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-rw-r--r--net/rxrpc/rxkad.c1161
1 files changed, 1161 insertions, 0 deletions
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
new file mode 100644
index 00000000..76351077
--- /dev/null
+++ b/net/rxrpc/rxkad.c
@@ -0,0 +1,1161 @@
+/* Kerberos-based RxRPC security
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/udp.h>
+#include <linux/crypto.h>
+#include <linux/scatterlist.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include <keys/rxrpc-type.h>
+#define rxrpc_debug rxkad_debug
+#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 */
+
+unsigned rxrpc_debug;
+module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(debug, "rxkad debugging mask");
+
+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 */
+};
+
+MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos 4)");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
+/*
+ * 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_blkcipher *rxkad_ci;
+static DEFINE_MUTEX(rxkad_ci_mutex);
+
+/*
+ * initialise connection security
+ */
+static int rxkad_init_connection_security(struct rxrpc_connection *conn)
+{
+ struct crypto_blkcipher *ci;
+ struct rxrpc_key_token *token;
+ int ret;
+
+ _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
+
+ token = conn->key->payload.data;
+ conn->security_ix = token->security_index;
+
+ ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(ci)) {
+ _debug("no cipher");
+ ret = PTR_ERR(ci);
+ goto error;
+ }
+
+ if (crypto_blkcipher_setkey(ci, token->kad->session_key,
+ sizeof(token->kad->session_key)) < 0)
+ BUG();
+
+ switch (conn->security_level) {
+ case RXRPC_SECURITY_PLAIN:
+ break;
+ case RXRPC_SECURITY_AUTH:
+ conn->size_align = 8;
+ conn->security_size = sizeof(struct rxkad_level1_hdr);
+ conn->header_size += sizeof(struct rxkad_level1_hdr);
+ break;
+ case RXRPC_SECURITY_ENCRYPT:
+ conn->size_align = 8;
+ conn->security_size = sizeof(struct rxkad_level2_hdr);
+ conn->header_size += sizeof(struct rxkad_level2_hdr);
+ break;
+ default:
+ ret = -EKEYREJECTED;
+ goto error;
+ }
+
+ conn->cipher = ci;
+ ret = 0;
+error:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * prime the encryption state with the invariant parts of a connection's
+ * description
+ */
+static void rxkad_prime_packet_security(struct rxrpc_connection *conn)
+{
+ struct rxrpc_key_token *token;
+ struct blkcipher_desc desc;
+ struct scatterlist sg[2];
+ struct rxrpc_crypt iv;
+ struct {
+ __be32 x[4];
+ } tmpbuf __attribute__((aligned(16))); /* must all be in same page */
+
+ _enter("");
+
+ if (!conn->key)
+ return;
+
+ token = conn->key->payload.data;
+ memcpy(&iv, token->kad->session_key, sizeof(iv));
+
+ desc.tfm = conn->cipher;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ tmpbuf.x[0] = conn->epoch;
+ tmpbuf.x[1] = conn->cid;
+ tmpbuf.x[2] = 0;
+ tmpbuf.x[3] = htonl(conn->security_ix);
+
+ sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
+ sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
+ crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
+
+ memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
+ ASSERTCMP(conn->csum_iv.n[0], ==, tmpbuf.x[2]);
+
+ _leave("");
+}
+
+/*
+ * partially encrypt a packet (level 1 security)
+ */
+static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
+ struct sk_buff *skb,
+ u32 data_size,
+ void *sechdr)
+{
+ struct rxrpc_skb_priv *sp;
+ struct blkcipher_desc desc;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg[2];
+ struct {
+ struct rxkad_level1_hdr hdr;
+ __be32 first; /* first four bytes of data and padding */
+ } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
+ u16 check;
+
+ sp = rxrpc_skb(skb);
+
+ _enter("");
+
+ check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
