Pégourié-Gonnard e744eab3b1 Adapt defaults and programs documentation 2019-06-06 13:02:14 +02:00
Manuel Pégourié-Gonnard a771160799 Introduce new config.h flag for TLS
For now the option has no effect.

Adapted existing example config files. The fact that I needed to do this
highlights that this is a slightly incompatible change: existing users need to
update their existing custom configs (if standalone as opposed to based on the
default config) in order to still get the same behaviour.

The alternative would be to have a negative config option (eg NO_TLS or
DTLS_ONLY) but this doesn't fit as nicely with the existing options, so
hopefully the minor incompatibility is acceptable.

I don't think it's worth adding a new component to all.sh:
- builds with both DTLS and TLS are done in the default (and full) config
- TLS-only builds are done with eg config-suite-b.h in test-ref-configs
- a DTLS-only build is done with config-thread.h in test-ref-configs
- builds with none of them (and SSL_TLS_C enabled) are forbidden
2019-06-06 12:59:48 +02:00
Hanno Becker aa8665ac26 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.
2019-06-05 13:16:55 +01:00
Simon Butcher 21d1c32b2b Merge remote-tracking branch 'origin/pr/574' into baremetal 2019-06-04 15:08:32 +01:00
Manuel Pégourié-Gonnard f3c43dde54 Merge branch 'mbedtls-2.16' into baremetal
* mbedtls-2.16:
  test: Always use `make clean` by itself
  list-symbols.sh: if the build fails, print the build transcript
  Document "check-names.sh -v"
  all.sh: invoke check-names.sh in print-trace-on-exit mode
  Print a command trace if the check-names.sh exits unexpectedly
  Only use submodule if present
  Update change log
  Reword ssl_conf_max_frag_len documentation for clarity
  Ignore more generated files: seedfile, apidoc
  Improve .gitignore grouping and documentation
  Generate tags for Vi, for Emacs and with Global
2019-06-04 09:39:51 +02:00
Hanno Becker 5dbcc9f441 Introduce specific error for ver/cfg mismatch on deserialization
This commit introduces a new SSL error code

  `MBEDTLS_ERR_SSL_VERSION_MISMATCH`

which can be used to indicate operation failure due to a
mismatch of version or configuration.

It is put to use in the implementation of `mbedtls_ssl_session_load()`
to signal the attempt to de-serialize a session which has been serialized
in a build of Mbed TLS using a different version or configuration.
2019-06-03 13:01:21 +01:00
Manuel Pégourié-Gonnard 35ccdbb636 Normalize spelling to serialiZation
We have explicit recommendations to use US spelling for technical writing, so
let's apply this to code as well for uniformity. (My fingers tend to prefer UK
spelling, so this needs to be fixed in many places.)

sed -i 's/\([Ss]eriali\)s/\1z/g' **/*.[ch] **/*.function **/*.data ChangeLog
2019-06-03 09:55:16 +02:00
Manuel Pégourié-Gonnard e0cd1d0184 Improve documentation 2019-06-03 09:51:08 +02:00
Manuel Pégourié-Gonnard 5363e1f496 Add list of coupled functions to struct definition 2019-06-03 09:51:08 +02:00
Manuel Pégourié-Gonnard 32ce596c35 Improve save API by always updating olen
This allows callers to discover what an appropriate size is. Otherwise they'd
have to either try repeatedly, or allocate an overly large buffer (or some
combination of those).

Adapt documentation an example usage in ssl_client2.
2019-06-03 09:51:08 +02:00
Manuel Pégourié-Gonnard 37a5324c74 Add mbedtls_ssl_get_session_pointer()
Avoid useless copy with mbedtls_ssl_get_session() before serialising.

Used in ssl_client2 for testing and demonstrating usage, but unfortunately
that means mbedtls_ssl_get_session() is no longer tested, which will be fixed
in the next commit.
2019-06-03 09:51:08 +02:00
Manuel Pégourié-Gonnard 2843fe10b9 Declare and document session save/load functions
The next commit with make the implementation publicly available as well.

