David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 1 | /* request_key_auth.c: request key authorisation controlling key def |
| 2 | * |
| 3 | * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
David Howells | f1a9bad | 2005-10-07 15:04:52 +0100 | [diff] [blame] | 10 | * |
| 11 | * See Documentation/keys-request-key.txt |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 12 | */ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/sched.h> |
| 16 | #include <linux/err.h> |
| 17 | #include <linux/seq_file.h> |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 18 | #include <asm/uaccess.h> |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 19 | #include "internal.h" |
| 20 | |
| 21 | static int request_key_auth_instantiate(struct key *, const void *, size_t); |
| 22 | static void request_key_auth_describe(const struct key *, struct seq_file *); |
| 23 | static void request_key_auth_destroy(struct key *); |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 24 | static long request_key_auth_read(const struct key *, char __user *, size_t); |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 25 | |
| 26 | /* |
| 27 | * the request-key authorisation key type definition |
| 28 | */ |
| 29 | struct key_type key_type_request_key_auth = { |
| 30 | .name = ".request_key_auth", |
| 31 | .def_datalen = sizeof(struct request_key_auth), |
| 32 | .instantiate = request_key_auth_instantiate, |
| 33 | .describe = request_key_auth_describe, |
| 34 | .destroy = request_key_auth_destroy, |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 35 | .read = request_key_auth_read, |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 36 | }; |
| 37 | |
| 38 | /*****************************************************************************/ |
| 39 | /* |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 40 | * instantiate a request-key authorisation key |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 41 | */ |
| 42 | static int request_key_auth_instantiate(struct key *key, |
| 43 | const void *data, |
| 44 | size_t datalen) |
| 45 | { |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 46 | key->payload.data = (struct request_key_auth *) data; |
| 47 | return 0; |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 48 | |
| 49 | } /* end request_key_auth_instantiate() */ |
| 50 | |
| 51 | /*****************************************************************************/ |
| 52 | /* |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 53 | * reading a request-key authorisation key retrieves the callout information |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 54 | */ |
| 55 | static void request_key_auth_describe(const struct key *key, |
| 56 | struct seq_file *m) |
| 57 | { |
| 58 | struct request_key_auth *rka = key->payload.data; |
| 59 | |
| 60 | seq_puts(m, "key:"); |
| 61 | seq_puts(m, key->description); |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 62 | seq_printf(m, " pid:%d ci:%zu", rka->pid, strlen(rka->callout_info)); |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 63 | |
| 64 | } /* end request_key_auth_describe() */ |
| 65 | |
| 66 | /*****************************************************************************/ |
| 67 | /* |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 68 | * read the callout_info data |
| 69 | * - the key's semaphore is read-locked |
| 70 | */ |
| 71 | static long request_key_auth_read(const struct key *key, |
| 72 | char __user *buffer, size_t buflen) |
| 73 | { |
| 74 | struct request_key_auth *rka = key->payload.data; |
| 75 | size_t datalen; |
| 76 | long ret; |
| 77 | |
| 78 | datalen = strlen(rka->callout_info); |
| 79 | ret = datalen; |
| 80 | |
| 81 | /* we can return the data as is */ |
| 82 | if (buffer && buflen > 0) { |
| 83 | if (buflen > datalen) |
| 84 | buflen = datalen; |
| 85 | |
| 86 | if (copy_to_user(buffer, rka->callout_info, buflen) != 0) |
| 87 | ret = -EFAULT; |
| 88 | } |
| 89 | |
| 90 | return ret; |
| 91 | |
| 92 | } /* end request_key_auth_read() */ |
| 93 | |
| 94 | /*****************************************************************************/ |
| 95 | /* |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 96 | * destroy an instantiation authorisation token key |
| 97 | */ |
| 98 | static void request_key_auth_destroy(struct key *key) |
| 99 | { |
| 100 | struct request_key_auth *rka = key->payload.data; |
| 101 | |
| 102 | kenter("{%d}", key->serial); |
| 103 | |
| 104 | key_put(rka->target_key); |
David Howells | 74fd92c | 2005-10-07 15:01:09 +0100 | [diff] [blame] | 105 | kfree(rka); |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 106 | |
| 107 | } /* end request_key_auth_destroy() */ |
| 108 | |
| 109 | /*****************************************************************************/ |
| 110 | /* |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 111 | * create an authorisation token for /sbin/request-key or whoever to gain |
