![Harvey Harrison](/assets/img/avatar_default.png)
Using NIPQUAD() with NIPQUAD_FMT, %d.%d.%d.%d or %u.%u.%u.%u can be replaced with %pI4 Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1160 lines
27 KiB
C
1160 lines
27 KiB
C
/* Kerberos-based RxRPC security
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/skbuff.h>
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#include <linux/udp.h>
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#include <linux/crypto.h>
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#include <linux/scatterlist.h>
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#include <linux/ctype.h>
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#include <net/sock.h>
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#include <net/af_rxrpc.h>
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#define rxrpc_debug rxkad_debug
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#include "ar-internal.h"
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#define RXKAD_VERSION 2
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#define MAXKRB5TICKETLEN 1024
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#define RXKAD_TKT_TYPE_KERBEROS_V5 256
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#define ANAME_SZ 40 /* size of authentication name */
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#define INST_SZ 40 /* size of principal's instance */
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#define REALM_SZ 40 /* size of principal's auth domain */
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#define SNAME_SZ 40 /* size of service name */
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unsigned rxrpc_debug;
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module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO);
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MODULE_PARM_DESC(debug, "rxkad debugging mask");
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struct rxkad_level1_hdr {
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__be32 data_size; /* true data size (excluding padding) */
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};
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struct rxkad_level2_hdr {
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__be32 data_size; /* true data size (excluding padding) */
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__be32 checksum; /* decrypted data checksum */
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};
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MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos)");
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MODULE_AUTHOR("Red Hat, Inc.");
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MODULE_LICENSE("GPL");
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/*
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* this holds a pinned cipher so that keventd doesn't get called by the cipher
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* alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
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* packets
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*/
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static struct crypto_blkcipher *rxkad_ci;
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static DEFINE_MUTEX(rxkad_ci_mutex);
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/*
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* initialise connection security
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*/
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static int rxkad_init_connection_security(struct rxrpc_connection *conn)
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{
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struct rxrpc_key_payload *payload;
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struct crypto_blkcipher *ci;
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int ret;
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_enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
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payload = conn->key->payload.data;
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conn->security_ix = payload->k.security_index;
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ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(ci)) {
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_debug("no cipher");
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ret = PTR_ERR(ci);
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goto error;
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}
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if (crypto_blkcipher_setkey(ci, payload->k.session_key,
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sizeof(payload->k.session_key)) < 0)
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BUG();
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switch (conn->security_level) {
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case RXRPC_SECURITY_PLAIN:
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break;
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case RXRPC_SECURITY_AUTH:
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conn->size_align = 8;
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conn->security_size = sizeof(struct rxkad_level1_hdr);
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conn->header_size += sizeof(struct rxkad_level1_hdr);
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break;
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case RXRPC_SECURITY_ENCRYPT:
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conn->size_align = 8;
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conn->security_size = sizeof(struct rxkad_level2_hdr);
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conn->header_size += sizeof(struct rxkad_level2_hdr);
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break;
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default:
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ret = -EKEYREJECTED;
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goto error;
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}
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conn->cipher = ci;
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ret = 0;
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error:
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* prime the encryption state with the invariant parts of a connection's
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* description
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*/
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static void rxkad_prime_packet_security(struct rxrpc_connection *conn)
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{
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struct rxrpc_key_payload *payload;
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struct blkcipher_desc desc;
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struct scatterlist sg[2];
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struct rxrpc_crypt iv;
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struct {
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__be32 x[4];
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} tmpbuf __attribute__((aligned(16))); /* must all be in same page */
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_enter("");
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if (!conn->key)
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return;
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payload = conn->key->payload.data;
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memcpy(&iv, payload->k.session_key, sizeof(iv));
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desc.tfm = conn->cipher;
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desc.info = iv.x;
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desc.flags = 0;
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tmpbuf.x[0] = conn->epoch;
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tmpbuf.x[1] = conn->cid;
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tmpbuf.x[2] = 0;
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tmpbuf.x[3] = htonl(conn->security_ix);
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sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
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sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
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crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
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memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
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ASSERTCMP(conn->csum_iv.n[0], ==, tmpbuf.x[2]);
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_leave("");
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}
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/*
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* partially encrypt a packet (level 1 security)
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*/
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static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
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struct sk_buff *skb,
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u32 data_size,
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void *sechdr)
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{
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struct rxrpc_skb_priv *sp;
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struct blkcipher_desc desc;
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struct rxrpc_crypt iv;
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struct scatterlist sg[2];
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struct {
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struct rxkad_level1_hdr hdr;
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__be32 first; /* first four bytes of data and padding */
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} tmpbuf __attribute__((aligned(8))); /* must all be in same page */
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u16 check;
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sp = rxrpc_skb(skb);
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_enter("");
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check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
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data_size |= (u32) check << 16;
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tmpbuf.hdr.data_size = htonl(data_size);
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memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first));
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/* start the encryption afresh */
