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-rw-r--r--net/rxrpc/rxkad.c1267
1 files changed, 1267 insertions, 0 deletions
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
new file mode 100644
index 0000000000..b52dedcebc
--- /dev/null
+++ b/net/rxrpc/rxkad.c
@@ -0,0 +1,1267 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Kerberos-based RxRPC security
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <crypto/skcipher.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/udp.h>
+#include <linux/scatterlist.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/key-type.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include <keys/rxrpc-type.h>
+#include "ar-internal.h"
+
+#define RXKAD_VERSION 2
+#define MAXKRB5TICKETLEN 1024
+#define RXKAD_TKT_TYPE_KERBEROS_V5 256
+#define ANAME_SZ 40 /* size of authentication name */
+#define INST_SZ 40 /* size of principal's instance */
+#define REALM_SZ 40 /* size of principal's auth domain */
+#define SNAME_SZ 40 /* size of service name */
+#define RXKAD_ALIGN 8
+
+struct rxkad_level1_hdr {
+ __be32 data_size; /* true data size (excluding padding) */
+};
+
+struct rxkad_level2_hdr {
+ __be32 data_size; /* true data size (excluding padding) */
+ __be32 checksum; /* decrypted data checksum */
+};
+
+static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
+ struct crypto_sync_skcipher *ci);
+
+/*
+ * this holds a pinned cipher so that keventd doesn't get called by the cipher
+ * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
+ * packets
+ */
+static struct crypto_sync_skcipher *rxkad_ci;
+static struct skcipher_request *rxkad_ci_req;
+static DEFINE_MUTEX(rxkad_ci_mutex);
+
+/*
+ * Parse the information from a server key
+ *
+ * The data should be the 8-byte secret key.
+ */
+static int rxkad_preparse_server_key(struct key_preparsed_payload *prep)
+{
+ struct crypto_skcipher *ci;
+
+ if (prep->datalen != 8)
+ return -EINVAL;
+
+ memcpy(&prep->payload.data[2], prep->data, 8);
+
+ ci = crypto_alloc_skcipher("pcbc(des)", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(ci)) {
+ _leave(" = %ld", PTR_ERR(ci));
+ return PTR_ERR(ci);
+ }
+
+ if (crypto_skcipher_setkey(ci, prep->data, 8) < 0)
+ BUG();
+
+ prep->payload.data[0] = ci;
+ _leave(" = 0");
+ return 0;
+}
+
+static void rxkad_free_preparse_server_key(struct key_preparsed_payload *prep)
+{
+
+ if (prep->payload.data[0])
+ crypto_free_skcipher(prep->payload.data[0]);
+}
+
+static void rxkad_destroy_server_key(struct key *key)
+{
+ if (key->payload.data[0]) {
+ crypto_free_skcipher(key->payload.data[0]);
+ key->payload.data[0] = NULL;
+ }
+}
+
+/*
+ * initialise connection security
+ */
+static int rxkad_init_connection_security(struct rxrpc_connection *conn,
+ struct rxrpc_key_token *token)
+{
+ struct crypto_sync_skcipher *ci;
+ int ret;
+
+ _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
+
+ conn->security_ix = token->security_index;
+
+ ci = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
+ if (IS_ERR(ci)) {
+ _debug("no cipher");
+ ret = PTR_ERR(ci);
+ goto error;
+ }
+
+ if (crypto_sync_skcipher_setkey(ci, token->kad->session_key,
+ sizeof(token->kad->session_key)) < 0)
+ BUG();
+
+ switch (conn->security_level) {
+ case RXRPC_SECURITY_PLAIN:
+ case RXRPC_SECURITY_AUTH:
+ case RXRPC_SECURITY_ENCRYPT:
+ break;
+ default:
+ ret = -EKEYREJECTED;
+ goto error;
+ }
+
+ ret = rxkad_prime_packet_security(conn, ci);
+ if (ret < 0)
+ goto error_ci;
+
+ conn->rxkad.cipher = ci;
+ return 0;
+
+error_ci:
+ crypto_free_sync_skcipher(ci);
+error:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Work out how much data we can put in a packet.
