diff options
Diffstat (limited to 'security/integrity/ima/ima_main.c')
| -rw-r--r-- | security/integrity/ima/ima_main.c | 239 |
1 files changed, 93 insertions, 146 deletions
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index a89f44d5e030..294b005d6520 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c | |||
| @@ -14,7 +14,7 @@ | |||
| 14 | * | 14 | * |
| 15 | * File: ima_main.c | 15 | * File: ima_main.c |
| 16 | * implements the IMA hooks: ima_bprm_check, ima_file_mmap, | 16 | * implements the IMA hooks: ima_bprm_check, ima_file_mmap, |
| 17 | * and ima_path_check. | 17 | * and ima_file_check. |
| 18 | */ | 18 | */ |
| 19 | #include <linux/module.h> | 19 | #include <linux/module.h> |
| 20 | #include <linux/file.h> | 20 | #include <linux/file.h> |
| @@ -84,6 +84,36 @@ out: | |||
| 84 | return found; | 84 | return found; |
| 85 | } | 85 | } |
| 86 | 86 | ||
| 87 | /* ima_read_write_check - reflect possible reading/writing errors in the PCR. | ||
| 88 | * | ||
| 89 | * When opening a file for read, if the file is already open for write, | ||
| 90 | * the file could change, resulting in a file measurement error. | ||
| 91 | * | ||
| 92 | * Opening a file for write, if the file is already open for read, results | ||
| 93 | * in a time of measure, time of use (ToMToU) error. | ||
| 94 | * | ||
| 95 | * In either case invalidate the PCR. | ||
| 96 | */ | ||
| 97 | enum iint_pcr_error { TOMTOU, OPEN_WRITERS }; | ||
| 98 | static void ima_read_write_check(enum iint_pcr_error error, | ||
| 99 | struct ima_iint_cache *iint, | ||
| 100 | struct inode *inode, | ||
| 101 | const unsigned char *filename) | ||
| 102 | { | ||
| 103 | switch (error) { | ||
| 104 | case TOMTOU: | ||
| 105 | if (iint->readcount > 0) | ||
| 106 | ima_add_violation(inode, filename, "invalid_pcr", | ||
| 107 | "ToMToU"); | ||
| 108 | break; | ||
| 109 | case OPEN_WRITERS: | ||
| 110 | if (iint->writecount > 0) | ||
| 111 | ima_add_violation(inode, filename, "invalid_pcr", | ||
| 112 | "open_writers"); | ||
| 113 | break; | ||
| 114 | } | ||
| 115 | } | ||
| 116 | |||
| 87 | /* | 117 | /* |
| 88 | * Update the counts given an fmode_t | 118 | * Update the counts given an fmode_t |
| 89 | */ | 119 | */ |
| @@ -99,6 +129,47 @@ static void ima_inc_counts(struct ima_iint_cache *iint, fmode_t mode) | |||
| 99 | } | 129 | } |
| 100 | 130 | ||
| 101 | /* | 131 | /* |
| 132 | * ima_counts_get - increment file counts | ||
| 133 | * | ||
| 134 | * Maintain read/write counters for all files, but only | ||
| 135 | * invalidate the PCR for measured files: | ||
| 136 | * - Opening a file for write when already open for read, | ||
| 137 | * results in a time of measure, time of use (ToMToU) error. | ||
| 138 | * - Opening a file for read when already open for write, | ||
| 139 | * could result in a file measurement error. | ||
| 140 | * | ||
| 141 | */ | ||
| 142 | void ima_counts_get(struct file *file) | ||
| 143 | { | ||
| 144 | struct dentry *dentry = file->f_path.dentry; | ||
| 145 | struct inode *inode = dentry->d_inode; | ||
| 146 | fmode_t mode = file->f_mode; | ||
| 147 | struct ima_iint_cache *iint; | ||
| 148 | int rc; | ||
| 149 | |||
| 150 | if (!ima_initialized || !S_ISREG(inode->i_mode)) | ||
| 151 | return; | ||
| 152 | iint = ima_iint_find_get(inode); | ||
| 153 | if (!iint) | ||
| 154 | return; | ||
| 155 | mutex_lock(&iint->mutex); | ||
| 156 | rc = ima_must_measure(iint, inode, MAY_READ, FILE_CHECK); | ||
| 157 | if (rc < 0) | ||
| 158 | goto out; | ||
| 159 | |||
| 160 | if (mode & FMODE_WRITE) { | ||
| 161 | ima_read_write_check(TOMTOU, iint, inode, dentry->d_name.name); | ||
| 162 | goto out; | ||
| 163 | } | ||
| 164 | ima_read_write_check(OPEN_WRITERS, iint, inode, dentry->d_name.name); | ||
| 165 | out: | ||
| 166 | ima_inc_counts(iint, file->f_mode); | ||
| 167 | mutex_unlock(&iint->mutex); | ||
| 168 | |||
| 169 | kref_put(&iint->refcount, iint_free); | ||
| 170 | } | ||
| 171 | |||
| 172 | /* | ||
