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Commit 161151d7 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Herbert Xu
Browse files

crypto: chacha20poly1305 - Skip encryption/decryption for 0-len 



If the length of the plaintext is zero, there's no need to waste cycles
on encryption and decryption. Using the chacha20poly1305 construction
for zero-length plaintexts is a common way of using a shared encryption
key for AAD authentication.

Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 3d5b1ecd

crypto/chacha20poly1305.c

+8 −0
Original line number Diff line number Diff line
@@ -130,6 +130,9 @@ static int chacha_decrypt(struct aead_request *req) 
	struct scatterlist *src, *dst;

	int err;



	if (rctx->cryptlen == 0)

		goto skip;



	chacha_iv(creq->iv, req, 1);



	sg_init_table(rctx->src, 2);
@@ -150,6 +153,7 @@ static int chacha_decrypt(struct aead_request *req) 
	if (err)

		return err;



skip:

	return poly_verify_tag(req);

}
@@ -415,6 +419,9 @@ static int chacha_encrypt(struct aead_request *req) 
	struct scatterlist *src, *dst;

	int err;



	if (req->cryptlen == 0)

		goto skip;



	chacha_iv(creq->iv, req, 1);



	sg_init_table(rctx->src, 2);
@@ -435,6 +442,7 @@ static int chacha_encrypt(struct aead_request *req) 
	if (err)

		return err;



skip:

	return poly_genkey(req);

}