crypto: Add userspace configuration API

This patch adds a basic userspace configuration API for the crypto layer.
With this it is possible to instantiate, remove and to show crypto
algorithms from userspace.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 404a846..a8442dc 100644 (file)
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -100,6 +100,13 @@ config CRYPTO_MANAGER2
        select CRYPTO_BLKCIPHER2
        select CRYPTO_PCOMP2
 
+config CRYPTO_USER
+       tristate "Userspace cryptographic algorithm configuration"
+       select CRYPTO_MANAGER
+       help
+         Userapace configuration for cryptographic instantiations such as
+         cbc(aes).
+
 config CRYPTO_MANAGER_DISABLE_TESTS
        bool "Disable run-time self tests"
        default y

diff --git a/crypto/Makefile b/crypto/Makefile
index fa8cbbb..9e6eee2 100644 (file)
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_CRYPTO_PCOMP2) += pcompress.o
 cryptomgr-y := algboss.o testmgr.o
 
 obj-$(CONFIG_CRYPTO_MANAGER2) += cryptomgr.o
+obj-$(CONFIG_CRYPTO_USER) += crypto_user.o
 obj-$(CONFIG_CRYPTO_HMAC) += hmac.o
 obj-$(CONFIG_CRYPTO_VMAC) += vmac.o
 obj-$(CONFIG_CRYPTO_XCBC) += xcbc.o

