Adding ble multiplication to GF128mul, and fixing up comments.
The ble multiplication functions multiply GF(2^128) elements in the
ble format. This format is preferable because the bits within each
byte map to polynomial coefficients in the natural order (lowest order
bit = coefficient of lowest degree polynomial term), and the bytes are
stored in little endian order which matches the endianness of most
modern CPUs.
These new functions will be used by the HEH algorithm.
Signed-off-by: Alex Cope <alexcope@google.com>
Bug: 32975945
Signed-off-by: Eric Biggers <ebiggers@google.com>
Change-Id: I39a58e8ee83e6f9b2e6bd51738f816dbfa2f3a47
Rename and clean up the GF(2^128) overflow macros and tables. Their
usage is more general than the name suggested, e.g. what was previously
known as the "bbe" table can actually be used for both "bbe" and "ble"
multiplication.
Bug: 32975945
Signed-off-by: Eric Biggers <ebiggers@google.com>
Change-Id: Ie6c47b4075ca40031eb1767e9b468cfd7bf1b2e4
GF(2^128) multiplication tables are typically used for secret
information, so it's a good idea to zero them on free.
Signed-off-by: Alex Cope <alexcope@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
(cherry-picked from 75aa0a7cafe951538c7cb7c5ed457a3371ec5bcd)
Bug: 32975945
Signed-off-by: Eric Biggers <ebiggers@google.com>
Change-Id: I37b1ae9544158007f9ee2caf070120f4a42153ab
In gf128mul_lle() and gf128mul_bbe() r isn't completely initialized with
zero because the size argument passed to memset() is the size of the
pointer, not the structure it points to.
Luckily there are no in-kernel users of those functions so the ABI
change implied by this fix should break no existing code.
Based on a patch by the PaX Team.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: PaX Team <pageexec@freemail.hu>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
XTS currently considered to be the successor of the LRW mode by the IEEE1619
workgroup. LRW was discarded, because it was not secure if the encyption key
itself is encrypted with LRW.
XTS does not have this problem. The implementation is pretty straightforward,
a new function was added to gf128mul to handle GF(128) elements in ble format.
Four testvectors from the specification
http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
were added, and they verify on my system.
Signed-off-by: Rik Snel <rsnel@cube.dyndns.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
A lot of cypher modes need multiplications in GF(2^128). LRW, ABL, GCM...
I use functions from this library in my LRW implementation and I will
also use them in my ABL (Arbitrary Block Length, an unencumbered (correct
me if I am wrong, wide block cipher mode).
Elements of GF(2^128) must be presented as u128 *, it encourages automatic
and proper alignment.
The library contains support for two different representations of GF(2^128),
see the comment in gf128mul.h. There different levels of optimization
(memory/speed tradeoff).
The code is based on work by Dr Brian Gladman. Notable changes:
- deletion of two optimization modes
- change from u32 to u64 for faster handling on 64bit machines
- support for 'bbe' representation in addition to the, already implemented,
'lle' representation.
- move 'inline void' functions from header to 'static void' in the
source file
- update to use the linux coding style conventions
The original can be found at:
http://fp.gladman.plus.com/AES/modes.vc8.19-06-06.zip
The copyright (and GPL statement) of the original author is preserved.
Signed-off-by: Rik Snel <rsnel@cube.dyndns.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
