Mimi Zohar | bab7393 | 2009-02-04 09:06:59 -0500 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2005,2006,2007,2008 IBM Corporation |
| 3 | * |
| 4 | * Authors: |
| 5 | * Kylene Hall <kjhall@us.ibm.com> |
| 6 | * Reiner Sailer <sailer@us.ibm.com> |
| 7 | * Mimi Zohar <zohar@us.ibm.com> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or |
| 10 | * modify it under the terms of the GNU General Public License as |
| 11 | * published by the Free Software Foundation, version 2 of the |
| 12 | * License. |
| 13 | * |
| 14 | * File: ima_fs.c |
| 15 | * implemenents security file system for reporting |
| 16 | * current measurement list and IMA statistics |
| 17 | */ |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/seq_file.h> |
| 20 | #include <linux/rculist.h> |
| 21 | #include <linux/rcupdate.h> |
| 22 | |
| 23 | #include "ima.h" |
| 24 | |
| 25 | #define TMPBUFLEN 12 |
| 26 | static ssize_t ima_show_htable_value(char __user *buf, size_t count, |
| 27 | loff_t *ppos, atomic_long_t *val) |
| 28 | { |
| 29 | char tmpbuf[TMPBUFLEN]; |
| 30 | ssize_t len; |
| 31 | |
| 32 | len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val)); |
| 33 | return simple_read_from_buffer(buf, count, ppos, tmpbuf, len); |
| 34 | } |
| 35 | |
| 36 | static ssize_t ima_show_htable_violations(struct file *filp, |
| 37 | char __user *buf, |
| 38 | size_t count, loff_t *ppos) |
| 39 | { |
| 40 | return ima_show_htable_value(buf, count, ppos, &ima_htable.violations); |
| 41 | } |
| 42 | |
| 43 | static struct file_operations ima_htable_violations_ops = { |
| 44 | .read = ima_show_htable_violations |
| 45 | }; |
| 46 | |
| 47 | static ssize_t ima_show_measurements_count(struct file *filp, |
| 48 | char __user *buf, |
| 49 | size_t count, loff_t *ppos) |
| 50 | { |
| 51 | return ima_show_htable_value(buf, count, ppos, &ima_htable.len); |
| 52 | |
| 53 | } |
| 54 | |
| 55 | static struct file_operations ima_measurements_count_ops = { |
| 56 | .read = ima_show_measurements_count |
| 57 | }; |
| 58 | |
| 59 | /* returns pointer to hlist_node */ |
| 60 | static void *ima_measurements_start(struct seq_file *m, loff_t *pos) |
| 61 | { |
| 62 | loff_t l = *pos; |
| 63 | struct ima_queue_entry *qe; |
| 64 | |
| 65 | /* we need a lock since pos could point beyond last element */ |
| 66 | rcu_read_lock(); |
| 67 | list_for_each_entry_rcu(qe, &ima_measurements, later) { |
| 68 | if (!l--) { |
| 69 | rcu_read_unlock(); |
| 70 | return qe; |
| 71 | } |
| 72 | } |
| 73 | rcu_read_unlock(); |
| 74 | return NULL; |
| 75 | } |
| 76 | |
| 77 | static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos) |
| 78 | { |
| 79 | struct ima_queue_entry *qe = v; |
| 80 | |
| 81 | /* lock protects when reading beyond last element |
| 82 | * against concurrent list-extension |
| 83 | */ |
| 84 | rcu_read_lock(); |
| 85 | qe = list_entry(rcu_dereference(qe->later.next), |
| 86 | struct ima_queue_entry, later); |
| 87 | rcu_read_unlock(); |
| 88 | (*pos)++; |
| 89 | |
| 90 | return (&qe->later == &ima_measurements) ? NULL : qe; |
| 91 | } |
| 92 | |
| 93 | static void ima_measurements_stop(struct seq_file *m, void *v) |
| 94 | { |
| 95 | } |
| 96 | |
| 97 | static void ima_putc(struct seq_file *m, void *data, int datalen) |
| 98 | { |
| 99 | while (datalen--) |
| 100 | seq_putc(m, *(char *)data++); |
