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Subject[PATCH 8/9] keys: Network namespace domain tag [ver #4]
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Create key domain tags for network namespaces and make it possible to
automatically tag keys that are used by networked services (e.g. AF_RXRPC,
AFS, DNS) with the default network namespace if not set by the caller.

This allows keys with the same description but in different namespaces to
coexist within a keyring.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: netdev@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-afs@lists.infradead.org
---

include/linux/key-type.h | 3 +++
include/net/net_namespace.h | 3 +++
net/core/net_namespace.c | 19 +++++++++++++++++++
net/dns_resolver/dns_key.c | 1 +
net/rxrpc/key.c | 2 ++
security/keys/keyring.c | 7 ++++++-
6 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/include/linux/key-type.h b/include/linux/key-type.h
index e49d1de0614e..2148a6bf58f1 100644
--- a/include/linux/key-type.h
+++ b/include/linux/key-type.h
@@ -74,6 +74,9 @@ struct key_type {
*/
size_t def_datalen;

+ unsigned int flags;
+#define KEY_TYPE_NET_DOMAIN 0x00000001 /* Keys of this type have a net namespace domain */
+
/* vet a description */
int (*vet_description)(const char *description);

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 12689ddfc24c..a56bf7fc7c2b 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -71,6 +71,9 @@ struct net {
*/
struct llist_node cleanup_list; /* namespaces on death row */

+#ifdef CONFIG_KEYS
+ struct key_tag *key_domain; /* Key domain of operation tag */
+#endif
struct user_namespace *user_ns; /* Owning user namespace */
struct ucounts *ucounts;
spinlock_t nsid_lock;
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 711b161505ac..076a75c73c9e 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -38,9 +38,16 @@ EXPORT_SYMBOL_GPL(net_namespace_list);
DECLARE_RWSEM(net_rwsem);
EXPORT_SYMBOL_GPL(net_rwsem);

+#ifdef CONFIG_KEYS
+static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) };
+#endif
+
struct net init_net = {
.count = REFCOUNT_INIT(1),
.dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
+#ifdef CONFIG_KEYS
+ .key_domain = &init_net_key_domain,
+#endif
};
EXPORT_SYMBOL(init_net);

@@ -386,10 +393,21 @@ static struct net *net_alloc(void)
if (!net)
goto out_free;

+#ifdef CONFIG_KEYS
+ net->key_domain = kzalloc(sizeof(struct key_tag), GFP_KERNEL);
+ if (!net->key_domain)
+ goto out_free_2;
+ refcount_set(&net->key_domain->usage, 1);
+#endif
+
rcu_assign_pointer(net->gen, ng);
out:
return net;

+#ifdef CONFIG_KEYS
+out_free_2:
+ kmem_cache_free(net_cachep, net);
+#endif
out_free:
kfree(ng);
goto out;
@@ -566,6 +584,7 @@ static void cleanup_net(struct work_struct *work)
list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
list_del_init(&net->exit_list);
dec_net_namespaces(net->ucounts);
+ key_remove_domain(net->key_domain);
put_user_ns(net->user_ns);
net_drop_ns(net);
}
diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
index a65d553e730d..3e1a90669006 100644
--- a/net/dns_resolver/dns_key.c
+++ b/net/dns_resolver/dns_key.c
@@ -314,6 +314,7 @@ static long dns_resolver_read(const struct key *key,

struct key_type key_type_dns_resolver = {
.name = "dns_resolver",
+ .flags = KEY_TYPE_NET_DOMAIN,
.preparse = dns_resolver_preparse,
.free_preparse = dns_resolver_free_preparse,
.instantiate = generic_key_instantiate,
diff --git a/net/rxrpc/key.c b/net/rxrpc/key.c
index e7f6b8823eb6..2722189ec273 100644
--- a/net/rxrpc/key.c
+++ b/net/rxrpc/key.c
@@ -43,6 +43,7 @@ static long rxrpc_read(const struct key *, char __user *, size_t);
*/
struct key_type key_type_rxrpc = {
.name = "rxrpc",
+ .flags = KEY_TYPE_NET_DOMAIN,
.preparse = rxrpc_preparse,
.free_preparse = rxrpc_free_preparse,
.instantiate = generic_key_instantiate,
@@ -58,6 +59,7 @@ EXPORT_SYMBOL(key_type_rxrpc);
*/
struct key_type key_type_rxrpc_s = {
.name = "rxrpc_s",
+ .flags = KEY_TYPE_NET_DOMAIN,
.vet_description = rxrpc_vet_description_s,
.preparse = rxrpc_preparse_s,
.free_preparse = rxrpc_free_preparse_s,
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index d3c86fda1510..bca070f6ab46 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -17,10 +17,12 @@
#include <linux/seq_file.h>
#include <linux/err.h>
#include <linux/user_namespace.h>
+#include <linux/nsproxy.h>
#include <keys/keyring-type.h>
#include <keys/user-type.h>
#include <linux/assoc_array_priv.h>
#include <linux/uaccess.h>
+#include <net/net_namespace.h>
#include "internal.h"

/*
@@ -220,7 +222,10 @@ void key_set_index_key(struct keyring_index_key *index_key)

memcpy(index_key->desc, index_key->description, n);

- index_key->domain_tag = &default_domain_tag;
+ if (index_key->type->flags & KEY_TYPE_NET_DOMAIN)
+ index_key->domain_tag = current->nsproxy->net_ns->key_domain;
+ else
+ index_key->domain_tag = &default_domain_tag;
hash_key_type_and_desc(index_key);
}

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