| 102 | * Decrement ima counts | 173 | * Decrement ima counts |
| 103 | */ | 174 | */ |
| 104 | static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode, | 175 | static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode, |
| @@ -153,123 +224,6 @@ void ima_file_free(struct file *file) | |||
| 153 | kref_put(&iint->refcount, iint_free); | 224 | kref_put(&iint->refcount, iint_free); |
| 154 | } | 225 | } |
| 155 | 226 | ||
| 156 | /* ima_read_write_check - reflect possible reading/writing errors in the PCR. | ||
| 157 | * | ||
| 158 | * When opening a file for read, if the file is already open for write, | ||
| 159 | * the file could change, resulting in a file measurement error. | ||
| 160 | * | ||
| 161 | * Opening a file for write, if the file is already open for read, results | ||
| 162 | * in a time of measure, time of use (ToMToU) error. | ||
| 163 | * | ||
| 164 | * In either case invalidate the PCR. | ||
| 165 | */ | ||
| 166 | enum iint_pcr_error { TOMTOU, OPEN_WRITERS }; | ||
| 167 | static void ima_read_write_check(enum iint_pcr_error error, | ||
| 168 | struct ima_iint_cache *iint, | ||
| 169 | struct inode *inode, | ||
| 170 | const unsigned char *filename) | ||
| 171 | { | ||
| 172 | switch (error) { | ||
| 173 | case TOMTOU: | ||
| 174 | if (iint->readcount > 0) | ||
| 175 | ima_add_violation(inode, filename, "invalid_pcr", | ||
| 176 | "ToMToU"); | ||
| 177 | break; | ||
| 178 | case OPEN_WRITERS: | ||
| 179 | if (iint->writecount > 0) | ||
| 180 | ima_add_violation(inode, filename, "invalid_pcr", | ||
| 181 | "open_writers"); | ||
| 182 | break; | ||
| 183 | } | ||
| 184 | } | ||
| 185 | |||
| 186 | static int get_path_measurement(struct ima_iint_cache *iint, struct file *file, | ||
| 187 | const unsigned char *filename) | ||
| 188 | { | ||
| 189 | int rc = 0; | ||
| 190 | |||
| 191 | ima_inc_counts(iint, file->f_mode); | ||
| 192 | |||
| 193 | rc = ima_collect_measurement(iint, file); | ||
| 194 | if (!rc) | ||
| 195 | ima_store_measurement(iint, file, filename); | ||
| 196 | return rc; | ||
| 197 | } | ||
| 198 | |||
| 199 | /** | ||
| 200 | * ima_path_check - based on policy, collect/store measurement. | ||
| 201 | * @path: contains a pointer to the path to be measured | ||
| 202 | * @mask: contains MAY_READ, MAY_WRITE or MAY_EXECUTE | ||
| 203 | * | ||
| 204 | * Measure the file being open for readonly, based on the | ||
| 205 | * ima_must_measure() policy decision. | ||
| 206 | * | ||
| 207 | * Keep read/write counters for all files, but only | ||
| 208 | * invalidate the PCR for measured files: | ||
| 209 | * - Opening a file for write when already open for read, | ||
| 210 | * results in a time of measure, time of use (ToMToU) error. | ||
| 211 | * - Opening a file for read when already open for write, | ||
| 212 | * could result in a file measurement error. | ||
| 213 | * | ||
| 214 | * Always return 0 and audit dentry_open failures. | ||
| 215 | * (Return code will be based upon measurement appraisal.) | ||
| 216 | */ | ||
| 217 | int ima_path_check(struct path *path, int mask) | ||
| 218 | { | ||
| 219 | struct inode *inode = path->dentry->d_inode; | ||
| 220 | struct ima_iint_cache *iint; | ||
| 221 | struct file *file = NULL; | ||
| 222 | int rc; | ||
| 223 | |||
| 224 | if (!ima_initialized || !S_ISREG(inode->i_mode)) | ||
| 225 | return 0; | ||
| 226 | iint = ima_iint_find_get(inode); | ||
| 227 | if (!iint) | ||
| 228 | return 0; | ||
| 229 | |||
| 230 | mutex_lock(&iint->mutex); | ||
| 231 | |||
| 232 | rc = ima_must_measure(iint, inode, MAY_READ, PATH_CHECK); | ||
| 233 | if (rc < 0) | ||
| 234 | goto out; | ||
| 235 | |||
| 236 | if ((mask & MAY_WRITE) || (mask == 0)) | ||
| 237 | ima_read_write_check(TOMTOU, iint, inode, | ||
| 238 | path->dentry->d_name.name); | ||
| 239 | |||
| 240 | if ((mask & (MAY_WRITE | MAY_READ | MAY_EXEC)) != MAY_READ) | ||
| 241 | goto out; | ||
| 242 | |||
| 243 | ima_read_write_check(OPEN_WRITERS, iint, inode, | ||