| 101 | } |
| 102 | |
| 103 | /* print format: |
| 104 | * 32bit-le=pcr# |
| 105 | * char[20]=template digest |
| 106 | * 32bit-le=template name size |
| 107 | * char[n]=template name |
| 108 | * eventdata[n]=template specific data |
| 109 | */ |
| 110 | static int ima_measurements_show(struct seq_file *m, void *v) |
| 111 | { |
| 112 | /* the list never shrinks, so we don't need a lock here */ |
| 113 | struct ima_queue_entry *qe = v; |
| 114 | struct ima_template_entry *e; |
| 115 | int namelen; |
| 116 | u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX; |
| 117 | |
| 118 | /* get entry */ |
| 119 | e = qe->entry; |
| 120 | if (e == NULL) |
| 121 | return -1; |
| 122 | |
| 123 | /* |
| 124 | * 1st: PCRIndex |
| 125 | * PCR used is always the same (config option) in |
| 126 | * little-endian format |
| 127 | */ |
| 128 | ima_putc(m, &pcr, sizeof pcr); |
| 129 | |
| 130 | /* 2nd: template digest */ |
| 131 | ima_putc(m, e->digest, IMA_DIGEST_SIZE); |
| 132 | |
| 133 | /* 3rd: template name size */ |
| 134 | namelen = strlen(e->template_name); |
| 135 | ima_putc(m, &namelen, sizeof namelen); |
| 136 | |
| 137 | /* 4th: template name */ |
| 138 | ima_putc(m, e->template_name, namelen); |
| 139 | |
| 140 | /* 5th: template specific data */ |
| 141 | ima_template_show(m, (struct ima_template_data *)&e->template, |
| 142 | IMA_SHOW_BINARY); |
| 143 | return 0; |
| 144 | } |
| 145 | |
| 146 | static struct seq_operations ima_measurments_seqops = { |
| 147 | .start = ima_measurements_start, |
| 148 | .next = ima_measurements_next, |
| 149 | .stop = ima_measurements_stop, |
| 150 | .show = ima_measurements_show |
| 151 | }; |
| 152 | |
| 153 | static int ima_measurements_open(struct inode *inode, struct file *file) |
| 154 | { |
| 155 | return seq_open(file, &ima_measurments_seqops); |
| 156 | } |
| 157 | |
| 158 | static struct file_operations ima_measurements_ops = { |
| 159 | .open = ima_measurements_open, |
| 160 | .read = seq_read, |
| 161 | .llseek = seq_lseek, |
| 162 | .release = seq_release, |
| 163 | }; |
| 164 | |
| 165 | static void ima_print_digest(struct seq_file *m, u8 *digest) |
| 166 | { |
| 167 | int i; |
| 168 | |
| 169 | for (i = 0; i < IMA_DIGEST_SIZE; i++) |
| 170 | seq_printf(m, "%02x", *(digest + i)); |
| 171 | } |
| 172 | |
| 173 | void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show) |
| 174 | { |
| 175 | struct ima_template_data *entry = e; |
| 176 | int namelen; |
| 177 | |
| 178 | switch (show) { |
| 179 | case IMA_SHOW_ASCII: |
| 180 | ima_print_digest(m, entry->digest); |
| 181 | seq_printf(m, " %s\n", entry->file_name); |
| 182 | break; |
| 183 | case IMA_SHOW_BINARY: |
| 184 | ima_putc(m, entry->digest, IMA_DIGEST_SIZE); |
| 185 | |
| 186 | namelen = strlen(entry->file_name); |
| 187 | ima_putc(m, &namelen, sizeof namelen); |
| 188 | ima_putc(m, entry->file_name, namelen); |
| 189 | default: |
| 190 | break; |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | /* print in ascii */ |
| 195 | static int ima_ascii_measurements_show(struct seq_file *m, void *v) |
| 196 | { |
| 197 | /* the list never shrinks, so we don't need a lock here */ |
| 198 | struct ima_queue_entry *qe = v; |
| 199 | struct ima_template_entry *e; |
| 200 | |
| 201 | /* get entry */ |
| 202 | e = qe->entry; |