+ */
+static int rxkad_how_much_data(struct rxrpc_call *call, size_t remain,
+ size_t *_buf_size, size_t *_data_size, size_t *_offset)
+{
+ size_t shdr, buf_size, chunk;
+
+ switch (call->conn->security_level) {
+ default:
+ buf_size = chunk = min_t(size_t, remain, RXRPC_JUMBO_DATALEN);
+ shdr = 0;
+ goto out;
+ case RXRPC_SECURITY_AUTH:
+ shdr = sizeof(struct rxkad_level1_hdr);
+ break;
+ case RXRPC_SECURITY_ENCRYPT:
+ shdr = sizeof(struct rxkad_level2_hdr);
+ break;
+ }
+
+ buf_size = round_down(RXRPC_JUMBO_DATALEN, RXKAD_ALIGN);
+
+ chunk = buf_size - shdr;
+ if (remain < chunk)
+ buf_size = round_up(shdr + remain, RXKAD_ALIGN);
+
+out:
+ *_buf_size = buf_size;
+ *_data_size = chunk;
+ *_offset = shdr;
+ return 0;
+}
+
+/*
+ * prime the encryption state with the invariant parts of a connection's
+ * description
+ */
+static int rxkad_prime_packet_security(struct rxrpc_connection *conn,
+ struct crypto_sync_skcipher *ci)
+{
+ struct skcipher_request *req;
+ struct rxrpc_key_token *token;
+ struct scatterlist sg;
+ struct rxrpc_crypt iv;
+ __be32 *tmpbuf;
+ size_t tmpsize = 4 * sizeof(__be32);
+
+ _enter("");
+
+ if (!conn->key)
+ return 0;
+
+ tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
+ if (!tmpbuf)
+ return -ENOMEM;
+
+ req = skcipher_request_alloc(&ci->base, GFP_NOFS);
+ if (!req) {
+ kfree(tmpbuf);
+ return -ENOMEM;
+ }
+
+ token = conn->key->payload.data[0];
+ memcpy(&iv, token->kad->session_key, sizeof(iv));
+
+ tmpbuf[0] = htonl(conn->proto.epoch);
+ tmpbuf[1] = htonl(conn->proto.cid);
+ tmpbuf[2] = 0;
+ tmpbuf[3] = htonl(conn->security_ix);
+
+ sg_init_one(&sg, tmpbuf, tmpsize);
+ skcipher_request_set_sync_tfm(req, ci);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
+ crypto_skcipher_encrypt(req);
+ skcipher_request_free(req);
+
+ memcpy(&conn->rxkad.csum_iv, tmpbuf + 2, sizeof(conn->rxkad.csum_iv));
+ kfree(tmpbuf);
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * Allocate and prepare the crypto request on a call. For any particular call,
+ * this is called serially for the packets, so no lock should be necessary.
+ */
+static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
+{
+ struct crypto_skcipher *tfm = &call->conn->rxkad.cipher->base;
+
+ return skcipher_request_alloc(tfm, GFP_NOFS);
+}
+
+/*
+ * Clean up the crypto on a call.
+ */
+static void rxkad_free_call_crypto(struct rxrpc_call *call)
+{
+}
+
+/*
+ * partially encrypt a packet (level 1 security)
+ */
+static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
+ struct rxrpc_txbuf *txb,
+ struct skcipher_request *req)
+{
+ struct rxkad_level1_hdr *hdr = (void *)txb->data;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg;
+ size_t pad;
+ u16 check;
+
+ _enter("");
+
+ check = txb->seq ^ ntohl(txb->wire.callNumber);
+ hdr->data_size = htonl((u32)check << 16 | txb->len);
+
+ txb->len += sizeof(struct rxkad_level1_hdr);
+ pad = txb->len;
+ pad = RXKAD_ALIGN - pad;
+ pad &= RXKAD_ALIGN - 1;
+ if (pad) {
+ memset(txb->data + txb->offset, 0, pad);
+ txb->len += pad;
+ }
+
+ /* start the encryption afresh */
+ memset(&iv, 0, sizeof(iv));
+
+ sg_init_one(&sg, txb->data, 8);
+ skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
+ crypto_skcipher_encrypt(req);
+ skcipher_request_zero(req);
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * wholly encrypt a packet (level 2 security)
+ */
+static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
+ struct rxrpc_txbuf *txb,
+ struct skcipher_request *req)
+{
+ const struct rxrpc_key_token *token;
+ struct rxkad_level2_hdr *rxkhdr = (void *)txb->data;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg;
+ size_t pad;
+ u16 check;
+ int ret;
+
+ _enter("");
+
+ check = txb->seq ^ ntohl(txb->wire.callNumber);
+
+ rxkhdr->data_size = htonl(txb->len | (u32)check << 16);
+ rxkhdr->checksum = 0;
+
+ txb->len += sizeof(struct rxkad_level2_hdr);
+ pad = txb->len;
+ pad = RXKAD_ALIGN - pad;
+ pad &= RXKAD_ALIGN - 1;
+ if (pad) {
+ memset(txb->data + txb->offset, 0, pad);
+ txb->len += pad;
+ }
+
+ /* encrypt from the session key */
+ token = call->conn->key->payload.data[0];
+ memcpy(&iv, token->kad->session_key, sizeof(iv));
