[RFC PATCH 23/24] rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)

David Howells
2025-01-17T18:38:11Z

Implement the basic parts of the yfs-rxgk security class (security index 6)
to support GSSAPI-negotiated security.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: "David S. Miller" <davem@davemloft.net>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
---
include/trace/events/rxrpc.h | 36 ++
net/rxrpc/Makefile | 2 +
net/rxrpc/ar-internal.h | 16 +
net/rxrpc/conn_event.c | 2 +-
net/rxrpc/output.c | 2 +-
net/rxrpc/protocol.h | 20 +
net/rxrpc/rxgk.c | 1026 ++++++++++++++++++++++++++++++++++
net/rxrpc/rxgk_app.c | 284 ++++++++++
net/rxrpc/rxgk_common.h | 92 +++
net/rxrpc/rxkad.c | 6 +-
net/rxrpc/security.c | 3 +
11 files changed, 1485 insertions(+), 4 deletions(-)
create mode 100644 net/rxrpc/rxgk.c
create mode 100644 net/rxrpc/rxgk_app.c

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 2f119d18a061..168f3ab7c0e4 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -68,6 +68,38 @@
EM(rxkad_abort_resp_tkt_sname, "rxkad-resp-tk-sname") \
EM(rxkad_abort_resp_unknown_tkt, "rxkad-resp-unknown-tkt") \
EM(rxkad_abort_resp_version, "rxkad-resp-version") \
+ /* RxGK security errors */ \
+ EM(rxgk_abort_1_verify_mic_eproto, "rxgk1-vfy-mic-eproto") \
+ EM(rxgk_abort_2_decrypt_eproto, "rxgk2-dec-eproto") \
+ EM(rxgk_abort_2_short_data, "rxgk2-short-data") \
+ EM(rxgk_abort_2_short_encdata, "rxgk2-short-encdata") \
+ EM(rxgk_abort_2_short_header, "rxgk2-short-hdr") \
+ EM(rxgk_abort_bad_key_number, "rxgk-bad-key-num") \
+ EM(rxgk_abort_chall_key_expired, "rxgk-chall-key-exp") \
+ EM(rxgk_abort_chall_no_key, "rxgk-chall-nokey") \
+ EM(rxgk_abort_chall_short, "rxgk-chall-short") \
+ EM(rxgk_abort_resp_auth_dec, "rxgk-resp-auth-dec") \
+ EM(rxgk_abort_resp_bad_callid, "rxgk-resp-bad-callid") \
+ EM(rxgk_abort_resp_bad_nonce, "rxgk-resp-bad-nonce") \
+ EM(rxgk_abort_resp_bad_param, "rxgk-resp-bad-param") \
+ EM(rxgk_abort_resp_call_ctr, "rxgk-resp-call-ctr") \
+ EM(rxgk_abort_resp_call_state, "rxgk-resp-call-state") \
+ EM(rxgk_abort_resp_internal_error, "rxgk-resp-int-error") \
+ EM(rxgk_abort_resp_nopkg, "rxgk-resp-nopkg") \
+ EM(rxgk_abort_resp_short_applen, "rxgk-resp-short-applen") \
+ EM(rxgk_abort_resp_short_auth, "rxgk-resp-short-auth") \
+ EM(rxgk_abort_resp_short_call_list, "rxgk-resp-short-callls") \
+ EM(rxgk_abort_resp_short_packet, "rxgk-resp-short-packet") \
+ EM(rxgk_abort_resp_short_yfs_klen, "rxgk-resp-short-yfs-klen") \
+ EM(rxgk_abort_resp_short_yfs_key, "rxgk-resp-short-yfs-key") \
+ EM(rxgk_abort_resp_short_yfs_tkt, "rxgk-resp-short-yfs-tkt") \
+ EM(rxgk_abort_resp_tok_dec, "rxgk-resp-tok-dec") \
+ EM(rxgk_abort_resp_tok_internal_error, "rxgk-resp-tok-int-err") \
+ EM(rxgk_abort_resp_tok_keyerr, "rxgk-resp-tok-keyerr") \
+ EM(rxgk_abort_resp_tok_nokey, "rxgk-resp-tok-nokey") \
+ EM(rxgk_abort_resp_tok_nopkg, "rxgk-resp-tok-nopkg") \
+ EM(rxgk_abort_resp_tok_short, "rxgk-resp-tok-short") \
+ EM(rxgk_abort_resp_xdr_align, "rxgk-resp-xdr-align") \
/* rxrpc errors */ \
EM(rxrpc_abort_call_improper_term, "call-improper-term") \
EM(rxrpc_abort_call_reset, "call-reset") \
@@ -454,6 +486,8 @@
EM(rxrpc_tx_point_call_final_resend, "CallFinalResend") \
EM(rxrpc_tx_point_conn_abort, "ConnAbort") \
EM(rxrpc_tx_point_reject, "Reject") \
+ EM(rxrpc_tx_point_rxgk_challenge, "RxGKChall") \
+ EM(rxrpc_tx_point_rxgk_response, "RxGKResp") \
EM(rxrpc_tx_point_rxkad_challenge, "RxkadChall") \
EM(rxrpc_tx_point_rxkad_response, "RxkadResp") \
EM(rxrpc_tx_point_version_keepalive, "VerKeepalive") \
@@ -472,6 +506,7 @@

#define rxrpc_txbuf_traces \
EM(rxrpc_txbuf_alloc_data, "ALLOC DATA ") \
+ EM(rxrpc_txbuf_alloc_response, "ALLOC RESP ") \
EM(rxrpc_txbuf_free, "FREE ") \
EM(rxrpc_txbuf_get_buffer, "GET BUFFER ") \
EM(rxrpc_txbuf_get_trans, "GET TRANS ") \
@@ -479,6 +514,7 @@
EM(rxrpc_txbuf_put_cleaned, "PUT CLEANED") \
EM(rxrpc_txbuf_put_nomem, "PUT NOMEM ") \
EM(rxrpc_txbuf_put_rotated, "PUT ROTATED") \
+ EM(rxrpc_txbuf_put_response_tx, "PUT RESP TX") \
EM(rxrpc_txbuf_put_send_aborted, "PUT SEND-X ") \
EM(rxrpc_txbuf_put_trans, "PUT TRANS ") \
EM(rxrpc_txbuf_see_lost, "SEE LOST ") \
diff --git a/net/rxrpc/Makefile b/net/rxrpc/Makefile
index 9c8eb1471054..2ef05701d6d1 100644
--- a/net/rxrpc/Makefile
+++ b/net/rxrpc/Makefile
@@ -40,6 +40,8 @@ rxrpc-$(CONFIG_PROC_FS) += proc.o
rxrpc-$(CONFIG_RXKAD) += rxkad.o
rxrpc-$(CONFIG_SYSCTL) += sysctl.o
rxrpc-$(CONFIG_RXGK) += \
+ rxgk.o \
+ rxgk_app.o \
rxgk_kdf.o

obj-$(CONFIG_RXPERF) += rxperf.o
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 2392f2e062c2..736dc6ea20ac 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -31,6 +31,7 @@ struct key_preparsed_payload;
struct rxrpc_connection;
struct rxrpc_txbuf;
struct rxrpc_txqueue;
+struct rxgk_context;

/*
* Mark applied to socket buffers in skb->mark. skb->priority is used
@@ -280,6 +281,11 @@ struct rxrpc_security {

