[PATCH 2/2] crypto: bcm - check assoclen for rfc4543/rfc4106

[Iuliana Prodan]

Validated assoclen for RFC4543 which expects an assoclen
of 16 or 20, the same as RFC4106.
Based on seqiv, IPsec ESP and RFC4543/RFC4106 the assoclen is sizeof
IP Header (spi, seq_no, extended seq_no) and IV len. This can be 16 or
20 bytes.

Signed-off-by: Iuliana Prodan <iuliana.prodan@xxxxxxx>
---
 drivers/crypto/bcm/cipher.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/crypto/bcm/cipher.c b/drivers/crypto/bcm/cipher.c
index d972ffa..02ef600 100644
--- a/drivers/crypto/bcm/cipher.c
+++ b/drivers/crypto/bcm/cipher.c
@@ -2640,6 +2640,19 @@ static int aead_need_fallback(struct aead_request *req)
 		return 1;
 	}
 
+	/*
+	 * RFC4106 and RFC4543 cannot handle the case where AAD is other than
+	 * 16 or 20 bytes long. So use fallback in this case.
+	 */
+	if (ctx->cipher.mode == CIPHER_MODE_GCM &&
+	    ctx->cipher.alg == CIPHER_ALG_AES &&
+	    rctx->iv_ctr_len == GCM_RFC4106_IV_SIZE &&
+	    req->assoclen != 16 && req->assoclen != 20) {
+		flow_log("RFC4106/RFC4543 needs fallback for assoclen"
+			 " other than 16 or 20 bytes\n");
+		return 1;
+	}
+
 	payload_len = req->cryptlen;
 	if (spu->spu_type == SPU_TYPE_SPUM)
 		payload_len += req->assoclen;
-- 
2.1.0