Fix possible error code mangling in psa_mac_verify_finish #345
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If psa_mac_finish_internal fails (which can only happen due to bad parameters or hardware problem), the error code was converted to PSA_ERROR_INVALID_SIGNATURE if the uninitialized stack variable actual_mac happened to contain the expected MAC. This is a minor bug but it may be possible to leverage it as part of a longer attack path in some scenarios. Reported externally. Found by static analysis.
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Looking at CI results in the pr-merge job, the only failures are with Mbed OS testing, which is expected as Mbed OS needs updating. All other tests pass, so this is as good as a pass. |
yanesca
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Mar 23, 2020
* ARMmbed#352: Parse RSA parameters DP, DQ and QP from PKCS1 private keys * ARMmbed#263: Introduce ASN.1 SEQUENCE traversal API * ARMmbed#345: Fix possible error code mangling in psa_mac_verify_finish * ARMmbed#357: Update Mbed Crypto with latest Mbed TLS changes as of 2020-02-03 * ARMmbed#350: test_suite_asn1parse: improve testing of trailing garbage in parse_prefixes * ARMmbed#346: Improve robustness and testing of mbedtls_mpi_copy
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If psa_mac_finish_internal fails (which can only happen due to bad
parameters or hardware problem), the error code was converted to
PSA_ERROR_INVALID_SIGNATURE if the uninitialized stack variable
actual_mac happened to contain the expected MAC. This is a minor bug
but it may be possible to leverage it as part of a longer attack path
in some scenarios.
Reported externally. Found by static analysis.