crypto: authenc - Export key parsing helper function

AEAD key parsing is duplicated to multiple places in the kernel. Add a
common helper function to consolidate that functionality.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Mathias Krause <mathias.krause@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 30 insertions, 18 deletions

diff --git a/crypto/authenc.c b/crypto/authenc.c
index 2b3f4abda929..1875e7026e8f 100644
--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -52,40 +52,52 @@ static void authenc_request_complete(struct aead_request *req, int err)
                 aead_request_complete(req, err);
 }
 
-static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
-                                 unsigned int keylen)
+int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key,
+                               unsigned int keylen)
 {
-        unsigned int authkeylen;
-        unsigned int enckeylen;
-        struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
-        struct crypto_ahash *auth = ctx->auth;
-        struct crypto_ablkcipher *enc = ctx->enc;
-        struct rtattr *rta = (void *)key;
+        struct rtattr *rta = (struct rtattr *)key;
         struct crypto_authenc_key_param *param;
-        int err = -EINVAL;
 
         if (!RTA_OK(rta, keylen))
-                goto badkey;
+                return -EINVAL;
         if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM)
-                goto badkey;
+                return -EINVAL;
         if (RTA_PAYLOAD(rta) < sizeof(*param))
-                goto badkey;
+                return -EINVAL;
 
         param = RTA_DATA(rta);
-        enckeylen = be32_to_cpu(param->enckeylen);
+        keys->enckeylen = be32_to_cpu(param->enckeylen);
 
         key += RTA_ALIGN(rta->rta_len);
         keylen -= RTA_ALIGN(rta->rta_len);
 
-        if (keylen < enckeylen)
-                goto badkey;
+        if (keylen < keys->enckeylen)
+                return -EINVAL;
 
-        authkeylen = keylen - enckeylen;
+        keys->authkeylen = keylen - keys->enckeylen;
+        keys->authkey = key;
+        keys->enckey = key + keys->authkeylen;
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys);
+
+static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
+                                 unsigned int keylen)
+{
+        struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
+        struct crypto_ahash *auth = ctx->auth;
+        struct crypto_ablkcipher *enc = ctx->enc;
+        struct crypto_authenc_keys keys;
+        int err = -EINVAL;
+
+        if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
+                goto badkey;
 
         crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
         crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) &
                                     CRYPTO_TFM_REQ_MASK);
-        err = crypto_ahash_setkey(auth, key, authkeylen);
+        err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
         crypto_aead_set_flags(authenc, crypto_ahash_get_flags(auth) &
                                        CRYPTO_TFM_RES_MASK);
 
@@ -95,7 +107,7 @@ static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
         crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
         crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) &
                                          CRYPTO_TFM_REQ_MASK);
-        err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen);
+        err = crypto_ablkcipher_setkey(enc, keys.enckey, keys.enckeylen);
         crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) &
                                        CRYPTO_TFM_RES_MASK);