/* clear connection security */
void (*clear)(struct rxrpc_connection *);
+
+ /* Default ticket -> key decoder */
+ int (*default_decode_ticket)(struct rxrpc_connection *conn, struct sk_buff *skb,
+ unsigned int ticket_offset, unsigned int ticket_len,
+ struct key **_key);
};

/*
@@ -527,7 +533,9 @@ struct rxrpc_connection {
u32 nonce; /* response re-use preventer */
} rxkad;
struct {
+ struct rxgk_context *keys[1];
u64 start_time; /* The start time for TK derivation */
+ u8 nonce[20]; /* Response re-use preventer */
} rxgk;
};
unsigned long flags;
@@ -870,6 +878,8 @@ struct rxrpc_txbuf {
unsigned short len; /* Amount of data in buffer */
unsigned short space; /* Remaining data space */
unsigned short offset; /* Offset of fill point */
+ unsigned short crypto_header; /* Size of crypto header */
+ unsigned short sec_header; /* Size of security header */
unsigned short pkt_len; /* Size of packet content */
unsigned short alloc_size; /* Amount of bufferage allocated */
unsigned int flags;
@@ -1295,6 +1305,7 @@ static inline struct rxrpc_net *rxrpc_net(struct net *net)
/*
* output.c
*/
+ssize_t do_udp_sendmsg(struct socket *socket, struct msghdr *msg, size_t len);
void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason,
rxrpc_serial_t serial, enum rxrpc_propose_ack_trace why);
void rxrpc_send_probe_for_pmtud(struct rxrpc_call *call);
@@ -1366,6 +1377,11 @@ void rxrpc_call_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
ktime_t rxrpc_get_rto_backoff(struct rxrpc_call *call, bool retrans);
void rxrpc_call_init_rtt(struct rxrpc_call *call);

+/*
+ * rxgk.c
+ */
+extern const struct rxrpc_security rxgk_yfs;
+
/*
* rxkad.c
*/
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index 713e04394ceb..3c1663318626 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -57,7 +57,7 @@ int rxrpc_abort_conn(struct rxrpc_connection *conn, struct sk_buff *skb,
sp->hdr.seq, abort_code, err);
rxrpc_poke_conn(conn, rxrpc_conn_get_poke_abort);
}
- return -EPROTO;
+ return err;
}

/*
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 6f7a125d6e90..6e2def0d8773 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -18,7 +18,7 @@

extern int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);

-static ssize_t do_udp_sendmsg(struct socket *socket, struct msghdr *msg, size_t len)
+ssize_t do_udp_sendmsg(struct socket *socket, struct msghdr *msg, size_t len)
{
struct sockaddr *sa = msg->msg_name;
struct sock *sk = socket->sk;
diff --git a/net/rxrpc/protocol.h b/net/rxrpc/protocol.h
index 42f70e4636f8..f8bfec12bc7e 100644
--- a/net/rxrpc/protocol.h
+++ b/net/rxrpc/protocol.h
@@ -181,4 +181,24 @@ struct rxkad_response {
__be32 ticket_len; /* Kerberos ticket length */
} __packed;