| 112 | * access to the caller's security data |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 113 | */ |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 114 | struct key *request_key_auth_new(struct key *target, const char *callout_info) |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 115 | { |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 116 | struct request_key_auth *rka, *irka; |
| 117 | struct key *authkey = NULL; |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 118 | char desc[20]; |
| 119 | int ret; |
| 120 | |
| 121 | kenter("%d,", target->serial); |
| 122 | |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 123 | /* allocate a auth record */ |
| 124 | rka = kmalloc(sizeof(*rka), GFP_KERNEL); |
| 125 | if (!rka) { |
| 126 | kleave(" = -ENOMEM"); |
| 127 | return ERR_PTR(-ENOMEM); |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 128 | } |
| 129 | |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 130 | /* see if the calling process is already servicing the key request of |
| 131 | * another process */ |
| 132 | if (current->request_key_auth) { |
| 133 | /* it is - use that instantiation context here too */ |
| 134 | irka = current->request_key_auth->payload.data; |
| 135 | rka->context = irka->context; |
| 136 | rka->pid = irka->pid; |
| 137 | } |
| 138 | else { |
| 139 | /* it isn't - use this process as the context */ |
| 140 | rka->context = current; |
| 141 | rka->pid = current->pid; |
| 142 | } |
| 143 | |
| 144 | rka->target_key = key_get(target); |
| 145 | rka->callout_info = callout_info; |
| 146 | |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 147 | /* allocate the auth key */ |
| 148 | sprintf(desc, "%x", target->serial); |
| 149 | |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 150 | authkey = key_alloc(&key_type_request_key_auth, desc, |
| 151 | current->fsuid, current->fsgid, |
| 152 | KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | |
| 153 | KEY_USR_VIEW, 1); |
| 154 | if (IS_ERR(authkey)) { |
| 155 | ret = PTR_ERR(authkey); |
| 156 | goto error_alloc; |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 157 | } |
| 158 | |
| 159 | /* construct and attach to the keyring */ |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 160 | ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); |
| 161 | if (ret < 0) |
| 162 | goto error_inst; |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 163 | |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 164 | kleave(" = {%d})", authkey->serial); |
| 165 | return authkey; |
| 166 | |
| 167 | error_inst: |
| 168 | key_revoke(authkey); |
| 169 | key_put(authkey); |
| 170 | error_alloc: |
| 171 | key_put(rka->target_key); |
| 172 | kfree(rka); |
| 173 | kleave("= %d", ret); |
| 174 | return ERR_PTR(ret); |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 175 | |
| 176 | } /* end request_key_auth_new() */ |
| 177 | |
| 178 | /*****************************************************************************/ |
| 179 | /* |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 180 | * see if an authorisation key is associated with a particular key |
| 181 | */ |
| 182 | static int key_get_instantiation_authkey_match(const struct key *key, |
| 183 | const void *_id) |
| 184 | { |
| 185 | struct request_key_auth *rka = key->payload.data; |
| 186 | key_serial_t id = (key_serial_t)(unsigned long) _id; |
| 187 | |
| 188 | return rka->target_key->serial == id; |
| 189 | |
| 190 | } /* end key_get_instantiation_authkey_match() */ |
| 191 | |
| 192 | /*****************************************************************************/ |
| 193 | /* |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 194 | * get the authorisation key for instantiation of a specific key if attached to |
| 195 | * the current process's keyrings |
| 196 | * - this key is inserted into a keyring and that is set as /sbin/request-key's |
| 197 | * session keyring |
| 198 | * - a target_id of zero specifies any valid token |
| 199 | */ |
| 200 | struct key *key_get_instantiation_authkey(key_serial_t target_id) |
| 201 | { |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 202 | struct key *authkey; |
| 203 | key_ref_t authkey_ref; |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 204 | |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 205 | authkey_ref = search_process_keyrings( |
| 206 | &key_type_request_key_auth, |
| 207 | (void *) (unsigned long) target_id, |
| 208 | key_get_instantiation_authkey_match, |
| 209 | current); |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 210 | |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 211 | if (IS_ERR(authkey_ref)) { |
| 212 | authkey = ERR_PTR(PTR_ERR(authkey_ref)); |
| 213 | goto error; |
| 214 | } |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 215 | |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 216 | authkey = key_ref_to_ptr(authkey_ref); |
| 217 | if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { |
| 218 | key_put(authkey); |
| 219 | authkey = ERR_PTR(-EKEYREVOKED); |
| 220 | } |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 221 | |
David Howells | b5f545c | 2006-01-08 01:02:47 -0800 | [diff] [blame] | 222 | error: |
| 223 | return authkey; |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 224 | |
| 225 | } /* end key_get_instantiation_authkey() */ |