+ data_size |= (u32) check << 16;
+
+ tmpbuf.hdr.data_size = htonl(data_size);
+ memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first));
+
+ /* start the encryption afresh */
+ memset(&iv, 0, sizeof(iv));
+ desc.tfm = call->conn->cipher;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
+ sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
+ crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
+
+ memcpy(sechdr, &tmpbuf, sizeof(tmpbuf));
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * wholly encrypt a packet (level 2 security)
+ */
+static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
+ struct sk_buff *skb,
+ u32 data_size,
+ void *sechdr)
+{
+ const struct rxrpc_key_token *token;
+ struct rxkad_level2_hdr rxkhdr
+ __attribute__((aligned(8))); /* must be all on one page */
+ struct rxrpc_skb_priv *sp;
+ struct blkcipher_desc desc;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg[16];
+ struct sk_buff *trailer;
+ unsigned len;
+ u16 check;
+ int nsg;
+
+ sp = rxrpc_skb(skb);
+
+ _enter("");
+
+ check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
+
+ rxkhdr.data_size = htonl(data_size | (u32) check << 16);
+ rxkhdr.checksum = 0;
+
+ /* encrypt from the session key */
+ token = call->conn->key->payload.data;
+ memcpy(&iv, token->kad->session_key, sizeof(iv));
+ desc.tfm = call->conn->cipher;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
+ sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
+ crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr));
+
+ /* we want to encrypt the skbuff in-place */
+ nsg = skb_cow_data(skb, 0, &trailer);
+ if (nsg < 0 || nsg > 16)
+ return -ENOMEM;
+
+ len = data_size + call->conn->size_align - 1;
+ len &= ~(call->conn->size_align - 1);
+
+ sg_init_table(sg, nsg);
+ skb_to_sgvec(skb, sg, 0, len);
+ crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * checksum an RxRPC packet header
+ */
+static int rxkad_secure_packet(const struct rxrpc_call *call,
+ struct sk_buff *skb,
+ size_t data_size,
+ void *sechdr)
+{
+ struct rxrpc_skb_priv *sp;
+ struct blkcipher_desc desc;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg[2];
+ struct {
+ __be32 x[2];
+ } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
+ __be32 x;
+ u32 y;
+ int ret;
+
+ sp = rxrpc_skb(skb);
+
+ _enter("{%d{%x}},{#%u},%zu,",
+ call->debug_id, key_serial(call->conn->key), ntohl(sp->hdr.seq),
+ data_size);
+
+ if (!call->conn->cipher)
+ return 0;
+
+ ret = key_validate(call->conn->key);
+ if (ret < 0)
+ return ret;
+
+ /* continue encrypting from where we left off */
+ memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
+ desc.tfm = call->conn->cipher;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ /* calculate the security checksum */
+ x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
+ x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
+ tmpbuf.x[0] = sp->hdr.callNumber;
+ tmpbuf.x[1] = x;
+
+ sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
+ sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
+ crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
+
+ y = ntohl(tmpbuf.x[1]);
+ y = (y >> 16) & 0xffff;
+ if (y == 0)
+ y = 1; /* zero checksums are not permitted */
+ sp->hdr.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, skb, data_size, sechdr);
+ break;
+ case RXRPC_SECURITY_ENCRYPT:
+ ret = rxkad_secure_packet_encrypt(call, skb, data_size,
+ sechdr);
+ break;
+ default:
+ ret = -EPERM;
+ break;
+ }
+
+ _leave(" = %d [set %hx]", ret, y);
+ return ret;
+}
+
+/*
+ * decrypt partial encryption on a packet (level 1 security)
+ */
+static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
+ struct sk_buff *skb,
+ u32 *_abort_code)
+{
+ struct rxkad_level1_hdr sechdr;