+/*
+ * GSSAPI security type-4 and type-6 data header.
+ */
+struct rxgk_header {
+ __be32 epoch;
+ __be32 cid;
+ __be32 call_number;
+ __be32 seq;
+ __be32 sec_index;
+ __be32 data_len;
+} __packed;
+
+/*
+ * GSSAPI security type-4 and type-6 response packet header.
+ */
+struct rxgk_response {
+ __be64 start_time;
+ __be32 token_len;
+} __packed;
+
#endif /* _LINUX_RXRPC_PACKET_H */
diff --git a/net/rxrpc/rxgk.c b/net/rxrpc/rxgk.c
new file mode 100644
index 000000000000..9c5c616c40cb
--- /dev/null
+++ b/net/rxrpc/rxgk.c
@@ -0,0 +1,1026 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* GSSAPI-based RxRPC security
+ *
+ * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/key-type.h>
+#include "ar-internal.h"
+#include "rxgk_common.h"
+
+/*
+ * Parse the information from a server key
+ */
+static int rxgk_preparse_server_key(struct key_preparsed_payload *prep)
+{
+ const struct krb5_enctype *krb5;
+ struct krb5_buffer *server_key = (void *)&prep->payload.data[2];
+ unsigned int service, sec_class, kvno, enctype;
+ int n = 0;
+
+ _enter("%zu", prep->datalen);
+
+ if (sscanf(prep->orig_description, "%u:%u:%u:%u%n",
+ &service, &sec_class, &kvno, &enctype, &n) != 4)
+ return -EINVAL;
+
+ if (prep->orig_description[n])
+ return -EINVAL;
+
+ krb5 = crypto_krb5_find_enctype(enctype);
+ if (!krb5)
+ return -ENOPKG;
+
+ prep->payload.data[0] = (struct krb5_enctype *)krb5;
+
+ if (prep->datalen != krb5->key_len)
+ return -EKEYREJECTED;
+
+ server_key->len = prep->datalen;
+ server_key->data = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
+ if (!server_key->data)
+ return -ENOMEM;
+
+ _leave(" = 0");
+ return 0;
+}
+
+static void rxgk_free_server_key(union key_payload *payload)
+{
+ struct krb5_buffer *server_key = (void *)&payload->data[2];
+
+ kfree_sensitive(server_key->data);
+}
+
+static void rxgk_free_preparse_server_key(struct key_preparsed_payload *prep)
+{
+ rxgk_free_server_key(&prep->payload);
+}
+
+static void rxgk_destroy_server_key(struct key *key)
+{
+ rxgk_free_server_key(&key->payload);
+}
+
+static void rxgk_describe_server_key(const struct key *key, struct seq_file *m)
+{
+ const struct krb5_enctype *krb5 = key->payload.data[0];
+
+ if (krb5)
+ seq_printf(m, ": %s", krb5->name);
+}
+
+static struct rxgk_context *rxgk_get_key(struct rxrpc_connection *conn,
+ u16 *specific_key_number)
+{
+ refcount_inc(&conn->rxgk.keys[0]->usage);
+ return conn->rxgk.keys[0];
+}
+
+/*
+ * initialise connection security
+ */
+static int rxgk_init_connection_security(struct rxrpc_connection *conn,
+ struct rxrpc_key_token *token)
+{
+ struct rxgk_context *gk;
+ int ret;
+
+ _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
+
+ conn->security_ix = token->security_index;
+ conn->security_level = token->rxgk->level;
+
+ if (rxrpc_conn_is_client(conn)) {
+ conn->rxgk.start_time = ktime_get();
+ do_div(conn->rxgk.start_time, 100);
+ }
+
+ gk = rxgk_generate_transport_key(conn, token->rxgk, 0, GFP_NOFS);
+ if (IS_ERR(gk))
+ return PTR_ERR(gk);
+ conn->rxgk.keys[0] = gk;
+
+ switch (conn->security_level) {
+ case RXRPC_SECURITY_PLAIN:
+ case RXRPC_SECURITY_AUTH:
+ case RXRPC_SECURITY_ENCRYPT:
+ break;
+ default:
+ ret = -EKEYREJECTED;
+ goto error;
+ }
+
+ ret = 0;
+error:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Clean up the crypto on a call.
+ */
+static void rxgk_free_call_crypto(struct rxrpc_call *call)
+{
+}
+
+/*
+ * Work out how much data we can put in a packet.
+ */
+static struct rxrpc_txbuf *rxgk_alloc_txbuf(struct rxrpc_call *call, size_t remain, gfp_t gfp)
+{
+ enum krb5_crypto_mode mode;
+ struct rxgk_context *gk;
+ struct rxrpc_txbuf *txb;
+ size_t shdr, alloc, limit, part, offset, gap;
+
+ switch (call->conn->security_level) {
+ default:
+ alloc = umin(remain, RXRPC_JUMBO_DATALEN);
+ return rxrpc_alloc_data_txbuf(call, alloc, 1, gfp);
+ case RXRPC_SECURITY_AUTH:
+ shdr = 0;
+ mode = KRB5_CHECKSUM_MODE;
+ break;
+ case RXRPC_SECURITY_ENCRYPT:
+ shdr = sizeof(struct rxgk_header);
+ mode = KRB5_ENCRYPT_MODE;
+ break;
+ }
+
+ gk = rxgk_get_key(call->conn, NULL);
+ if (IS_ERR(gk))
+ return NULL;
+
+ /* Work out the maximum amount of data that will fit. */
+ alloc = RXRPC_JUMBO_DATALEN;
+ limit = crypto_krb5_how_much_data(gk->krb5, mode, &alloc, &offset);
+
+ if (remain < limit - shdr) {
+ part = remain;
+ alloc = crypto_krb5_how_much_buffer(gk->krb5, mode,
+ shdr + part, &offset);
+ gap = 0;
+ } else {
+ part = limit - shdr;
+ gap = RXRPC_JUMBO_DATALEN - alloc;
+ alloc = RXRPC_JUMBO_DATALEN;
+ }
+
+ rxgk_put(gk);
+
+ txb = rxrpc_alloc_data_txbuf(call, alloc, 16, gfp);
+ if (!txb)
+ return NULL;
+
+ txb->crypto_header = offset;
+ txb->sec_header = shdr;
+ txb->offset += offset + shdr;
+ txb->space = part;
+
+ /* Clear excess space in the packet */
+ if (gap) {
+ struct rxrpc_wire_header *whdr = txb->kvec[0].iov_base;
+ void *p = whdr + 1;
+
+ memset(p + alloc - gap, 0, gap);
+ }
+ return txb;
+}
+
+/*
+ * Integrity mode (sign a packet - level 1 security)
+ */
+static int rxgk_secure_packet_integrity(const struct rxrpc_call *call,
+ struct rxgk_context *gk,
+ struct rxrpc_txbuf *txb)
+{
+ struct rxrpc_wire_header *whdr = txb->kvec[0].iov_base;
+ struct rxgk_header *hdr;
+ struct scatterlist sg[1];
+ struct krb5_buffer metadata;
+ void *payload = whdr + 1;
+ int ret = -ENOMEM;
+
+ _enter("");
+
+ hdr = kzalloc(sizeof(*hdr), GFP_NOFS);
+ if (!hdr)
+ goto error_gk;
+
+ hdr->epoch = htonl(call->conn->proto.epoch);
+ hdr->cid = htonl(call->cid);
+ hdr->call_number = htonl(call->call_id);
+ hdr->seq = htonl(txb->seq);
+ hdr->sec_index = htonl(call->security_ix);
+ hdr->data_len = htonl(txb->len);
+ metadata.len = sizeof(*hdr);
+ metadata.data = hdr;
+
+ sg_init_table(sg, 1);
+ sg_set_buf(&sg[0], payload, txb->alloc_size);
+
+ ret = crypto_krb5_get_mic(gk->krb5, gk->tx_Kc, &metadata,
+ sg, 1, txb->alloc_size,
+ txb->crypto_header, txb->sec_header + txb->len);
+ if (ret >= 0) {
+ txb->pkt_len = ret;
+ if (txb->alloc_size == RXRPC_JUMBO_DATALEN)
+ txb->jumboable = true;
+ gk->bytes_remaining -= ret;
+ }
+ kfree(hdr);
+error_gk:
+ rxgk_put(gk);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * wholly encrypt a packet (level 2 security)
+ */
+static int rxgk_secure_packet_encrypted(const struct rxrpc_call *call,
+ struct rxgk_context *gk,
+ struct rxrpc_txbuf *txb)
+{
+ struct rxrpc_wire_header *whdr = txb->kvec[0].iov_base;
+ struct rxgk_header *hdr;
+ struct scatterlist sg[1];
+ void *payload = whdr + 1;
+ int ret;
+
+ _enter("%x", txb->len);
+
+ /* Insert the header into the buffer. */
+ hdr = payload + txb->crypto_header;
+ hdr->epoch = htonl(call->conn->proto.epoch);
+ hdr->cid = htonl(call->cid);
+ hdr->call_number = htonl(call->call_id);