| 203 | if (e == NULL) |
| 204 | return -1; |
| 205 | |
| 206 | /* 1st: PCR used (config option) */ |
| 207 | seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX); |
| 208 | |
| 209 | /* 2nd: SHA1 template hash */ |
| 210 | ima_print_digest(m, e->digest); |
| 211 | |
| 212 | /* 3th: template name */ |
| 213 | seq_printf(m, " %s ", e->template_name); |
| 214 | |
| 215 | /* 4th: template specific data */ |
| 216 | ima_template_show(m, (struct ima_template_data *)&e->template, |
| 217 | IMA_SHOW_ASCII); |
| 218 | return 0; |
| 219 | } |
| 220 | |
| 221 | static struct seq_operations ima_ascii_measurements_seqops = { |
| 222 | .start = ima_measurements_start, |
| 223 | .next = ima_measurements_next, |
| 224 | .stop = ima_measurements_stop, |
| 225 | .show = ima_ascii_measurements_show |
| 226 | }; |
| 227 | |
| 228 | static int ima_ascii_measurements_open(struct inode *inode, struct file *file) |
| 229 | { |
| 230 | return seq_open(file, &ima_ascii_measurements_seqops); |
| 231 | } |
| 232 | |
| 233 | static struct file_operations ima_ascii_measurements_ops = { |
| 234 | .open = ima_ascii_measurements_open, |
| 235 | .read = seq_read, |
| 236 | .llseek = seq_lseek, |
| 237 | .release = seq_release, |
| 238 | }; |
| 239 | |
| 240 | static struct dentry *ima_dir; |
| 241 | static struct dentry *binary_runtime_measurements; |
| 242 | static struct dentry *ascii_runtime_measurements; |
| 243 | static struct dentry *runtime_measurements_count; |
| 244 | static struct dentry *violations; |
| 245 | |
| 246 | int ima_fs_init(void) |
| 247 | { |
| 248 | ima_dir = securityfs_create_dir("ima", NULL); |
| 249 | if (IS_ERR(ima_dir)) |
| 250 | return -1; |
| 251 | |
| 252 | binary_runtime_measurements = |
| 253 | securityfs_create_file("binary_runtime_measurements", |
| 254 | S_IRUSR | S_IRGRP, ima_dir, NULL, |
| 255 | &ima_measurements_ops); |
| 256 | if (IS_ERR(binary_runtime_measurements)) |
| 257 | goto out; |
| 258 | |
| 259 | ascii_runtime_measurements = |
| 260 | securityfs_create_file("ascii_runtime_measurements", |
| 261 | S_IRUSR | S_IRGRP, ima_dir, NULL, |
| 262 | &ima_ascii_measurements_ops); |
| 263 | if (IS_ERR(ascii_runtime_measurements)) |
| 264 | goto out; |
| 265 | |
| 266 | runtime_measurements_count = |
| 267 | securityfs_create_file("runtime_measurements_count", |
| 268 | S_IRUSR | S_IRGRP, ima_dir, NULL, |
| 269 | &ima_measurements_count_ops); |
| 270 | if (IS_ERR(runtime_measurements_count)) |
| 271 | goto out; |
| 272 | |
| 273 | violations = |
| 274 | securityfs_create_file("violations", S_IRUSR | S_IRGRP, |
| 275 | ima_dir, NULL, &ima_htable_violations_ops); |
| 276 | if (IS_ERR(violations)) |
| 277 | goto out; |
| 278 | |
| 279 | return 0; |
| 280 | |
| 281 | out: |
| 282 | securityfs_remove(runtime_measurements_count); |
| 283 | securityfs_remove(ascii_runtime_measurements); |
| 284 | securityfs_remove(binary_runtime_measurements); |
| 285 | securityfs_remove(ima_dir); |
| 286 | return -1; |
| 287 | } |
| 288 | |
| 289 | void __exit ima_fs_cleanup(void) |
| 290 | { |
| 291 | securityfs_remove(violations); |
| 292 | securityfs_remove(runtime_measurements_count); |
| 293 | securityfs_remove(ascii_runtime_measurements); |
| 294 | securityfs_remove(binary_runtime_measurements); |
| 295 | securityfs_remove(ima_dir); |
| 296 | } |