Previously, MAC validation for an incoming record proceeded as follows:
1) Make a copy of the MAC contained in the record;
2) Compute the expected MAC in place, overwriting the presented one;
3) Compare both.
This resulted in a record buffer overflow if truncated MAC was used, as in this
case the record buffer only reserved 10 bytes for the MAC, but the MAC
computation routine in 2) always wrote a full digest.
For specially crafted records, this could be used to perform a controlled write of
up to 6 bytes past the boundary of the heap buffer holding the record, thereby
corrupting the heap structures and potentially leading to a crash or remote code
execution.
This commit fixes this by making the following change:
1) Compute the expected MAC in a temporary buffer that has the size of the
underlying message digest.
2) Compare to this to the MAC contained in the record, potentially
restricting to the first 10 bytes if truncated HMAC is used.
A similar fix is applied to the encryption routine `ssl_encrypt_buf`.
This commit adds a build with default config except
MBEDTLS_SSL_MAX_FRAGMENT_LENGTH to all.sh, as well as a run of the MFL-related
tests in ssl-opt.sh.
Some tests in ssl-opt.sh require MBEDTLS_SSL_MAX_CONTENT_LEN to be set to its
default value of 16384 to succeed. While ideally such a dependency should not
exist, as a short-term remedy this commit adds a small check that will at least
lead to graceful exit if that assumption is violated.
This commit adds four tests to ssl-opt.sh testing the library's behavior when
`mbedtls_ssl_write` is called with messages beyond 16384 bytes. The combinations
tested are TLS vs. DTLS and MBEDTLS_SSL_MAX_FRAGMENT_LENGTH enabled vs. disabled.
For a key of size 8N+1, check that the first byte after applying the
public key operation is 0 (it could have been 1 instead). The code was
incorrectly doing a no-op check instead, which led to invalid
signatures being accepted. Not a security flaw, since you would need the
private key to craft such an invalid signature, but a bug nonetheless.
The check introduced by the previous security fix was off by one. It
fixed the buffer overflow but was not compliant with the definition of
PSS which technically led to accepting some invalid signatures (but
not signatures made without the private key).
Fix buffer overflow in RSA-PSS signature verification when the hash is
too large for the key size. Found by Seth Terashima, Qualcomm.
Added a non-regression test and a positive test with the smallest
permitted key size for a SHA-512 hash.
This commit adds regression tests for the bug when we didn't parse the
Signature Algorithm extension when renegotiating. (By nature, this bug
affected only the server)
The tests check for the fallback hash (SHA1) in the server log to detect
that the Signature Algorithm extension hasn't been parsed at least in
one of the handshakes.
A more direct way of testing is not possible with the current test
framework, since the Signature Algorithm extension is parsed in the
first handshake and any corresponding debug message is present in the
logs.
Previously, 2048-bit and 4096-bit RSA key files had their bitsize indicated in their filename, while the original
1024-bit keys hadn't. This commit unifies the naming scheme by always indicating the bitsize in the filename.
For uniformity, this commit adds tests for DER encoded, SHA1-2DES and SHA1-RC4-128-encrypted RSA keys; for SHA1-3DES encrypted keys, these were already present.
This commit adds the commands used to generate the various RSA keys to tests/Makefile so that they can be easily
regenerated or modified, e.g. if larger key sizes or other encryption algorithms need to be tested in the future.
Add a test case calling ssl_set_hostname twice to test_suite_ssl.
When run in CMake build mode ASan, this catches the current leak,
but will hopefully be fine with the new version.
A bug in the dhm_check_range() function makes it pass even when the
parameters are not in the range. This commit adds tests for signalling
this problem as well as a couple of other negative tests.