+ hdr->seq = htonl(txb->seq);
+ hdr->sec_index = htonl(call->security_ix);
+ hdr->data_len = htonl(txb->len);
+
+ sg_init_table(sg, 1);
+ sg_set_buf(&sg[0], payload, txb->alloc_size);
+
+ ret = crypto_krb5_encrypt(gk->krb5, gk->tx_enc,
+ sg, 1, txb->alloc_size,
+ txb->crypto_header, txb->sec_header + txb->len,
+ false);
+ if (ret >= 0) {
+ txb->pkt_len = ret;
+ if (txb->alloc_size == RXRPC_JUMBO_DATALEN)
+ txb->jumboable = true;
+ gk->bytes_remaining -= ret;
+ }
+
+ rxgk_put(gk);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * checksum an RxRPC packet header
+ */
+static int rxgk_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
+{
+ struct rxgk_context *gk;
+ int ret;
+
+ _enter("{%d{%x}},{#%u},%u,",
+ call->debug_id, key_serial(call->conn->key), txb->seq, txb->len);
+
+ gk = rxgk_get_key(call->conn, NULL);
+ if (IS_ERR(gk))
+ return PTR_ERR(gk) == -ESTALE ? -EKEYREJECTED : PTR_ERR(gk);
+
+ ret = key_validate(call->conn->key);
+ if (ret < 0)
+ return ret;
+
+ txb->cksum = htons(gk->key_number);
+
+ switch (call->conn->security_level) {
+ case RXRPC_SECURITY_PLAIN:
+ rxgk_put(gk);
+ txb->pkt_len = txb->len;
+ return 0;
+ case RXRPC_SECURITY_AUTH:
+ return rxgk_secure_packet_integrity(call, gk, txb);
+ case RXRPC_SECURITY_ENCRYPT:
+ return rxgk_secure_packet_encrypted(call, gk, txb);
+ default:
+ rxgk_put(gk);
+ return -EPERM;
+ }
+}
+
+/*
+ * Integrity mode (check the signature on a packet - level 1 security)
+ */
+static int rxgk_verify_packet_integrity(struct rxrpc_call *call,
+ struct rxgk_context *gk,
+ struct sk_buff *skb)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxgk_header *hdr;
+ struct krb5_buffer metadata;
+ unsigned int offset = sp->offset, len = sp->len;
+ size_t data_offset = 0, data_len = len;
+ u32 ac;
+ int ret = -ENOMEM;
+
+ _enter("");
+
+ crypto_krb5_where_is_the_data(gk->krb5, KRB5_CHECKSUM_MODE,
+ &data_offset, &data_len);
+
+ hdr = kzalloc(sizeof(*hdr), GFP_NOFS);
+ if (!hdr)
+ return -ENOMEM;
+
+ hdr->epoch = htonl(call->conn->proto.epoch);
+ hdr->cid = htonl(call->cid);
+ hdr->call_number = htonl(call->call_id);
+ hdr->seq = htonl(sp->hdr.seq);
+ hdr->sec_index = htonl(call->security_ix);
+ hdr->data_len = htonl(data_len);
+
+ metadata.len = sizeof(*hdr);
+ metadata.data = hdr;
+ ret = rxgk_verify_mic_skb(gk->krb5, gk->rx_Kc, &metadata,
+ skb, &offset, &len, &ac);
+ kfree(hdr);
+ if (ret == -EPROTO) {
+ rxrpc_abort_eproto(call, skb, ac,
+ rxgk_abort_1_verify_mic_eproto);
+ } else {
+ sp->offset = offset;
+ sp->len = len;
+ }
+
+ rxgk_put(gk);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Decrypt an encrypted packet (level 2 security).
+ */
+static int rxgk_verify_packet_encrypted(struct rxrpc_call *call,
+ struct rxgk_context *gk,
+ struct sk_buff *skb)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxgk_header hdr;
+ unsigned int offset = sp->offset, len = sp->len;
+ int ret;
+ u32 ac;
+
+ _enter("");
+
+ ret = rxgk_decrypt_skb(gk->krb5, gk->rx_enc, skb, &offset, &len, &ac);
+ if (ret == -EPROTO)
+ rxrpc_abort_eproto(call, skb, ac, rxgk_abort_2_decrypt_eproto);
+ if (ret < 0)
+ goto error;
+
+ if (len < sizeof(hdr)) {
+ ret = rxrpc_abort_eproto(call, skb, RXGK_PACKETSHORT,
+ rxgk_abort_2_short_header);
+ goto error;
+ }
+
+ /* Extract the header from the skb */
+ ret = skb_copy_bits(skb, offset, &hdr, sizeof(hdr));
+ if (ret < 0) {
+ ret = rxrpc_abort_eproto(call, skb, RXGK_PACKETSHORT,
+ rxgk_abort_2_short_encdata);
+ goto error;
+ }
+ offset += sizeof(hdr);
+ len -= sizeof(hdr);
+
+ if (ntohl(hdr.epoch) != call->conn->proto.epoch ||
+ ntohl(hdr.cid) != call->cid ||
+ ntohl(hdr.call_number) != call->call_id ||
+ ntohl(hdr.seq) != sp->hdr.seq ||
+ ntohl(hdr.sec_index) != call->security_ix ||
+ ntohl(hdr.data_len) > len) {
+ ret = rxrpc_abort_eproto(call, skb, RXGK_SEALED_INCON,
+ rxgk_abort_2_short_data);
+ goto error;
+ }
+
+ sp->offset = offset;
+ sp->len = ntohl(hdr.data_len);
+ ret = 0;
+error:
+ rxgk_put(gk);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Verify the security on a received packet or subpacket (if part of a
+ * jumbo packet).
+ */
+static int rxgk_verify_packet(struct rxrpc_call *call, struct sk_buff *skb)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxgk_context *gk;
+ u16 key_number = sp->hdr.cksum;
+
+ _enter("{%d{%x}},{#%u}",
+ call->debug_id, key_serial(call->conn->key), sp->hdr.seq);
+
+ gk = rxgk_get_key(call->conn, &key_number);
+ if (IS_ERR(gk)) {
+ switch (PTR_ERR(gk)) {
+ case -ESTALE:
+ return rxrpc_abort_eproto(call, skb, RXGK_BADKEYNO,
+ rxgk_abort_bad_key_number);
+ default:
+ return PTR_ERR(gk);
+ }
+ }
+
+ switch (call->conn->security_level) {
+ case RXRPC_SECURITY_PLAIN:
+ return 0;
+ case RXRPC_SECURITY_AUTH:
+ return rxgk_verify_packet_integrity(call, gk, skb);
+ case RXRPC_SECURITY_ENCRYPT:
+ return rxgk_verify_packet_encrypted(call, gk, skb);
+ default:
+ rxgk_put(gk);
+ return -ENOANO;
+ }
+}
+
+/*
+ * Allocate memory to hold a challenge or a response packet. We're not running
+ * in the io_thread, so we can't use ->tx_alloc.
+ */
+static struct page *rxgk_alloc_packet(size_t total_len)
+{
+ gfp_t gfp = GFP_NOFS;
+ int order;
+
+ order = get_order(total_len);
+ if (order > 0)
+ gfp |= __GFP_COMP;
+ return alloc_pages(gfp, order);
+}
+
+/*
+ * Issue a challenge.
+ */
+static int rxgk_issue_challenge(struct rxrpc_connection *conn)
+{
+ struct rxrpc_wire_header *whdr;
+ struct bio_vec bvec[1];
+ struct msghdr msg;
+ struct page *page;
+ size_t len = sizeof(*whdr) + sizeof(conn->rxgk.nonce);
+ u32 serial;
+ int ret;
+
+ _enter("{%d}", conn->debug_id);
+
+ get_random_bytes(&conn->rxgk.nonce, sizeof(conn->rxgk.nonce));
+
+ /* We can't use conn->tx_alloc without a lock */
+ page = rxgk_alloc_packet(sizeof(*whdr) + sizeof(conn->rxgk.nonce));
+ if (!page)
+ return -ENOMEM;
+
+ bvec[0].bv_page = page;
+ bvec[0].bv_len = len;
+ iov_iter_bvec(&msg.msg_iter, WRITE, bvec, 1, len);
+
+ 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 = MSG_SPLICE_PAGES;
+
+ whdr = page_address(page);
+ 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);
+
+ memcpy(whdr + 1, conn->rxgk.nonce, sizeof(conn->rxgk.nonce));
+
+ serial = rxrpc_get_next_serials(conn, 1);
+ whdr->serial = htonl(serial);
+
+ ret = do_udp_sendmsg(conn->local->socket, &msg, len);
+ if (ret > 0)
+ conn->peer->last_tx_at = ktime_get_seconds();
+ __free_page(page);
+
+ if (ret < 0) {
+ trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
+ rxrpc_tx_point_rxgk_challenge);
+ return -EAGAIN;
+ }
+
+ trace_rxrpc_tx_packet(conn->debug_id, whdr,
+ rxrpc_tx_point_rxgk_challenge);
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * Send a response packet.
+ */
+static int rxgk_send_response(struct rxrpc_connection *conn,