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memset(&iv, 0, sizeof(iv));
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desc.tfm = call->conn->cipher;
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desc.info = iv.x;
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desc.flags = 0;
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sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
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sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
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crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
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memcpy(sechdr, &tmpbuf, sizeof(tmpbuf));
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_leave(" = 0");
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return 0;
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}
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/*
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* wholly encrypt a packet (level 2 security)
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*/
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static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
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struct sk_buff *skb,
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u32 data_size,
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void *sechdr)
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{
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const struct rxrpc_key_payload *payload;
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struct rxkad_level2_hdr rxkhdr
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__attribute__((aligned(8))); /* must be all on one page */
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struct rxrpc_skb_priv *sp;
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struct blkcipher_desc desc;
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struct rxrpc_crypt iv;
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struct scatterlist sg[16];
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struct sk_buff *trailer;
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unsigned len;
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u16 check;
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int nsg;
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sp = rxrpc_skb(skb);
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_enter("");
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check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
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rxkhdr.data_size = htonl(data_size | (u32) check << 16);
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rxkhdr.checksum = 0;
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/* encrypt from the session key */
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payload = call->conn->key->payload.data;
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memcpy(&iv, payload->k.session_key, sizeof(iv));
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desc.tfm = call->conn->cipher;
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desc.info = iv.x;
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desc.flags = 0;
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sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
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sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
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crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr));
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/* we want to encrypt the skbuff in-place */
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nsg = skb_cow_data(skb, 0, &trailer);
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if (nsg < 0 || nsg > 16)
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return -ENOMEM;
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len = data_size + call->conn->size_align - 1;
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len &= ~(call->conn->size_align - 1);
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sg_init_table(sg, nsg);
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skb_to_sgvec(skb, sg, 0, len);
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crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
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_leave(" = 0");
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return 0;
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}
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/*
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* checksum an RxRPC packet header
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*/
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static int rxkad_secure_packet(const struct rxrpc_call *call,
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struct sk_buff *skb,
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size_t data_size,
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void *sechdr)
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{
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struct rxrpc_skb_priv *sp;
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struct blkcipher_desc desc;
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struct rxrpc_crypt iv;
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struct scatterlist sg[2];
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struct {
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__be32 x[2];
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} tmpbuf __attribute__((aligned(8))); /* must all be in same page */
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__be32 x;
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u32 y;
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int ret;
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sp = rxrpc_skb(skb);
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_enter("{%d{%x}},{#%u},%zu,",
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call->debug_id, key_serial(call->conn->key), ntohl(sp->hdr.seq),
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data_size);
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if (!call->conn->cipher)
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return 0;
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ret = key_validate(call->conn->key);
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if (ret < 0)
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return ret;
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/* continue encrypting from where we left off */
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memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
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desc.tfm = call->conn->cipher;
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desc.info = iv.x;
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desc.flags = 0;
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/* calculate the security checksum */
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x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
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x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
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tmpbuf.x[0] = sp->hdr.callNumber;
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tmpbuf.x[1] = x;
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sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
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sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
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crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
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y = ntohl(tmpbuf.x[1]);
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y = (y >> 16) & 0xffff;
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if (y == 0)
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y = 1; /* zero checksums are not permitted */
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sp->hdr.cksum = htons(y);
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switch (call->conn->security_level) {
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case RXRPC_SECURITY_PLAIN:
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ret = 0;
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break;
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case RXRPC_SECURITY_AUTH:
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ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
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break;
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case RXRPC_SECURITY_ENCRYPT:
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ret = rxkad_secure_packet_encrypt(call, skb, data_size,
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sechdr);
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break;
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default:
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ret = -EPERM;
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break;
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}
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_leave(" = %d [set %hx]", ret, y);
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return ret;
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}
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/*
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* decrypt partial encryption on a packet (level 1 security)
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*/
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static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
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struct sk_buff *skb,
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u32 *_abort_code)
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{
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struct rxkad_level1_hdr sechdr;
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struct rxrpc_skb_priv *sp;
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struct blkcipher_desc desc;
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struct rxrpc_crypt iv;
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struct scatterlist sg[16];
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struct sk_buff *trailer;
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u32 data_size, buf;
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u16 check;
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int nsg;
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_enter("");
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sp = rxrpc_skb(skb);
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/* we want to decrypt the skbuff in-place */
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nsg = skb_cow_data(skb, 0, &trailer);
