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Switch from the old AES library functions (which use struct
crypto_aes_ctx) to the new ones (which use struct aes_enckey). This
eliminates the unnecessary computation and caching of the decryption
round keys. The new AES en/decryption functions are also much faster
and use AES instructions when supported by the CPU.
Note that in addition to the change in the key preparation function and
the key struct type itself, the change in the type of the key struct
results in aes_encrypt() (which is temporarily a type-generic macro)
calling the new encryption function rather than the old one.
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260112192035.10427-34-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
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Implement a minimal library version of AES-GCM based on the existing
library implementations of AES and multiplication in GF(2^128). Using
these primitives, GCM can be implemented in a straight-forward manner.
GCM has a couple of sharp edges, i.e., the amount of input data
processed with the same initialization vector (IV) should be capped to
protect the counter from 32-bit rollover (or carry), and the size of the
authentication tag should be fixed for a given key. [0]
The former concern is addressed trivially, given that the function call
API uses 32-bit signed types for the input lengths. It is still up to
the caller to avoid IV reuse in general, but this is not something we
can police at the implementation level.
As for the latter concern, let's make the authentication tag size part
of the key schedule, and only permit it to be configured as part of the
key expansion routine.
Note that table based AES implementations are susceptible to known
plaintext timing attacks on the encryption key. The AES library already
attempts to mitigate this to some extent, but given that the counter
mode encryption used by GCM operates exclusively on known plaintext by
construction (the IV and therefore the initial counter value are known
to an attacker), let's take some extra care to mitigate this, by calling
the AES library with interrupts disabled.
[0] https://nvlpubs.nist.gov/nistpubs/legacy/sp/nistspecialpublication800-38d.pdf
Link: https://lore.kernel.org/all/c6fb9b25-a4b6-2e4a-2dd1-63adda055a49@amd.com/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Added inline helper functions to check authsize and assoclen for
gcm, rfc4106 and rfc4543.
These are used in the generic implementation of gcm, rfc4106 and
rfc4543.
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Many GCM users use directly GCM IV size instead of using some constant.
This patch add all IV size constant used by GCM.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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