[PATCH v2] 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>
---
Changes since v1:
- use helper functions added in crypto API, in series:
https://patchwork.kernel.org/project/linux-crypto/list/?series=150651

 crypto/gcm.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/crypto/gcm.c b/crypto/gcm.c
index f69c251..3346e1f 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -1037,11 +1037,23 @@ static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc)
 
 static int crypto_rfc4543_encrypt(struct aead_request *req)
 {
+	int err;
+
+	err = check_ipsec_assoclen(req->assoclen);
+	if (err)
+		return err;
+
 	return crypto_rfc4543_crypt(req, true);
 }
 
 static int crypto_rfc4543_decrypt(struct aead_request *req)
 {
+	int err;
+
+	err = check_ipsec_assoclen(req->assoclen);
+	if (err)
+		return err;
+
 	return crypto_rfc4543_crypt(req, false);
 }
 
-- 
2.1.0