In some cases, we were calling `mbedtls_test_ssl_endpoint_free()` on an
uninitialized `mbedtls_test_ssl_endpoint` object if the test case failed
early, e.g. due to `psa_crypto_init()` failing. This was largely harmless,
but could have caused weird test results in case of failure, and was flagged
by Coverity.
Use a more systematic style for initializing the stack object as soon as
it's declared.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Now that Base64 validates the number of trailing equals, adjust the PEM test
case that has a Base64 payload with a wrong number of trailing equals, where
`mbedtls_pem_read_buffer()` now returns a different error code. I'm not sure
what the exact intent of the test was, so add a variant with trailing equals
as well.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Fix a race condition in `mbedtls_aes_ni_has_support()` with some compilers.
A compiler could hoist the assignment `done = 1` above the assignment to `c`,
in which case if two threads call `mbedtls_aes_ni_has_support()` at almost
the same time, they could be interleaved as follows:
Initially: done = 0, c = 0
thread A thread B
if (!done)
done = 1; # hoisted
if (!done)
return c & what; # wrong!
c = cpuid();
return c & what
This would lead to thread B using software AES even though AESNI was
available. This is a very minor performance bug. But also, given a very
powerful adversary who can block thread A indefinitely (which may be
possible when attacking an SGX enclave), thread B could use software AES for
a long time, opening the way to a timing side channel attack.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Correct base64 input (excluding ignored characters such as spaces) consists
of exactly 4*k, 4*k-1 or 4*k-2 digits, followed by 0, 1 or 2 equal signs
respectively.
Previously, any number of trailing equal signs up to 2 was accepted, but if
there fewer than 4*k digits-or-equals, the last partial block was counted in
`*olen` in buffer-too-small mode, but was not output despite returning 0.
Now `mbedtls_base64_decode()` insists on correct padding. This is
backward-compatible since the only plausible useful inputs that used to be
accepted were inputs with 4*k-1 or 4*k-2 digits and no trailing equal signs,
and those led to invalid (truncated) output. Furthermore the function now
always reports the exact output size in buffer-too-small mode.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Add unit tests covering cases where the number of digits plus equal signs is
not a multiple of 4. These are invalid inputs, but they are currently
accepted as long as the number of equal signs is at most 2.
The tests assert the current behavior, not behavior that is desirable.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Reinforce the unit test for `mbedtls_base64_decode()` with valid inputs to
systematically call the function with a smaller output buffer and with an
empty output buffer. Assert the reported necessary output length in those
cases.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