+
+ sg_init_one(&sg, txb->data, txb->len);
+ skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, &sg, &sg, txb->len, iv.x);
+ ret = crypto_skcipher_encrypt(req);
+ skcipher_request_zero(req);
+ return ret;
+}
+
+/*
+ * checksum an RxRPC packet header
+ */
+static int rxkad_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
+{
+ struct skcipher_request *req;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg;
+ union {
+ __be32 buf[2];
+ } crypto __aligned(8);
+ u32 x, y;
+ int ret;
+
+ _enter("{%d{%x}},{#%u},%u,",
+ call->debug_id, key_serial(call->conn->key),
+ txb->seq, txb->len);
+
+ if (!call->conn->rxkad.cipher)
+ return 0;
+
+ ret = key_validate(call->conn->key);
+ if (ret < 0)
+ return ret;
+
+ req = rxkad_get_call_crypto(call);
+ if (!req)
+ return -ENOMEM;
+
+ /* continue encrypting from where we left off */
+ memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
+
+ /* calculate the security checksum */
+ x = (ntohl(txb->wire.cid) & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
+ x |= txb->seq & 0x3fffffff;
+ crypto.buf[0] = txb->wire.callNumber;
+ crypto.buf[1] = htonl(x);
+
+ sg_init_one(&sg, crypto.buf, 8);
+ skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
+ crypto_skcipher_encrypt(req);
+ skcipher_request_zero(req);
+
+ y = ntohl(crypto.buf[1]);
+ y = (y >> 16) & 0xffff;
+ if (y == 0)
+ y = 1; /* zero checksums are not permitted */
+ txb->wire.cksum = htons(y);
+
+ switch (call->conn->security_level) {
+ case RXRPC_SECURITY_PLAIN:
+ ret = 0;
+ break;
+ case RXRPC_SECURITY_AUTH:
+ ret = rxkad_secure_packet_auth(call, txb, req);
+ break;
+ case RXRPC_SECURITY_ENCRYPT:
+ ret = rxkad_secure_packet_encrypt(call, txb, req);
+ break;
+ default:
+ ret = -EPERM;
+ break;
+ }
+
+ skcipher_request_free(req);
+ _leave(" = %d [set %x]", ret, y);
+ return ret;
+}
+
+/*
+ * decrypt partial encryption on a packet (level 1 security)
+ */
+static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
+ rxrpc_seq_t seq,
+ struct skcipher_request *req)
+{
+ struct rxkad_level1_hdr sechdr;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxrpc_crypt iv;
+ struct scatterlist sg[16];
+ u32 data_size, buf;
+ u16 check;
+ int ret;
+
+ _enter("");
+
+ if (sp->len < 8)
+ return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
+ rxkad_abort_1_short_header);
+
+ /* Decrypt the skbuff in-place. TODO: We really want to decrypt
+ * directly into the target buffer.
+ */
+ sg_init_table(sg, ARRAY_SIZE(sg));
+ ret = skb_to_sgvec(skb, sg, sp->offset, 8);
+ if (unlikely(ret < 0))
+ return ret;
+
+ /* start the decryption afresh */
+ memset(&iv, 0, sizeof(iv));
+
+ skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
+ crypto_skcipher_decrypt(req);
+ skcipher_request_zero(req);
+
+ /* Extract the decrypted packet length */
+ if (skb_copy_bits(skb, sp->offset, &sechdr, sizeof(sechdr)) < 0)
+ return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
+ rxkad_abort_1_short_encdata);
+ sp->offset += sizeof(sechdr);
+ sp->len -= sizeof(sechdr);
+
+ buf = ntohl(sechdr.data_size);
+ data_size = buf & 0xffff;
+
+ check = buf >> 16;
+ check ^= seq ^ call->call_id;
+ check &= 0xffff;
+ if (check != 0)
+ return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
+ rxkad_abort_1_short_check);
+ if (data_size > sp->len)
+ return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
+ rxkad_abort_1_short_data);
+ sp->len = data_size;
+
+ _leave(" = 0 [dlen=%x]", data_size);
+ return 0;
+}
+
+/*
+ * wholly decrypt a packet (level 2 security)
+ */
+static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
+ rxrpc_seq_t seq,
+ struct skcipher_request *req)
+{
+ const struct rxrpc_key_token *token;
+ struct rxkad_level2_hdr sechdr;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxrpc_crypt iv;
+ struct scatterlist _sg[4], *sg;
+ u32 data_size, buf;
+ u16 check;
+ int nsg, ret;
+
+ _enter(",{%d}", sp->len);
+
+ if (sp->len < 8)
+ return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
+ rxkad_abort_2_short_header);
+
+ /* Decrypt the skbuff in-place. TODO: We really want to decrypt
+ * directly into the target buffer.