diff --git a/crypto/crypto_user.c b/crypto/crypto_user.c
new file mode 100644 (file)
index 0000000..513cfe7
--- /dev/null
+++ b/crypto/crypto_user.c
@@ -0,0 +1,372 @@
+/*
+ * Crypto user configuration API.
+ *
+ * Copyright (C) 2011 secunet Security Networks AG
+ * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <linux/module.h>
+#include <linux/crypto.h>
+#include <linux/cryptouser.h>
+#include <net/netlink.h>
+#include <linux/security.h>
+#include <net/net_namespace.h>
+#include "internal.h"
+
+DEFINE_MUTEX(crypto_cfg_mutex);
+
+/* The crypto netlink socket */
+static struct sock *crypto_nlsk;
+
+struct crypto_dump_info {
+       struct sk_buff *in_skb;
+       struct sk_buff *out_skb;
+       u32 nlmsg_seq;
+       u16 nlmsg_flags;
+};
+
+static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
+{
+       int match;
+       struct crypto_alg *q, *alg = NULL;
+
+       down_read(&crypto_alg_sem);
+
+       if (list_empty(&crypto_alg_list))
+               return NULL;
+
+       list_for_each_entry(q, &crypto_alg_list, cra_list) {
+
+               if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
+                       continue;
+
+               if (strlen(p->cru_driver_name))
+                       match = !strcmp(q->cra_driver_name,
+                                       p->cru_driver_name);
+               else if (!exact)
+                       match = !strcmp(q->cra_name, p->cru_name);
+
+               if (match) {
+                       alg = q;
+                       break;
+               }
+       }
+
+       up_read(&crypto_alg_sem);
+
+       return alg;
+}
+
+static int crypto_report_one(struct crypto_alg *alg,
+                            struct crypto_user_alg *ualg, struct sk_buff *skb)
+{
+       memcpy(&ualg->cru_name, &alg->cra_name, sizeof(ualg->cru_name));
+       memcpy(&ualg->cru_driver_name, &alg->cra_driver_name,
+              sizeof(ualg->cru_driver_name));
+       memcpy(&ualg->cru_module_name, module_name(alg->cra_module),
+              CRYPTO_MAX_ALG_NAME);
+
+       ualg->cru_flags = alg->cra_flags;
+       ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
+
+       NLA_PUT_U32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority);
+
+       return 0;
+
+nla_put_failure:
+       return -EMSGSIZE;
+}
+
+static int crypto_report_alg(struct crypto_alg *alg,
+                            struct crypto_dump_info *info)
+{
+       struct sk_buff *in_skb = info->in_skb;
+       struct sk_buff *skb = info->out_skb;
+       struct nlmsghdr *nlh;
+       struct crypto_user_alg *ualg;
+       int err = 0;
+
+       nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, info->nlmsg_seq,
+                       CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
+       if (!nlh) {
+               err = -EMSGSIZE;
+               goto out;
+       }
+
+       ualg = nlmsg_data(nlh);
+
+       err = crypto_report_one(alg, ualg, skb);
+       if (err) {
+               nlmsg_cancel(skb, nlh);
+               goto out;
+       }
+
+       nlmsg_end(skb, nlh);
+
+out:
+       return err;
+}
+
+static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
+                        struct nlattr **attrs)
+{
+       struct crypto_user_alg *p = nlmsg_data(in_nlh);
+       struct crypto_alg *alg;
+       struct sk_buff *skb;
+       struct crypto_dump_info info;
+       int err;
+
+       if (!p->cru_driver_name)
+               return -EINVAL;
+
+       alg = crypto_alg_match(p, 1);
+       if (!alg)
+               return -ENOENT;
+
+       skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+       if (!skb)
+               return -ENOMEM;
+
+       info.in_skb = in_skb;
+       info.out_skb = skb;
+       info.nlmsg_seq = in_nlh->nlmsg_seq;
+       info.nlmsg_flags = 0;
+
+       err = crypto_report_alg(alg, &info);
+       if (err)
+               return err;
+
+       return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid);
+}
+
+static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
+{
+       struct crypto_alg *alg;
+       struct crypto_dump_info info;
+       int err;
+
+       if (cb->args[0])
+               goto out;
+
+       cb->args[0] = 1;
+
+       info.in_skb = cb->skb;
+       info.out_skb = skb;
+       info.nlmsg_seq = cb->nlh->nlmsg_seq;
+       info.nlmsg_flags = NLM_F_MULTI;
+
+       list_for_each_entry(alg, &crypto_alg_list, cra_list) {
+               err = crypto_report_alg(alg, &info);
+               if (err)
+                       goto out_err;
+       }
+
+out:
+       return skb->len;
+out_err:
+       return err;
+}
+
+static int crypto_dump_report_done(struct netlink_callback *cb)
+{
+       return 0;
+}
+
+static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
+                            struct nlattr **attrs)
+{
+       struct crypto_alg *alg;
+       struct crypto_user_alg *p = nlmsg_data(nlh);
+       struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
+       LIST_HEAD(list);
+
+       if (priority && !strlen(p->cru_driver_name))
+               return -EINVAL;
+
+       alg = crypto_alg_match(p, 1);
+       if (!alg)
+               return -ENOENT;
+
+       down_write(&crypto_alg_sem);
+
+       crypto_remove_spawns(alg, &list, NULL);
+
+       if (priority)
+               alg->cra_priority = nla_get_u32(priority);
+
+       up_write(&crypto_alg_sem);
+
+       crypto_remove_final(&list);
+
+       return 0;
+}
+
+static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
+                         struct nlattr **attrs)
+{
+       struct crypto_alg *alg;
+       struct crypto_user_alg *p = nlmsg_data(nlh);
+
+       alg = crypto_alg_match(p, 1);
+       if (!alg)
+               return -ENOENT;
+
+       /* We can not unregister core algorithms such as aes-generic.
+        * We would loose the reference in the crypto_alg_list to this algorithm
+        * if we try to unregister. Unregistering such an algorithm without
+        * removing the module is not possible, so we restrict to crypto
+        * instances that are build from templates. */
+       if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
+               return -EINVAL;
+
+       if (atomic_read(&alg->cra_refcnt) != 1)
+               return -EBUSY;
+
+       return crypto_unregister_alg(alg);
+}
+
+static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
+                         struct nlattr **attrs)
+{
+       int exact;
+       const char *name;
+       struct crypto_alg *alg;
+       struct crypto_user_alg *p = nlmsg_data(nlh);
+       struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
+
+       if (strlen(p->cru_driver_name))
+               exact = 1;
+
+       if (priority && !exact)
+               return -EINVAL;
+
+       alg = crypto_alg_match(p, exact);
+       if (alg)
+               return -EEXIST;
+
+       if (strlen(p->cru_driver_name))
+               name = p->cru_driver_name;
+       else
+               name = p->cru_name;
+
+       alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
+       if (IS_ERR(alg))
+               return PTR_ERR(alg);
+
+       down_write(&crypto_alg_sem);
+
+       if (priority)
+               alg->cra_priority = nla_get_u32(priority);
+
+       up_write(&crypto_alg_sem);
+
+       crypto_mod_put(alg);
+
+       return 0;
+}
+
+#define MSGSIZE(type) sizeof(struct type)
+
+static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
+       [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
+       [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
+       [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
+       [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
+};
+
+static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
+       [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
+};
+
+#undef MSGSIZE
+
+static struct crypto_link {
+       int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
+       int (*dump)(struct sk_buff *, struct netlink_callback *);
+       int (*done)(struct netlink_callback *);
+} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
+       [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
+       [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
+       [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
+       [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
+                                                      .dump = crypto_dump_report,
+                                                      .done = crypto_dump_report_done},
+};
+
+static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+       struct nlattr *attrs[CRYPTOCFGA_MAX+1];
+       struct crypto_link *link;
+       int type, err;
+
+       type = nlh->nlmsg_type;
+       if (type > CRYPTO_MSG_MAX)
+               return -EINVAL;
+
+       type -= CRYPTO_MSG_BASE;
+       link = &crypto_dispatch[type];
+
+       if (security_netlink_recv(skb, CAP_NET_ADMIN))
+               return -EPERM;
+
+       if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
+           (nlh->nlmsg_flags & NLM_F_DUMP))) {
+               if (link->dump == NULL)
+                       return -EINVAL;
+
+               return netlink_dump_start(crypto_nlsk, skb, nlh,
+                                         link->dump, link->done, 0);
+       }
+
+       err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
+                         crypto_policy);
+       if (err < 0)
+               return err;
+
+       if (link->doit == NULL)
+               return -EINVAL;
+
+       return link->doit(skb, nlh, attrs);
+}
+
+static void crypto_netlink_rcv(struct sk_buff *skb)
+{
+       mutex_lock(&crypto_cfg_mutex);
+       netlink_rcv_skb(skb, &crypto_user_rcv_msg);
+       mutex_unlock(&crypto_cfg_mutex);
+}
+
+static int __init crypto_user_init(void)
+{
+       crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO,
+                                           0, crypto_netlink_rcv,
+                                           NULL, THIS_MODULE);
+       if (!crypto_nlsk)
+               return -ENOMEM;
+
+       return 0;
+}
+
+static void __exit crypto_user_exit(void)
+{
+       netlink_kernel_release(crypto_nlsk);
+}
+
+module_init(crypto_user_init);
+module_exit(crypto_user_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
+MODULE_DESCRIPTION("Crypto userspace configuration API");