+ struct page *page, size_t total_len)
+{
+ struct rxrpc_wire_header *whdr = page_address(page);
+ struct bio_vec bvec[1];
+ struct msghdr msg;
+ 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 = MSG_SPLICE_PAGES;
+
+ bvec[0].bv_page = page;
+ bvec[0].bv_len = total_len;
+ iov_iter_bvec(&msg.msg_iter, WRITE, bvec, 1, total_len);
+
+ serial = rxrpc_get_next_serials(conn, 1);
+ whdr->serial = htonl(serial);
+
+ ret = do_udp_sendmsg(conn->local->socket, &msg, total_len);
+ if (ret < 0) {
+ trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
+ rxrpc_tx_point_rxgk_response);
+ return -EAGAIN;
+ }
+
+ conn->peer->last_tx_at = ktime_get_seconds();
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * Construct the authenticator to go in the response packet
+ *
+ * struct RXGK_Authenticator {
+ * opaque nonce[20];
+ * opaque appdata<>;
+ * RXGK_Level level;
+ * unsigned int epoch;
+ * unsigned int cid;
+ * unsigned int call_numbers<>;
+ * };
+ */
+static void rxgk_construct_authenticator(struct rxrpc_connection *conn,
+ const u8 *nonce, __be32 *xdr)
+{
+ memcpy(xdr, nonce, 20);
+ xdr += 5;
+ *xdr++ = htonl(0); /* appdata len */
+ *xdr++ = htonl(conn->security_level);
+ *xdr++ = htonl(conn->proto.epoch);
+ *xdr++ = htonl(conn->proto.cid);
+ *xdr++ = htonl(4); /* # call_numbers */
+ *xdr++ = htonl(conn->channels[0].call_counter);
+ *xdr++ = htonl(conn->channels[1].call_counter);
+ *xdr++ = htonl(conn->channels[2].call_counter);
+ *xdr = htonl(conn->channels[3].call_counter);
+}
+
+/*
+ * Construct the response.
+ *
+ * struct RXGK_Response {
+ * rxgkTime start_time;
+ * RXGK_Data token;
+ * opaque authenticator<RXGK_MAXAUTHENTICATOR>
+ * };
+ */
+static int rxgk_construct_response(struct rxrpc_connection *conn,
+ struct sk_buff *challenge,
+ const u8 *nonce)
+{
+ struct rxrpc_wire_header *whdr;
+ struct rxrpc_skb_priv *csp = rxrpc_skb(challenge);
+ struct rxgk_context *gk;
+ struct scatterlist sg[1];
+ struct page *page;
+ size_t resp_len, auth_len, authx_len, auth_offset, authx_offset;
+ __be32 *xdr;
+ void *payload;
+ int ret;
+
+ gk = rxgk_get_key(conn, NULL);
+ if (IS_ERR(gk))
+ return PTR_ERR(gk);
+
+ auth_len = 20 + 4 /* appdatalen */ + 12 + (1 + 4) * 4;
+ authx_len = crypto_krb5_how_much_buffer(gk->krb5, KRB5_ENCRYPT_MODE,
+ auth_len, &auth_offset);
+
+ resp_len = 8;
+ resp_len += 4 + xdr_round_up(gk->key->ticket.len);
+ resp_len += 4 + xdr_round_up(authx_len);
+
+ ret = -ENOMEM;
+ page = rxgk_alloc_packet(sizeof(*whdr) + resp_len);
+ if (!page)
+ goto error_gk;
+
+ whdr = page_address(page);
+ whdr->epoch = htonl(csp->hdr.epoch);
+ whdr->cid = htonl(csp->hdr.cid);
+ whdr->callNumber = 0;
+ whdr->serial = 0;
+ whdr->seq = 0;
+ whdr->type = RXRPC_PACKET_TYPE_RESPONSE;
+ whdr->flags = conn->out_clientflag;
+ whdr->userStatus = 0;
+ whdr->securityIndex = csp->hdr.securityIndex;
+ whdr->cksum = htons(gk->key_number);
+ whdr->serviceId = htons(csp->hdr.serviceId);
+
+ payload = whdr + 1;
+ xdr = payload;
+
+ *xdr++ = htonl(upper_32_bits(conn->rxgk.start_time));
+ *xdr++ = htonl(lower_32_bits(conn->rxgk.start_time));
+ *xdr++ = htonl(gk->key->ticket.len);
+ memcpy(xdr, gk->key->ticket.data, xdr_round_up(gk->key->ticket.len));
+ xdr += xdr_round_up(gk->key->ticket.len) / sizeof(*xdr);
+ *xdr++ = htonl(authx_len);
+
+ authx_offset = (void *)xdr - payload;
+ auth_offset += authx_offset;
+
+ xdr = (void *)payload + auth_offset;
+ rxgk_construct_authenticator(conn, nonce, xdr);
+
+ sg_init_table(sg, 1);
+ sg_set_buf(&sg[0], payload + authx_offset, authx_len);
+ ret = crypto_krb5_encrypt(gk->krb5, gk->resp_enc,
+ sg, 1, authx_len,
+ auth_offset - authx_offset, auth_len, false);
+ if (ret < 0)
+ goto error;
+
+ ret = rxgk_send_response(conn, page, sizeof(*whdr) + authx_offset + ret);
+error:
+ __free_page(page);
+error_gk:
+ rxgk_put(gk);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Respond to a challenge packet
+ */
+static int rxgk_respond_to_challenge(struct rxrpc_connection *conn,
+ struct sk_buff *skb)
+{
+ u8 nonce[20];
+
+ _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
+
+ if (!conn->key)
+ return rxrpc_abort_conn(conn, skb, RX_PROTOCOL_ERROR, -EPROTO,
+ rxgk_abort_chall_no_key);
+
+ if (key_validate(conn->key) < 0)
+ return rxrpc_abort_conn(conn, skb, RXGK_EXPIRED, -EPROTO,
+ rxgk_abort_chall_key_expired);
+
+ if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+ nonce, sizeof(nonce)) < 0)
+ return rxrpc_abort_conn(conn, skb, RXGK_PACKETSHORT, -EPROTO,
+ rxgk_abort_chall_short);
+
+ return rxgk_construct_response(conn, skb, nonce);
+}
+
+/*
+ * Verify the authenticator.
+ *
+ * struct RXGK_Authenticator {
+ * opaque nonce[20];
+ * opaque appdata<>;
+ * RXGK_Level level;
+ * unsigned int epoch;
+ * unsigned int cid;
+ * unsigned int call_numbers<>;
+ * };
+ */
+static int rxgk_do_verify_authenticator(struct rxrpc_connection *conn,
+ const struct krb5_enctype *krb5,
+ struct sk_buff *skb,
+ __be32 *p, __be32 *end)
+{
+ u32 app_len, call_count, level, epoch, cid, i;
+
+ _enter("");
+
+ if (memcmp(p, conn->rxgk.nonce, 20) != 0)
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_bad_nonce);
+ p += 20 / sizeof(__be32);
+
+ app_len = ntohl(*p++);
+ if (app_len > (end - p) * sizeof(__be32))
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_short_applen);
+
+ p += xdr_round_up(app_len) / sizeof(__be32);
+ if (end - p < 4)
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_short_applen);
+
+ level = ntohl(*p++);
+ epoch = ntohl(*p++);
+ cid = ntohl(*p++);
+ call_count = ntohl(*p++);
+
+ if (level != conn->security_level ||
+ epoch != conn->proto.epoch ||
+ cid != conn->proto.cid ||
+ call_count > 4)
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_bad_param);
+
+ if (end - p < call_count)
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_short_call_list);
+
+ for (i = 0; i < call_count; i++) {
+ u32 call_id = ntohl(*p++);
+
+ if (call_id > INT_MAX)
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_bad_callid);
+
+ if (call_id < conn->channels[i].call_counter)
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_call_ctr);
+
+ if (call_id > conn->channels[i].call_counter) {
+ if (conn->channels[i].call)
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_call_state);
+
+ conn->channels[i].call_counter = call_id;
+ }
+ }
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * Extract the authenticator and verify it.
+ */
+static int rxgk_verify_authenticator(struct rxrpc_connection *conn,
+ const struct krb5_enctype *krb5,
+ struct sk_buff *skb,
+ unsigned int auth_offset, unsigned int auth_len)
+{
+ void *auth;
+ __be32 *p;
+ int ret;
+
+ auth = kmalloc(auth_len, GFP_NOFS);
+ if (!auth)
+ return -ENOMEM;
+