+ */
+ sg = _sg;
+ nsg = skb_shinfo(skb)->nr_frags + 1;
+ if (nsg <= 4) {
+ nsg = 4;
+ } else {
+ sg = kmalloc_array(nsg, sizeof(*sg), GFP_NOIO);
+ if (!sg)
+ return -ENOMEM;
+ }
+
+ sg_init_table(sg, nsg);
+ ret = skb_to_sgvec(skb, sg, sp->offset, sp->len);
+ if (unlikely(ret < 0)) {
+ if (sg != _sg)
+ kfree(sg);
+ return ret;
+ }
+
+ /* decrypt from the session key */
+ token = call->conn->key->payload.data[0];
+ memcpy(&iv, token->kad->session_key, sizeof(iv));
+
+ skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, sg, sg, sp->len, iv.x);
+ crypto_skcipher_decrypt(req);
+ skcipher_request_zero(req);
+ if (sg != _sg)
+ kfree(sg);
+
+ /* Extract the decrypted packet length */
+ if (skb_copy_bits(skb, sp->offset, &sechdr, sizeof(sechdr)) < 0)
+ return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
+ rxkad_abort_2_short_len);
+ sp->offset += sizeof(sechdr);
+ sp->len -= sizeof(sechdr);
+
+ buf = ntohl(sechdr.data_size);
+ data_size = buf & 0xffff;
+
+ check = buf >> 16;
+ check ^= seq ^ call->call_id;
+ check &= 0xffff;
+ if (check != 0)
+ return rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
+ rxkad_abort_2_short_check);
+
+ if (data_size > sp->len)
+ return rxrpc_abort_eproto(call, skb, RXKADDATALEN,
+ rxkad_abort_2_short_data);
+
+ sp->len = data_size;
+ _leave(" = 0 [dlen=%x]", data_size);
+ return 0;
+}
+
+/*
+ * Verify the security on a received packet and the subpackets therein.
+ */
+static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct skcipher_request *req;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg;
+ union {
+ __be32 buf[2];
+ } crypto __aligned(8);
+ rxrpc_seq_t seq = sp->hdr.seq;
+ int ret;
+ u16 cksum;
+ u32 x, y;
+
+ _enter("{%d{%x}},{#%u}",
+ call->debug_id, key_serial(call->conn->key), seq);
+
+ if (!call->conn->rxkad.cipher)
+ return 0;
+
+ req = rxkad_get_call_crypto(call);
+ if (!req)
+ return -ENOMEM;
+
+ /* continue encrypting from where we left off */
+ memcpy(&iv, call->conn->rxkad.csum_iv.x, sizeof(iv));
+
+ /* validate the security checksum */
+ x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
+ x |= seq & 0x3fffffff;
+ crypto.buf[0] = htonl(call->call_id);
+ crypto.buf[1] = htonl(x);
+
+ sg_init_one(&sg, crypto.buf, 8);
+ skcipher_request_set_sync_tfm(req, call->conn->rxkad.cipher);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
+ crypto_skcipher_encrypt(req);
+ skcipher_request_zero(req);
+
+ y = ntohl(crypto.buf[1]);
+ cksum = (y >> 16) & 0xffff;
+ if (cksum == 0)
+ cksum = 1; /* zero checksums are not permitted */
+
+ if (cksum != sp->hdr.cksum) {
+ ret = rxrpc_abort_eproto(call, skb, RXKADSEALEDINCON,
+ rxkad_abort_bad_checksum);
+ goto out;
+ }
+
+ switch (call->conn->security_level) {
+ case RXRPC_SECURITY_PLAIN:
+ ret = 0;
+ break;
+ case RXRPC_SECURITY_AUTH:
+ ret = rxkad_verify_packet_1(call, skb, seq, req);
+ break;
+ case RXRPC_SECURITY_ENCRYPT:
+ ret = rxkad_verify_packet_2(call, skb, seq, req);
+ break;
+ default:
+ ret = -ENOANO;
+ break;
+ }
+
+out:
+ skcipher_request_free(req);
+ return ret;
+}
+
+/*
+ * issue a challenge
+ */
+static int rxkad_issue_challenge(struct rxrpc_connection *conn)
+{
+ struct rxkad_challenge challenge;
+ struct rxrpc_wire_header whdr;
+ struct msghdr msg;
+ struct kvec iov[2];
+ size_t len;
+ u32 serial;
+ int ret;
+
+ _enter("{%d}", conn->debug_id);
+
+ get_random_bytes(&conn->rxkad.nonce, sizeof(conn->rxkad.nonce));
+
+ challenge.version = htonl(2);
+ challenge.nonce = htonl(conn->rxkad.nonce);
+ challenge.min_level = htonl(0);
+ challenge.__padding = 0;
+
+ msg.msg_name = &conn->peer->srx.transport;
+ msg.msg_namelen = conn->peer->srx.transport_len;
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = 0;
+
+ whdr.epoch = htonl(conn->proto.epoch);
+ whdr.cid = htonl(conn->proto.cid);
+ whdr.callNumber = 0;
+ whdr.seq = 0;
+ whdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
+ whdr.flags = conn->out_clientflag;
+ whdr.userStatus = 0;
+ whdr.securityIndex = conn->security_ix;
+ whdr._rsvd = 0;
+ whdr.serviceId = htons(conn->service_id);
+
+ iov[0].iov_base = &whdr;
+ iov[0].iov_len = sizeof(whdr);
