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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 | /* 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/sched.h> #include <linux/slab.h> #include <linux/seq_file.h> #include <linux/err.h> #include <asm/uaccess.h> #include "internal.h" static int user_instantiate(struct key *key, const void *data, size_t datalen); static int user_duplicate(struct key *key, const struct key *source); static int user_update(struct key *key, const void *data, size_t datalen); static int user_match(const struct key *key, const void *criterion); static void user_destroy(struct key *key); static void user_describe(const struct key *user, struct seq_file *m); static long user_read(const struct key *key, char __user *buffer, size_t buflen); /* * 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, .duplicate = user_duplicate, .update = user_update, .match = user_match, .destroy = user_destroy, .describe = user_describe, .read = user_read, }; /*****************************************************************************/ /* * instantiate a user defined key */ static int user_instantiate(struct key *key, const void *data, size_t datalen) { int ret; ret = -EINVAL; if (datalen <= 0 || datalen > 32767 || !data) goto error; ret = key_payload_reserve(key, datalen); if (ret < 0) goto error; /* attach the data */ ret = -ENOMEM; key->payload.data = kmalloc(datalen, GFP_KERNEL); if (!key->payload.data) goto error; memcpy(key->payload.data, data, datalen); ret = 0; error: return ret; } /* end user_instantiate() */ /*****************************************************************************/ /* * duplicate a user defined key */ static int user_duplicate(struct key *key, const struct key *source) { int ret; /* just copy the payload */ ret = -ENOMEM; key->payload.data = kmalloc(source->datalen, GFP_KERNEL); if (key->payload.data) { key->datalen = source->datalen; memcpy(key->payload.data, source->payload.data, source->datalen); ret = 0; } return ret; } /* end user_duplicate() */ /*****************************************************************************/ /* * update a user defined key */ static int user_update(struct key *key, const void *data, size_t datalen) { void *new, *zap; int ret; ret = -EINVAL; if (datalen <= 0 || datalen > 32767 || !data) goto error; /* copy the data */ ret = -ENOMEM; new = kmalloc(datalen, GFP_KERNEL); if (!new) goto error; memcpy(new, data, datalen); /* check the quota and attach the new data */ zap = new; write_lock(&key->lock); ret = key_payload_reserve(key, datalen); if (ret == 0) { /* attach the new data, displacing the old */ zap = key->payload.data; key->payload.data = new; key->expiry = 0; } write_unlock(&key->lock); kfree(zap); error: return ret; } /* end user_update() */ /*****************************************************************************/ /* * match users on their name */ static int user_match(const struct key *key, const void *description) { return strcmp(key->description, description) == 0; } /* end user_match() */ /*****************************************************************************/ /* * dispose of the data dangling from the corpse of a user */ static void user_destroy(struct key *key) { kfree(key->payload.data); } /* end user_destroy() */ /*****************************************************************************/ /* * describe the user */ static void user_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); seq_printf(m, ": %u", key->datalen); } /* end user_describe() */ /*****************************************************************************/ /* * read the key data */ static long user_read(const struct key *key, char __user *buffer, size_t buflen) { long ret = key->datalen; /* we can return the data as is */ if (buffer && buflen > 0) { if (buflen > key->datalen) buflen = key->datalen; if (copy_to_user(buffer, key->payload.data, buflen) != 0) ret = -EFAULT; } return ret; } /* end user_read() */ |