237 строки
5.7 KiB
C
237 строки
5.7 KiB
C
// SPDX-License-Identifier: LGPL-2.1
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/*
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* SPNEGO upcall management for CIFS
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*
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* Copyright (c) 2007 Red Hat, Inc.
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* Author(s): Jeff Layton (jlayton@redhat.com)
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*
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*/
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <keys/user-type.h>
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#include <linux/key-type.h>
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#include <linux/keyctl.h>
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#include <linux/inet.h>
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#include "cifsglob.h"
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#include "cifs_spnego.h"
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#include "cifs_debug.h"
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#include "cifsproto.h"
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static const struct cred *spnego_cred;
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/* create a new cifs key */
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static int
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cifs_spnego_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
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{
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char *payload;
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int ret;
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ret = -ENOMEM;
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payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
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if (!payload)
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goto error;
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/* attach the data */
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key->payload.data[0] = payload;
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ret = 0;
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error:
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return ret;
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}
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static void
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cifs_spnego_key_destroy(struct key *key)
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{
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kfree(key->payload.data[0]);
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}
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/*
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* keytype for CIFS spnego keys
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*/
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struct key_type cifs_spnego_key_type = {
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.name = "cifs.spnego",
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.instantiate = cifs_spnego_key_instantiate,
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.destroy = cifs_spnego_key_destroy,
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.describe = user_describe,
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};
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/* length of longest version string e.g. strlen("ver=0xFF") */
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#define MAX_VER_STR_LEN 8
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/* length of longest security mechanism name, eg in future could have
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* strlen(";sec=ntlmsspi") */
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#define MAX_MECH_STR_LEN 13
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/* strlen of "host=" */
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#define HOST_KEY_LEN 5
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/* strlen of ";ip4=" or ";ip6=" */
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#define IP_KEY_LEN 5
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/* strlen of ";uid=0x" */
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#define UID_KEY_LEN 7
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/* strlen of ";creduid=0x" */
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#define CREDUID_KEY_LEN 11
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/* strlen of ";user=" */
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#define USER_KEY_LEN 6
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/* strlen of ";pid=0x" */
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#define PID_KEY_LEN 7
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/* get a key struct with a SPNEGO security blob, suitable for session setup */
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struct key *
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cifs_get_spnego_key(struct cifs_ses *sesInfo)
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{
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struct TCP_Server_Info *server = cifs_ses_server(sesInfo);
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struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
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struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
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char *description, *dp;
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size_t desc_len;
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struct key *spnego_key;
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const char *hostname = server->hostname;
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const struct cred *saved_cred;
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/* length of fields (with semicolons): ver=0xyz ip4=ipaddress
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host=hostname sec=mechanism uid=0xFF user=username */
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desc_len = MAX_VER_STR_LEN +
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HOST_KEY_LEN + strlen(hostname) +
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IP_KEY_LEN + INET6_ADDRSTRLEN +
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MAX_MECH_STR_LEN +
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UID_KEY_LEN + (sizeof(uid_t) * 2) +
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CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
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PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
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if (sesInfo->user_name)
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desc_len += USER_KEY_LEN + strlen(sesInfo->user_name);
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spnego_key = ERR_PTR(-ENOMEM);
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description = kzalloc(desc_len, GFP_KERNEL);
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if (description == NULL)
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goto out;
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dp = description;
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/* start with version and hostname portion of UNC string */
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spnego_key = ERR_PTR(-EINVAL);
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sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
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hostname);
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dp = description + strlen(description);
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/* add the server address */
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if (server->dstaddr.ss_family == AF_INET)
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sprintf(dp, "ip4=%pI4", &sa->sin_addr);
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else if (server->dstaddr.ss_family == AF_INET6)
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sprintf(dp, "ip6=%pI6", &sa6->sin6_addr);
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else
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goto out;
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dp = description + strlen(description);
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/* for now, only sec=krb5 and sec=mskrb5 are valid */
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if (server->sec_kerberos)
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sprintf(dp, ";sec=krb5");
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else if (server->sec_mskerberos)
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sprintf(dp, ";sec=mskrb5");
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else {
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cifs_dbg(VFS, "unknown or missing server auth type, use krb5\n");
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sprintf(dp, ";sec=krb5");
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}
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dp = description + strlen(description);
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sprintf(dp, ";uid=0x%x",
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from_kuid_munged(&init_user_ns, sesInfo->linux_uid));
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dp = description + strlen(description);
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sprintf(dp, ";creduid=0x%x",
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from_kuid_munged(&init_user_ns, sesInfo->cred_uid));
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if (sesInfo->user_name) {
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dp = description + strlen(description);
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sprintf(dp, ";user=%s", sesInfo->user_name);
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}
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dp = description + strlen(description);
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sprintf(dp, ";pid=0x%x", current->pid);
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cifs_dbg(FYI, "key description = %s\n", description);
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saved_cred = override_creds(spnego_cred);
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spnego_key = request_key(&cifs_spnego_key_type, description, "");
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revert_creds(saved_cred);
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#ifdef CONFIG_CIFS_DEBUG2
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if (cifsFYI && !IS_ERR(spnego_key)) {
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struct cifs_spnego_msg *msg = spnego_key->payload.data[0];
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cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
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msg->secblob_len + msg->sesskey_len));
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}
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#endif /* CONFIG_CIFS_DEBUG2 */
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out:
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kfree(description);
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return spnego_key;
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}
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int
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init_cifs_spnego(void)
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{
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struct cred *cred;
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struct key *keyring;
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int ret;
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cifs_dbg(FYI, "Registering the %s key type\n",
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cifs_spnego_key_type.name);
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/*
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* Create an override credential set with special thread keyring for
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* spnego upcalls.
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*/
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cred = prepare_kernel_cred(NULL);
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if (!cred)
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return -ENOMEM;
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keyring = keyring_alloc(".cifs_spnego",
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GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
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(KEY_POS_ALL & ~KEY_POS_SETATTR) |
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KEY_USR_VIEW | KEY_USR_READ,
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KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
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if (IS_ERR(keyring)) {
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ret = PTR_ERR(keyring);
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goto failed_put_cred;
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}
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ret = register_key_type(&cifs_spnego_key_type);
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if (ret < 0)
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goto failed_put_key;
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/*
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* instruct request_key() to use this special keyring as a cache for
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* the results it looks up
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*/
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set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
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cred->thread_keyring = keyring;
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cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
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spnego_cred = cred;
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cifs_dbg(FYI, "cifs spnego keyring: %d\n", key_serial(keyring));
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return 0;
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failed_put_key:
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key_put(keyring);
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failed_put_cred:
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put_cred(cred);
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return ret;
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}
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void
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exit_cifs_spnego(void)
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{
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key_revoke(spnego_cred->thread_keyring);
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unregister_key_type(&cifs_spnego_key_type);
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put_cred(spnego_cred);
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cifs_dbg(FYI, "Unregistered %s key type\n", cifs_spnego_key_type.name);
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}
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