+ iov[1].iov_base = &challenge;
+ iov[1].iov_len = sizeof(challenge);
+
+ len = iov[0].iov_len + iov[1].iov_len;
+
+ serial = atomic_inc_return(&conn->serial);
+ whdr.serial = htonl(serial);
+
+ ret = kernel_sendmsg(conn->local->socket, &msg, iov, 2, len);
+ if (ret < 0) {
+ trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
+ rxrpc_tx_point_rxkad_challenge);
+ return -EAGAIN;
+ }
+
+ conn->peer->last_tx_at = ktime_get_seconds();
+ trace_rxrpc_tx_packet(conn->debug_id, &whdr,
+ rxrpc_tx_point_rxkad_challenge);
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * send a Kerberos security response
+ */
+static int rxkad_send_response(struct rxrpc_connection *conn,
+ struct rxrpc_host_header *hdr,
+ struct rxkad_response *resp,
+ const struct rxkad_key *s2)
+{
+ struct rxrpc_wire_header whdr;
+ struct msghdr msg;
+ struct kvec iov[3];
+ size_t len;
+ u32 serial;
+ int ret;
+
+ _enter("");
+
+ msg.msg_name = &conn->peer->srx.transport;
+ msg.msg_namelen = conn->peer->srx.transport_len;
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = 0;
+
+ memset(&whdr, 0, sizeof(whdr));
+ whdr.epoch = htonl(hdr->epoch);
+ whdr.cid = htonl(hdr->cid);
+ whdr.type = RXRPC_PACKET_TYPE_RESPONSE;
+ whdr.flags = conn->out_clientflag;
+ whdr.securityIndex = hdr->securityIndex;
+ whdr.serviceId = htons(hdr->serviceId);
+
+ iov[0].iov_base = &whdr;
+ iov[0].iov_len = sizeof(whdr);
+ iov[1].iov_base = resp;
+ iov[1].iov_len = sizeof(*resp);
+ iov[2].iov_base = (void *)s2->ticket;
+ iov[2].iov_len = s2->ticket_len;
+
+ len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
+
+ serial = atomic_inc_return(&conn->serial);
+ whdr.serial = htonl(serial);
+
+ rxrpc_local_dont_fragment(conn->local, false);
+ ret = kernel_sendmsg(conn->local->socket, &msg, iov, 3, len);
+ rxrpc_local_dont_fragment(conn->local, true);
+ if (ret < 0) {
+ trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
+ rxrpc_tx_point_rxkad_response);
+ return -EAGAIN;
+ }
+
+ conn->peer->last_tx_at = ktime_get_seconds();
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * calculate the response checksum
+ */
+static void rxkad_calc_response_checksum(struct rxkad_response *response)
+{
+ u32 csum = 1000003;
+ int loop;
+ u8 *p = (u8 *) response;
+
+ for (loop = sizeof(*response); loop > 0; loop--)
+ csum = csum * 0x10204081 + *p++;
+
+ response->encrypted.checksum = htonl(csum);
+}
+
+/*
+ * encrypt the response packet
+ */
+static int rxkad_encrypt_response(struct rxrpc_connection *conn,
+ struct rxkad_response *resp,
+ const struct rxkad_key *s2)
+{
+ struct skcipher_request *req;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg[1];
+
+ req = skcipher_request_alloc(&conn->rxkad.cipher->base, GFP_NOFS);
+ if (!req)
+ return -ENOMEM;
+
+ /* continue encrypting from where we left off */
+ memcpy(&iv, s2->session_key, sizeof(iv));
+
+ sg_init_table(sg, 1);
+ sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
+ skcipher_request_set_sync_tfm(req, conn->rxkad.cipher);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
+ crypto_skcipher_encrypt(req);
+ skcipher_request_free(req);
+ return 0;
+}
+
+/*
+ * respond to a challenge packet
+ */
+static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
+ struct sk_buff *skb)
+{
+ const struct rxrpc_key_token *token;
+ struct rxkad_challenge challenge;
+ struct rxkad_response *resp;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ u32 version, nonce, min_level;
+ int ret = -EPROTO;
+
+ _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
+
+ if (!conn->key)
+ return rxrpc_abort_conn(conn, skb, RX_PROTOCOL_ERROR, -EPROTO,
+ rxkad_abort_chall_no_key);
+
+ ret = key_validate(conn->key);
+ if (ret < 0)
+ return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, ret,
+ rxkad_abort_chall_key_expired);
+
+ if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+ &challenge, sizeof(challenge)) < 0)
+ return rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
+ rxkad_abort_chall_short);
+
+ version = ntohl(challenge.version);
+ nonce = ntohl(challenge.nonce);
+ min_level = ntohl(challenge.min_level);
+
