This commit is a step towards the goal of allowing to hardcode the choice
of a single ciphersuite at compile-time. The hoped for benefit of this is
that whereever a ciphersuite attribute is queried and checked against a
compile-time constant, the check can be recognized as either true or false
at compile-time, hence leading to a code-size reduction.
For this to work, the ciphersuite attribute getter functions
mbedtls_ssl_suite_get_xxx() will be modified to return something
the compiler can recognize as a compile-time constant. In particular,
in order to avoid relying on constant propagation abilities of the
compiler, these functions should ideally return constant symbols
(instead of, say, fields in a globally const structure instance).
This puts us in the following situation: On the one hand, there's the
array of ciphersuite information structures defining the attribute of
those ciphersuites the stack knows about. On the other hand, we need
direct access to those fields through constant symbols in the getter
functions.
In order to avoid any duplication of information, this commit exemplifies
how ciphersuites can be conveniently defined on the basis of macro
definitions, and how the corresponding instances of the ciphersuite
information structure can be auto-generated from this.
In the approach, to add support for a ciphersuite with official name
NAME (such as TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8), the following macro
constants need to be defined in ssl_ciphersuites.h:
MBEDTLS_SUITE__ NAME __ID
MBEDTLS_SUITE__ NAME __NAME
MBEDTLS_SUITE__ NAME __CIPHER
MBEDTLS_SUITE__ NAME __MAC
...
To make check-names.sh happy, one also needs a dummy macro
MBEDTLS_SUITE__ NAME()
These ciphersuite attribute values can then be queried via
MBEDTLS_SSL_SUITE_ID( NAME_MACRO )
...
where NAME_MACRO can be any macro expanding to a defined NAME.
Further, a convenience macro
MBEDTLS_SSL_SUITE_INFO( NAME_MACRO )
is provided that again takes a macro NAME_MACRO expanding to a
defined NAME, and itself expands to an instance of
mbedtls_ssl_ciphersuite_info_t using the macro attributes
defined for NAME. This macro is then used in ssl_ciphersuites.c
when defining the array of known ciphersuite information structures,
(a) without duplicating the information, and (b) with increased
readability, because there's only one line for each ciphersuite.
This commit introduces an internal zero-cost abstraction layer for
SSL ciphersuites: Instead of addressing ciphersuites via pointers
to instances of mbedtls_ssl_ciphersuite_t and accessing their fields
directly, this commit introduces an opaque type
mbedtls_ssl_ciphersuite_handle_t,
and getter functions
mbedtls_ssl_suite_get_xxx()
operating on ciphersuite handles.
The role of NULL is played by a new macro constant
MBEDTLS_SSL_CIPHERSUITE_INVALID_HANDLE
which results of functions returning handles can be checked against.
(For example, when doing a lookup of a ciphersuite from a peer-provided
ciphersuite ID in the per's Hello message).
The getter functions have the validity of the handle as a precondition
and are undefined if the handle is invalid.
So far, there's only one implementation of this abstraction layer, namely
mbedtls_ssl_ciphersuite_handle_t being mbedtls_ssl_ciphersuite_t const *
and
getter functions being field accesses.
In subsequent commits, however, the abstraction layer will be useful
to save code in the situation where only a single ciphersuite is enabled.
Those suites were defined in ciphersuite_definitions[] but not included in
ciphersuite_preference[] which meant they couldn't be negotiated unless
explicitly added by the user. Add them so that they're usable by default like
any other suite.
This commit changes `ssl_parse_signature_algorithms_ext` to remember
one suitable ( := supported by client and by our config ) hash
algorithm per signature algorithm.
It also modifies the ciphersuite checking function
`ssl_ciphersuite_match` to refuse a suite if there
is no suitable hash algorithm.
Finally, it adds the corresponding entry to the ChangeLog.
The routine `mbedtls_ssl_write_server_key_exchange` heavily depends on
what kind of cipher suite is active: some don't need a
ServerKeyExchange at all, some need (EC)DH parameters but no server
signature, some require both. Each time we want to restrict a certain
piece of code to some class of ciphersuites, it is guarded by a
lengthy concatentation of configuration checks determining whether at
least one of the relevant cipher suites is enabled in the config; on
the code level, it is guarded by the check whether one of these
cipher suites is the active one.
To ease readability of the code, this commit introduces several helper
macros and helper functions that can be used to determine whether a
certain class of ciphersuites (a) is active in the config, and
(b) contains the currently present ciphersuite.
Separates platform time abstraction into it's own header from the
general platform abstraction as both depend on different build options.
(MBEDTLS_PLATFORM_C vs MBEDTLS_HAVE_TIME)
* mbedtls-1.3:
Rename website and repository
Move private macro from header to C file
Add some missing 'static' on a few objects
Fix whitespace issues
Minor portability fix in benchmark
* development: (100 commits)
Update Changelog for the mem-measure branch
Fix issues introduced when rebasing
Fix compile error in memory_buffer_alloc_selftest
Code cosmetics
Add curve25519 to ecc-heap.sh
Add curve25519 to the benchmark program
Fix compile issue when buffer_alloc not available
New script ecc-heap.sh
Fix unused variable issue in some configs
Rm usunused member in private struct
Add heap usage for PK in benchmark
Use memory_buffer_alloc() in benchmark if available
Only define mode_func if mode is enabled (CBC etc)
PKCS8 encrypted key depend on PKCS5 or PKCS12
Disable SRV_C for client measurement
Output stack+heap usage with massif
Enable NIST_OPTIM by default for config-suite-b
Refactor memory.sh
Adapt memory.sh to config-suite-b
Adapt mini-client for config-suite-b.h
...
Conflicts:
ChangeLog
include/polarssl/net.h
library/Makefile
library/error.c
library/ssl_tls.c
programs/Makefile
programs/ssl/ssl_client2.c
programs/ssl/ssl_server2.c
tests/Makefile
* development: (46 commits)
Fix url again
Fix small bug in base64_encode()
Fix depend that was checked but not documented
Fix dependency that was not checked
Minor gitginore fixes
Move some ignore patterns to subdirectories
Ignore CMake/MSVC-related build files.
Re-categorize changelog entry
Fix misattribution
Minor nits with stdout/stderr.
Add cmake compatibility targets
Add script for polarssl symlink creation
Fix more stdio inclusion issues
Add debug info for cert/suite selection
Fix possible portability issue
Fix bug in ssl_get_verify_result()
aescrypt2.c local char array not initial
Update Changelog
Fix mips64 bignum implementation
Fix usage string of ssl_client2
...
Conflicts:
include/polarssl/ssl.h
library/CMakeLists.txt
library/Makefile
programs/Makefile
programs/ssl/ssl_client2.c
programs/ssl/ssl_server2.c
visualc/VS2010/PolarSSL.sln
visualc/VS2010/mbedTLS.vcxproj
visualc/VS6/mbedtls.dsp
visualc/VS6/mbedtls.dsw
* development:
Update copyright
Fix issue in compat.sh
Rename doxyfile
Rename to mbed TLS in tests/
Rename to mbed TLS in examples
Remove old test certificates.
Rename to mbed TLS in the documentation/comments
Change name to mbed TLS in the copyright notice
Conflicts:
doxygen/input/doc_mainpage.h
doxygen/mbedtls.doxyfile
include/polarssl/version.h
tests/compat.sh
It's not clear if, with SSL3, one should include send the two length bytes for
EncryptedPreMasterSecret or not, so require TLS to avoid interop issues.
