Due to the way the current PK API works, it may have not been clear
for the library clients, how big output buffers they should pass
to the signing functions. Depending on the key type they depend on
MPI or EC specific compile-time constants.
Inside the library, there were places, where it was assumed that
the MPI size will always be enough, even for ECDSA signatures.
However, for very small sizes of the MBEDTLS_MPI_MAX_SIZE and
sufficiently large key, the EC signature could exceed the MPI size
and cause a stack overflow.
This test establishes both conditions -- small MPI size and the use
of a long ECDSA key -- and attempts to sign an arbitrary file.
This can cause a stack overvlow if the signature buffers are not
big enough, therefore the test is performed for an ASan build.
For unit tests and sample programs, CFLAGS=-m32 is enough to get a
32-bit build, because these programs are all compiled directly
from *.c to the executable in one shot. But with makefile rules that
first build object files and then link them, LDFLAGS=-m32 is also
needed.
Remove the "Decrypt empty buffer" test, as ChaCha20 is a stream cipher
and 0 bytes encrypted is identical to a 0 length buffer. The "ChaCha20
Encrypt and decrypt 0 bytes" test will test decryption of a 0 length
buffer.
Previously, even in the Chacha20 and Chacha20-Poly1305 tests, we would
test that decryption of an empty buffer would work with
MBEDTLS_CIPHER_AES_128_CBC.
Make the cipher used with the dec_empty_buf() test configurable, so that
Chacha20 and Chacha20-Poly1305 empty buffer tests can use ciphers other
than AES CBC. Then, make the Chacha20 and Chacha20-Poly1305 empty buffer
tests use the MBEDTLS_CIPHER_CHACHA20 and
MBEDTLS_CIPHER_CHACHA20_POLY1305 cipher suites.
When testing a configuration where no ciphersuites have MAC, via
component_test_when_no_ciphersuites_have_mac(), perform a targeted test
of only encrypt-then-MAC tests within ssl-opt.sh.
When MBEDTLS_SSL_ENCRYPT_THEN_MAC is enabled, but not
MBEDTLS_SSL_SOME_MODES_USE_MAC, mbedtls_ssl_derive_keys() and
build_transforms() will attempt to use a non-existent `encrypt_then_mac`
field in the ssl_transform.
Compile [ 93.7%]: ssl_tls.c
[Error] ssl_tls.c@865,14: 'mbedtls_ssl_transform {aka struct mbedtls_ssl_transform}' ha
s no member named 'encrypt_then_mac'
[ERROR] ./mbed-os/features/mbedtls/src/ssl_tls.c: In function 'mbedtls_ssl_derive_keys'
:
./mbed-os/features/mbedtls/src/ssl_tls.c:865:14: error: 'mbedtls_ssl_transform {aka str
uct mbedtls_ssl_transform}' has no member named 'encrypt_then_mac'
transform->encrypt_then_mac = session->encrypt_then_mac;
^~
Change mbedtls_ssl_derive_keys() and build_transforms() to only access
`encrypt_then_mac` if `encrypt_then_mac` is actually present.
Add a regression test to detect when we have regressions with
configurations that do not include any MAC ciphersuites.
Fixes d56ed2491b ("Reduce size of `ssl_transform` if no MAC ciphersuite is enabled")
Lengths below 128 Bytes must be encoded as a single 'XX' byte in DER,
but two tests in the X.509 CRT parsing suite used the BER but non-DER
encoding '81 XX' (the first byte 10000001 indicating that the length
is to follow (high bit) and has length 1 byte (low bit)).
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.
- Explain the use of explicit ASN.1 tagging for the extensions structuree
- Remove misleading comment which suggests that mbedtls_x509_get_ext()
also parsed the header of the first extension, which is not the case.
