crypto: user - Fix lookup of algorithms with IV generator

We lookup algorithms with crypto_alg_mod_lookup() when instantiating via
crypto_add_alg(). However, algorithms that are wrapped by an IV genearator
(e.g. aead or genicv type algorithms) need special care. The userspace
process hangs until it gets a timeout when we use crypto_alg_mod_lookup()
to lookup these algorithms. So export the lookup functions for these
algorithms and use them in crypto_add_alg().

Signed-off-by: Steffen Klassert <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

crypto/ablkcipher.c

···
 	return err;
 }
 
-static struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type,
-						 u32 mask)
+struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type, u32 mask)
 {
 	struct crypto_alg *alg;
 
···
 
 	return ERR_PTR(crypto_givcipher_default(alg, type, mask));
 }
+EXPORT_SYMBOL_GPL(crypto_lookup_skcipher);
 
 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn, const char *name,
 			 u32 type, u32 mask)

crypto/aead.c

···
 	return err;
 }
 
-static struct crypto_alg *crypto_lookup_aead(const char *name, u32 type,
-					     u32 mask)
+struct crypto_alg *crypto_lookup_aead(const char *name, u32 type, u32 mask)
 {
 	struct crypto_alg *alg;
 
···
 
 	return ERR_PTR(crypto_nivaead_default(alg, type, mask));
 }
+EXPORT_SYMBOL_GPL(crypto_lookup_aead);
 
 int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
 		     u32 type, u32 mask)

crypto/crypto_user.c

···
 #include <linux/module.h>
 #include <linux/crypto.h>
 #include <linux/cryptouser.h>
+#include <linux/sched.h>
 #include <net/netlink.h>
 #include <linux/security.h>
 #include <net/net_namespace.h>
+#include <crypto/internal/aead.h>
+#include <crypto/internal/skcipher.h>
+
 #include "internal.h"
 
 DEFINE_MUTEX(crypto_cfg_mutex);
···
 	return crypto_unregister_instance(alg);
 }
 
+static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
+						   u32 mask)
+{
+	int err;
+	struct crypto_alg *alg;
+
+	type = crypto_skcipher_type(type);
+	mask = crypto_skcipher_mask(mask);
+
+	for (;;) {
+		alg = crypto_lookup_skcipher(name,  type, mask);
+		if (!IS_ERR(alg))
+			return alg;
+
+		err = PTR_ERR(alg);
+		if (err != -EAGAIN)
+			break;
+		if (signal_pending(current)) {
+			err = -EINTR;
+			break;
+		}
+	}
+
+	return ERR_PTR(err);
+}
+
+static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
+					       u32 mask)
+{
+	int err;
+	struct crypto_alg *alg;
+
+	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
+	type |= CRYPTO_ALG_TYPE_AEAD;
+	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
+	mask |= CRYPTO_ALG_TYPE_MASK;
+
+	for (;;) {
+		alg = crypto_lookup_aead(name,  type, mask);
+		if (!IS_ERR(alg))
+			return alg;
+
+		err = PTR_ERR(alg);
+		if (err != -EAGAIN)
+			break;
+		if (signal_pending(current)) {
+			err = -EINTR;
+			break;
+		}
+	}
+
+	return ERR_PTR(err);
+}
+
 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			  struct nlattr **attrs)
 {
···
 	else
 		name = p->cru_name;
 
-	alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
+	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
+	case CRYPTO_ALG_TYPE_AEAD:
+		alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
+		break;
+	case CRYPTO_ALG_TYPE_GIVCIPHER:
+	case CRYPTO_ALG_TYPE_BLKCIPHER:
+	case CRYPTO_ALG_TYPE_ABLKCIPHER:
+		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
+		break;
+	default:
+		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
+	}
+
 	if (IS_ERR(alg))
 		return PTR_ERR(alg);
 

include/crypto/internal/aead.h

···
 	crypto_set_spawn(&spawn->base, inst);
 }
 
+struct crypto_alg *crypto_lookup_aead(const char *name, u32 type, u32 mask);
+
 int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
 		     u32 type, u32 mask);
 

include/crypto/internal/skcipher.h

···
 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn, const char *name,
 			 u32 type, u32 mask);
 
+struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type, u32 mask);
+
 static inline void crypto_drop_skcipher(struct crypto_skcipher_spawn *spawn)
 {
 	crypto_drop_spawn(&spawn->base);