[PATCH] crypto: gcm - restrict assoclen for rfc4543

[Iuliana Prodan]

Based on seqiv, IPsec ESP and rfc4543/rfc4106 the assoclen can be 16 or
20 bytes.

>From esp4/esp6, assoclen is sizeof IP Header. This includes spi, seq_no
and extended seq_no, that is 8 or 12 bytes.
In seqiv, to asscolen is added the IV size (8 bytes).
Therefore, the assoclen, for rfc4543, should be restricted to 16 or 20
bytes, as for rfc4106.

Signed-off-by: Iuliana Prodan <iuliana.prodan@xxxxxxx>
---
 crypto/gcm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/crypto/gcm.c b/crypto/gcm.c
index 33f45a9..4d720e6 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -1048,11 +1048,17 @@ static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc)
 
 static int crypto_rfc4543_encrypt(struct aead_request *req)
 {
+	if (req->assoclen != 16 && req->assoclen != 20)
+		return -EINVAL;
+
 	return crypto_rfc4543_crypt(req, true);
 }
 
 static int crypto_rfc4543_decrypt(struct aead_request *req)
 {
+	if (req->assoclen != 16 && req->assoclen != 20)
+		return -EINVAL;
+
 	return crypto_rfc4543_crypt(req, false);
 }
 
-- 
2.1.0