[CRYPTO] skcipher: Add skcipher_geniv_alloc/skcipher_geniv_free

This patch creates the infrastructure to help the construction of givcipher
templates that wrap around existing blkcipher/ablkcipher algorithms by adding
an IV generator to them.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 32 insertions, 4 deletions

diff --git a/include/crypto/internal/skcipher.h b/include/crypto/internal/skcipher.h
index c9402dd12d03..07e7c82324ad 100644
--- a/include/crypto/internal/skcipher.h
+++ b/include/crypto/internal/skcipher.h
@@ -15,6 +15,9 @@
 
 #include <crypto/algapi.h>
 #include <crypto/skcipher.h>
+#include <linux/types.h>
+
+struct rtattr;
 
 struct crypto_skcipher_spawn {
         struct crypto_spawn base;
@@ -50,6 +53,21 @@ static inline struct crypto_ablkcipher *crypto_spawn_skcipher(
                                  crypto_skcipher_mask(0)));
 }
 
+const char *crypto_default_geniv(const struct crypto_alg *alg);
+
+struct crypto_instance *skcipher_geniv_alloc(struct crypto_template *tmpl,
+                                             struct rtattr **tb, u32 type,
+                                             u32 mask);
+void skcipher_geniv_free(struct crypto_instance *inst);
+int skcipher_geniv_init(struct crypto_tfm *tfm);
+void skcipher_geniv_exit(struct crypto_tfm *tfm);
+
+static inline struct crypto_ablkcipher *skcipher_geniv_cipher(
+        struct crypto_ablkcipher *geniv)
+{
+        return crypto_ablkcipher_crt(geniv)->base;
+}
+
 static inline void *skcipher_givcrypt_reqctx(
         struct skcipher_givcrypt_request *req)
 {
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index facafa1bd8ca..fa7afa9b9f4f 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -53,6 +53,12 @@
 #define CRYPTO_ALG_NEED_FALLBACK        0x00000100
 
 /*
+ * This bit is set for symmetric key ciphers that have already been wrapped
+ * with a generic IV generator to prevent them from being wrapped again.
+ */
+#define CRYPTO_ALG_GENIV                0x00000200
+
+/*
  * Transform masks and values (for crt_flags).
  */
 #define CRYPTO_TFM_REQ_MASK             0x000fff00
@@ -331,6 +337,8 @@ struct ablkcipher_tfm {
         int (*givencrypt)(struct skcipher_givcrypt_request *req);
         int (*givdecrypt)(struct skcipher_givcrypt_request *req);
 
+        struct crypto_ablkcipher *base;
+
         unsigned int ivsize;
         unsigned int reqsize;
 };
@@ -541,14 +549,14 @@ static inline struct crypto_ablkcipher *__crypto_ablkcipher_cast(
 
 static inline u32 crypto_skcipher_type(u32 type)
 {
-        type &= ~CRYPTO_ALG_TYPE_MASK;
+        type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
         type |= CRYPTO_ALG_TYPE_BLKCIPHER;
         return type;
 }
 
 static inline u32 crypto_skcipher_mask(u32 mask)
 {
-        mask &= ~CRYPTO_ALG_TYPE_MASK;
+        mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
         mask |= CRYPTO_ALG_TYPE_BLKCIPHER_MASK;
         return mask;
 }
@@ -623,7 +631,9 @@ static inline void crypto_ablkcipher_clear_flags(struct crypto_ablkcipher *tfm,
 static inline int crypto_ablkcipher_setkey(struct crypto_ablkcipher *tfm,
                                            const u8 *key, unsigned int keylen)
 {
-        return crypto_ablkcipher_crt(tfm)->setkey(tfm, key, keylen);
+        struct ablkcipher_tfm *crt = crypto_ablkcipher_crt(tfm);
+
+        return crt->setkey(crt->base, key, keylen);
 }
 
 static inline struct crypto_ablkcipher *crypto_ablkcipher_reqtfm(
@@ -655,7 +665,7 @@ static inline unsigned int crypto_ablkcipher_reqsize(
 static inline void ablkcipher_request_set_tfm(
         struct ablkcipher_request *req, struct crypto_ablkcipher *tfm)
 {
-        req->base.tfm = crypto_ablkcipher_tfm(tfm);
+        req->base.tfm = crypto_ablkcipher_tfm(crypto_ablkcipher_crt(tfm)->base);
 }
 
 static inline struct ablkcipher_request *ablkcipher_request_cast(