For now the API is kept unchanged. The save function API has a serious drawback in that the user
must guess what an appropriate buffer size is.
Internally so far this didn't matter because we were only using that API for
ticket creation, and tickets are written to the SSL output buffer whose size
is fixed anyway, but for external users this might not be suitable. Improving
that is left for later.

Also, so far the functions are defined unconditionally. Whether we want to
re-use existing flags or introduce a new one is left for later.

Finally, currently suggested usage of calling get_session() then
session_save() is memory-inefficient in that get_session() already makes a
copy. I don't want to recommend accessing `ssl->session` directly as we want
to prohibit direct access to struct member in the future. Providing a clean
and efficient way is also left to a later commit.
2019-06-03 09:51:08 +02:00
Hanno Becker 72309d0847 Document origin of hardcoded certificates in library/certs.c
All of them are copied from (former) CRT and key files in `tests/data_files`.
For files which have been regenerated since they've been copied to `certs.c`,
update the copy.

Add declarations for DER encoded test CRTs to certs.h

Add DER encoded versions of CRTs to certs.c

fix comment in certs.c

Don't use (signed) char for DER encoded certificates

Consistently use `const char *` for test CRTs regardless of encoding

Remove non-sensical and unused PW variable for DER encoded key

Provide test CRTs in PEM and DER fmt, + pick suitable per config

This commit modifies `certs.h` and `certs.c` to start following the
following pattern for the provided test certificates and files:

- Raw test data is named `NAME_ATTR1_ATTR2_..._ATTRn`

  For example, there are
     `TEST_CA_CRT_{RSA|EC}_{PEM|DER}_{SHA1|SHA256}`.

- Derived test data with fewer attributes, iteratively defined as one
  of the raw test data instances which suits the current configuration.

  For example,
     `TEST_CA_CRT_RSA_PEM`
  is one of `TEST_CA_CRT_RSA_PEM_SHA1` or `TEST_CA_CRT_RSA_PEM_SHA256`,
  depending on whether SHA-1 and/or SHA-256 are defined in the current
  config.

Add missing public declaration of test key password

Fix signedness and naming mismatches

Further improve structure of certs.h and certs.c

Fix definition of mbedtls_test_cas test CRTs depending on config

Remove semicolon after macro string constant in certs.c
2019-05-30 10:27:49 +01:00
Simon Butcher 0d1d76f987 Merge remote-tracking branch 'origin/pr/561' into baremetal 2019-05-29 15:09:24 +01:00
Renz Christian Bagaporo ac859f39bd Create link to include/mbedtls only when testing is enabled 2019-05-27 15:58:36 +08:00
Simon Butcher d5e1bfc6b4 Merge remote-tracking branch 'origin/pr/569' into baremetal 2019-05-24 15:07:10 +01:00
Simon Butcher 0edb924e16 Merge remote-tracking branch 'origin/pr/565' into baremetal 2019-05-24 15:06:56 +01:00
Simon Butcher 5a790f9214 Merge remote-tracking branch 'origin/pr/563' into baremetal 2019-05-24 15:06:16 +01:00
Hanno Becker 4753e65e9b Disable Connection ID feature by default 2019-05-23 17:02:14 +01:00
Hanno Becker 948d2d5611 Expand CID to Connection ID in documentation of mbedtls_ssl_conf_cid 2019-05-23 16:55:50 +01:00
Jaeden Amero cbcd327376 Merge remote-tracking branch 'origin/pr/2611' into mbedtls-2.16
* origin/pr/2611:
  Update change log
  Reword ssl_conf_max_frag_len documentation for clarity
2019-05-23 15:14:06 +01:00
Hanno Becker 633d604837 Allow passing NULL pointers to mbedtls_ssl_get_peer_cid()
This commit modifies mbedtls_ssl_get_peer_cid() to also allow passing
NULL pointers in the arguments for the peer's CID value and length, in
case this information is needed.

