ThePassionate opened a new pull request, #19396:
URL: https://github.com/apache/nuttx/pull/19396
## Summary
Add a raw CRYPTO_CHACHA20 stream cipher to the OCF crypto framework
(/dev/crypto) so applications such as an SSH server (chacha20-poly1305) can use
ChaCha20 directly, not only as part of the ChaCha20-Poly1305 AEAD.
Instead of introducing a separate multi-buffer stream path (parallel
encrypt_multi/decrypt_multi callbacks), extend the existing enc_xform
encrypt/decrypt callback signature with a length argument:
void (*encrypt)(caddr_t, FAR uint8_t *, size_t len);
void (*decrypt)(caddr_t, FAR uint8_t *, size_t len);
With that single change every cipher, block or stream, flows through the
same swcr_encdec path. swcr_encdec already handles a short final block via
buflen = MIN(i, blocksize), so arbitrary-length data works without a second
code path. This is exactly how the existing stream ciphers (AES-CTR/OFB/CFB)
already behave: the cipher keeps its own counter in the context and swcr_encdec
feeds it whole blocks (only the last one may be shorter). chacha20_crypt
likewise relies on the underlying chacha state block counter (input[12]) to
continue the keystream across calls, so no per-call keystream caching is needed.
* xform.h/xform.c: add size_t len to encrypt/decrypt; add enc_xform_chacha20
(blocksize 64, 12-byte IV, RFC 8439 layout).
* chachapoly.c/chacha_private.h: chacha_ivsetup now uses a 4-byte counter
and a 12-byte nonce (RFC 8439); chacha20_crypt encrypts the requested length in
one pass, mirroring aes_ctr_crypt.
* cryptodev.c/cryptosoft.c: register CRYPTO_CHACHA20 as a txform cipher and
route new sessions to enc_xform_chacha20.
This keeps all ciphers on one uniform path instead of maintaining two, and
any future stream cipher drops in with just an xform table entry.
## Impact
extends an internal kernel callback signature (enc_xform encrypt/decrypt).
All in-tree implementations are updated in the same commit and the user-facing
/dev/crypto ABI is unchanged, so this is self-contained and not a breaking
change for existing configurations.
## Testing
Build host: Ubuntu Linux x86_64, GCC (host sim toolchain)
Target: sim:crypto (CONFIG_ARCH=sim)
Enabled regression tests (cover both code paths through swcr_encdec):
3DES-CBC, AES-CBC — block ciphers, non-reinit CBC branch
AES-CTR — stream cipher, reinit branch (same path as the new CHACHA20)
AES-XTS — block cipher with reinit
CHACHA20 — new algorithm, incl. a 375-byte multi-block vector
HMAC — auth path
NuttShell (NSH) NuttX-13.0.0-RC0
nsh> des3cbc
ok, encrypt with /dev/crypto, decrypt with /dev/crypto
nsh> aescbc
aescbc test ok
nsh> aesctr
OK test vector 0
OK test vector 1
OK test vector 2
OK test vector 3
OK test vector 4
OK test vector 5
OK test vector 6
OK test vector 7
OK test vector 8
nsh> aesxts
OK encrypt test vector 0
OK decrypt test vector 0
OK encrypt test vector 1
OK decrypt test vector 1
OK encrypt test vector 2
OK decrypt test vector 2
OK encrypt test vector 3
OK decrypt test vector 3
OK encrypt test vector 4
OK decrypt test vector 4
OK encrypt test vector 5
OK decrypt test vector 5
OK encrypt test vector 6
OK decrypt test vector 6
OK encrypt test vector 7
OK decrypt test vector 7
OK encrypt test vector 8
OK decrypt test vector 8
OK encrypt test vector 9
OK decrypt test vector 9
OK encrypt test vector 10
OK decrypt test vector 10
OK encrypt test vector 11
OK decrypt test vector 11
OK encrypt test vector 12
OK decrypt test vector 12
OK encrypt test vector 13
OK decrypt test vector 13
nsh> chacha20
run(0) start
OK test vector 0
run(1) start
OK test vector 1
chacha20: 2/2 vectors passed
nsh> hmac
hmac md5 success
hmac md5 success
hmac md5 success
hmac md5 success
hmac md5 success
hmac sha1 success
hmac sha1 success
hmac sha1 success
hmac sha1 success
hmac sha1 success
hmac sha256 success
hmac sha256 success
hmac sha256 success
hmac sha256 success
hmac sha256 success
nsh>
*Note: Please adhere to [Contributing
Guidelines](https://github.com/apache/nuttx/blob/master/CONTRIBUTING.md).*
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