+ ret = skb_copy_bits(skb, auth_offset, auth, auth_len);
+ if (ret < 0) {
+ ret = rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EPROTO,
+ rxgk_abort_resp_short_auth);
+ goto error;
+ }
+
+ p = auth;
+ ret = rxgk_do_verify_authenticator(conn, krb5, skb, p, p + auth_len);
+error:
+ kfree(auth);
+ return ret;
+}
+
+/*
+ * Verify a response.
+ *
+ * struct RXGK_Response {
+ * rxgkTime start_time;
+ * RXGK_Data token;
+ * opaque authenticator<RXGK_MAXAUTHENTICATOR>
+ * };
+ */
+static int rxgk_verify_response(struct rxrpc_connection *conn,
+ struct sk_buff *skb)
+{
+ const struct krb5_enctype *krb5;
+ struct rxrpc_key_token *token;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rxgk_response rhdr;
+ struct rxgk_context *gk;
+ struct key *key = NULL;
+ unsigned int offset = sizeof(struct rxrpc_wire_header);
+ unsigned int len = skb->len - sizeof(struct rxrpc_wire_header);
+ unsigned int token_offset, token_len;
+ unsigned int auth_offset, auth_len;
+ __be32 xauth_len;
+ int ret, ec;
+
+ _enter("{%d}", conn->debug_id);
+
+ /* Parse the RXGK_Response object */
+ if (sizeof(rhdr) + sizeof(__be32) > len)
+ goto short_packet;
+
+ if (skb_copy_bits(skb, offset, &rhdr, sizeof(rhdr)) < 0)
+ goto short_packet;
+ offset += sizeof(rhdr);
+ len -= sizeof(rhdr);
+
+ token_offset = offset;
+ token_len = ntohl(rhdr.token_len);
+ if (xdr_round_up(token_len) + sizeof(__be32) > len)
+ goto short_packet;
+
+ offset += xdr_round_up(token_len);
+ len -= xdr_round_up(token_len);
+
+ if (skb_copy_bits(skb, offset, &xauth_len, sizeof(xauth_len)) < 0)
+ goto short_packet;
+ offset += sizeof(xauth_len);
+ len -= sizeof(xauth_len);
+
+ auth_offset = offset;
+ auth_len = ntohl(xauth_len);
+ if (auth_len < len)
+ goto short_packet;
+ if (auth_len & 3)
+ goto inconsistent;
+ if (auth_len < 20 + 9 * 4)
+ goto auth_too_short;
+
+ /* We need to extract and decrypt the token and instantiate a session
+ * key for it. This bit, however, is application-specific. If
+ * possible, we use a default parser, but we might end up bumping this
+ * to the app to deal with - which might mean a round trip to
+ * userspace.
+ */
+ ret = rxgk_extract_token(conn, skb, token_offset, token_len, &key);
+ if (ret < 0)
+ goto out;
+
+ /* We now have a key instantiated from the decrypted ticket. We can
+ * pass this to the application so that they can parse the ticket
+ * content and we can use the session key it contains to derive the
+ * keys we need.
+ *
+ * Note that we have to switch enctype at this point as the enctype of
+ * the ticket doesn't necessarily match that of the transport.
+ */
+ token = key->payload.data[0];
+ conn->security_level = token->rxgk->level;
+ conn->rxgk.start_time = __be64_to_cpu(rhdr.start_time);
+
+ gk = rxgk_generate_transport_key(conn, token->rxgk, sp->hdr.cksum, GFP_NOFS);
+ if (IS_ERR(gk)) {
+ ret = PTR_ERR(gk);
+ goto cant_get_token;
+ }
+
+ krb5 = gk->krb5;
+
+ /* Decrypt, parse and verify the authenticator. */
+ ret = rxgk_decrypt_skb(krb5, gk->resp_enc, skb,
+ &auth_offset, &auth_len, &ec);
+ if (ret < 0) {
+ rxrpc_abort_conn(conn, skb, RXGK_SEALED_INCON, ret,
+ rxgk_abort_resp_auth_dec);
+ goto out;
+ }
+
+ ret = rxgk_verify_authenticator(conn, krb5, skb, auth_offset, auth_len);
+ if (ret < 0)
+ goto out;
+
+ conn->key = key;
+ key = NULL;
+ ret = 0;
+out:
+ key_put(key);
+ _leave(" = %d", ret);
+ return ret;
+
+inconsistent:
+ ret = rxrpc_abort_conn(conn, skb, RXGK_INCONSISTENCY, -EPROTO,
+ rxgk_abort_resp_xdr_align);
+ goto out;
+auth_too_short:
+ ret = rxrpc_abort_conn(conn, skb, RXGK_PACKETSHORT, -EPROTO,
+ rxgk_abort_resp_short_auth);
+ goto out;
+short_packet:
+ ret = rxrpc_abort_conn(conn, skb, RXGK_PACKETSHORT, -EPROTO,
+ rxgk_abort_resp_short_packet);
+ goto out;
+
+cant_get_token:
+ switch (ret) {
+ case -ENOMEM:
+ goto temporary_error;
+ case -EINVAL:
+ ret = rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EKEYREJECTED,
+ rxgk_abort_resp_internal_error);
+ goto out;
+ case -ENOPKG:
+ ret = rxrpc_abort_conn(conn, skb, RXGK_BADETYPE, -EKEYREJECTED,
+ rxgk_abort_resp_nopkg);
+ goto out;
+ }
+
+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.
+ */
+ goto out;
+}
+
+/*
+ * clear the connection security
+ */
+static void rxgk_clear(struct rxrpc_connection *conn)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(conn->rxgk.keys); i++)
+ rxgk_put(conn->rxgk.keys[i]);
+}
+
+/*
+ * Initialise the RxGK security service.
+ */
+static int rxgk_init(void)
+{
+ return 0;
+}
+
+/*
+ * Clean up the RxGK security service.
+ */
+static void rxgk_exit(void)
+{
+}
+
+/*
+ * RxRPC YFS GSSAPI-based security
+ */
+const struct rxrpc_security rxgk_yfs = {
+ .name = "yfs-rxgk",
+ .security_index = RXRPC_SECURITY_YFS_RXGK,
+ .no_key_abort = RXGK_NOTAUTH,
+ .init = rxgk_init,
+ .exit = rxgk_exit,
+ .preparse_server_key = rxgk_preparse_server_key,
+ .free_preparse_server_key = rxgk_free_preparse_server_key,
+ .destroy_server_key = rxgk_destroy_server_key,
+ .describe_server_key = rxgk_describe_server_key,
+ .init_connection_security = rxgk_init_connection_security,
+ .alloc_txbuf = rxgk_alloc_txbuf,
+ .secure_packet = rxgk_secure_packet,
+ .verify_packet = rxgk_verify_packet,
+ .free_call_crypto = rxgk_free_call_crypto,
+ .issue_challenge = rxgk_issue_challenge,
+ .respond_to_challenge = rxgk_respond_to_challenge,
+ .verify_response = rxgk_verify_response,
+ .clear = rxgk_clear,
+ .default_decode_ticket = rxgk_yfs_decode_ticket,
+};
diff --git a/net/rxrpc/rxgk_app.c b/net/rxrpc/rxgk_app.c
new file mode 100644
index 000000000000..6ca9d1d3e4c6
--- /dev/null
+++ b/net/rxrpc/rxgk_app.c
@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Application-specific bits for GSSAPI-based RxRPC security
+ *
+ * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/key-type.h>
+#include "ar-internal.h"
+#include "rxgk_common.h"
+
+/*
+ * Decode a default-style YFS ticket in a response and turn it into an
+ * rxrpc-type key.
+ *
+ * struct rxgk_key {
+ * afs_uint32 enctype;
+ * opaque key<>;
+ * };
+ *
+ * struct RXGK_AuthName {
+ * afs_int32 kind;
+ * opaque data<AUTHDATAMAX>;
+ * opaque display<AUTHPRINTABLEMAX>;
+ * };
+ *
+ * struct RXGK_Token {
+ * rxgk_key K0;
+ * RXGK_Level level;
+ * rxgkTime starttime;
+ * afs_int32 lifetime;
+ * afs_int32 bytelife;
+ * rxgkTime expirationtime;
+ * struct RXGK_AuthName identities<>;
+ * };
+ */
+int rxgk_yfs_decode_ticket(struct rxrpc_connection *conn, struct sk_buff *skb,
+ unsigned int ticket_offset, unsigned int ticket_len,
+ struct key **_key)
+{
+ struct rxrpc_key_token *token;
+ const struct cred *cred = current_cred(); // TODO - use socket creds
+ struct key *key;
+ size_t pre_ticket_len, payload_len;
+ unsigned int klen, enctype;
