[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both

Provide AF_RXRPC sockets that can be used to talk to AFS servers, or serve
answers to AFS clients.  KerberosIV security is fully supported.  The patches
and some example test programs can be found in:

	http://people.redhat.com/~dhowells/rxrpc/

This will eventually replace the old implementation of kernel-only RxRPC
currently resident in net/rxrpc/.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 334 insertions, 0 deletions

diff --git a/net/rxrpc/ar-key.c b/net/rxrpc/ar-key.c
new file mode 100644
index 000000000000..7e049ff6ae60
--- /dev/null
+++ b/net/rxrpc/ar-key.c
@@ -0,0 +1,334 @@
+/* RxRPC key management
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * RxRPC keys should have a description of describing their purpose:
+ *      "afs@CAMBRIDGE.REDHAT.COM>
+ */
+
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/key.h>
+#include <linux/crypto.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include <keys/rxrpc-type.h>
+#include <keys/user-type.h>
+#include "ar-internal.h"
+
+static int rxrpc_instantiate(struct key *, const void *, size_t);
+static int rxrpc_instantiate_s(struct key *, const void *, size_t);
+static void rxrpc_destroy(struct key *);
+static void rxrpc_destroy_s(struct key *);
+static void rxrpc_describe(const struct key *, struct seq_file *);
+
+/*
+ * rxrpc defined keys take an arbitrary string as the description and an
+ * arbitrary blob of data as the payload
+ */
+struct key_type key_type_rxrpc = {
+        .name           = "rxrpc",
+        .instantiate    = rxrpc_instantiate,
+        .match          = user_match,
+        .destroy        = rxrpc_destroy,
+        .describe       = rxrpc_describe,
+};
+
+EXPORT_SYMBOL(key_type_rxrpc);
+
+/*
+ * rxrpc server defined keys take "<serviceId>:<securityIndex>" as the
+ * description and an 8-byte decryption key as the payload
+ */
+struct key_type key_type_rxrpc_s = {
+        .name           = "rxrpc_s",
+        .instantiate    = rxrpc_instantiate_s,
+        .match          = user_match,
+        .destroy        = rxrpc_destroy_s,
+        .describe       = rxrpc_describe,
+};
+
+/*
+ * instantiate an rxrpc defined key
+ * data should be of the form:
+ *      OFFSET  LEN     CONTENT
+ *      0       4       key interface version number
+ *      4       2       security index (type)
+ *      6       2       ticket length
+ *      8       4       key expiry time (time_t)
+ *      12      4       kvno
+ *      16      8       session key
+ *      24      [len]   ticket
+ *
+ * if no data is provided, then a no-security key is made
+ */
+static int rxrpc_instantiate(struct key *key, const void *data, size_t datalen)
+{
+        const struct rxkad_key *tsec;
+        struct rxrpc_key_payload *upayload;
+        size_t plen;
+        u32 kver;
+        int ret;
+
+        _enter("{%x},,%zu", key_serial(key), datalen);
+
+        /* handle a no-security key */
+        if (!data && datalen == 0)
+                return 0;
+
+        /* get the key interface version number */
+        ret = -EINVAL;
+        if (datalen <= 4 || !data)
+                goto error;
+        memcpy(&kver, data, sizeof(kver));
+        data += sizeof(kver);
+        datalen -= sizeof(kver);
+
+        _debug("KEY I/F VERSION: %u", kver);
+
+        ret = -EKEYREJECTED;
+        if (kver != 1)
+                goto error;
+
+        /* deal with a version 1 key */
+        ret = -EINVAL;
+        if (datalen < sizeof(*tsec))
+                goto error;
+
+        tsec = data;
+        if (datalen != sizeof(*tsec) + tsec->ticket_len)
+                goto error;
+
+        _debug("SCIX: %u", tsec->security_index);
+        _debug("TLEN: %u", tsec->ticket_len);
+        _debug("EXPY: %x", tsec->expiry);
+        _debug("KVNO: %u", tsec->kvno);
+        _debug("SKEY: %02x%02x%02x%02x%02x%02x%02x%02x",
+               tsec->session_key[0], tsec->session_key[1],
+               tsec->session_key[2], tsec->session_key[3],
+               tsec->session_key[4], tsec->session_key[5],
+               tsec->session_key[6], tsec->session_key[7]);
+        if (tsec->ticket_len >= 8)
+                _debug("TCKT: %02x%02x%02x%02x%02x%02x%02x%02x",
+                       tsec->ticket[0], tsec->ticket[1],
+                       tsec->ticket[2], tsec->ticket[3],
+                       tsec->ticket[4], tsec->ticket[5],
+                       tsec->ticket[6], tsec->ticket[7]);
+
+        ret = -EPROTONOSUPPORT;
+        if (tsec->security_index != 2)
+                goto error;
+
+        key->type_data.x[0] = tsec->security_index;
+
+        plen = sizeof(*upayload) + tsec->ticket_len;
+        ret = key_payload_reserve(key, plen);
+        if (ret < 0)
+                goto error;
+
+        ret = -ENOMEM;
+        upayload = kmalloc(plen, GFP_KERNEL);
+        if (!upayload)
+                goto error;
+
+        /* attach the data */
