[PATCH] crypto: hisilicon/sec2: fix CCM algorithm long packet failure

[Chenghai Huang <huangchenghai2@huawei.com>]

From: Zhushuai Yin <yinzhushuai@huawei.com>

In the CCM B0 block the message-length field Q spans L bytes, where
L (cl in the driver) is derived from the cipher IV flags byte as
c_ivin[0] + 1. set_aead_auth_iv() hardcoded writing only the last 2
bytes of a_ivin with cryptlen, implicitly assuming cl = 2.

When cl = 3 (a shorter nonce yielding a 3-byte length field) and the
packet is longer than 65535 bytes, cryptlen no longer fits in 2 bytes.
The dropped high byte made the auth IV built by the driver differ from
the one consumed by the hardware, so the software/hardware comparison
failed and the CCM request errored out.

Write the last cl bytes of a_ivin in a loop driven by the IV's CL
value, so the length-field width always matches the algorithm
configuration instead of assuming a fixed 2-byte field.

Fixes: c16a70c1f253 ("crypto: hisilicon/sec - add new algorithm mode for AEAD")
Signed-off-by: Zhushuai Yin <yinzhushuai@huawei.com>
Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
---
 drivers/crypto/hisilicon/sec2/sec_crypto.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/crypto/hisilicon/sec2/sec_crypto.c b/drivers/crypto/hisilicon/sec2/sec_crypto.c
index 01eb76f616fc..0a2f7c8b44fc 100644
--- a/drivers/crypto/hisilicon/sec2/sec_crypto.c
+++ b/drivers/crypto/hisilicon/sec2/sec_crypto.c
@@ -96,7 +96,6 @@
 #define IV_FLAGS_OFFSET	0x6
 #define IV_CM_OFFSET		0x3
 #define IV_LAST_BYTE1		1
-#define IV_LAST_BYTE2		2
 #define IV_LAST_BYTE_MASK	0xFF
 #define IV_CTR_INIT		0x1
 #define IV_BYTE_OFFSET		0x8
@@ -1700,7 +1699,7 @@ static void set_aead_auth_iv(struct sec_ctx *ctx, struct sec_req *req)
 	struct sec_cipher_req *c_req = &req->c_req;
 	u32 data_size = aead_req->cryptlen;
 	u8 flage = 0;
-	u8 cm, cl;
+	u8 cm, cl, i;
 
 	/* the specification has been checked in aead_iv_demension_check() */
 	cl = c_req->c_ivin[0] + 1;
@@ -1724,15 +1723,16 @@ static void set_aead_auth_iv(struct sec_ctx *ctx, struct sec_req *req)
 	 * the last 32bit is counter's initial number,
 	 * but the nonce uses the first 16bit
 	 * the tail 16bit fill with the cipher length
+	 * When CL is 3, the tail 24bit fill with the cipher length.
 	 */
 	if (!c_req->encrypt)
 		data_size = aead_req->cryptlen - authsize;
 
-	a_req->a_ivin[ctx->c_ctx.ivsize - IV_LAST_BYTE1] =
-			data_size & IV_LAST_BYTE_MASK;
-	data_size >>= IV_BYTE_OFFSET;
-	a_req->a_ivin[ctx->c_ctx.ivsize - IV_LAST_BYTE2] =
+	for (i = 1; i <= cl; i++) {
+		a_req->a_ivin[ctx->c_ctx.ivsize - i] =
 			data_size & IV_LAST_BYTE_MASK;
+		data_size >>= IV_BYTE_OFFSET;
+	}
 }
 
 static void sec_aead_set_iv(struct sec_ctx *ctx, struct sec_req *req)
-- 
2.43.0