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2017-11-29crypto: chacha20 - Fix keystream alignment for chacha20_block()Eric Biggers
When chacha20_block() outputs the keystream block, it uses 'u32' stores directly. However, the callers (crypto/chacha20_generic.c and drivers/char/random.c) declare the keystream buffer as a 'u8' array, which is not guaranteed to have the needed alignment. Fix it by having both callers declare the keystream as a 'u32' array. For now this is preferable to switching over to the unaligned access macros because chacha20_block() is only being used in cases where we can easily control the alignment (stack buffers). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-29crypto: chacha20 - Remove cra_alignmaskEric Biggers
Now that crypto_chacha20_setkey() and crypto_chacha20_init() use the unaligned access macros and crypto_xor() also accepts unaligned buffers, there is no need to have a cra_alignmask set for chacha20-generic. Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-29crypto: chacha20 - Use unaligned access macros when loading key and IVEric Biggers
The generic ChaCha20 implementation has a cra_alignmask of 3, which ensures that the key passed into crypto_chacha20_setkey() and the IV passed into crypto_chacha20_init() are 4-byte aligned. However, these functions are also called from the ARM and ARM64 implementations of ChaCha20, which intentionally do not have a cra_alignmask set. This is broken because 32-bit words are being loaded from potentially-unaligned buffers without the unaligned access macros. Fix it by using the unaligned access macros when loading the key and IV. Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-29crypto: chacha20 - Fix unaligned access when loading constantsEric Biggers
The four 32-bit constants for the initial state of ChaCha20 were loaded from a char array which is not guaranteed to have the needed alignment. Fix it by just assigning the constants directly instead. Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-08-22crypto: chacha20 - fix handling of chunked inputArd Biesheuvel
Commit 9ae433bc79f9 ("crypto: chacha20 - convert generic and x86 versions to skcipher") ported the existing chacha20 code to use the new skcipher API, and introduced a bug along the way. Unfortunately, the tcrypt tests did not catch the error, and it was only found recently by Tobias. Stefan kindly diagnosed the error, and proposed a fix which is similar to the one below, with the exception that 'walk.stride' is used rather than the hardcoded block size. This does not actually matter in this case, but it's a better example of how to use the skcipher walk API. Fixes: 9ae433bc79f9 ("crypto: chacha20 - convert generic and x86 ...") Cc: <stable@vger.kernel.org> # v4.11+ Cc: Steffen Klassert <steffen.klassert@secunet.com> Reported-by: Tobias Brunner <tobias@strongswan.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-27crypto: chacha20 - convert generic and x86 versions to skcipherArd Biesheuvel
This converts the ChaCha20 code from a blkcipher to a skcipher, which is now the preferred way to implement symmetric block and stream ciphers. This ports the generic and x86 versions at the same time because the latter reuses routines of the former. Note that the skcipher_walk() API guarantees that all presented blocks except the final one are a multiple of the chunk size, so we can simplify the encrypt() routine somewhat. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-07-03random: replace non-blocking pool with a Chacha20-based CRNGTheodore Ts'o
The CRNG is faster, and we don't pretend to track entropy usage in the CRNG any more. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-17crypto: chacha20 - Export common ChaCha20 helpersMartin Willi
As architecture specific drivers need a software fallback, export a ChaCha20 en-/decryption function together with some helpers in a header file. Signed-off-by: Martin Willi <martin@strongswan.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-06-04crypto: chacha20 - Add a generic ChaCha20 stream cipher implementationMartin Willi
ChaCha20 is a high speed 256-bit key size stream cipher algorithm designed by Daniel J. Bernstein. It is further specified in RFC7539 for use in IETF protocols as a building block for the ChaCha20-Poly1305 AEAD. This is a portable C implementation without any architecture specific optimizations. It uses a 16-byte IV, which includes the 12-byte ChaCha20 nonce prepended by the initial block counter. Some algorithms require an explicit counter value, for example the mentioned AEAD construction. Signed-off-by: Martin Willi <martin@strongswan.org> Acked-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>