crypto: user - Allow CRYPTO_MSG_GETALG without CAP_NET_ADMIN

CRYPTO_USER requires CAP_NET_ADMIN for all operations. Most information
provided by CRYPTO_MSG_GETALG is also accessible through /proc/modules
and AF_ALG. CRYPTO_MSG_GETALG should not require CAP_NET_ADMIN so that
processes without CAP_NET_ADMIN can use CRYPTO_MSG_GETALG to get cipher
details, such as cipher priorities, for AF_ALG.

Signed-off-by: Matthias-Christian Ott <ott@mirix.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Author: ott

crypto/crypto_user.c

@@ -265,6 +265,9 @@ static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 	LIST_HEAD(list);
 
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 		return -EINVAL;
 
@@ -295,6 +298,9 @@ static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 	struct crypto_alg *alg;
 	struct crypto_user_alg *p = nlmsg_data(nlh);
 
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 		return -EINVAL;
 
@@ -379,6 +385,9 @@ static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 	struct crypto_user_alg *p = nlmsg_data(nlh);
 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 		return -EINVAL;
 
@@ -466,9 +475,6 @@ static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	type -= CRYPTO_MSG_BASE;
 	link = &crypto_dispatch[type];
 
-	if (!capable(CAP_NET_ADMIN))
-		return -EPERM;
-
 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
 		struct crypto_alg *alg;