+ trace_rxrpc_rx_challenge(conn, sp->hdr.serial, version, nonce, min_level);
+
+ if (version != RXKAD_VERSION)
+ return rxrpc_abort_conn(conn, skb, RXKADINCONSISTENCY, -EPROTO,
+ rxkad_abort_chall_version);
+
+ if (conn->security_level < min_level)
+ return rxrpc_abort_conn(conn, skb, RXKADLEVELFAIL, -EACCES,
+ rxkad_abort_chall_level);
+
+ token = conn->key->payload.data[0];
+
+ /* build the response packet */
+ resp = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
+ if (!resp)
+ return -ENOMEM;
+
+ resp->version = htonl(RXKAD_VERSION);
+ resp->encrypted.epoch = htonl(conn->proto.epoch);
+ resp->encrypted.cid = htonl(conn->proto.cid);
+ resp->encrypted.securityIndex = htonl(conn->security_ix);
+ resp->encrypted.inc_nonce = htonl(nonce + 1);
+ resp->encrypted.level = htonl(conn->security_level);
+ resp->kvno = htonl(token->kad->kvno);
+ resp->ticket_len = htonl(token->kad->ticket_len);
+ resp->encrypted.call_id[0] = htonl(conn->channels[0].call_counter);
+ resp->encrypted.call_id[1] = htonl(conn->channels[1].call_counter);
+ resp->encrypted.call_id[2] = htonl(conn->channels[2].call_counter);
+ resp->encrypted.call_id[3] = htonl(conn->channels[3].call_counter);
+
+ /* calculate the response checksum and then do the encryption */
+ rxkad_calc_response_checksum(resp);
+ ret = rxkad_encrypt_response(conn, resp, token->kad);
+ if (ret == 0)
+ ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
+ kfree(resp);
+ return ret;
+}
+
+/*
+ * decrypt the kerberos IV ticket in the response
+ */
+static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
+ struct key *server_key,
+ struct sk_buff *skb,
+ void *ticket, size_t ticket_len,
+ struct rxrpc_crypt *_session_key,
+ time64_t *_expiry)
+{
+ struct skcipher_request *req;
+ struct rxrpc_crypt iv, key;
+ struct scatterlist sg[1];
+ struct in_addr addr;
+ unsigned int life;
+ time64_t issue, now;
+ bool little_endian;
+ u8 *p, *q, *name, *end;
+
+ _enter("{%d},{%x}", conn->debug_id, key_serial(server_key));
+
+ *_expiry = 0;
+
+ ASSERT(server_key->payload.data[0] != NULL);
+ ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
+
+ memcpy(&iv, &server_key->payload.data[2], sizeof(iv));
+
+ req = skcipher_request_alloc(server_key->payload.data[0], GFP_NOFS);
+ if (!req)
+ return -ENOMEM;
+
+ sg_init_one(&sg[0], ticket, ticket_len);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
+ crypto_skcipher_decrypt(req);
+ skcipher_request_free(req);
+
+ p = ticket;
+ end = p + ticket_len;
+
+#define Z(field, fieldl) \
+ ({ \
+ u8 *__str = p; \
+ q = memchr(p, 0, end - p); \
+ if (!q || q - p > field##_SZ) \
+ return rxrpc_abort_conn( \
+ conn, skb, RXKADBADTICKET, -EPROTO, \
+ rxkad_abort_resp_tkt_##fieldl); \
+ for (; p < q; p++) \
+ if (!isprint(*p)) \
+ return rxrpc_abort_conn( \
+ conn, skb, RXKADBADTICKET, -EPROTO, \
+ rxkad_abort_resp_tkt_##fieldl); \
+ p++; \
+ __str; \
+ })
+
+ /* extract the ticket flags */
+ _debug("KIV FLAGS: %x", *p);
+ little_endian = *p & 1;
+ p++;
+
+ /* extract the authentication name */
+ name = Z(ANAME, aname);
+ _debug("KIV ANAME: %s", name);
+
+ /* extract the principal's instance */
+ name = Z(INST, inst);
+ _debug("KIV INST : %s", name);
+
+ /* extract the principal's authentication domain */
+ name = Z(REALM, realm);
+ _debug("KIV REALM: %s", name);
+
+ if (end - p < 4 + 8 + 4 + 2)
+ return rxrpc_abort_conn(conn, skb, RXKADBADTICKET, -EPROTO,
+ rxkad_abort_resp_tkt_short);
+
+ /* get the IPv4 address of the entity that requested the ticket */
+ memcpy(&addr, p, sizeof(addr));
+ p += 4;
+ _debug("KIV ADDR : %pI4", &addr);
+
+ /* get the session key from the ticket */
+ memcpy(&key, p, sizeof(key));
+ p += 8;
+ _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
+ memcpy(_session_key, &key, sizeof(key));
+
+ /* get the ticket's lifetime */
+ life = *p++ * 5 * 60;
+ _debug("KIV LIFE : %u", life);
+
+ /* get the issue time of the ticket */
+ if (little_endian) {
+ __le32 stamp;
+ memcpy(&stamp, p, 4);
+ issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
+ } else {
+ __be32 stamp;
+ memcpy(&stamp, p, 4);
+ issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
+ }
+ p += 4;
