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authorArd Biesheuvel <ardb@kernel.org>2019-11-08 13:22:40 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2019-11-17 09:02:44 +0800
commitd95312a3ccc0cd544d374be2fc45aeaa803e5fd9 (patch)
tree30bf7798f3ec70784487b321609da30dc757e0b7 /include/crypto
parented20078b7e3331e82828be357147af6a3282e4ce (diff)
crypto: lib/chacha20poly1305 - reimplement crypt_from_sg() routine
Reimplement the library routines to perform chacha20poly1305 en/decryption on scatterlists, without [ab]using the [deprecated] blkcipher interface, which is rather heavyweight and does things we don't really need. Instead, we use the sg_miter API in a novel and clever way, to iterate over the scatterlist in-place (i.e., source == destination, which is the only way this library is expected to be used). That way, we don't have to iterate over two scatterlists in parallel. Another optimization is that, instead of relying on the blkcipher walker to present the input in suitable chunks, we recognize that ChaCha is a streamcipher, and so we can simply deal with partial blocks by keeping a block of cipherstream on the stack and use crypto_xor() to mix it with the in/output. Finally, we omit the scatterwalk_and_copy() call if the last element of the scatterlist covers the MAC as well (which is the common case), avoiding the need to walk the scatterlist and kmap() the page twice. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include/crypto')
-rw-r--r--include/crypto/chacha20poly1305.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/crypto/chacha20poly1305.h b/include/crypto/chacha20poly1305.h
index ad3b1de58df8..234ee28078ef 100644
--- a/include/crypto/chacha20poly1305.h
+++ b/include/crypto/chacha20poly1305.h
@@ -7,6 +7,7 @@
#define __CHACHA20POLY1305_H
#include <linux/types.h>
+#include <linux/scatterlist.h>
enum chacha20poly1305_lengths {
XCHACHA20POLY1305_NONCE_SIZE = 24,
@@ -34,4 +35,14 @@ bool __must_check xchacha20poly1305_decrypt(
const size_t ad_len, const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+bool chacha20poly1305_encrypt_sg_inplace(struct scatterlist *src, size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u64 nonce,
+ const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+
+bool chacha20poly1305_decrypt_sg_inplace(struct scatterlist *src, size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u64 nonce,
+ const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+
#endif /* __CHACHA20POLY1305_H */