+ struct rxrpc_skb_priv *sp;
+ struct blkcipher_desc desc;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg[16];
+ struct sk_buff *trailer;
+ u32 data_size, buf;
+ u16 check;
+ int nsg;
+
+ _enter("");
+
+ sp = rxrpc_skb(skb);
+
+ /* we want to decrypt the skbuff in-place */
+ nsg = skb_cow_data(skb, 0, &trailer);
+ if (nsg < 0 || nsg > 16)
+ goto nomem;
+
+ sg_init_table(sg, nsg);
+ skb_to_sgvec(skb, sg, 0, 8);
+
+ /* start the decryption afresh */
+ memset(&iv, 0, sizeof(iv));
+ desc.tfm = call->conn->cipher;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ crypto_blkcipher_decrypt_iv(&desc, sg, sg, 8);
+
+ /* remove the decrypted packet length */
+ if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
+ goto datalen_error;
+ if (!skb_pull(skb, sizeof(sechdr)))
+ BUG();
+
+ buf = ntohl(sechdr.data_size);
+ data_size = buf & 0xffff;
+
+ check = buf >> 16;
+ check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
+ check &= 0xffff;
+ if (check != 0) {
+ *_abort_code = RXKADSEALEDINCON;
+ goto protocol_error;
+ }
+
+ /* shorten the packet to remove the padding */
+ if (data_size > skb->len)
+ goto datalen_error;
+ else if (data_size < skb->len)
+ skb->len = data_size;
+
+ _leave(" = 0 [dlen=%x]", data_size);
+ return 0;
+
+datalen_error:
+ *_abort_code = RXKADDATALEN;
+protocol_error:
+ _leave(" = -EPROTO");
+ return -EPROTO;
+
+nomem:
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+}
+
+/*
+ * wholly decrypt a packet (level 2 security)
+ */
+static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
+ struct sk_buff *skb,
+ u32 *_abort_code)
+{
+ const struct rxrpc_key_token *token;
+ struct rxkad_level2_hdr sechdr;
+ struct rxrpc_skb_priv *sp;
+ struct blkcipher_desc desc;
+ struct rxrpc_crypt iv;
+ struct scatterlist _sg[4], *sg;
+ struct sk_buff *trailer;
+ u32 data_size, buf;
+ u16 check;
+ int nsg;
+
+ _enter(",{%d}", skb->len);
+
+ sp = rxrpc_skb(skb);
+
+ /* we want to decrypt the skbuff in-place */
+ nsg = skb_cow_data(skb, 0, &trailer);
+ if (nsg < 0)
+ goto nomem;
+
+ sg = _sg;
+ if (unlikely(nsg > 4)) {
+ sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
+ if (!sg)
+ goto nomem;
+ }
+
+ sg_init_table(sg, nsg);
+ skb_to_sgvec(skb, sg, 0, skb->len);
+
+ /* decrypt from the session key */
+ token = call->conn->key->payload.data;
+ memcpy(&iv, token->kad->session_key, sizeof(iv));
+ desc.tfm = call->conn->cipher;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ crypto_blkcipher_decrypt_iv(&desc, sg, sg, skb->len);
+ if (sg != _sg)
+ kfree(sg);
+
+ /* remove the decrypted packet length */
+ if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
+ goto datalen_error;
+ if (!skb_pull(skb, sizeof(sechdr)))
+ BUG();
+
+ buf = ntohl(sechdr.data_size);
+ data_size = buf & 0xffff;
+
+ check = buf >> 16;
+ check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
+ check &= 0xffff;
+ if (check != 0) {
+ *_abort_code = RXKADSEALEDINCON;
+ goto protocol_error;
+ }
+
+ /* shorten the packet to remove the padding */
+ if (data_size > skb->len)
+ goto datalen_error;
+ else if (data_size < skb->len)
+ skb->len = data_size;
+
+ _leave(" = 0 [dlen=%x]", data_size);
+ return 0;
+
+datalen_error:
+ *_abort_code = RXKADDATALEN;
+protocol_error:
+ _leave(" = -EPROTO");
+ return -EPROTO;
+
+nomem:
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+}
+
+/*
+ * verify the security on a received packet
+ */
+static int rxkad_verify_packet(const struct rxrpc_call *call,
+ struct sk_buff *skb,
+ u32 *_abort_code)
+{
+ struct blkcipher_desc desc;
+ struct rxrpc_skb_priv *sp;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg[2];
+ struct {
+ __be32 x[2];
+ } tmpbuf __attribute__((aligned(8))); /* must all be in same page */
+ __be32 x;
+ __be16 cksum;
