commit a253662b1063c7bb866fd21afca550eb6d70b8f4
author Joakim Bech <joakim.bech@linaro.org> Fri Aug 02 09:47:19 2019 +0200
committer Jérôme Forissier <jerome@forissier.org> Wed Oct 09 17:20:30 2019 +0200
tree e6881ec253a0665cc61a32911e978399f8f50914
parent c4108ef5980e9cc9a33a2c13ea682f210836b9eb

ltc: check range in _rijndael_ecb_ functions

There is no check that the 'skey' structure has been properly
initialized. For example, the skey->rijndael.Nr is assumed to contain a
positive number corresponding to the number of AES rounds to perform. In
_rijndael_ecb_encrypt the skey->rijndael.Nr is subtracted by two, which
can result in an integer underflow if the structure hasn't been
initialized correctly.

By clamping the value for skey->rijndael.Nr into the valid rounds for
AES we can return an error instead of ending up reading outside the
boundaries (of skey->rijndael.eK).

Patch manually picked from [1].

Link: [1] https://github.com/libtom/libtomcrypt/commit/7b4a5c1dcf2803e9c6cbcbc2458db9317e6fb8ca
Signed-off-by: Joakim Bech <joakim.bech@linaro.org>
Tested-by: Joakim Bech <joakim.bech@linaro.org> (QEMU v7)
Reported-by: Martijn Bogaard <bogaard@riscure.com>
Acked-by: Jerome Forissier <jerome@forissier.org>