Merge pull request #4522 from mpg/fix-ssl-cf-hmac-alt-dev

Fix misuse of MD API in SSL constant-flow HMAC
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Gilles Peskine 2021-06-07 20:53:33 +02:00 committed by GitHub
commit 8d4e32b888
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@ -0,0 +1,5 @@
Bugfix
* Fix a regression introduced in 2.24.0 which broke (D)TLS CBC ciphersuites
(when the encrypt-then-MAC extension is not in use) with some ALT
implementations of the underlying hash (SHA-1, SHA-256, SHA-384), causing
the affected side to wrongly reject valid messages. Fixes #4118.

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@ -1148,6 +1148,9 @@ MBEDTLS_STATIC_TESTABLE int mbedtls_ssl_cf_hmac(
MD_CHK( mbedtls_md_update( ctx, data + offset, 1 ) );
}
/* The context needs to finish() before it starts() again */
MD_CHK( mbedtls_md_finish( ctx, aux_out ) );
/* Now compute HASH(okey + inner_hash) */
MD_CHK( mbedtls_md_starts( ctx ) );
MD_CHK( mbedtls_md_update( ctx, okey, block_size ) );