For example, some users might only be interested in whether the use of
the CID was negotiated, in which case both CID value and length pointers
can be set to NULL. Other users might only be interested in confirming
that the use of CID was negotiated and the peer chose the empty CID,
in which case the CID value pointer only would be set to NULL.
It doesn't make sense to pass a NULL pointer for the CID length but a
non-NULL pointer for the CID value, as the caller has no way of telling
the length of the returned CID - and this case is therefore forbidden.
2019-05-22 16:50:35 +01:00
Hanno Becker 2f8c804d79 Fix typo in Doxygen documentation of mbedtls_ssl_conf_cid() 2019-05-20 15:35:36 +01:00
Hanno Becker a5a2b08a05 Rename MBEDTLS_SSL_CID to MBEDTLS_SSL_DTLS_CONNECTION_ID
Files modified via

sed -i 's/MBEDTLS_SSL_CID\([^_]\|$\)/MBEDTLS_SSL_DTLS_CONNECTION_ID\1/g' **/*.c **/*.h **/*.sh **/*.function
2019-05-20 15:35:36 +01:00
Hanno Becker 3cdf8fe50b Consistently reference CID draft through name + URL 2019-05-20 15:32:36 +01:00
Hanno Becker cfa6be76bd Fix typo in documentation of mbedtls_ssl_context::cid_in_use 2019-05-20 15:32:36 +01:00
Hanno Becker 96f35b4f06 Improve wording of documentation of mbedtls_ssl_get_peer_cid() 2019-05-20 15:32:36 +01:00
Hanno Becker 5fcac0dc99 Slightly reword documentation of mbedtls_ssl_set_cid() 2019-05-20 15:32:36 +01:00
Hanno Becker 53f36e9230 Use full sentences in Doxygen documentation of mbedtls_ssl_set_cid() 2019-05-20 15:32:36 +01:00
Hanno Becker dc19b41eb3 Use uniform spacing in def's of MBEDTLS_SSL_CID_{IN|OUT}_LEN_MAX 2019-05-20 15:32:36 +01:00
Hanno Becker f83017ccd1 Improve wording in documentation of mbedtls_ssl_set_cid() 2019-05-20 15:32:36 +01:00
Hanno Becker 75b334f33a Update references to CID draft to version 5 2019-05-20 15:32:36 +01:00
Hanno Becker ef2b8b0dcf Improve wording in documentation of MBEDTLS_SSL_CID 2019-05-20 15:32:36 +01:00
Hanno Becker a69b4315eb Modify MBEDTLS_SSL_UNEXPECTED_CID_{FAIL|IGNORE} to ignore by default 2019-05-20 15:32:36 +01:00
Hanno Becker e8eff9a517 Allow to configure the stack's behaviour on unexpected CIDs
This commit modifies the CID configuration API mbedtls_ssl_conf_cid_len()
to allow the configuration of the stack's behaviour when receiving an
encrypted DTLS record with unexpected CID.
2019-05-20 15:32:36 +01:00
Hanno Becker 7c3cdb62de Add specific SSL error code for unexpected CIDs
Currently, the stack silently ignores DTLS frames with an unexpected CID.
However, in a system which performs CID-based demultiplexing before passing
datagrams to the Mbed TLS stack, unexpected CIDs are a sign of something not
working properly, and users might want to know about it.