+ u32 y;
+ int ret;
+
+ sp = rxrpc_skb(skb);
+
+ _enter("{%d{%x}},{#%u}",
+ call->debug_id, key_serial(call->conn->key),
+ ntohl(sp->hdr.seq));
+
+ if (!call->conn->cipher)
+ return 0;
+
+ if (sp->hdr.securityIndex != RXRPC_SECURITY_RXKAD) {
+ *_abort_code = RXKADINCONSISTENCY;
+ _leave(" = -EPROTO [not rxkad]");
+ return -EPROTO;
+ }
+
+ /* continue encrypting from where we left off */
+ memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
+ desc.tfm = call->conn->cipher;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ /* validate the security checksum */
+ x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
+ x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
+ tmpbuf.x[0] = call->call_id;
+ tmpbuf.x[1] = x;
+
+ sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
+ sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
+ crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
+
+ y = ntohl(tmpbuf.x[1]);
+ y = (y >> 16) & 0xffff;
+ if (y == 0)
+ y = 1; /* zero checksums are not permitted */
+
+ cksum = htons(y);
+ if (sp->hdr.cksum != cksum) {
+ *_abort_code = RXKADSEALEDINCON;
+ _leave(" = -EPROTO [csum failed]");
+ return -EPROTO;
+ }
+
+ switch (call->conn->security_level) {
+ case RXRPC_SECURITY_PLAIN:
+ ret = 0;
+ break;
+ case RXRPC_SECURITY_AUTH:
+ ret = rxkad_verify_packet_auth(call, skb, _abort_code);
+ break;
+ case RXRPC_SECURITY_ENCRYPT:
+ ret = rxkad_verify_packet_encrypt(call, skb, _abort_code);
+ break;
+ default:
+ ret = -ENOANO;
+ break;
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * issue a challenge
+ */
+static int rxkad_issue_challenge(struct rxrpc_connection *conn)
+{
+ struct rxkad_challenge challenge;
+ struct rxrpc_header hdr;
+ struct msghdr msg;
+ struct kvec iov[2];
+ size_t len;
+ int ret;
+
+ _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
+
+ ret = key_validate(conn->key);
+ if (ret < 0)
+ return ret;
+
+ get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
+
+ challenge.version = htonl(2);
+ challenge.nonce = htonl(conn->security_nonce);
+ challenge.min_level = htonl(0);
+ challenge.__padding = 0;
+
+ msg.msg_name = &conn->trans->peer->srx.transport.sin;
+ msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = 0;
+
+ hdr.epoch = conn->epoch;
+ hdr.cid = conn->cid;
+ hdr.callNumber = 0;
+ hdr.seq = 0;
+ hdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
+ hdr.flags = conn->out_clientflag;
+ hdr.userStatus = 0;
+ hdr.securityIndex = conn->security_ix;
+ hdr._rsvd = 0;
+ hdr.serviceId = conn->service_id;
+
+ iov[0].iov_base = &hdr;
+ iov[0].iov_len = sizeof(hdr);
+ iov[1].iov_base = &challenge;
+ iov[1].iov_len = sizeof(challenge);
+
+ len = iov[0].iov_len + iov[1].iov_len;
+
+ hdr.serial = htonl(atomic_inc_return(&conn->serial));
+ _proto("Tx CHALLENGE %%%u", ntohl(hdr.serial));
+
+ ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len);
+ if (ret < 0) {
+ _debug("sendmsg failed: %d", ret);
+ return -EAGAIN;
+ }
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * send a Kerberos security response
+ */
+static int rxkad_send_response(struct rxrpc_connection *conn,
+ struct rxrpc_header *hdr,
+ struct rxkad_response *resp,
+ const struct rxkad_key *s2)
+{
+ struct msghdr msg;
+ struct kvec iov[3];
+ size_t len;
+ int ret;
+
+ _enter("");
+
+ msg.msg_name = &conn->trans->peer->srx.transport.sin;
+ msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = 0;
+
+ hdr->epoch = conn->epoch;
+ hdr->seq = 0;
+ hdr->type = RXRPC_PACKET_TYPE_RESPONSE;
+ hdr->flags = conn->out_clientflag;
+ hdr->userStatus = 0;
+ hdr->_rsvd = 0;
+
+ iov[0].iov_base = hdr;
+ iov[0].iov_len = sizeof(*hdr);
+ 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;
+
+ hdr->serial = htonl(atomic_inc_return(&conn->serial));
