20240516-wc_AesXtsEnDecryptFinal #7549
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…API consistency, and add error-checking (block alignment check) to wc_AesXtsEncryptUpdate() and wc_AesXtsDecryptUpdate().
| { | ||
| int ret; | ||
| if (sz > 0) | ||
| ret = AesXtsEncryptUpdate(xaes, out, in, sz, i); |
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Does this input "sz" not have to be multiple of block size?
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that's right. for the last call, the input can have any length >= AES_BLOCK_SIZE. if the length isn't a multiple of the block size, then the ciphertext stealing stuff is used to finish out the message. and btw that's exactly why only the last call can be non-block-aligned.
| return AesXtsEncryptUpdate(xaes, out, in, sz, i); | ||
| } | ||
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| int wc_AesXtsEncryptFinal(XtsAes* xaes, byte* out, const byte* in, word32 sz, |
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What value does "final" add? Is it the zero'ing of "i"?
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it's a couple things:
(1) lets us add error-checking for all calls to Update() to make sure they're correctly block-aligned (trying to get ahead of ZenDesk tickets on that).
(2) the zeroing lets us check for API abuse, in that it guarantees a wrong result if the user calls Update after a Final, and of course it also prevents anything valuable from leaking out through the IV.
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Answers satisfy my concerns. @SparkiDev please finalize. Thanks
…yptFinal 20240516-wc_AesXtsEnDecryptFinal
AES-XTS: add
wc_AesXtsEncryptFinal()andwc_AesXtsDecryptFinal()for API consistency, and add error-checking (block alignment check) towc_AesXtsEncryptUpdate()andwc_AesXtsDecryptUpdate().tested with
wolfssl-multi-test.sh ... linuxkm-aesxts-cryptonly-noasm-LKCAPI-no-twc-insmod-crypto-fuzzer linuxkm-aesxts-cryptonly-aesni-LKCAPI-no-twc-insmod-crypto-fuzzer linuxkm-aesxts-cryptonly-noasm-ECB-LKCAPI-no-twc-insmod-crypto-fuzzer linuxkm-aesxts-cryptonly-aesni-ECB-LKCAPI-no-twc-insmod-crypto-fuzzer linuxkm-fips-dev-static-hash-intelasm-LKCS-insmod-6.1.73-fortify check-source-text all-g++