+        memcpy(&upayload->k, tsec, sizeof(*tsec));
+        memcpy(&upayload->k.ticket, (void *)tsec + sizeof(*tsec),
+               tsec->ticket_len);
+        key->payload.data = upayload;
+        key->expiry = tsec->expiry;
+        ret = 0;
+
+error:
+        return ret;
+}
+
+/*
+ * instantiate a server secret key
+ * data should be a pointer to the 8-byte secret key
+ */
+static int rxrpc_instantiate_s(struct key *key, const void *data,
+                               size_t datalen)
+{
+        struct crypto_blkcipher *ci;
+
+        _enter("{%x},,%zu", key_serial(key), datalen);
+
+        if (datalen != 8)
+                return -EINVAL;
+
+        memcpy(&key->type_data, data, 8);
+
+        ci = crypto_alloc_blkcipher("pcbc(des)", 0, CRYPTO_ALG_ASYNC);
+        if (IS_ERR(ci)) {
+                _leave(" = %ld", PTR_ERR(ci));
+                return PTR_ERR(ci);
+        }
+
+        if (crypto_blkcipher_setkey(ci, data, 8) < 0)
+                BUG();
+
+        key->payload.data = ci;
+        _leave(" = 0");
+        return 0;
+}
+
+/*
+ * dispose of the data dangling from the corpse of a rxrpc key
+ */
+static void rxrpc_destroy(struct key *key)
+{
+        kfree(key->payload.data);
+}
+
+/*
+ * dispose of the data dangling from the corpse of a rxrpc key
+ */
+static void rxrpc_destroy_s(struct key *key)
+{
+        if (key->payload.data) {
+                crypto_free_blkcipher(key->payload.data);
+                key->payload.data = NULL;
+        }
+}
+
+/*
+ * describe the rxrpc key
+ */
+static void rxrpc_describe(const struct key *key, struct seq_file *m)
+{
+        seq_puts(m, key->description);
+}
+
+/*
+ * grab the security key for a socket
+ */
+int rxrpc_request_key(struct rxrpc_sock *rx, char __user *optval, int optlen)
+{
+        struct key *key;
+        char *description;
+
+        _enter("");
+
+        if (optlen <= 0 || optlen > PAGE_SIZE - 1)
+                return -EINVAL;
+
+        description = kmalloc(optlen + 1, GFP_KERNEL);
+        if (!description)
+                return -ENOMEM;
+
+        if (copy_from_user(description, optval, optlen)) {
+                kfree(description);
+                return -EFAULT;
+        }
+        description[optlen] = 0;
+
+        key = request_key(&key_type_rxrpc, description, NULL);
+        if (IS_ERR(key)) {
+                kfree(description);
+                _leave(" = %ld", PTR_ERR(key));
+                return PTR_ERR(key);
+        }
+
+        rx->key = key;
+        kfree(description);
+        _leave(" = 0 [key %x]", key->serial);
+        return 0;
+}
+
+/*
+ * grab the security keyring for a server socket
+ */
+int rxrpc_server_keyring(struct rxrpc_sock *rx, char __user *optval,
+                         int optlen)
+{
+        struct key *key;
+        char *description;
+
+        _enter("");
+
+        if (optlen <= 0 || optlen > PAGE_SIZE - 1)
+                return -EINVAL;
+
+        description = kmalloc(optlen + 1, GFP_KERNEL);
+        if (!description)
+                return -ENOMEM;
+
+        if (copy_from_user(description, optval, optlen)) {
+                kfree(description);
+                return -EFAULT;
+        }
+        description[optlen] = 0;
+
+        key = request_key(&key_type_keyring, description, NULL);
+        if (IS_ERR(key)) {
+                kfree(description);
+                _leave(" = %ld", PTR_ERR(key));
+                return PTR_ERR(key);
+        }
+
+        rx->securities = key;
+        kfree(description);
+        _leave(" = 0 [key %x]", key->serial);
+        return 0;
+}
+
+/*
+ * generate a server data key
+ */
+int rxrpc_get_server_data_key(struct rxrpc_connection *conn,
+                              const void *session_key,
+                              time_t expiry,
+                              u32 kvno)
+{
+        struct key *key;
+        int ret;
+
+        struct {
+                u32 kver;
+                struct rxkad_key tsec;
+        } data;
+
+        _enter("");
+
+        key = key_alloc(&key_type_rxrpc, "x", 0, 0, current, 0,
+                        KEY_ALLOC_NOT_IN_QUOTA);
+        if (IS_ERR(key)) {
+                _leave(" = -ENOMEM [alloc %ld]", PTR_ERR(key));
+                return -ENOMEM;
+        }
+
+        _debug("key %d", key_serial(key));
+
+        data.kver = 1;
+        data.tsec.security_index = 2;
+        data.tsec.ticket_len = 0;
+        data.tsec.expiry = expiry;
+        data.tsec.kvno = 0;
+
+        memcpy(&data.tsec.session_key, session_key,
+               sizeof(data.tsec.session_key));
+
+        ret = key_instantiate_and_link(key, &data, sizeof(data), NULL, NULL);
+        if (ret < 0)
+                goto error;
+
+        conn->key = key;
+        _leave(" = 0 [%d]", key_serial(key));
+        return 0;
+
+error:
+        key_revoke(key);
+        key_put(key);
+        _leave(" = -ENOMEM [ins %d]", ret);
+        return -ENOMEM;
+}
+
+EXPORT_SYMBOL(rxrpc_get_server_data_key);