diff --git a/include/linux/cryptouser.h b/include/linux/cryptouser.h
new file mode 100644 (file)
index 0000000..b874e38
--- /dev/null
+++ b/include/linux/cryptouser.h
@@ -0,0 +1,52 @@
+/*
+ * Crypto user configuration API.
+ *
+ * Copyright (C) 2011 secunet Security Networks AG
+ * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/* Netlink configuration messages.  */
+enum {
+       CRYPTO_MSG_BASE = 0x10,
+       CRYPTO_MSG_NEWALG = 0x10,
+       CRYPTO_MSG_DELALG,
+       CRYPTO_MSG_UPDATEALG,
+       CRYPTO_MSG_GETALG,
+       __CRYPTO_MSG_MAX
+};
+#define CRYPTO_MSG_MAX (__CRYPTO_MSG_MAX - 1)
+#define CRYPTO_NR_MSGTYPES (CRYPTO_MSG_MAX + 1 - CRYPTO_MSG_BASE)
+
+#define CRYPTO_MAX_NAME CRYPTO_MAX_ALG_NAME
+
+/* Netlink message attributes.  */
+enum crypto_attr_type_t {
+       CRYPTOCFGA_UNSPEC,
+       CRYPTOCFGA_PRIORITY_VAL,        /* __u32 */
+       __CRYPTOCFGA_MAX
+
+#define CRYPTOCFGA_MAX (__CRYPTOCFGA_MAX - 1)
+};
+
+struct crypto_user_alg {
+       char cru_name[CRYPTO_MAX_ALG_NAME];
+       char cru_driver_name[CRYPTO_MAX_ALG_NAME];
+       char cru_module_name[CRYPTO_MAX_ALG_NAME];
+       __u32 cru_type;
+       __u32 cru_mask;
+       __u32 cru_refcnt;
+       __u32 cru_flags;
+};

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 2e17c5d..464ace0 100644 (file)
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -25,6 +25,7 @@
 #define NETLINK_SCSITRANSPORT  18      /* SCSI Transports */
 #define NETLINK_ECRYPTFS       19
 #define NETLINK_RDMA           20
+#define NETLINK_CRYPTO         21      /* Crypto layer */
 
 #define MAX_LINKS 32