This commit introduces an SSL error code MBEDTLS_ERR_SSL_UNEXPECTED_CID
which the stack can return in response to an unexpected CID. It will
conditionally be put to use in subsequent commits.
2019-05-20 15:32:36 +01:00
Hanno Becker 7842609e3b Remove restriction on value of MBEDTLS_SSL_CID_PADDING_GRANULARITY 2019-05-20 15:32:36 +01:00
Hanno Becker 241947d062 Reword CID documentation 2019-05-20 15:32:36 +01:00
Hanno Becker 550e1662c7 Allow the configuration of padding when using CID extension 2019-05-20 15:32:36 +01:00
Hanno Becker 043a2a4869 Remove indicators and warnings about unfinished CID implementation 2019-05-20 15:32:36 +01:00
Hanno Becker 70e7928d76 Add pointers to in/out CID fields to mbedtls_ssl_context
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.
2019-05-20 15:32:36 +01:00
Hanno Becker add0190059 Account for additional record expansion when using CIDs
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.
2019-05-20 15:32:36 +01:00
Hanno Becker eec2be9c9f Add CID configuration API
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.
2019-05-20 15:32:36 +01:00
Hanno Becker ccc2456db9 Re-implement mbedtls_ssl_{in/out}_hdr_len() via in/out pointers 2019-05-20 15:32:36 +01:00
Hanno Becker 4339576208 Split mbedtls_ssl_hdr_len() in separate functions for in/out records
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.
2019-05-20 15:32:36 +01:00
Hanno Becker 346a590c1c Unify documentation of internal SSL record structure
- Don't use Doxygen style comments
- Document CID and CID length fields.
2019-05-20 14:49:02 +01:00
Hanno Becker 2e7cd5aa4c Use MBEDTLS_ namespace for internal CID length constant 2019-05-17 10:23:47 +01:00
Hanno Becker 92c930f7c4 Implement inner plaintext parsing/writing for CID-based connections 2019-05-17 10:23:47 +01:00
Hanno Becker 80fe63e082 Add CID field to internal structure representing TLS records
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.
2019-05-17 10:23:47 +01:00
Hanno Becker 8013b27481 Replace 'ingoing' -> 'incoming' in CID debug messages 2019-05-17 10:20:41 +01:00
Hanno Becker cb063f5a5b Document behaviour of mbedtls_ssl_get_peer_cid() for empty CIDs 2019-05-17 10:20:41 +01:00
Hanno Becker fc7ff9289f Use unused extension ID as tentative ID for CID extension 2019-05-17 10:20:41 +01:00
Hanno Becker 4f0b15faec Add fields holding in/out CIDs to SSL record transformation struct
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.
2019-05-17 10:20:41 +01:00
Hanno Becker 46629717c9 Check static bounds of CID lengths in check_config.h 2019-05-17 10:20:41 +01:00
Hanno Becker 4baec2c4bf Add identifier for CID extension
Note: The current draft

   https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-04

does not yet specify the extension value, so we
use a temporary value of 42.
2019-05-17 10:20:41 +01:00
Hanno Becker e5e7f621cc Add fields to SSL structures describing state and config of CID ext
* 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.
2019-05-17 10:20:41 +01:00
Hanno Becker fce6f836ba Merge branch 'mbedtls-2.16' into baremetal 2019-05-17 10:06:02 +01:00
Simon Butcher 724a695534 Merge remote-tracking branch 'origin/pr/562' into baremetal 2019-05-09 17:11:38 +01:00
Simon Butcher e372d5fb8f Merge remote-tracking branch 'origin/pr/558' into baremetal 2019-05-09 17:03:18 +01:00
Simon Butcher 999ac174cc Merge remote-tracking branch 'origin/pr/566' into baremetal 2019-05-09 16:59:02 +01:00
Manuel Pégourié-Gonnard 00c99d776a Clarify origin and licensing of TinyCrypt files 2019-05-09 11:38:19 +02:00
Manuel Pégourié-Gonnard afdc1b5cbd Consistently use the name tinycrypt over uecc
We called in tinycrypt in the file names, but uecc in config.h, all.sh and
other places, which could be confusing. Just use tinycrypt everywhere because
that's the name of the project and repo where we took the files.

The changes were made using the following commands (with GNU sed and zsh):

