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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 | /* user_defined.c: user defined key type * * Copyright (C) 2004 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. */ #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/seq_file.h> #include <linux/err.h> #include <keys/user-type.h> #include <asm/uaccess.h> #include "internal.h" static int logon_vet_description(const char *desc); /* * user defined keys take an arbitrary string as the description and an * arbitrary blob of data as the payload */ struct key_type key_type_user = { .name = "user", .instantiate = user_instantiate, .update = user_update, .match = user_match, .revoke = user_revoke, .destroy = user_destroy, .describe = user_describe, .read = user_read, }; EXPORT_SYMBOL_GPL(key_type_user); /* * This key type is essentially the same as key_type_user, but it does * not define a .read op. This is suitable for storing username and * password pairs in the keyring that you do not want to be readable * from userspace. */ struct key_type key_type_logon = { .name = "logon", .instantiate = user_instantiate, .update = user_update, .match = user_match, .revoke = user_revoke, .destroy = user_destroy, .describe = user_describe, .vet_description = logon_vet_description, }; EXPORT_SYMBOL_GPL(key_type_logon); /* * instantiate a user defined key */ int user_instantiate(struct key *key, struct key_preparsed_payload *prep) { struct user_key_payload *upayload; size_t datalen = prep->datalen; int ret; ret = -EINVAL; if (datalen <= 0 || datalen > 32767 || !prep->data) goto error; ret = key_payload_reserve(key, datalen); if (ret < 0) goto error; ret = -ENOMEM; upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); if (!upayload) goto error; /* attach the data */ upayload->datalen = datalen; memcpy(upayload->data, prep->data, datalen); rcu_assign_keypointer(key, upayload); ret = 0; error: return ret; } EXPORT_SYMBOL_GPL(user_instantiate); /* * update a user defined key * - the key's semaphore is write-locked */ int user_update(struct key *key, struct key_preparsed_payload *prep) { struct user_key_payload *upayload, *zap; size_t datalen = prep->datalen; int ret; ret = -EINVAL; if (datalen <= 0 || datalen > 32767 || !prep->data) goto error; /* construct a replacement payload */ ret = -ENOMEM; upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); if (!upayload) goto error; upayload->datalen = datalen; memcpy(upayload->data, prep->data, datalen); /* check the quota and attach the new data */ zap = upayload; ret = key_payload_reserve(key, datalen); if (ret == 0) { /* attach the new data, displacing the old */ zap = key->payload.data; rcu_assign_keypointer(key, upayload); key->expiry = 0; } if (zap) kfree_rcu(zap, rcu); error: return ret; } EXPORT_SYMBOL_GPL(user_update); /* * match users on their name */ int user_match(const struct key *key, const void *description) { return strcmp(key->description, description) == 0; } EXPORT_SYMBOL_GPL(user_match); /* * dispose of the links from a revoked keyring * - called with the key sem write-locked */ void user_revoke(struct key *key) { struct user_key_payload *upayload = key->payload.data; /* clear the quota */ key_payload_reserve(key, 0); if (upayload) { rcu_assign_keypointer(key, NULL); kfree_rcu(upayload, rcu); } } EXPORT_SYMBOL(user_revoke); /* * dispose of the data dangling from the corpse of a user key */ void user_destroy(struct key *key) { struct user_key_payload *upayload = key->payload.data; kfree(upayload); } EXPORT_SYMBOL_GPL(user_destroy); /* * describe the user key */ void user_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); if (key_is_instantiated(key)) seq_printf(m, ": %u", key->datalen); } EXPORT_SYMBOL_GPL(user_describe); /* * read the key data * - the key's semaphore is read-locked */ long user_read(const struct key *key, char __user *buffer, size_t buflen) { struct user_key_payload *upayload; long ret; upayload = rcu_dereference_key(key); ret = upayload->datalen; /* we can return the data as is */ if (buffer && buflen > 0) { if (buflen > upayload->datalen) buflen = upayload->datalen; if (copy_to_user(buffer, upayload->data, buflen) != 0) ret = -EFAULT; } return ret; } EXPORT_SYMBOL_GPL(user_read); /* Vet the description for a "logon" key */ static int logon_vet_description(const char *desc) { char *p; /* require a "qualified" description string */ p = strchr(desc, ':'); if (!p) return -EINVAL; /* also reject description with ':' as first char */ if (p == desc) return -EINVAL; return 0; } |