| /* request_key_auth.c: request key authorisation controlling key def |
| * |
| * Copyright (C) 2005 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. |
| * |
| * See Documentation/keys-request-key.txt |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/sched.h> |
| #include <linux/err.h> |
| #include <linux/seq_file.h> |
| #include <asm/uaccess.h> |
| #include "internal.h" |
| |
| static int request_key_auth_instantiate(struct key *, const void *, size_t); |
| static void request_key_auth_describe(const struct key *, struct seq_file *); |
| static void request_key_auth_destroy(struct key *); |
| static long request_key_auth_read(const struct key *, char __user *, size_t); |
| |
| /* |
| * the request-key authorisation key type definition |
| */ |
| struct key_type key_type_request_key_auth = { |
| .name = ".request_key_auth", |
| .def_datalen = sizeof(struct request_key_auth), |
| .instantiate = request_key_auth_instantiate, |
| .describe = request_key_auth_describe, |
| .destroy = request_key_auth_destroy, |
| .read = request_key_auth_read, |
| }; |
| |
| /*****************************************************************************/ |
| /* |
| * instantiate a request-key authorisation key |
| */ |
| static int request_key_auth_instantiate(struct key *key, |
| const void *data, |
| size_t datalen) |
| { |
| key->payload.data = (struct request_key_auth *) data; |
| return 0; |
| |
| } /* end request_key_auth_instantiate() */ |
| |
| /*****************************************************************************/ |
| /* |
| * reading a request-key authorisation key retrieves the callout information |
| */ |
| static void request_key_auth_describe(const struct key *key, |
| struct seq_file *m) |
| { |
| struct request_key_auth *rka = key->payload.data; |
| |
| seq_puts(m, "key:"); |
| seq_puts(m, key->description); |
| seq_printf(m, " pid:%d ci:%zu", rka->pid, strlen(rka->callout_info)); |
| |
| } /* end request_key_auth_describe() */ |
| |
| /*****************************************************************************/ |
| /* |
| * read the callout_info data |
| * - the key's semaphore is read-locked |
| */ |
| static long request_key_auth_read(const struct key *key, |
| char __user *buffer, size_t buflen) |
| { |
| struct request_key_auth *rka = key->payload.data; |
| size_t datalen; |
| long ret; |
| |
| datalen = strlen(rka->callout_info); |
| ret = datalen; |
| |
| /* we can return the data as is */ |
| if (buffer && buflen > 0) { |
| if (buflen > datalen) |
| buflen = datalen; |
| |
| if (copy_to_user(buffer, rka->callout_info, buflen) != 0) |
| ret = -EFAULT; |
| } |
| |
| return ret; |
| |
| } /* end request_key_auth_read() */ |
| |
| /*****************************************************************************/ |
| /* |
| * destroy an instantiation authorisation token key |
| */ |
| static void request_key_auth_destroy(struct key *key) |
| { |
| struct request_key_auth *rka = key->payload.data; |
| |
| kenter("{%d}", key->serial); |
| |
| key_put(rka->target_key); |
| kfree(rka); |
| |
| } /* end request_key_auth_destroy() */ |
| |
| /*****************************************************************************/ |
| /* |
| * create an authorisation token for /sbin/request-key or whoever to gain |
| * access to the caller's security data |
| */ |
| struct key *request_key_auth_new(struct key *target, const char *callout_info) |
| { |
| struct request_key_auth *rka, *irka; |
| struct key *authkey = NULL; |
| char desc[20]; |
| int ret; |
| |
| kenter("%d,", target->serial); |
| |
| /* allocate a auth record */ |
| rka = kmalloc(sizeof(*rka), GFP_KERNEL); |
| if (!rka) { |
| kleave(" = -ENOMEM"); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| /* see if the calling process is already servicing the key request of |
| * another process */ |
| if (current->request_key_auth) { |
| /* it is - use that instantiation context here too */ |
| irka = current->request_key_auth->payload.data; |
| rka->context = irka->context; |
| rka->pid = irka->pid; |
| } |
| else { |
| /* it isn't - use this process as the context */ |
| rka->context = current; |
| rka->pid = current->pid; |
| } |
| |
| rka->target_key = key_get(target); |
| rka->callout_info = callout_info; |
| |
| /* allocate the auth key */ |
| sprintf(desc, "%x", target->serial); |
| |
| authkey = key_alloc(&key_type_request_key_auth, desc, |
| current->fsuid, current->fsgid, current, |
| KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | |
| KEY_USR_VIEW, 1); |
| if (IS_ERR(authkey)) { |
| ret = PTR_ERR(authkey); |
| goto error_alloc; |
| } |
| |
| /* construct and attach to the keyring */ |
| ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); |
| if (ret < 0) |
| goto error_inst; |
| |
| kleave(" = {%d})", authkey->serial); |
| return authkey; |
| |
| error_inst: |
| key_revoke(authkey); |
| key_put(authkey); |
| error_alloc: |
| key_put(rka->target_key); |
| kfree(rka); |
| kleave("= %d", ret); |
| return ERR_PTR(ret); |
| |
| } /* end request_key_auth_new() */ |
| |
| /*****************************************************************************/ |
| /* |
| * see if an authorisation key is associated with a particular key |
| */ |
| static int key_get_instantiation_authkey_match(const struct key *key, |
| const void *_id) |
| { |
| struct request_key_auth *rka = key->payload.data; |
| key_serial_t id = (key_serial_t)(unsigned long) _id; |
| |
| return rka->target_key->serial == id; |
| |
| } /* end key_get_instantiation_authkey_match() */ |
| |
| /*****************************************************************************/ |
| /* |
| * get the authorisation key for instantiation of a specific key if attached to |
| * the current process's keyrings |
| * - this key is inserted into a keyring and that is set as /sbin/request-key's |
| * session keyring |
| * - a target_id of zero specifies any valid token |
| */ |
| struct key *key_get_instantiation_authkey(key_serial_t target_id) |
| { |
| struct key *authkey; |
| key_ref_t authkey_ref; |
| |
| authkey_ref = search_process_keyrings( |
| &key_type_request_key_auth, |
| (void *) (unsigned long) target_id, |
| key_get_instantiation_authkey_match, |
| current); |
| |
| if (IS_ERR(authkey_ref)) { |
| authkey = ERR_PTR(PTR_ERR(authkey_ref)); |
| goto error; |
| } |
| |
| authkey = key_ref_to_ptr(authkey_ref); |
| if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { |
| key_put(authkey); |
| authkey = ERR_PTR(-EKEYREVOKED); |
| } |
| |
| error: |
| return authkey; |
| |
| } /* end key_get_instantiation_authkey() */ |