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if (nsg < 0 || nsg > 16)
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goto nomem;
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sg_init_table(sg, nsg);
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skb_to_sgvec(skb, sg, 0, 8);
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/* start the decryption afresh */
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memset(&iv, 0, sizeof(iv));
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desc.tfm = call->conn->cipher;
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desc.info = iv.x;
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desc.flags = 0;
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crypto_blkcipher_decrypt_iv(&desc, sg, sg, 8);
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/* remove the decrypted packet length */
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if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
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goto datalen_error;
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if (!skb_pull(skb, sizeof(sechdr)))
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BUG();
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buf = ntohl(sechdr.data_size);
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data_size = buf & 0xffff;
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check = buf >> 16;
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check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
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check &= 0xffff;
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if (check != 0) {
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*_abort_code = RXKADSEALEDINCON;
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goto protocol_error;
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}
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/* shorten the packet to remove the padding */
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if (data_size > skb->len)
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goto datalen_error;
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else if (data_size < skb->len)
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skb->len = data_size;
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_leave(" = 0 [dlen=%x]", data_size);
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return 0;
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datalen_error:
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*_abort_code = RXKADDATALEN;
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protocol_error:
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_leave(" = -EPROTO");
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return -EPROTO;
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nomem:
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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/*
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* wholly decrypt a packet (level 2 security)
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*/
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static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
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struct sk_buff *skb,
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u32 *_abort_code)
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{
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const struct rxrpc_key_payload *payload;
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struct rxkad_level2_hdr sechdr;
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struct rxrpc_skb_priv *sp;
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struct blkcipher_desc desc;
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struct rxrpc_crypt iv;
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struct scatterlist _sg[4], *sg;
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struct sk_buff *trailer;
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u32 data_size, buf;
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u16 check;
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int nsg;
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_enter(",{%d}", skb->len);
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sp = rxrpc_skb(skb);
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/* we want to decrypt the skbuff in-place */
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nsg = skb_cow_data(skb, 0, &trailer);
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if (nsg < 0)
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goto nomem;
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sg = _sg;
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if (unlikely(nsg > 4)) {
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sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
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if (!sg)
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goto nomem;
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}
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sg_init_table(sg, nsg);
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skb_to_sgvec(skb, sg, 0, skb->len);
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|
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/* decrypt from the session key */
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payload = call->conn->key->payload.data;
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memcpy(&iv, payload->k.session_key, sizeof(iv));
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desc.tfm = call->conn->cipher;
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desc.info = iv.x;
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desc.flags = 0;
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crypto_blkcipher_decrypt_iv(&desc, sg, sg, skb->len);
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if (sg != _sg)
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kfree(sg);
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|
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/* remove the decrypted packet length */
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if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
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goto datalen_error;
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if (!skb_pull(skb, sizeof(sechdr)))
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BUG();
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buf = ntohl(sechdr.data_size);
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data_size = buf & 0xffff;
|
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|
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check = buf >> 16;
|
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check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
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check &= 0xffff;
|
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if (check != 0) {
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*_abort_code = RXKADSEALEDINCON;
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goto protocol_error;
|
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}
|
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|
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/* shorten the packet to remove the padding */
|
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if (data_size > skb->len)
|
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goto datalen_error;
|
|
else if (data_size < skb->len)
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skb->len = data_size;
|
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|
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_leave(" = 0 [dlen=%x]", data_size);
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return 0;
|
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|
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datalen_error:
|
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*_abort_code = RXKADDATALEN;
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protocol_error:
|
|
_leave(" = -EPROTO");
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return -EPROTO;
|
|
|
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nomem:
|
|
_leave(" = -ENOMEM");
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|
return -ENOMEM;
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|
}
|
|
|
|
/*
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|
* verify the security on a received packet
|
|
*/
|
|
static int rxkad_verify_packet(const struct rxrpc_call *call,
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struct sk_buff *skb,
|
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u32 *_abort_code)
|
|
{
|
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struct blkcipher_desc desc;
|
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struct rxrpc_skb_priv *sp;
|
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struct rxrpc_crypt iv;
|
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struct scatterlist sg[2];
|
|
struct {
|
|
__be32 x[2];
|
|
} tmpbuf __attribute__((aligned(8))); /* must all be in same page */
|
|
__be32 x;
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__be16 cksum;
|
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u32 y;
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int ret;
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|
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sp = rxrpc_skb(skb);
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|
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_enter("{%d{%x}},{#%u}",
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call->debug_id, key_serial(call->conn->key),
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ntohl(sp->hdr.seq));
|
|
|
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if (!call->conn->cipher)
|
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return 0;
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|
|
|
if (sp->hdr.securityIndex != 2) {
|
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*_abort_code = RXKADINCONSISTENCY;
|
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_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_payload *payload;
|
|
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;
|
|
|
|
payload = 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(payload->k.kvno);
|
|
resp.ticket_len = htonl(payload->k.ticket_len);
|
|
|
|
/* calculate the response checksum and then do the encryption */
|
|
rxkad_calc_response_checksum(&resp);
|
|
rxkad_encrypt_response(conn, &resp, &payload->k);
|
|
return rxkad_send_response(conn, &sp->hdr, &resp, &payload->k);
|
|
|
|
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 = RXKAD_VERSION,
|
|
.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);
|