Clang was complaining and check-names.sh too
This only duplicates macros, so no impact on code size. In 3.0 we can
probably avoid the duplication by using an internal header under
library/ but this won't work for 2.16.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@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.
Fix initialization of mbedtls_psa_cipher_operation_t by not initializing the mbedtls_cipher_context_t typed field completely.
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
This makes it easier to ensure that crypto_spe.h is included everywhere it
needs to be, and that it's included early enough to do its job (it must be
included before any mention of psa_xxx() functions with external linkage,
because it defines macros to rename these functions).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Introduce psa_mac_compute_internal with an
additional `is_sign` parameter compared to
the psa_mac_compute API. The intent is to
call psa_mac_compute_internal() from
psa_mac_verify() as well to compute the
message MAC.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Re-organize psa_mac_setup() to prepare the move
to a dedicated function of the additional checks
on the algorithm and the key attributes done by
this function. We want to move those checks in
a dedicated function to be able to do them
without duplicating them in psa_mac_compute().
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Implement one-shot MAC APIs, psa_mac_compute and psa_mac_verify, introduced in PSA Crypto API 1.0.
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
Remove a case that cannot be triggered as PSA_ALG_SIGN_GET_HASH always
returns 0 for raw algorithms.
Signed-off-by: Janos Follath <janos.follath@arm.com>
PSA Crypto always passed MBEDTLS_MD_NONE to Mbed TLS, which worked well
as Mbed TLS does not use this parameter for anything beyond determining
the input lengths.
Some alternative implementations however check the consistency of the
algorithm used for pre-hash and for other uses in verification (verify
operation and mask generation) and fail if they don't match. This makes
all such verifications fail.
Furthermore, the PSA Crypto API mandates that the pre-hash and internal
uses are aligned as well.
Fixes#3990.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The loop exits early iff there is a nonzero limb, so i==0 means that
all limbs are 0, whether the number of limbs is 0 or not.
Signed-off-by: Gilles Peskine <Gilles.Peskine@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>
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>
Shifting TA and TB before the loop is not necessary. If A != 0, it will be
done at the start of the loop iteration. If A == 0, then lz==0 and G is
correctly set to B after 0 loop iterations.
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>
* development_2.x:
Reword changelog - Test Resource Leak
Fix fd range for select on Windows
Refactor file descriptor checks into a common function
Update changelog formatting - Missing Free Context
Update changelog formatting Missing Free Context
Update changelog formatting - Missing Free Context
Changelog entry for Free Context in test_suite_aes fix
Free context in at the end of aes_crypt_xts_size()
Fix copypasta in test data
Use UNUSED wherever applicable in derive_input tests
Fix missing state check for tls12_prf output
Key derivation: add test cases where the secret is missing
Add bad-workflow key derivation tests
More explicit names for some bad-workflow key derivation tests
Fix mbedtls_net_poll() and mbedtls_net_recv_timeout() often failing with
MBEDTLS_ERR_NET_POLL_FAILED on Windows: they were testing that the file
descriptor is in range for fd_set, but on Windows socket descriptors are not
limited to a small range. Fixes#4465.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Unrelated to RSA (only used in ECP), but while improving one
mbedtls_safe_cond_xxx function, let's improve the other as well.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
mbedtls_mpi_cf_bool_eq() is a verbatim copy of mbedtls_ssl_cf_bool_eq()
Deduplication will be part of a future task.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Rewrite mbedtls_debug_print_mpi to be simpler and smaller. Leverage
mbedtls_mpi_bitlen() instead of manually looking for the leading
zeros.
Fix#4608: the old code made an invalid memory dereference when
X->n==0 (freshly initialized bignum with the value 0).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Calling mbedtls_mpi_cmp_int reveals the number of leading zero limbs
to an adversary who is capable of very fine-grained timing
measurements. This is very little information, but could be practical
with secp521r1 (1/512 chance of the leading limb being 0) if the
adversary can measure the precise timing of a large number of
signature operations.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The idiom "resize an mpi to a given size" appeared 4 times. Unify it
in a single function. Guarantee that the value is set to 0, which is
required by some of the callers and not a significant expense where
not required.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Since the internal function mpi_fill_random_internal() assumes that X
has the right size, there is no need to call grow().
To further simplify the function, set the sign outside, and zero out
the non-randomized part directly.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
In real life, min << N and the probability that mbedtls_mpi_random()
fails to find a suitable value after 30 iterations is less than one in
a billion. But at least for testing purposes, it's useful to not
outright reject "silly" small values of N, and for such values, 30
iterations is not enough to have a good probability of success.
