[CRYPTO] gcm: Allow block cipher parameter

This patch adds the gcm_base template which takes a block cipher
parameter instead of cipher.  This allows the user to specify a
specific CTR implementation.

This also fixes a leak of the cipher algorithm that was previously
looked up but never freed.

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

1 files changed, 89 insertions, 24 deletions

diff --git a/crypto/gcm.c b/crypto/gcm.c
index f6bee6f209a6..e87e5de8e7b3 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -413,30 +413,23 @@ static void crypto_gcm_exit_tfm(struct crypto_tfm *tfm)
         crypto_free_ablkcipher(ctx->ctr);
 }
 
-static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb)
+static struct crypto_instance *crypto_gcm_alloc_common(struct rtattr **tb,
+                                                       const char *full_name,
+                                                       const char *ctr_name)
 {
+        struct crypto_attr_type *algt;
         struct crypto_instance *inst;
         struct crypto_alg *ctr;
-        struct crypto_alg *cipher;
         struct gcm_instance_ctx *ctx;
         int err;
-        char ctr_name[CRYPTO_MAX_ALG_NAME];
 
-        err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD);
-        if (err)
+        algt = crypto_get_attr_type(tb);
+        err = PTR_ERR(algt);
+        if (IS_ERR(algt))
                 return ERR_PTR(err);
 
-        cipher = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
-                              CRYPTO_ALG_TYPE_MASK);
-
-        inst = ERR_PTR(PTR_ERR(cipher));
-        if (IS_ERR(cipher))
-                return inst;
-
-        inst = ERR_PTR(ENAMETOOLONG);
-        if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
-                     cipher->cra_name) >= CRYPTO_MAX_ALG_NAME)
-                return inst;
+        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
+                return ERR_PTR(-EINVAL);
 
         ctr = crypto_alg_mod_lookup(ctr_name, CRYPTO_ALG_TYPE_BLKCIPHER,
                                     CRYPTO_ALG_TYPE_MASK);
@@ -444,7 +437,14 @@ static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb)
         if (IS_ERR(ctr))
                 return ERR_PTR(PTR_ERR(ctr));
 
-        if (cipher->cra_blocksize != 16)
+        /* We only support 16-byte blocks. */
+        if ((ctr->cra_type == &crypto_blkcipher_type ?
+             ctr->cra_blkcipher.ivsize : ctr->cra_ablkcipher.ivsize) != 16)
+                goto out_put_ctr;
+
+        /* Not a stream cipher? */
+        err = -EINVAL;
+        if (ctr->cra_blocksize != 1)
                 goto out_put_ctr;
 
         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
@@ -453,21 +453,21 @@ static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb)
                 goto out_put_ctr;
 
         err = -ENAMETOOLONG;
-        if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
-                     "gcm(%s)", cipher->cra_name) >= CRYPTO_MAX_ALG_NAME ||
-            snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
-                     "gcm(%s)", cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
+        if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+                     "gcm_base(%s)", ctr->cra_driver_name) >=
+            CRYPTO_MAX_ALG_NAME)
                 goto err_free_inst;
 
-
         ctx = crypto_instance_ctx(inst);
         err = crypto_init_spawn(&ctx->ctr, ctr, inst, CRYPTO_ALG_TYPE_MASK);
         if (err)
                 goto err_free_inst;
 
+        memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
+
         inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC;
         inst->alg.cra_priority = ctr->cra_priority;
-        inst->alg.cra_blocksize = 16;
+        inst->alg.cra_blocksize = 1;
         inst->alg.cra_alignmask = ctr->cra_alignmask | (__alignof__(u64) - 1);
         inst->alg.cra_type = &crypto_aead_type;
         inst->alg.cra_aead.ivsize = 16;
@@ -489,6 +489,29 @@ out_put_ctr:
         goto out;
 }
 
+static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb)
+{
+        int err;
+        const char *cipher_name;
+        char ctr_name[CRYPTO_MAX_ALG_NAME];
+        char full_name[CRYPTO_MAX_ALG_NAME];
+
+        cipher_name = crypto_attr_alg_name(tb[1]);
+        err = PTR_ERR(cipher_name);
+        if (IS_ERR(cipher_name))
+                return ERR_PTR(err);
+
+        if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)", cipher_name) >=
+            CRYPTO_MAX_ALG_NAME)
+                return ERR_PTR(-ENAMETOOLONG);
+
+        if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "gcm(%s)", cipher_name) >=
+            CRYPTO_MAX_ALG_NAME)
+                return ERR_PTR(-ENAMETOOLONG);
+
+        return crypto_gcm_alloc_common(tb, full_name, ctr_name);
+}
+
 static void crypto_gcm_free(struct crypto_instance *inst)
 {
         struct gcm_instance_ctx *ctx = crypto_instance_ctx(inst);
@@ -504,14 +527,55 @@ static struct crypto_template crypto_gcm_tmpl = {
         .module = THIS_MODULE,
 };
 
+static struct crypto_instance *crypto_gcm_base_alloc(struct rtattr **tb)
+{
+        int err;
+        const char *ctr_name;
+        char full_name[CRYPTO_MAX_ALG_NAME];
+
+        ctr_name = crypto_attr_alg_name(tb[1]);
+        err = PTR_ERR(ctr_name);
+        if (IS_ERR(ctr_name))
+                return ERR_PTR(err);
+
+        if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "gcm_base(%s)",
+                     ctr_name) >= CRYPTO_MAX_ALG_NAME)
+                return ERR_PTR(-ENAMETOOLONG);
+
+        return crypto_gcm_alloc_common(tb, full_name, ctr_name);
+}
+
+static struct crypto_template crypto_gcm_base_tmpl = {
+        .name = "gcm_base",
+        .alloc = crypto_gcm_base_alloc,
+        .free = crypto_gcm_free,
+        .module = THIS_MODULE,
+};
+
 static int __init crypto_gcm_module_init(void)
 {
-        return crypto_register_template(&crypto_gcm_tmpl);
+        int err;
+
+        err = crypto_register_template(&crypto_gcm_base_tmpl);
+        if (err)
+                goto out;
+
+        err = crypto_register_template(&crypto_gcm_tmpl);
+        if (err)
+                goto out_undo_base;
+
+out:
+        return err;
+
+out_undo_base:
+        crypto_unregister_template(&crypto_gcm_base_tmpl);
+        goto out;
 }
 
 static void __exit crypto_gcm_module_exit(void)
 {
         crypto_unregister_template(&crypto_gcm_tmpl);
+        crypto_unregister_template(&crypto_gcm_base_tmpl);
 }
 
 module_init(crypto_gcm_module_init);
@@ -520,3 +584,4 @@ module_exit(crypto_gcm_module_exit);
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Galois/Counter Mode");
 MODULE_AUTHOR("Mikko Herranen <mh1@iki.fi>");
+MODULE_ALIAS("gcm_base");