Our current behaviour is a bit inconsistent here:
- when the bad signature is made by a trusted CA, we stop here and don't
include the trusted CA in the chain (don't call vrfy on it)
- otherwise, we just add NOT_TRUSTED to the flags but keep building the chain
and call vrfy on the upper certs
This ensures that the callback can actually clear that flag, and that it is
seen by the callback at the right level. This flag is not set at the same
place than others, and this difference will get bigger in the upcoming
refactor, so let's ensure we don't break anything here.
When a trusted CA is rolling its root keys, it could happen that for some
users the list of trusted roots contains two versions of the same CA with the
same name but different keys. Currently this is supported but wasn't tested.
Note: the intermediate file test-ca-alt.csr is commited on purpose, as not
commiting intermediate files causes make to regenerate files that we don't
want it to touch.
As we accept EE certs that are explicitly trusted (in the list of trusted
roots) and usually look for parent by subject, and in the future we might want
to avoid checking the self-signature on trusted certs, there could a risk that we
incorrectly accept a cert that looks like a trusted root except it doesn't
have the same key. This test ensures this will never happen.
The tests cover chains of length 0, 1 and 2, with one error, located at any of
the available levels in the chain. This exercises all three call sites of
f_vrfy (two in verify_top, one in verify_child). Chains of greater length
would not cover any new code path or behaviour that I can see.
So far there was no test ensuring that the flags passed to the vrfy callback
are correct (ie the flags for the current certificate, not including those of
the parent).
Actual tests case making use of that test function will be added in the next
commit.
We have code to skip them but didn't have explicit tests ensuring they are
(the corresponding branch was never taken).
While at it, remove extra copy of the chain in server10*.crt, which was
duplicated for no reason.
This shows inconsistencies in how flags are handled when callback fails:
- sometimes the flags set by the callback are transmitted, sometimes not
- when the cert if not trusted, sometimes BADCERT_NOT_TRUSTED is set,
sometimes not
This adds coverage for 9 lines and 9 branches. Now all lines related to
callback failure are covered.
Now all checks related to profile are covered in:
- verify_with_profile()
- verify_child()
- verify_top()
(that's 10 lines that were previously not covered)
Leaving aside profile enforcement in CRLs for now, as the focus is on
preparing to refactor cert verification.
Previously flags was left to whatever value it had before. It's cleaner to
make sure it has a definite value, and all bits set looks like the safest way
for when it went very wrong.
This change fixes a problem in the tests pk_rsa_alt() and
pk_rsa_overflow() from test_suite_pk.function that would cause a
segmentation fault. The problem is that these tests are only designed
to run in computers where the sizeof(size_t) > sizeof(unsigned int).
1) The MPI test for prime generation missed a return value
check for a call to `mbedtls_mpi_shift_r`. This is neither
critical nor new but should be fixed.
2) The RSA keygeneration example program contained code
initializing an RSA context after a potentially failing
call to CTR DRBG initialization, leaving the corresponding
RSA context free call in the cleanup section orphaned.
The commit fixes this by moving the initializtion of the
RSA context prior to the first potentially failing call.
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.
