Negative x coordinate was tested with the value -1. It happens to be one
of the low order points both for Curve25519 and Curve448 and might be
rejected because of that and not because it is negative. Make sure that
x < 0 is the only plausible reason for the point to be rejected.
Signed-off-by: Janos Follath <janos.follath@arm.com>
A test case for which the loop would take practically forever if it was
reached. The point would be to validate that the loop is not reached.
The test case should cause the CI to time out if starting with the
current code, ecp_check_pubkey_mx() was changed to call
ecp_check_pubkey_x25519() first and run the mbedtls_mpi_size(() test
afterwards, which would make no semantic difference in terms of memory
contents when the function returns, but would open the way for a DoS.
Signed-off-by: Janos Follath <janos.follath@arm.com>
We were already rejecting them at the end, due to the fact that with the
usual (x, z) formulas they lead to the result (0, 0) so when we want to
normalize at the end, trying to compute the modular inverse of z will
give an error.
If we wanted to support those points, we'd a special case in
ecp_normalize_mxz(). But it's actually permitted by all sources
(RFC 7748 say we MAY reject 0 as a result) and recommended by some to
reject those points (either to ensure contributory behaviour, or to
protect against timing attack when the underlying field arithmetic is
not constant-time).
Since our field arithmetic is indeed not constant-time, let's reject
those points before they get mixed with sensitive data (in
ecp_mul_mxz()), in order to avoid exploitable leaks caused by the
special cases they would trigger. (See the "May the Fourth" paper
https://eprint.iacr.org/2017/806.pdf)
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Backport 2.x: Fix and test the MBEDTLS_PSA_CRYPTO_SPM build
Straightforward backport from development to developement_2.x plus one trivial commit, only one approval is enough.
Modify tests to test mbedtls_psa_cipher_operation_t,
mbedtls_transparent_test_driver_cipher_operation_t and
mbedtls_opaque_test_driver_cipher_operation_t struct initialization macros.
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
Tests for psa_cipher_encrypt and psa_cipher_decrypt functions.
The psa_cipher_encrypt function takes no parameter for IV and always generates
it therefore there will be a randomness in the calculation and cannot be
validated by comparing the actual output with the expected output.
The function is tested by:
- doing a prtially randomized test with an encryption then a decryption
and validating the input with output of the decryption
- validating against the multipart encryption
The combination of this two methods provides enough coverage like a
known answer test.
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
Various functions for PSA hash operations call abort
on failure; test that this is done. The PSA spec does not require
this behaviour, but it makes our implementation more robust in
case the user does not abort the operation as required by the
PSA spec.
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
Remove late binding of iterators to enable the creation of an object
with an actual state of a variable.
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
Various functions for PSA cipher and mac operations call abort
on failure; test that this is done. The PSA spec does not require
this behaviour, but it makes our implementation more robust in
case the user does not abort the operation as required by the
PSA spec.
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
The cipher_bad_order test happened to pass, but was not testing the
failure case it intended to test.
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
Tests for psa_mac_compute and psa_mac_verify functions.
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Hash and sign algorithms require the alignment of the input length with
the hash length at verification as well not just when signing.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The psa_verify_hash() is the pre-hashed version of the API and supposed
to work on hashes generated by the user. There were tests passing that
were getting "hashes" of sizes different from the expected.
Transform these into properly failing tests.
Signed-off-by: Janos Follath <janos.follath@arm.com>
Fix a bug introduced in "Fix multiplication producing a negative zero" that
caused the sign to be forced to +1 when A > 0, B < 0 and B's low-order limb
is 0.
Add a non-regression test. More generally, systematically test combinations
of leading zeros, trailing zeros and signs.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
No need to bypass the API to fill limbs. It's a better test to just
set the top bit that we want to have set, and it's one less bypass of
the API.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
In mbedtls_mpi_read_string, if the string is empty, return an empty bignum
rather than a bignum with one limb with the value 0.
Both representations are correct, so this is not, in principle, a
user-visible change. The change does leak however through
mbedtls_mpi_write_string in base 16 (but not in other bases), as it writes a
bignum with 0 limbs as "" but a bignum with the value 0 and at least one
limb as "00".
This change makes it possible to construct an empty bignum through
mbedtls_mpi_read_string, which is especially useful to construct test
cases (a common use of mbedtls_mpi_read_string, as most formats use in
production encode numbers in binary, to be read with mbedtls_mpi_read_binary
or mbedtls_mpi_read_binary_le).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Fix mbedtls_mpi_mul_mpi() when one of the operands is zero and the
other is negative. The sign of the result must be 1, since some
library functions do not treat {-1, 0, NULL} or {-1, n, {0}} as
representing the value 0.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Fix a null pointer dereference in mbedtls_mpi_exp_mod(X, A, N, E, _RR) when
A is the value 0 represented with 0 limbs.
Make the code a little more robust against similar bugs.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Test both 0 represented with 0 limbs ("0 (null)") and 0 represented
with 1 limb ("0 (1 limb)"), because occasionally there are bugs with
0-limb bignums and occasionally there are bugs with removing leading
zero limbs.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
mbedtls_mpi_exp_mod can be called in three ways regarding the speed-up
parameter _RR: null (unused), zero (will be updated), nonzero (will be
used). Systematically test all three.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
