summaryrefslogtreecommitdiffstats
path: root/crypto/ofb.c
AgeCommit message (Collapse)AuthorFilesLines
2019-01-11crypto: ofb - convert to skcipher_alloc_instance_simple()Eric Biggers1-112/+7
The OFB template just wraps a single block cipher algorithm, so simplify it by converting it to use skcipher_alloc_instance_simple(). Cc: Gilad Ben-Yossef <gilad@benyossef.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-01-11crypto: ofb - fix handling partial blocks and make thread-safeEric Biggers1-54/+37
Fix multiple bugs in the OFB implementation: 1. It stored the per-request state 'cnt' in the tfm context, which can be used by multiple threads concurrently (e.g. via AF_ALG). 2. It didn't support messages not a multiple of the block cipher size, despite being a stream cipher. 3. It didn't set cra_blocksize to 1 to indicate it is a stream cipher. To fix these, set the 'chunksize' property to the cipher block size to guarantee that when walking through the scatterlist, a partial block can only occur at the end. Then change the implementation to XOR a block at a time at first, then XOR the partial block at the end if needed. This is the same way CTR and CFB are implemented. As a bonus, this also improves performance in most cases over the current approach. Fixes: e497c51896b3 ("crypto: ofb - add output feedback mode") Cc: <stable@vger.kernel.org> # v4.20+ Cc: Gilad Ben-Yossef <gilad@benyossef.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Gilad Ben-Yossef <gilad@benyossef.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-09-28crypto: ofb - add output feedback modeGilad Ben-Yossef1-0/+225
Add a generic version of output feedback mode. We already have support of several hardware based transformations of this mode and the needed test vectors but we somehow missed adding a generic software one. Fix this now. Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>