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Backport 3.6: Make some edge cases of not-supported or invalid mechanisms more uniform #9782

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@gilles-peskine-arm gilles-peskine-arm commented Nov 19, 2024

Fix a few edge cases related to invalid or not-supported cryptographic mechanisms in PSA. These are not user-level bugs, but the changes here make testing easier, in particular allowing more uniform automatically generated test cases.

This is the (small) part of the forward port of #9025 that goes into each branch. Most of the changes will be in the framework repository.

PR checklist

Uniformly return PSA_ERROR_NOT_SUPPORTED if given an algorithm that includes
a hash, but that hash algorithm is not supported. This will make it easier
to have a uniform treatment of unsupported hashes in automatically generated
tests.

Signed-off-by: Gilles Peskine <[email protected]>
Allow imports of an ECC public key on an unsupported curve to return
INVALID_ARGUMENT rather than NOT_SUPPORTED. This can happen in our library
code in edge cases when only certain curve families are supported, and it's
acceptable.

The new code does not trigger yet, but it will be useful for a future commit
"Do run not-supported test cases on not-implemented mechanisms"
(forward port of 995d7d4).

Signed-off-by: Gilles Peskine <[email protected]>
@gilles-peskine-arm gilles-peskine-arm added component-crypto Crypto primitives and low-level interfaces needs-ci Needs to pass CI tests priority-high High priority - will be reviewed soon size-xs Estimated task size: extra small (a few hours at most) labels Nov 19, 2024
@gilles-peskine-arm gilles-peskine-arm force-pushed the psa-storage-test-cases-never-supported-preliminaries-3.6 branch from 0d712f9 to 25f5eb7 Compare November 19, 2024 17:42
Following "PSA sign/verify: more uniform error on an unsupported hash", some
error cases are detected earlier, so there is some sloppiness in test case
dependencies that is not longer acceptable.

* In test_suite_psa_crypto, one test case for a hash+sign algorithm now
  returns NOT_SUPPORTED rather than INVALID_ARGUMENT when the hash is not
  supported and the key is invalid.
* In test_suite_psa_crypto_se_driver_hal_mocks, some test cases now error
  out before reaching the mocks rather than after when they attempt to
  use an unsupported hash.

Signed-off-by: Gilles Peskine <[email protected]>
@gilles-peskine-arm gilles-peskine-arm force-pushed the psa-storage-test-cases-never-supported-preliminaries-3.6 branch from 25f5eb7 to 009f517 Compare November 19, 2024 21:12
@gilles-peskine-arm gilles-peskine-arm force-pushed the psa-storage-test-cases-never-supported-preliminaries-3.6 branch from 76939b7 to 8144435 Compare November 20, 2024 19:35
ECDSA has two variants: deterministic (PSA_ALG_DETERMINISTIC_ECDSA) and
randomized (PSA_ALG_ECDSA). The two variants are different for signature but
identical for verification. Mbed TLS accepts either variant as the algorithm
parameter for verification even when only the other variant is supported,
so we need to handle this as a special case when generating not-supported
test cases.

In this commit:

* Add manually written not-supported test cases for the signature
  operation when exactly one variant is supported.
* Add manually written positive test cases for the verification
  operation when exactly one variant is supported.
* Register that !ECDSA but DETERMINISTIC_ECDSA is not tested yet
  (Mbed-TLS#9592).

A commit in the framework will take care of automatically generated test cases.

Signed-off-by: Gilles Peskine <[email protected]>
In particular, if interruptible ECDSA is supported but not the deterministic
variant, detect this in psa_sign_hash_start(), whereas before start() would
succeed and psa_sign_hash_complete() would fail. This avoids an
inconsistency between psa_sign_hash() and psa_sign_hash_start() that would
be annoying to handle in test_suite_psa_crypto_op_fail.

Signed-off-by: Gilles Peskine <[email protected]>
For ECDSA verification, there is no difference between the deterministic and
randomized algorithm. The PSA core consider the two variants as identical as
far as key policies are concerned, and the built-in implementation accepts
either variant even if only the other variant is supported for signature.

In p256-m, accept to perform an ECDSA verification when the algorithm is
specified as deterministic ECDSA. This makes the behavior identical to the
built-in implementation, which is less surprising for users and saves us
from having to cope with a difference in our testing.

Signed-off-by: Gilles Peskine <[email protected]>
@gilles-peskine-arm gilles-peskine-arm force-pushed the psa-storage-test-cases-never-supported-preliminaries-3.6 branch from 8144435 to ad04f96 Compare November 21, 2024 08:48
@gilles-peskine-arm gilles-peskine-arm added needs-review Every commit must be reviewed by at least two team members, needs-reviewer This PR needs someone to pick it up for review and removed needs-ci Needs to pass CI tests labels Nov 21, 2024
Signed-off-by: Gilles Peskine <[email protected]>
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LGTM, faithful backport!

@gilles-peskine-arm gilles-peskine-arm removed the needs-reviewer This PR needs someone to pick it up for review label Dec 10, 2024
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This is a faithful backport of the original.

@yanesca yanesca added this pull request to the merge queue Dec 10, 2024
Merged via the queue into Mbed-TLS:mbedtls-3.6 with commit a770f30 Dec 10, 2024
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component-crypto Crypto primitives and low-level interfaces needs-review Every commit must be reviewed by at least two team members, priority-high High priority - will be reviewed soon size-xs Estimated task size: extra small (a few hours at most)
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3 participants