+ now = ktime_get_real_seconds();
+ _debug("KIV ISSUE: %llx [%llx]", issue, now);
+
+ /* check the ticket is in date */
+ if (issue > now)
+ return rxrpc_abort_conn(conn, skb, RXKADNOAUTH, -EKEYREJECTED,
+ rxkad_abort_resp_tkt_future);
+ if (issue < now - life)
+ return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, -EKEYEXPIRED,
+ rxkad_abort_resp_tkt_expired);
+
+ *_expiry = issue + life;
+
+ /* get the service name */
+ name = Z(SNAME, sname);
+ _debug("KIV SNAME: %s", name);
+
+ /* get the service instance name */
+ name = Z(INST, sinst);
+ _debug("KIV SINST: %s", name);
+ return 0;
+}
+
+/*
+ * decrypt the response packet
+ */
+static void rxkad_decrypt_response(struct rxrpc_connection *conn,
+ struct rxkad_response *resp,
+ const struct rxrpc_crypt *session_key)
+{
+ struct skcipher_request *req = rxkad_ci_req;
+ struct scatterlist sg[1];
+ struct rxrpc_crypt iv;
+
+ _enter(",,%08x%08x",
+ ntohl(session_key->n[0]), ntohl(session_key->n[1]));
+
+ mutex_lock(&rxkad_ci_mutex);
+ if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
+ sizeof(*session_key)) < 0)
+ BUG();
+
+ memcpy(&iv, session_key, sizeof(iv));
+
+ sg_init_table(sg, 1);
+ sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
+ skcipher_request_set_sync_tfm(req, rxkad_ci);
+ skcipher_request_set_callback(req, 0, NULL, NULL);
+ skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
+ crypto_skcipher_decrypt(req);
+ skcipher_request_zero(req);
+
+ mutex_unlock(&rxkad_ci_mutex);
+
+ _leave("");
+}
+
+/*
+ * verify a response
+ */
+static int rxkad_verify_response(struct rxrpc_connection *conn,
+ struct sk_buff *skb)
+{
+ struct rxkad_response *response;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxrpc_crypt session_key;
+ struct key *server_key;
+ time64_t expiry;
+ void *ticket;
+ u32 version, kvno, ticket_len, level;
+ __be32 csum;
+ int ret, i;
+
+ _enter("{%d}", conn->debug_id);
+
+ server_key = rxrpc_look_up_server_security(conn, skb, 0, 0);
+ if (IS_ERR(server_key)) {
+ ret = PTR_ERR(server_key);
+ switch (ret) {
+ case -ENOKEY:
+ return rxrpc_abort_conn(conn, skb, RXKADUNKNOWNKEY, ret,
+ rxkad_abort_resp_nokey);
+ case -EKEYEXPIRED:
+ return rxrpc_abort_conn(conn, skb, RXKADEXPIRED, ret,
+ rxkad_abort_resp_key_expired);
+ default:
+ return rxrpc_abort_conn(conn, skb, RXKADNOAUTH, ret,
+ rxkad_abort_resp_key_rejected);
+ }
+ }
+
+ ret = -ENOMEM;
+ response = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
+ if (!response)
+ goto temporary_error;
+
+ if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+ response, sizeof(*response)) < 0) {
+ rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
+ rxkad_abort_resp_short);
+ goto protocol_error;
+ }
+
+ version = ntohl(response->version);
+ ticket_len = ntohl(response->ticket_len);
+ kvno = ntohl(response->kvno);
+
+ trace_rxrpc_rx_response(conn, sp->hdr.serial, version, kvno, ticket_len);
+
+ if (version != RXKAD_VERSION) {
+ rxrpc_abort_conn(conn, skb, RXKADINCONSISTENCY, -EPROTO,
+ rxkad_abort_resp_version);
+ goto protocol_error;
+ }
+
+ if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN) {
+ rxrpc_abort_conn(conn, skb, RXKADTICKETLEN, -EPROTO,
+ rxkad_abort_resp_tkt_len);
+ goto protocol_error;
+ }
+
+ if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5) {
+ rxrpc_abort_conn(conn, skb, RXKADUNKNOWNKEY, -EPROTO,
+ rxkad_abort_resp_unknown_tkt);
+ goto protocol_error;
+ }
+
+ /* extract the kerberos ticket and decrypt and decode it */
+ ret = -ENOMEM;
+ ticket = kmalloc(ticket_len, GFP_NOFS);
+ if (!ticket)
+ goto temporary_error_free_resp;
+
+ if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header) + sizeof(*response),
+ ticket, ticket_len) < 0) {
+ rxrpc_abort_conn(conn, skb, RXKADPACKETSHORT, -EPROTO,
+ rxkad_abort_resp_short_tkt);
+ goto protocol_error;
+ }
+
+ ret = rxkad_decrypt_ticket(conn, server_key, skb, ticket, ticket_len,
+ &session_key, &expiry);
+ if (ret < 0)
+ goto temporary_error_free_ticket;
+
+ /* use the session key from inside the ticket to decrypt the
+ * response */
+ rxkad_decrypt_response(conn, response, &session_key);
+
+ if (ntohl(response->encrypted.epoch) != conn->proto.epoch ||