+ _proto("Tx RESPONSE %%%u", ntohl(hdr->serial));
+
+ ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 3, len);
+ if (ret < 0) {
+ _debug("sendmsg failed: %d", ret);
+ return -EAGAIN;
+ }
+
+ _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);
+}
+
+/*
+ * load a scatterlist with a potentially split-page buffer
+ */
+static void rxkad_sg_set_buf2(struct scatterlist sg[2],
+ void *buf, size_t buflen)
+{
+ int nsg = 1;
+
+ sg_init_table(sg, 2);
+
+ sg_set_buf(&sg[0], buf, buflen);
+ if (sg[0].offset + buflen > PAGE_SIZE) {
+ /* the buffer was split over two pages */
+ sg[0].length = PAGE_SIZE - sg[0].offset;
+ sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
+ nsg++;
+ }
+
+ sg_mark_end(&sg[nsg - 1]);
+
+ ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
+}
+
+/*
+ * encrypt the response packet
+ */
+static void rxkad_encrypt_response(struct rxrpc_connection *conn,
+ struct rxkad_response *resp,
+ const struct rxkad_key *s2)
+{
+ struct blkcipher_desc desc;
+ struct rxrpc_crypt iv;
+ struct scatterlist sg[2];
+
+ /* continue encrypting from where we left off */
+ memcpy(&iv, s2->session_key, sizeof(iv));
+ desc.tfm = conn->cipher;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
+ crypto_blkcipher_encrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
+}
+
+/*
+ * respond to a challenge packet
+ */
+static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
+ struct sk_buff *skb,
+ u32 *_abort_code)
+{
+ const struct rxrpc_key_token *token;
+ struct rxkad_challenge challenge;
+ struct rxkad_response resp
+ __attribute__((aligned(8))); /* must be aligned for crypto */
+ struct rxrpc_skb_priv *sp;
+ u32 version, nonce, min_level, abort_code;
+ int ret;
+
+ _enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
+
+ if (!conn->key) {
+ _leave(" = -EPROTO [no key]");
+ return -EPROTO;
+ }
+
+ ret = key_validate(conn->key);
+ if (ret < 0) {
+ *_abort_code = RXKADEXPIRED;
+ return ret;
+ }
+
+ abort_code = RXKADPACKETSHORT;
+ sp = rxrpc_skb(skb);
+ if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0)
+ goto protocol_error;
+
+ version = ntohl(challenge.version);
+ nonce = ntohl(challenge.nonce);
+ min_level = ntohl(challenge.min_level);
+
+ _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
+ ntohl(sp->hdr.serial), version, nonce, min_level);
+
+ abort_code = RXKADINCONSISTENCY;
+ if (version != RXKAD_VERSION)
+ goto protocol_error;
+
+ abort_code = RXKADLEVELFAIL;
+ if (conn->security_level < min_level)
+ goto protocol_error;
+
+ token = conn->key->payload.data;
+
+ /* build the response packet */
+ memset(&resp, 0, sizeof(resp));
+
+ resp.version = RXKAD_VERSION;
+ resp.encrypted.epoch = conn->epoch;
+ resp.encrypted.cid = conn->cid;
+ resp.encrypted.securityIndex = htonl(conn->security_ix);
+ resp.encrypted.call_id[0] =
+ (conn->channels[0] ? conn->channels[0]->call_id : 0);
+ resp.encrypted.call_id[1] =
+ (conn->channels[1] ? conn->channels[1]->call_id : 0);
+ resp.encrypted.call_id[2] =
+ (conn->channels[2] ? conn->channels[2]->call_id : 0);
+ resp.encrypted.call_id[3] =
+ (conn->channels[3] ? conn->channels[3]->call_id : 0);
+ 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);
+
+ /* calculate the response checksum and then do the encryption */
+ rxkad_calc_response_checksum(&resp);
+ rxkad_encrypt_response(conn, &resp, token->kad);
+ return rxkad_send_response(conn, &sp->hdr, &resp, token->kad);
+
+protocol_error:
+ *_abort_code = abort_code;
+ _leave(" = -EPROTO [%d]", abort_code);
+ return -EPROTO;
+}
+
+/*
+ * decrypt the kerberos IV ticket in the response
+ */
+static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
+ void *ticket, size_t ticket_len,
+ struct rxrpc_crypt *_session_key,
+ time_t *_expiry,
+ u32 *_abort_code)
