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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2015-12-06 02:51:38 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2015-12-09 20:16:04 +0800 |
| commit | 161151d79ff4f7ed35d4ebb0eb7727a517c34ef2 (patch) | |
| tree | 8987b80f9b613c8a30280f73873dad1239247a83 /crypto/chacha20poly1305.c | |
| parent | 3d5b1ecdea6fb94f8c61554fcb2ba776a2d3d0e6 (diff) | |
| download | lwn-161151d79ff4f7ed35d4ebb0eb7727a517c34ef2.tar.gz lwn-161151d79ff4f7ed35d4ebb0eb7727a517c34ef2.zip | |
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: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/chacha20poly1305.c')
| -rw-r--r-- | crypto/chacha20poly1305.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/crypto/chacha20poly1305.c b/crypto/chacha20poly1305.c index 99c3cce01290..7b6b935cef23 100644 --- a/crypto/chacha20poly1305.c +++ b/crypto/chacha20poly1305.c @@ -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); } |