sed -i 's/uecc/tinycrypt/g' **/*.[ch] tests/scripts/all.sh
sed -i 's/MBEDTLS_USE_UECC/MBEDTLS_USE_TINYCRYPT/g' **/*.[ch] tests/scripts/all.sh scripts/config.pl
2019-05-09 11:24:11 +02:00
Manuel Pégourié-Gonnard a575975280 Make calc_verify() return the length as well
Simplifies ssl_compute_hash(), but unfortunately not so much the other uses.
2019-05-07 09:59:32 +02:00
Manuel Pégourié-Gonnard ed3b7a9492 Constify ssl_context param of calc_verify() 2019-05-03 10:00:45 +02:00
Jarno Lamsa 0668b8f59e Description of MBEDTLS_USE_UECC 2019-05-02 09:39:09 +03:00
Hanno Becker f832343c1d Improve documentation of mbedtls_record 2019-04-29 12:19:07 +02:00
Hanno Becker a198bb7359 Improve documentation of mbedtls_ssl_transform 2019-04-29 12:18:11 +02:00
Hanno Becker 611a83b571 Add tests for record encryption/decryption
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.
2019-04-29 12:15:21 +02:00
Hanno Becker 92231325a7 Reduce size of ssl_transform if no MAC ciphersuite is enabled
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.
2019-04-29 12:15:05 +02:00
Hanno Becker 4c6876b134 Provide standalone version of ssl_decrypt_buf
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
2019-04-29 12:13:25 +02:00
k-stachowiak d707783cf3 Reword ssl_conf_max_frag_len documentation for clarity 2019-04-29 11:39:58 +02:00
Hanno Becker 3307b53413 Provide standalone version of ssl_encrypt_buf
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.
2019-04-29 10:58:15 +02:00
Hanno Becker 4a5eeaee2e Improve documentation of mbedtls_ssl_transform 2019-04-29 10:37:01 +02:00
Hanno Becker 9d2e4b4742 Add structure representing TLS records
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.
2019-04-29 10:36:44 +02:00
Hanno Becker b628a80b76 Fix definition of SSL_SOME_MODES_USE_MAC
The previous definition was lacking the case of the ARIA and DES ciphers.
2019-04-29 10:36:26 +02:00
Hanno Becker 5cc04d5ae7 Correct space needed for MAC in case of NULL cipher
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`.
2019-04-29 10:36:09 +02:00
Hanno Becker 8759e16242 Remove ciphersuite_info from ssl_transform
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.
2019-04-29 10:36:01 +02:00
Hanno Becker e7f2df03a3 Remove key length field from ssl_transform
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.
2019-04-29 09:32:08 +02:00
Jarno Lamsa 5b871285f5 MBEDTLS_USE_UECC and MBEDTLS_NO_64BIT_MULTIPLICATION conflicting 2019-04-29 10:29:06 +03:00
Jarno Lamsa 55427964b1 Guard tinycrypt files with MBEDTLS_USE_UECC 2019-04-29 10:25:23 +03:00
Jarno Lamsa 9454dfaed4 Add a new flag for the micro-ecc 2019-04-24 16:28:59 +03:00
Jarno Lamsa 79e3b946db Add CMake support for uecc 2019-04-24 16:17:10 +03:00
Jarno Lamsa 18987a420b Add micro-ecc based ecc-files to mbedtls
The files are from https://github.com/intel/tinycrypt
Using commit 6e0eb53fc8403988f97345e94081b0453f47231d as a base.
2019-04-24 15:40:43 +03:00
Hanno Becker d6028a1894 Improve macro hygiene
This commit improves hygiene and formatting of macro definitions
throughout the library. Specifically:
- It adds brackets around parameters to avoid unintended
  interpretation of arguments, e.g. due to operator precedence.
- It adds uses of the `do { ... } while( 0 )` idiom for macros that
  can be used as commands.
2019-04-24 10:51:54 +02:00
Hanno Becker 8d0893d0b0 Add warnings about status of implementation of CID API 2019-04-23 12:01:20 +01:00
Hanno Becker b9b7e29536 Clarify that mbedtls_ssl_set_cid() applies to all subsequent HSs 2019-04-23 11:38:47 +01:00
Hanno Becker d928c06d01 Document that the use of CID is disabled by default.
(Even if MBEDTLS_SSL_CID is set in config.h)
2019-04-23 11:37:38 +01:00
Hanno Becker efde5b2e96 Reference CID Draft in Connection ID documentation in config.h 2019-04-23 11:36:56 +01:00
Hanno Becker 29a54c8415 Add dep of MBEDTLS_SSL_CID on MBEDTLS_SSL_PROTO_DTLS to config check 2019-04-09 18:26:59 +01:00
Hanno Becker 6198af33a0 Add API for the use of the DTLS Connection ID extension 2019-04-09 18:26:53 +01:00
Hanno Becker 81bd97149f Add new configuration option controlling CID extension 2019-04-09 15:12:41 +01:00