+{
+ struct blkcipher_desc desc;
+ struct rxrpc_crypt iv, key;
+ struct scatterlist sg[1];
+ struct in_addr addr;
+ unsigned life;
+ time_t issue, now;
+ bool little_endian;
+ int ret;
+ u8 *p, *q, *name, *end;
+
+ _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
+
+ *_expiry = 0;
+
+ ret = key_validate(conn->server_key);
+ if (ret < 0) {
+ switch (ret) {
+ case -EKEYEXPIRED:
+ *_abort_code = RXKADEXPIRED;
+ goto error;
+ default:
+ *_abort_code = RXKADNOAUTH;
+ goto error;
+ }
+ }
+
+ ASSERT(conn->server_key->payload.data != NULL);
+ ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
+
+ memcpy(&iv, &conn->server_key->type_data, sizeof(iv));
+
+ desc.tfm = conn->server_key->payload.data;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ sg_init_one(&sg[0], ticket, ticket_len);
+ crypto_blkcipher_decrypt_iv(&desc, sg, sg, ticket_len);
+
+ p = ticket;
+ end = p + ticket_len;
+
+#define Z(size) \
+ ({ \
+ u8 *__str = p; \
+ q = memchr(p, 0, end - p); \
+ if (!q || q - p > (size)) \
+ goto bad_ticket; \
+ for (; p < q; p++) \
+ if (!isprint(*p)) \
+ goto bad_ticket; \
+ p++; \
+ __str; \
+ })
+
+ /* extract the ticket flags */
+ _debug("KIV FLAGS: %x", *p);
+ little_endian = *p & 1;
+ p++;
+
+ /* extract the authentication name */
+ name = Z(ANAME_SZ);
+ _debug("KIV ANAME: %s", name);
+
+ /* extract the principal's instance */
+ name = Z(INST_SZ);
+ _debug("KIV INST : %s", name);
+
+ /* extract the principal's authentication domain */
+ name = Z(REALM_SZ);
+ _debug("KIV REALM: %s", name);
+
+ if (end - p < 4 + 8 + 4 + 2)
+ goto bad_ticket;
+
+ /* 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 = le32_to_cpu(stamp);
+ } else {
+ __be32 stamp;
+ memcpy(&stamp, p, 4);
+ issue = be32_to_cpu(stamp);
+ }
+ p += 4;
+ now = get_seconds();
+ _debug("KIV ISSUE: %lx [%lx]", issue, now);
+
+ /* check the ticket is in date */
+ if (issue > now) {
+ *_abort_code = RXKADNOAUTH;
+ ret = -EKEYREJECTED;
+ goto error;
+ }
+
+ if (issue < now - life) {
+ *_abort_code = RXKADEXPIRED;
+ ret = -EKEYEXPIRED;
+ goto error;
+ }
+
+ *_expiry = issue + life;
+
+ /* get the service name */
+ name = Z(SNAME_SZ);
+ _debug("KIV SNAME: %s", name);
+
+ /* get the service instance name */
+ name = Z(INST_SZ);
+ _debug("KIV SINST: %s", name);
+
+ ret = 0;
+error:
+ _leave(" = %d", ret);
+ return ret;
+
+bad_ticket:
+ *_abort_code = RXKADBADTICKET;
+ ret = -EBADMSG;
+ goto error;
+}
+
+/*
+ * decrypt the response packet
+ */
+static void rxkad_decrypt_response(struct rxrpc_connection *conn,
+ struct rxkad_response *resp,
+ const struct rxrpc_crypt *session_key)
+{
+ struct blkcipher_desc desc;
+ struct scatterlist sg[2];
+ struct rxrpc_crypt iv;
+
+ _enter(",,%08x%08x",
+ ntohl(session_key->n[0]), ntohl(session_key->n[1]));
+
+ ASSERT(rxkad_ci != NULL);
+
+ mutex_lock(&rxkad_ci_mutex);
+ if (crypto_blkcipher_setkey(rxkad_ci, session_key->x,
+ sizeof(*session_key)) < 0)
+ BUG();
+
+ memcpy(&iv, session_key, sizeof(iv));
+ desc.tfm = rxkad_ci;
+ desc.info = iv.x;
+ desc.flags = 0;
+
+ rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
+ crypto_blkcipher_decrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
+ mutex_unlock(&rxkad_ci_mutex);
+
+ _leave("");
+}
+
+/*
+ * verify a response
+ */
+static int rxkad_verify_response(struct rxrpc_connection *conn,
+ struct sk_buff *skb,
+ u32 *_abort_code)
+{
+ struct rxkad_response response
+ __attribute__((aligned(8))); /* must be aligned for crypto */
+ struct rxrpc_skb_priv *sp;
+ struct rxrpc_crypt session_key;
+ time_t expiry;
+ void *ticket;
+ u32 abort_code, version, kvno, ticket_len, level;
+ __be32 csum;
+ int ret;
+
+ _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
+
+ abort_code = RXKADPACKETSHORT;
+ if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0)
