crypto: algapi - use common mechanism for inheriting flags

The flag CRYPTO_ALG_ASYNC is "inherited" in the sense that when a
template is instantiated, the template will have CRYPTO_ALG_ASYNC set if
any of the algorithms it uses has CRYPTO_ALG_ASYNC set.

We'd like to add a second flag (CRYPTO_ALG_ALLOCATES_MEMORY) that gets
"inherited" in the same way.  This is difficult because the handling of
CRYPTO_ALG_ASYNC is hardcoded everywhere.  Address this by:

  - Add CRYPTO_ALG_INHERITED_FLAGS, which contains the set of flags that
    have these inheritance semantics.

  - Add crypto_algt_inherited_mask(), for use by template ->create()
    methods.  It returns any of these flags that the user asked to be
    unset and thus must be passed in the 'mask' to crypto_grab_*().

  - Also modify crypto_check_attr_type() to handle computing the 'mask'
    so that most templates can just use this.

  - Make crypto_grab_*() propagate these flags to the template instance
    being created so that templates don't have to do this themselves.

Make crypto/simd.c propagate these flags too, since it "wraps" another
algorithm, similar to a template.

Based on a patch by Mikulas Patocka <mpatocka@redhat.com>
(https://lore.kernel.org/r/alpine.LRH.2.02.2006301414580.30526@file01.intranet.prod.int.rdu2.redhat.com).

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 30 insertions, 29 deletions

diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index 283212262adb..a1bea0f4baa8 100644
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -191,17 +191,20 @@ static inline struct cryptd_queue *cryptd_get_queue(struct crypto_tfm *tfm)
 	return ictx->queue;
 }
 
-static inline void cryptd_check_internal(struct rtattr **tb, u32 *type,
-					 u32 *mask)
+static void cryptd_type_and_mask(struct crypto_attr_type *algt,
+				 u32 *type, u32 *mask)
 {
-	struct crypto_attr_type *algt;
+	/*
+	 * cryptd is allowed to wrap internal algorithms, but in that case the
+	 * resulting cryptd instance will be marked as internal as well.
+	 */
+	*type = algt->type & CRYPTO_ALG_INTERNAL;
+	*mask = algt->mask & CRYPTO_ALG_INTERNAL;
 
-	algt = crypto_get_attr_type(tb);
-	if (IS_ERR(algt))
-		return;
+	/* No point in cryptd wrapping an algorithm that's already async. */
+	*mask |= CRYPTO_ALG_ASYNC;
 
-	*type |= algt->type & CRYPTO_ALG_INTERNAL;
-	*mask |= algt->mask & CRYPTO_ALG_INTERNAL;
+	*mask |= crypto_algt_inherited_mask(algt);
 }
 
 static int cryptd_init_instance(struct crypto_instance *inst,
@@ -364,6 +367,7 @@ static void cryptd_skcipher_free(struct skcipher_instance *inst)
 
 static int cryptd_create_skcipher(struct crypto_template *tmpl,
 				  struct rtattr **tb,
+				  struct crypto_attr_type *algt,
 				  struct cryptd_queue *queue)
 {
 	struct skcipherd_instance_ctx *ctx;
@@ -373,10 +377,7 @@ static int cryptd_create_skcipher(struct crypto_template *tmpl,
 	u32 mask;
 	int err;
 
-	type = 0;
-	mask = CRYPTO_ALG_ASYNC;
-
-	cryptd_check_internal(tb, &type, &mask);
+	cryptd_type_and_mask(algt, &type, &mask);
 
 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 	if (!inst)
@@ -395,9 +396,8 @@ static int cryptd_create_skcipher(struct crypto_template *tmpl,
 	if (err)
 		goto err_free_inst;
 
-	inst->alg.base.cra_flags = CRYPTO_ALG_ASYNC |
-				   (alg->base.cra_flags & CRYPTO_ALG_INTERNAL);
-
+	inst->alg.base.cra_flags |= CRYPTO_ALG_ASYNC |
+		(alg->base.cra_flags & CRYPTO_ALG_INTERNAL);
 	inst->alg.ivsize = crypto_skcipher_alg_ivsize(alg);
 	inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
 	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg);
@@ -633,16 +633,17 @@ static void cryptd_hash_free(struct ahash_instance *inst)
 }
 
 static int cryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb,
+			      struct crypto_attr_type *algt,
 			      struct cryptd_queue *queue)
 {
 	struct hashd_instance_ctx *ctx;
 	struct ahash_instance *inst;
 	struct shash_alg *alg;
-	u32 type = 0;
-	u32 mask = 0;
+	u32 type;
+	u32 mask;
 	int err;
 
-	cryptd_check_internal(tb, &type, &mask);
+	cryptd_type_and_mask(algt, &type, &mask);
 
 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 	if (!inst)
@@ -661,10 +662,9 @@ static int cryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb,
 	if (err)
 		goto err_free_inst;
 
-	inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC |
-		(alg->base.cra_flags & (CRYPTO_ALG_INTERNAL |
+	inst->alg.halg.base.cra_flags |= CRYPTO_ALG_ASYNC |
+		(alg->base.cra_flags & (CRYPTO_ALG_INTERNAL|
 					CRYPTO_ALG_OPTIONAL_KEY));
-
 	inst->alg.halg.digestsize = alg->digestsize;
 	inst->alg.halg.statesize = alg->statesize;
 	inst->alg.halg.base.cra_ctxsize = sizeof(struct cryptd_hash_ctx);
@@ -820,16 +820,17 @@ static void cryptd_aead_free(struct aead_instance *inst)
 
 static int cryptd_create_aead(struct crypto_template *tmpl,
 		              struct rtattr **tb,
+			      struct crypto_attr_type *algt,
 			      struct cryptd_queue *queue)
 {
 	struct aead_instance_ctx *ctx;
 	struct aead_instance *inst;
 	struct aead_alg *alg;
-	u32 type = 0;
-	u32 mask = CRYPTO_ALG_ASYNC;
+	u32 type;
+	u32 mask;
 	int err;
 
-	cryptd_check_internal(tb, &type, &mask);
+	cryptd_type_and_mask(algt, &type, &mask);
 
 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 	if (!inst)
@@ -848,8 +849,8 @@ static int cryptd_create_aead(struct crypto_template *tmpl,
 	if (err)
 		goto err_free_inst;
 
-	inst->alg.base.cra_flags = CRYPTO_ALG_ASYNC |
-				   (alg->base.cra_flags & CRYPTO_ALG_INTERNAL);
+	inst->alg.base.cra_flags |= CRYPTO_ALG_ASYNC |
+		(alg->base.cra_flags & CRYPTO_ALG_INTERNAL);
 	inst->alg.base.cra_ctxsize = sizeof(struct cryptd_aead_ctx);
 
 	inst->alg.ivsize = crypto_aead_alg_ivsize(alg);
@@ -884,11 +885,11 @@ static int cryptd_create(struct crypto_template *tmpl, struct rtattr **tb)
 
 	switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
 	case CRYPTO_ALG_TYPE_SKCIPHER:
-		return cryptd_create_skcipher(tmpl, tb, &queue);
+		return cryptd_create_skcipher(tmpl, tb, algt, &queue);
 	case CRYPTO_ALG_TYPE_HASH:
-		return cryptd_create_hash(tmpl, tb, &queue);
+		return cryptd_create_hash(tmpl, tb, algt, &queue);
 	case CRYPTO_ALG_TYPE_AEAD:
-		return cryptd_create_aead(tmpl, tb, &queue);
+		return cryptd_create_aead(tmpl, tb, algt, &queue);
 	}
 
 	return -EINVAL;