[PATCH v3] crypto: gcm - restrict assoclen for rfc4543

From: Iuliana Prodan <iuliana.prodan@nxp.com>
To: Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-imx <linux-imx@nxp.com>
Subject: [PATCH v3] crypto: gcm - restrict assoclen for rfc4543
Date: Tue, 30 Jul 2019 13:54:37 +0300	[thread overview]
Message-ID: <1564484077-27727-1-git-send-email-iuliana.prodan@nxp.com> (raw)

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@nxp.com>
---
Changes since v2:
- use, newly renamed, helper functions added in crypto API, in series:
https://patchwork.kernel.org/project/linux-crypto/list/?series=152649

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

diff --git a/crypto/gcm.c b/crypto/gcm.c
index 2f3b50f..7eb5ced 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -1034,11 +1034,23 @@ 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 = crypto_ipsec_check_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 = crypto_ipsec_check_assoclen(req->assoclen);
+	if (err)
+		return err;
+
 	return crypto_rfc4543_crypt(req, false);
 }
 
-- 
2.1.0

