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-rw-r--r--fs/smb/client/cifs_spnego.c236
1 files changed, 236 insertions, 0 deletions
diff --git a/fs/smb/client/cifs_spnego.c b/fs/smb/client/cifs_spnego.c
new file mode 100644
index 0000000000..af7849e597
--- /dev/null
+++ b/fs/smb/client/cifs_spnego.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * SPNEGO upcall management for CIFS
+ *
+ * Copyright (c) 2007 Red Hat, Inc.
+ * Author(s): Jeff Layton (jlayton@redhat.com)
+ *
+ */
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <keys/user-type.h>
+#include <linux/key-type.h>
+#include <linux/keyctl.h>
+#include <linux/inet.h>
+#include "cifsglob.h"
+#include "cifs_spnego.h"
+#include "cifs_debug.h"
+#include "cifsproto.h"
+static const struct cred *spnego_cred;
+
+/* create a new cifs key */
+static int
+cifs_spnego_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
+{
+ char *payload;
+ int ret;
+
+ ret = -ENOMEM;
+ payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
+ if (!payload)
+ goto error;
+
+ /* attach the data */
+ key->payload.data[0] = payload;
+ ret = 0;
+
+error:
+ return ret;
+}
+
+static void
+cifs_spnego_key_destroy(struct key *key)
+{
+ kfree(key->payload.data[0]);
+}
+
+
+/*
+ * keytype for CIFS spnego keys
+ */
+struct key_type cifs_spnego_key_type = {
+ .name = "cifs.spnego",
+ .instantiate = cifs_spnego_key_instantiate,
+ .destroy = cifs_spnego_key_destroy,
+ .describe = user_describe,
+};
+
+/* length of longest version string e.g. strlen("ver=0xFF") */
+#define MAX_VER_STR_LEN 8
+
+/* length of longest security mechanism name, eg in future could have
+ * strlen(";sec=ntlmsspi") */
+#define MAX_MECH_STR_LEN 13
+
+/* strlen of ";host=" */
+#define HOST_KEY_LEN 6
+
+/* strlen of ";ip4=" or ";ip6=" */
+#define IP_KEY_LEN 5
+
+/* strlen of ";uid=0x" */
+#define UID_KEY_LEN 7
+
+/* strlen of ";creduid=0x" */
+#define CREDUID_KEY_LEN 11
+
+/* strlen of ";user=" */
+#define USER_KEY_LEN 6
+
+/* strlen of ";pid=0x" */
+#define PID_KEY_LEN 7
+
+/* get a key struct with a SPNEGO security blob, suitable for session setup */
+struct key *
+cifs_get_spnego_key(struct cifs_ses *sesInfo,
+ struct TCP_Server_Info *server)
+{
+ struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
+ struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
+ char *description, *dp;
+ size_t desc_len;
+ struct key *spnego_key;
+ const char *hostname = server->hostname;
+ const struct cred *saved_cred;
+
+ /* length of fields (with semicolons): ver=0xyz ip4=ipaddress
+ host=hostname sec=mechanism uid=0xFF user=username */
+ desc_len = MAX_VER_STR_LEN +
+ HOST_KEY_LEN + strlen(hostname) +
+ IP_KEY_LEN + INET6_ADDRSTRLEN +
+ MAX_MECH_STR_LEN +
+ UID_KEY_LEN + (sizeof(uid_t) * 2) +
+ CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
+ PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
+
+ if (sesInfo->user_name)
+ desc_len += USER_KEY_LEN + strlen(sesInfo->user_name);
+
+ spnego_key = ERR_PTR(-ENOMEM);
+ description = kzalloc(desc_len, GFP_KERNEL);
+ if (description == NULL)
+ goto out;
+
+ dp = description;
+ /* start with version and hostname portion of UNC string */
+ spnego_key = ERR_PTR(-EINVAL);
+ sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
+ hostname);
+ dp = description + strlen(description);
+
+ /* add the server address */
+ if (server->dstaddr.ss_family == AF_INET)
+ sprintf(dp, "ip4=%pI4", &sa->sin_addr);
+ else if (server->dstaddr.ss_family == AF_INET6)
+ sprintf(dp, "ip6=%pI6", &sa6->sin6_addr);
+ else
+ goto out;
+
+ dp = description + strlen(description);
+
+ /* for now, only sec=krb5 and sec=mskrb5 are valid */
+ if (server->sec_kerberos)
+ sprintf(dp, ";sec=krb5");
+ else if (server->sec_mskerberos)
+ sprintf(dp, ";sec=mskrb5");
+ else {
+ cifs_dbg(VFS, "unknown or missing server auth type, use krb5\n");
+ sprintf(dp, ";sec=krb5");
+ }
+
+ dp = description + strlen(description);
+ sprintf(dp, ";uid=0x%x",
+ from_kuid_munged(&init_user_ns, sesInfo->linux_uid));
+
+ dp = description + strlen(description);
+ sprintf(dp, ";creduid=0x%x",
+ from_kuid_munged(&init_user_ns, sesInfo->cred_uid));
+
+ if (sesInfo->user_name) {
+ dp = description + strlen(description);
+ sprintf(dp, ";user=%s", sesInfo->user_name);
+ }
+
+ dp = description + strlen(description);
+ sprintf(dp, ";pid=0x%x", current->pid);
+
+ cifs_dbg(FYI, "key description = %s\n", description);
+ saved_cred = override_creds(spnego_cred);
+ spnego_key = request_key(&cifs_spnego_key_type, description, "");
+ revert_creds(saved_cred);
+
+#ifdef CONFIG_CIFS_DEBUG2
+ if (cifsFYI && !IS_ERR(spnego_key)) {
+ struct cifs_spnego_msg *msg = spnego_key->payload.data[0];
+ cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
+ msg->secblob_len + msg->sesskey_len));
+ }
+#endif /* CONFIG_CIFS_DEBUG2 */
+
+out:
+ kfree(description);
+ return spnego_key;
+}
+
+int
+init_cifs_spnego(void)
+{
+ struct cred *cred;
+ struct key *keyring;
+ int ret;
+
+ cifs_dbg(FYI, "Registering the %s key type\n",
+ cifs_spnego_key_type.name);
+
+ /*
+ * Create an override credential set with special thread keyring for
+ * spnego upcalls.
+ */
+
+ cred = prepare_kernel_cred(&init_task);
+ if (!cred)
+ return -ENOMEM;
+
+ keyring = keyring_alloc(".cifs_spnego",
+ GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
+ (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ,
+ KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto failed_put_cred;
+ }
+
+ ret = register_key_type(&cifs_spnego_key_type);
+ if (ret < 0)
+ goto failed_put_key;
+
+ /*
+ * instruct request_key() to use this special keyring as a cache for
+ * the results it looks up
+ */
+ set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
+ cred->thread_keyring = keyring;
+ cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
+ spnego_cred = cred;
+
+ cifs_dbg(FYI, "cifs spnego keyring: %d\n", key_serial(keyring));
+ return 0;
+
+failed_put_key:
+ key_put(keyring);
+failed_put_cred:
+ put_cred(cred);
+ return ret;
+}
+
+void
+exit_cifs_spnego(void)
+{
+ key_revoke(spnego_cred->thread_keyring);
+ unregister_key_type(&cifs_spnego_key_type);
+ put_cred(spnego_cred);
+ cifs_dbg(FYI, "Unregistered %s key type\n", cifs_spnego_key_type.name);
+}