+ void *payload, *ticket;
+ __be32 *t, *p, *q, tmp[2];
+ int ret;
+
+ _enter("");
+
+ /* Get the session key length */
+ ret = skb_copy_bits(skb, ticket_offset, tmp, sizeof(tmp));
+ if (ret < 0)
+ return rxrpc_abort_conn(conn, skb, RXGK_INCONSISTENCY, -EPROTO,
+ rxgk_abort_resp_short_yfs_klen);
+ enctype = ntohl(tmp[0]);
+ klen = ntohl(tmp[1]);
+
+ if (klen > ticket_len - 10 * sizeof(__be32))
+ return rxrpc_abort_conn(conn, skb, RXGK_INCONSISTENCY, -EPROTO,
+ rxgk_abort_resp_short_yfs_key);
+
+ pre_ticket_len = ((5 + 14) * sizeof(__be32) +
+ xdr_round_up(klen) +
+ sizeof(__be32));
+ payload_len = pre_ticket_len + xdr_round_up(ticket_len);
+
+ payload = kzalloc(payload_len, GFP_NOFS);
+ if (!payload)
+ return -ENOMEM;
+
+ /* We need to fill out the XDR form for a key payload that we can pass
+ * to add_key(). Start by copying in the ticket so that we can parse
+ * it.
+ */
+ ticket = payload + pre_ticket_len;
+ ret = skb_copy_bits(skb, ticket_offset, ticket, ticket_len);
+ if (ret < 0) {
+ ret = rxrpc_abort_conn(conn, skb, RXGK_INCONSISTENCY, -EPROTO,
+ rxgk_abort_resp_short_yfs_tkt);
+ goto error;
+ }
+
+ /* Fill out the form header. */
+ p = payload;
+ p[0] = htonl(0); /* Flags */
+ p[1] = htonl(1); /* len(cellname) */
+ p[2] = htonl(0x20000000); /* Cellname " " */
+ p[3] = htonl(1); /* #tokens */
+ p[4] = htonl(15 * sizeof(__be32) + xdr_round_up(klen) +
+ xdr_round_up(ticket_len)); /* Token len */
+
+ /* Now fill in the body. Most of this we can just scrape directly from
+ * the ticket.
+ */
+ t = ticket + sizeof(__be32) * 2 + xdr_round_up(klen);
+ q = payload + 5 * sizeof(__be32);
+ q[0] = htonl(RXRPC_SECURITY_YFS_RXGK);
+ q[1] = t[1]; /* begintime - msw */
+ q[2] = t[2]; /* - lsw */
+ q[3] = t[5]; /* endtime - msw */
+ q[4] = t[6]; /* - lsw */
+ q[5] = 0; /* level - msw */
+ q[6] = t[0]; /* - lsw */
+ q[7] = 0; /* lifetime - msw */
+ q[8] = t[3]; /* - lsw */
+ q[9] = 0; /* bytelife - msw */
+ q[10] = t[4]; /* - lsw */
+ q[11] = 0; /* enctype - msw */
+ q[12] = htonl(enctype); /* - lsw */
+ q[13] = htonl(klen); /* Key length */
+
+ q += 14;
+
+ memcpy(q, ticket + sizeof(__be32) * 2, klen);
+ q += xdr_round_up(klen) / 4;
+ q[0] = htonl(ticket_len);
+ q++;
+ if (WARN_ON((unsigned long)q != (unsigned long)ticket)) {
+ ret = -EIO;
+ goto error;
+ }
+
+ /* Ticket read in with skb_copy_bits above */
+ q += xdr_round_up(ticket_len) / 4;
+ if (WARN_ON((unsigned long)q - (unsigned long)payload != payload_len)) {
+ ret = -EIO;
+ goto error;
+ }
+
+ /* Now turn that into a key. */
+ key = key_alloc(&key_type_rxrpc, "x",
+ GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred, 0, // TODO: Use socket owner
+ KEY_ALLOC_NOT_IN_QUOTA, NULL);
+ if (IS_ERR(key)) {
+ _leave(" = -ENOMEM [alloc %ld]", PTR_ERR(key));
+ goto error;
+ }
+
+ _debug("key %d", key_serial(key));
+
+ ret = key_instantiate_and_link(key, payload, payload_len, NULL, NULL);
+ if (ret < 0)
+ goto error_key;
+
+ token = key->payload.data[0];
+ token->no_leak_key = true;
+ *_key = key;
+ key = NULL;
+ ret = 0;
+ goto error;
+
+error_key:
+ key_put(key);
+error:
+ kfree_sensitive(payload);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Extract the token and set up a session key from the details.
+ *
+ * struct RXGK_TokenContainer {
+ * afs_int32 kvno;
+ * afs_int32 enctype;
+ * opaque encrypted_token<>;
+ * };
+ *
+ * [tools.ietf.org/html/draft-wilkinson-afs3-rxgk-afs-08 sec 6.1]
+ */
+int rxgk_extract_token(struct rxrpc_connection *conn, struct sk_buff *skb,
+ unsigned int token_offset, unsigned int token_len,
+ struct key **_key)
+{
+ const struct krb5_enctype *krb5;
+ const struct krb5_buffer *server_secret;
+ struct crypto_aead *token_enc = NULL;
+ struct key *server_key;
+ unsigned int ticket_offset, ticket_len;
+ u32 kvno, enctype;
+ int ret, ec;
+
+ struct {
+ __be32 kvno;
+ __be32 enctype;
+ __be32 token_len;
+ } container;
+
+ /* Decode the RXGK_TokenContainer object. This tells us which server
+ * key we should be using. We can then fetch the key, get the secret
+ * and set up the crypto to extract the token.
+ */
+ if (skb_copy_bits(skb, token_offset, &container, sizeof(container)) < 0)
+ return rxrpc_abort_conn(conn, skb, RXGK_PACKETSHORT, -EPROTO,
+ rxgk_abort_resp_tok_short);
+
+ kvno = ntohl(container.kvno);
+ enctype = ntohl(container.enctype);
+ ticket_len = ntohl(container.token_len);
+ ticket_offset = token_offset + sizeof(container);
+
+ if (xdr_round_up(ticket_len) > token_len - 3 * 4)
+ return rxrpc_abort_conn(conn, skb, RXGK_PACKETSHORT, -EPROTO,
+ rxgk_abort_resp_tok_short);
+
+ _debug("KVNO %u", kvno);
+ _debug("ENC %u", enctype);
+ _debug("TLEN %u", ticket_len);
+
+ server_key = rxrpc_look_up_server_security(conn, skb, kvno, enctype);
+ if (IS_ERR(server_key))
+ goto cant_get_server_key;
+
+ down_read(&server_key->sem);
+ server_secret = (const void *)&server_key->payload.data[2];
+ ret = rxgk_set_up_token_cipher(server_secret, &token_enc, enctype, &krb5, GFP_NOFS);
+ up_read(&server_key->sem);
+ key_put(server_key);
+ if (ret < 0)
+ goto cant_get_token;
+
+ /* We can now decrypt and parse the token/ticket. This allows us to
+ * gain access to K0, from which we can derive the transport key and
+ * thence decode the authenticator.
+ */
+ ret = rxgk_decrypt_skb(krb5, token_enc, skb,
+ &ticket_offset, &ticket_len, &ec);
+ crypto_free_aead(token_enc);
+ token_enc = NULL;
+ if (ret < 0)
+ return rxrpc_abort_conn(conn, skb, ec, ret,
+ rxgk_abort_resp_tok_dec);
+
+ ret = conn->security->default_decode_ticket(conn, skb, ticket_offset,
+ ticket_len, _key);
+ if (ret < 0)
+ goto cant_get_token;
+
+ _leave(" = 0");
+ return ret;
+
+cant_get_server_key:
+ ret = PTR_ERR(server_key);
+ switch (ret) {
+ case -ENOMEM:
+ goto temporary_error;
+ case -ENOKEY:
+ case -EKEYREJECTED:
+ case -EKEYEXPIRED:
+ case -EKEYREVOKED:
+ case -EPERM:
+ return rxrpc_abort_conn(conn, skb, RXGK_BADKEYNO, -EKEYREJECTED,
+ rxgk_abort_resp_tok_nokey);
+ default:
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EKEYREJECTED,
+ rxgk_abort_resp_tok_keyerr);
+ }
+
+cant_get_token:
+ switch (ret) {
+ case -ENOMEM:
+ goto temporary_error;
+ case -EINVAL:
+ return rxrpc_abort_conn(conn, skb, RXGK_NOTAUTH, -EKEYREJECTED,
+ rxgk_abort_resp_tok_internal_error);
+ case -ENOPKG:
+ return rxrpc_abort_conn(conn, skb, RXGK_BADETYPE, -EKEYREJECTED,
+ rxgk_abort_resp_tok_nopkg);
+ }
+
+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.
+ */
+ return ret;
+}
diff --git a/net/rxrpc/rxgk_common.h b/net/rxrpc/rxgk_common.h
index c07a5386b303..e5becb16fe64 100644
--- a/net/rxrpc/rxgk_common.h
+++ b/net/rxrpc/rxgk_common.h
@@ -33,6 +33,18 @@ struct rxgk_context {
struct crypto_aead *resp_enc; /* Response packet enc key */
};

