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, 5 insertions, 9 deletions

diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
index 8bddc65cd509..cbc383a1a3fe 100644
--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -226,18 +226,14 @@ static int pcrypt_init_instance(struct crypto_instance *inst,
 }
 
 static int pcrypt_create_aead(struct crypto_template *tmpl, struct rtattr **tb,
-			      u32 type, u32 mask)
+			      struct crypto_attr_type *algt)
 {
 	struct pcrypt_instance_ctx *ctx;
-	struct crypto_attr_type *algt;
 	struct aead_instance *inst;
 	struct aead_alg *alg;
+	u32 mask = crypto_algt_inherited_mask(algt);
 	int err;
 
-	algt = crypto_get_attr_type(tb);
-	if (IS_ERR(algt))
-		return PTR_ERR(algt);
-
 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 	if (!inst)
 		return -ENOMEM;
@@ -254,7 +250,7 @@ static int pcrypt_create_aead(struct crypto_template *tmpl, struct rtattr **tb,
 		goto err_free_inst;
 
 	err = crypto_grab_aead(&ctx->spawn, aead_crypto_instance(inst),
-			       crypto_attr_alg_name(tb[1]), 0, 0);
+			       crypto_attr_alg_name(tb[1]), 0, mask);
 	if (err)
 		goto err_free_inst;
 
@@ -263,7 +259,7 @@ static int pcrypt_create_aead(struct crypto_template *tmpl, struct rtattr **tb,
 	if (err)
 		goto err_free_inst;
 
-	inst->alg.base.cra_flags = CRYPTO_ALG_ASYNC;
+	inst->alg.base.cra_flags |= CRYPTO_ALG_ASYNC;
 
 	inst->alg.ivsize = crypto_aead_alg_ivsize(alg);
 	inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg);
@@ -298,7 +294,7 @@ static int pcrypt_create(struct crypto_template *tmpl, struct rtattr **tb)
 
 	switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
 	case CRYPTO_ALG_TYPE_AEAD:
-		return pcrypt_create_aead(tmpl, tb, algt->type, algt->mask);
+		return pcrypt_create_aead(tmpl, tb, algt);
 	}
 
 	return -EINVAL;