]> Gentwo Git Trees - linux/.git/commit
lib/crypto: sha3: Move SHA3 Iota step mapping into round function
authorDavid Howells <dhowells@redhat.com>
Sun, 26 Oct 2025 05:50:21 +0000 (22:50 -0700)
committerEric Biggers <ebiggers@kernel.org>
Thu, 6 Nov 2025 04:02:35 +0000 (20:02 -0800)
commitc0db39e253ebca9dea57e8885450ff0a0a6d6155
tree54c7f18fabfcafbd6bc3c3e661ad8f01d462201d
parent0593447248044ab609b43b947d0e198c887ac281
lib/crypto: sha3: Move SHA3 Iota step mapping into round function

In crypto/sha3_generic.c, the keccakf() function calls keccakf_round()
to do four of Keccak-f's five step mappings.  However, it does not do
the Iota step mapping - presumably because that is dependent on round
number, whereas Theta, Rho, Pi and Chi are not.

Note that the keccakf_round() function needs to be explicitly
non-inlined on certain architectures as gcc's produced output will (or
used to) use over 1KiB of stack space if inlined.

Now, this code was copied more or less verbatim into lib/crypto/sha3.c,
so that has the same aesthetic issue.  Fix this there by passing the
round number into sha3_keccakf_one_round_generic() and doing the Iota
step mapping there.

crypto/sha3_generic.c is left untouched as that will be converted to use
lib/crypto/sha3.c at some point.

Suggested-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251026055032.1413733-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
lib/crypto/sha3.c