+#define xdr_round_up(x) (round_up((x), sizeof(__be32)))
+
+/*
+ * rxgk_app.c
+ */
+int rxgk_yfs_decode_ticket(struct rxrpc_connection *conn, struct sk_buff *skb,
+ unsigned int ticket_offset, unsigned int ticket_len,
+ struct key **_key);
+int rxgk_extract_token(struct rxrpc_connection *conn, struct sk_buff *skb,
+ unsigned int token_offset, unsigned int token_len,
+ struct key **_key);
+
/*
* rxgk_kdf.c
*/
@@ -46,3 +58,83 @@ int rxgk_set_up_token_cipher(const struct krb5_buffer *server_key,
unsigned int enctype,
const struct krb5_enctype **_krb5,
gfp_t gfp);
+
+/*
+ * Apply decryption and checksumming functions to part of an skbuff. The
+ * offset and length are updated to reflect the actual content of the encrypted
+ * region.
+ */
+static inline
+int rxgk_decrypt_skb(const struct krb5_enctype *krb5,
+ struct crypto_aead *aead,
+ struct sk_buff *skb,
+ unsigned int *_offset, unsigned int *_len,
+ int *_error_code)
+{
+ struct scatterlist sg[16];
+ size_t offset = 0, len = *_len;
+ int nr_sg, ret;
+
+ sg_init_table(sg, ARRAY_SIZE(sg));
+ nr_sg = skb_to_sgvec(skb, sg, *_offset, len);
+ if (unlikely(nr_sg < 0))
+ return nr_sg;
+
+ ret = crypto_krb5_decrypt(krb5, aead, sg, nr_sg,
+ &offset, &len);
+ switch (ret) {
+ case 0:
+ *_offset += offset;
+ *_len = len;
+ break;
+ case -EPROTO:
+ case -EBADMSG:
+ *_error_code = RXGK_SEALED_INCON;
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+/*
+ * Check the MIC on a region of an skbuff. The offset and length are updated
+ * to reflect the actual content of the secure region.
+ */
+static inline
+int rxgk_verify_mic_skb(const struct krb5_enctype *krb5,
+ struct crypto_shash *shash,
+ const struct krb5_buffer *metadata,
+ struct sk_buff *skb,
+ unsigned int *_offset, unsigned int *_len,
+ u32 *_error_code)
+{
+ struct scatterlist sg[16];
+ size_t offset = 0, len = *_len;
+ int nr_sg, ret;
+
+ sg_init_table(sg, ARRAY_SIZE(sg));
+ nr_sg = skb_to_sgvec(skb, sg, *_offset, len);
+ if (unlikely(nr_sg < 0))
+ return nr_sg;
+
+ ret = crypto_krb5_verify_mic(krb5, shash, metadata, sg, nr_sg,
+ &offset, &len);
+ switch (ret) {
+ case 0:
+ *_offset += offset;
+ *_len = len;
+ break;
+ case -EPROTO:
+ case -EBADMSG:
+ *_error_code = RXGK_SEALED_INCON;
+ break;
+ default:
+ break;
+ }
+
+ *_offset += offset;
+ *_len = len;
+ return ret;
+}
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 62b09d23ec08..773405b55392 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -177,8 +177,10 @@ static struct rxrpc_txbuf *rxkad_alloc_txbuf(struct rxrpc_call *call, size_t rem
if (!txb)
return NULL;

- txb->offset += shdr;
- txb->space = part;
+ txb->crypto_header = 0;
+ txb->sec_header = shdr;
+ txb->offset += shdr;
+ txb->space = part;
return txb;
}

diff --git a/net/rxrpc/security.c b/net/rxrpc/security.c
index 9784adc8f275..078d91a6b77f 100644
--- a/net/rxrpc/security.c
+++ b/net/rxrpc/security.c
@@ -20,6 +20,9 @@ static const struct rxrpc_security *rxrpc_security_types[] = {
#ifdef CONFIG_RXKAD
[RXRPC_SECURITY_RXKAD] = &rxkad,
#endif
+#ifdef CONFIG_RXGK
+ [RXRPC_SECURITY_YFS_RXGK] = &rxgk_yfs,
+#endif
};

int __init rxrpc_init_security(void)