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()`.
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.
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.
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.
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.
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.
Previously, a test exercising the X.509 CRT parser's behaviour
on unexpected tags would use a '00' byte in place of the tag
for the expected structure. This makes reviewing the examples
harder because the binary data isn't valid DER-encoded ASN.1.
This commit uses the ASN.1 NULL TLV '05 00' to test invalid
tags, and adapts surrounding structures' length values accordingly.
This eases reviewing because now the ASN.1 structures are still
well-formed at the place where the mismatch occurs.
Multiple tests in ssl-opt.sh grep for debug output that's omitted
if MBEDTLS_X509_REMOVE_INFO is defined. This commit modifies ssl-opt.sh
to skip those tests in this case.
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
In a reduced configuration without PEM, PKCS5 or PKCS12, armc5 found that ret
was set but not used. Fixing that lead to a new warning about the variable not
being used at all. Now the variable is only declared when it's needed.
Only effective together with --rom, makes two changes:
- abort in case of build warnings
- skip writing statistics
The goal is to make sure we build cleanly in the configuration used for
measuring code size, with all the compilers we use, both because we care about
that configuration and those compilers, and because any warnings would cast a
shadow on the code size measurements.
Currently the build fails with armc5 due to a pre-existing warning in PK, this
will be fixed in the next commit.
The next commit will also add an all.sh component to make sure we have no
regression in the future. (Which is the motivation for --check skipping
statistics: an all.sh component should probably not leave files around.)
While at it, fix two things:
1. The call to gcc --version was redundant with the echo line below
2. WARNING_CFLAGS shouldn't be overriden with armclang, as it would remove the
-Wall -Wextra and any directory-specific warning (such as
-Wdeclaration-after-statement in library). It's meant to be overriden only
with compilers that don't accept the default value (namely armc5 here).
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.