+ goto protocol_error;
+ if (!pskb_pull(skb, sizeof(response)))
+ BUG();
+
+ version = ntohl(response.version);
+ ticket_len = ntohl(response.ticket_len);
+ kvno = ntohl(response.kvno);
+ sp = rxrpc_skb(skb);
+ _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
+ ntohl(sp->hdr.serial), version, kvno, ticket_len);
+
+ abort_code = RXKADINCONSISTENCY;
+ if (version != RXKAD_VERSION)
+ goto protocol_error;
+
+ abort_code = RXKADTICKETLEN;
+ if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
+ goto protocol_error;
+
+ abort_code = RXKADUNKNOWNKEY;
+ if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
+ goto protocol_error;
+
+ /* extract the kerberos ticket and decrypt and decode it */
+ ticket = kmalloc(ticket_len, GFP_NOFS);
+ if (!ticket)
+ return -ENOMEM;
+
+ abort_code = RXKADPACKETSHORT;
+ if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
+ goto protocol_error_free;
+
+ ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
+ &expiry, &abort_code);
+ if (ret < 0) {
+ *_abort_code = abort_code;
+ kfree(ticket);
+ return ret;
+ }
+
+ /* use the session key from inside the ticket to decrypt the
+ * response */
+ rxkad_decrypt_response(conn, &response, &session_key);
+
+ abort_code = RXKADSEALEDINCON;
+ if (response.encrypted.epoch != conn->epoch)
+ goto protocol_error_free;
+ if (response.encrypted.cid != conn->cid)
+ goto protocol_error_free;
+ if (ntohl(response.encrypted.securityIndex) != conn->security_ix)
+ goto protocol_error_free;
+ csum = response.encrypted.checksum;
+ response.encrypted.checksum = 0;
+ rxkad_calc_response_checksum(&response);
+ if (response.encrypted.checksum != csum)
+ goto protocol_error_free;
+
+ if (ntohl(response.encrypted.call_id[0]) > INT_MAX ||
+ ntohl(response.encrypted.call_id[1]) > INT_MAX ||
+ ntohl(response.encrypted.call_id[2]) > INT_MAX ||
+ ntohl(response.encrypted.call_id[3]) > INT_MAX)
+ goto protocol_error_free;
+
+ abort_code = RXKADOUTOFSEQUENCE;
+ if (response.encrypted.inc_nonce != htonl(conn->security_nonce + 1))
+ goto protocol_error_free;
+
+ abort_code = RXKADLEVELFAIL;
+ level = ntohl(response.encrypted.level);
+ if (level > RXRPC_SECURITY_ENCRYPT)
+ 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) {
+ kfree(ticket);
+ return ret;
+ }
+
+ kfree(ticket);
+ _leave(" = 0");
+ return 0;
+
+protocol_error_free:
+ kfree(ticket);
+protocol_error:
+ *_abort_code = abort_code;
+ _leave(" = -EPROTO [%d]", abort_code);
+ return -EPROTO;
+}
+
+/*
+ * clear the connection security
+ */
+static void rxkad_clear(struct rxrpc_connection *conn)
+{
+ _enter("");
+
+ if (conn->cipher)
+ crypto_free_blkcipher(conn->cipher);
+}
+
+/*
+ * RxRPC Kerberos-based security
+ */
+static struct rxrpc_security rxkad = {
+ .owner = THIS_MODULE,
+ .name = "rxkad",
+ .security_index = RXRPC_SECURITY_RXKAD,
+ .init_connection_security = rxkad_init_connection_security,
+ .prime_packet_security = rxkad_prime_packet_security,
+ .secure_packet = rxkad_secure_packet,
+ .verify_packet = rxkad_verify_packet,
+ .issue_challenge = rxkad_issue_challenge,
+ .respond_to_challenge = rxkad_respond_to_challenge,
+ .verify_response = rxkad_verify_response,
+ .clear = rxkad_clear,
+};
+
+static __init int rxkad_init(void)
+{
+ _enter("");
+
+ /* pin the cipher we need so that the crypto layer doesn't invoke
+ * keventd to go get it */
+ rxkad_ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(rxkad_ci))
+ return PTR_ERR(rxkad_ci);
+
+ return rxrpc_register_security(&rxkad);
+}
+
+module_init(rxkad_init);
+
+static __exit void rxkad_exit(void)
+{
+ _enter("");
+
+ rxrpc_unregister_security(&rxkad);
+ crypto_free_blkcipher(rxkad_ci);
+}
+
+module_exit(rxkad_exit);
generated by cgit (git 2.34.1) at 2024-12-20 11:21:59 +0000