From: Iuliana Prodan <iuliana.prodan@nxp.com>
Date: Wed, 31 Jul 2019 16:05:55 +0300
Subject: crypto: aes - helper function to validate key length for AES
 algorithms
Git-commit: bc67d04e75260942fb534fb91673103dcad7ca96
Patch-mainline: v5.4-rc1
References: jsc#SLE-16106

Add inline helper function to check key length for AES algorithms.
The key can be 128, 192 or 256 bits size.
This function is used in the generic aes implementation.

Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 include/crypto/aes.h |   17 +++++++++++++++++
 lib/crypto/aes.c     |    8 ++++----
 2 files changed, 21 insertions(+), 4 deletions(-)

--- a/include/crypto/aes.h
+++ b/include/crypto/aes.h
@@ -31,6 +31,23 @@ struct crypto_aes_ctx {
 extern const u32 crypto_ft_tab[4][256] ____cacheline_aligned;
 extern const u32 crypto_it_tab[4][256] ____cacheline_aligned;
 
+/*
+ * validate key length for AES algorithms
+ */
+static inline int aes_check_keylen(unsigned int keylen)
+{
+	switch (keylen) {
+	case AES_KEYSIZE_128:
+	case AES_KEYSIZE_192:
+	case AES_KEYSIZE_256:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 		unsigned int key_len);
 
--- a/lib/crypto/aes.c
+++ b/lib/crypto/aes.c
@@ -187,11 +187,11 @@ int aes_expandkey(struct crypto_aes_ctx
 {
 	u32 kwords = key_len / sizeof(u32);
 	u32 rc, i, j;
+	int err;
 
-	if (key_len != AES_KEYSIZE_128 &&
-	    key_len != AES_KEYSIZE_192 &&
-	    key_len != AES_KEYSIZE_256)
-		return -EINVAL;
+	err = aes_check_keylen(key_len);
+	if (err)
+		return err;
 
 	ctx->key_length = key_len;