+ ntohl(response->encrypted.cid) != conn->proto.cid ||
+ ntohl(response->encrypted.securityIndex) != conn->security_ix) {
+ rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
+ rxkad_abort_resp_bad_param);
+ goto protocol_error_free;
+ }
+
+ csum = response->encrypted.checksum;
+ response->encrypted.checksum = 0;
+ rxkad_calc_response_checksum(response);
+ if (response->encrypted.checksum != csum) {
+ rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
+ rxkad_abort_resp_bad_checksum);
+ goto protocol_error_free;
+ }
+
+ for (i = 0; i < RXRPC_MAXCALLS; i++) {
+ u32 call_id = ntohl(response->encrypted.call_id[i]);
+ u32 counter = READ_ONCE(conn->channels[i].call_counter);
+
+ if (call_id > INT_MAX) {
+ rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
+ rxkad_abort_resp_bad_callid);
+ goto protocol_error_free;
+ }
+
+ if (call_id < counter) {
+ rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
+ rxkad_abort_resp_call_ctr);
+ goto protocol_error_free;
+ }
+
+ if (call_id > counter) {
+ if (conn->channels[i].call) {
+ rxrpc_abort_conn(conn, skb, RXKADSEALEDINCON, -EPROTO,
+ rxkad_abort_resp_call_state);
+ goto protocol_error_free;
+ }
+ conn->channels[i].call_counter = call_id;
+ }
+ }
+
+ if (ntohl(response->encrypted.inc_nonce) != conn->rxkad.nonce + 1) {
+ rxrpc_abort_conn(conn, skb, RXKADOUTOFSEQUENCE, -EPROTO,
+ rxkad_abort_resp_ooseq);
+ goto protocol_error_free;
+ }
+
+ level = ntohl(response->encrypted.level);
+ if (level > RXRPC_SECURITY_ENCRYPT) {
+ rxrpc_abort_conn(conn, skb, RXKADLEVELFAIL, -EPROTO,
+ rxkad_abort_resp_level);
+ goto protocol_error_free;
+ }
+ conn->security_level = level;
+
+ /* create a key to hold the security data and expiration time - after
+ * this the connection security can be handled in exactly the same way
+ * as for a client connection */
+ ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
+ if (ret < 0)
+ goto temporary_error_free_ticket;
+
+ kfree(ticket);
+ kfree(response);
+ _leave(" = 0");
+ return 0;
+
+protocol_error_free:
+ kfree(ticket);
+protocol_error:
+ kfree(response);
+ key_put(server_key);
+ return -EPROTO;
+
+temporary_error_free_ticket:
+ kfree(ticket);
+temporary_error_free_resp:
+ kfree(response);
+temporary_error:
+ /* Ignore the response packet if we got a temporary error such as
+ * ENOMEM. We just want to send the challenge again. Note that we
+ * also come out this way if the ticket decryption fails.
+ */
+ key_put(server_key);
+ return ret;
+}
+
+/*
+ * clear the connection security
+ */
+static void rxkad_clear(struct rxrpc_connection *conn)
+{
+ _enter("");
+
+ if (conn->rxkad.cipher)
+ crypto_free_sync_skcipher(conn->rxkad.cipher);
+}
+
+/*
+ * Initialise the rxkad security service.
+ */
+static int rxkad_init(void)
+{
+ struct crypto_sync_skcipher *tfm;
+ struct skcipher_request *req;
+
+ /* pin the cipher we need so that the crypto layer doesn't invoke
+ * keventd to go get it */
+ tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
+ if (!req)
+ goto nomem_tfm;
+
+ rxkad_ci_req = req;
+ rxkad_ci = tfm;
+ return 0;
+
+nomem_tfm:
+ crypto_free_sync_skcipher(tfm);
+ return -ENOMEM;
+}
+
+/*
+ * Clean up the rxkad security service.
+ */
+static void rxkad_exit(void)
+{
+ crypto_free_sync_skcipher(rxkad_ci);
+ skcipher_request_free(rxkad_ci_req);
+}
+
+/*
+ * RxRPC Kerberos-based security
+ */
+const struct rxrpc_security rxkad = {
+ .name = "rxkad",
+ .security_index = RXRPC_SECURITY_RXKAD,
+ .no_key_abort = RXKADUNKNOWNKEY,
+ .init = rxkad_init,
+ .exit = rxkad_exit,
+ .preparse_server_key = rxkad_preparse_server_key,
+ .free_preparse_server_key = rxkad_free_preparse_server_key,
+ .destroy_server_key = rxkad_destroy_server_key,
+ .init_connection_security = rxkad_init_connection_security,
+ .how_much_data = rxkad_how_much_data,
+ .secure_packet = rxkad_secure_packet,
+ .verify_packet = rxkad_verify_packet,
+ .free_call_crypto = rxkad_free_call_crypto,
+ .issue_challenge = rxkad_issue_challenge,
+ .respond_to_challenge = rxkad_respond_to_challenge,
+ .verify_response = rxkad_verify_response,
+ .clear = rxkad_clear,
+};