Pick 250 iterations, which is enough for cases like (min=3, N=4), but
not for cases like (min=255, N=256).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This comment is no longer in the specific context of generating a
random point on an elliptic curve.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
mbedtls_mpi_random() uses mbedtls_mpi_cmp_mpi_ct(), which requires its
two arguments to have the same storage size. This was not the case
when the upper bound passed to mbedtls_mpi_random() had leading zero
limbs.
Fix this by forcing the result MPI to the desired size. Since this is
not what mbedtls_mpi_fill_random() does, don't call it from
mbedtls_mpi_random(), but instead call a new auxiliary function.
Add tests to cover this and other conditions with varying sizes for
the two arguments.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Instead of generating blinding values and keys in a not-quite-uniform way
(https://github.com/ARMmbed/mbedtls/issues/4245) with copy-pasted code,
use mbedtls_mpi_random().
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
dhm_make_common includes a piece of code that is identical to
dhm_random_below except for returning a different error code in one
case. Call dhm_random_below instead of repeating the code.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
P-1 is as bad as 1 as a blinding value. Don't accept it.
The chance that P-1 would be randomly generated is infinitesimal, so
this is not a practical issue, but it makes the code cleaner. It was
inconsistent to accept P-1 as a blinding value but not as a private key.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Unify the common parts of mbedtls_dhm_make_params and mbedtls_dhm_make_public.
No intended behavior change, except that the exact error code may
change in some corner cases which are too exotic for the existing unit
tests.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Instead of generating blinding values in a not-quite-uniform way
(https://github.com/ARMmbed/mbedtls/issues/4245) with copy-pasted
code, use mbedtls_mpi_random().
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Since mbedtls_mpi_random() is not specific to ECC code, move it from
the ECP module to the bignum module.
This increases the code size in builds without short Weierstrass
curves (including builds without ECC at all) that do not optimize out
unused functions.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Rename mbedtls_ecp_gen_privkey_sw to mbedtls_mpi_random since it has
no particular connection to elliptic curves beyond the fact that its
operation is defined by the deterministic ECDSA specification. This is
a generic function that generates a random MPI between 1 inclusive and
N exclusive.
Slightly generalize the function to accept a different lower bound,
which adds a negligible amount of complexity.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
mbedtls_ecp_gen_privkey_mx generates a random number with a certain
top bit set. Depending on the size, it would either generate a number
with that top bit being random, then forcibly set the top bit to
1 (when high_bit is not a multiple of 8); or generate a number with
that top bit being 0, then set the top bit to 1 (when high_bit is a
multiple of 8). Change it to always generate the top bit randomly
first.
This doesn't make any difference in practice: the probability
distribution is the same either way, and no supported or plausible
curve has a size of the form 8n+1 anyway. But it slightly simplifies
reasoning about the behavior of this function.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Don't calculate the bit-size of the initially generated random number.
This is not necessary to reach the desired distribution of private
keys, and creates a (tiny) side channel opportunity.
This changes the way the result is derived from the random number, but
does not affect the resulting distribution.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The library rejected an RNG input of all-bits-zero, which led to the
key 2^{254} (for Curve25519) having a 31/32 chance of being generated
compared to other keys. This had no practical impact because the
probability of non-compliance was 2^{-256}, but needlessly
complicated the code.
The exception was added in 98e28a74e3 to
avoid the case where b - 1 wraps because b is 0. Instead, change the
comparison code to avoid calculating b - 1.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
For Montgomery keys, n_bits is actually the position of the highest
bit and not the number of bits, which would be 1 more (fence vs
posts). Rename the variable accordingly to lessen the confusion.
No semantic change.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Put the Montgomery and short Weierstrass implementations of
mbedtls_ecp_gen_privkey into their own function which can be tested
independently, but will not be part of the public ABI/API.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
When mbedtls_nist_kw_wrap was called with output=NULL and out_size=0, it
performed arithmetic on the null pointer before detecting that the output
buffer is too small and returning an error code. This was unlikely to have
consequences on real-world hardware today, but it is undefined behavior and
UBSan with Clang 10 flagged it. So fix it (fix#4025).
Fix a similar-looking pattern in unwrap, though I haven't verified that it's
reachable there.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The persistence level PSA_KEY_PERSISTENCE_READ_ONLY can now only be used
as intended, for keys that cannot be modified through normal use of the API.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
mbedtls_psa_get_stats() was written back before lifetimes were
structured as persistence and location. Fix its classification of
volatile external keys and internal keys with a non-default
persistence.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