| 244 | path->dentry->d_name.name); | ||
| 245 | if (!(iint->flags & IMA_MEASURED)) { | ||
| 246 | struct dentry *dentry = dget(path->dentry); | ||
| 247 | struct vfsmount *mnt = mntget(path->mnt); | ||
| 248 | |||
| 249 | file = dentry_open(dentry, mnt, O_RDONLY | O_LARGEFILE, | ||
| 250 | current_cred()); | ||
| 251 | if (IS_ERR(file)) { | ||
| 252 | int audit_info = 0; | ||
| 253 | |||
| 254 | integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, | ||
| 255 | dentry->d_name.name, | ||
| 256 | "add_measurement", | ||
| 257 | "dentry_open failed", | ||
| 258 | 1, audit_info); | ||
| 259 | file = NULL; | ||
| 260 | goto out; | ||
| 261 | } | ||
| 262 | rc = get_path_measurement(iint, file, dentry->d_name.name); | ||
| 263 | } | ||
| 264 | out: | ||
| 265 | mutex_unlock(&iint->mutex); | ||
| 266 | if (file) | ||
| 267 | fput(file); | ||
| 268 | kref_put(&iint->refcount, iint_free); | ||
| 269 | return 0; | ||
| 270 | } | ||
| 271 | EXPORT_SYMBOL_GPL(ima_path_check); | ||
| 272 | |||
| 273 | static int process_measurement(struct file *file, const unsigned char *filename, | 227 | static int process_measurement(struct file *file, const unsigned char *filename, |
| 274 | int mask, int function) | 228 | int mask, int function) |
| 275 | { | 229 | { |
| @@ -297,33 +251,6 @@ out: | |||
| 297 | return rc; | 251 | return rc; |
| 298 | } | 252 | } |
| 299 | 253 | ||
| 300 | /* | ||
| 301 | * ima_counts_get - increment file counts | ||
| 302 | * | ||
| 303 | * - for IPC shm and shmat file. | ||
| 304 | * - for nfsd exported files. | ||
| 305 | * | ||
| 306 | * Increment the counts for these files to prevent unnecessary | ||
| 307 | * imbalance messages. | ||
| 308 | */ | ||
| 309 | void ima_counts_get(struct file *file) | ||
| 310 | { | ||
| 311 | struct inode *inode = file->f_dentry->d_inode; | ||
| 312 | struct ima_iint_cache *iint; | ||
| 313 | |||
| 314 | if (!ima_initialized || !S_ISREG(inode->i_mode)) | ||
| 315 | return; | ||
| 316 | iint = ima_iint_find_get(inode); | ||
| 317 | if (!iint) | ||
| 318 | return; | ||
| 319 | mutex_lock(&iint->mutex); | ||
| 320 | ima_inc_counts(iint, file->f_mode); | ||
| 321 | mutex_unlock(&iint->mutex); | ||
| 322 | |||
| 323 | kref_put(&iint->refcount, iint_free); | ||
| 324 | } | ||
| 325 | EXPORT_SYMBOL_GPL(ima_counts_get); | ||
| 326 | |||
| 327 | /** | 254 | /** |
| 328 | * ima_file_mmap - based on policy, collect/store measurement. | 255 | * ima_file_mmap - based on policy, collect/store measurement. |
| 329 | * @file: pointer to the file to be measured (May be NULL) | 256 | * @file: pointer to the file to be measured (May be NULL) |
| @@ -369,11 +296,31 @@ int ima_bprm_check(struct linux_binprm *bprm) | |||
| 369 | return 0; | 296 | return 0; |
| 370 | } | 297 | } |
| 371 | 298 | ||
| 299 | /** | ||
| 300 | * ima_path_check - based on policy, collect/store measurement. | ||
| 301 | * @file: pointer to the file to be measured | ||
| 302 | * @mask: contains MAY_READ, MAY_WRITE or MAY_EXECUTE | ||
| 303 | * | ||
| 304 | * Measure files based on the ima_must_measure() policy decision. | ||
| 305 | * | ||
| 306 | * Always return 0 and audit dentry_open failures. | ||
| 307 | * (Return code will be based upon measurement appraisal.) | ||
| 308 | */ | ||
| 309 | int ima_file_check(struct file *file, int mask) | ||
| 310 | { | ||
| 311 | int rc; | ||
| 312 | |||
| 313 | rc = process_measurement(file, file->f_dentry->d_name.name, | ||
| 314 | mask & (MAY_READ | MAY_WRITE | MAY_EXEC), | ||
| 315 | FILE_CHECK); | ||
| 316 | return 0; | ||
| 317 | } | ||
| 318 | EXPORT_SYMBOL_GPL(ima_file_check); | ||
| 319 | |||
| 372 | static int __init init_ima(void) | 320 | static int __init init_ima(void) |
| 373 | { | 321 | { |
| 374 | int error; | 322 | int error; |
| 375 | 323 | ||
| 376 | ima_iintcache_init(); | ||
| 377 | error = ima_init(); | 324 | error = ima_init(); |
| 378 | ima_initialized = 1; | 325 | ima_initialized = 1; |
| 379 | return error; | 326 | return error; |
