return found;
}
-/* ima_read_write_check - reflect possible reading/writing errors in the PCR.
- *
- * When opening a file for read, if the file is already open for write,
- * the file could change, resulting in a file measurement error.
- *
- * Opening a file for write, if the file is already open for read, results
- * in a time of measure, time of use (ToMToU) error.
- *
- * In either case invalidate the PCR.
- */
-enum iint_pcr_error { TOMTOU, OPEN_WRITERS };
-static void ima_read_write_check(enum iint_pcr_error error,
- struct ima_iint_cache *iint,
- struct inode *inode,
- const unsigned char *filename)
-{
- switch (error) {
- case TOMTOU:
- if (iint->readcount > 0)
- ima_add_violation(inode, filename, "invalid_pcr",
- "ToMToU");
- break;
- case OPEN_WRITERS:
- if (iint->writecount > 0)
- ima_add_violation(inode, filename, "invalid_pcr",
- "open_writers");
- break;
- }
-}
-
-/*
- * Update the counts given an fmode_t
- */
-static void ima_inc_counts(struct ima_iint_cache *iint, fmode_t mode)
-{
- BUG_ON(!mutex_is_locked(&iint->mutex));
-
- iint->opencount++;
- if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
- iint->readcount++;
- if (mode & FMODE_WRITE)
- iint->writecount++;
-}
-
/*
* ima_counts_get - increment file counts
*
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
fmode_t mode = file->f_mode;
- struct ima_iint_cache *iint;
int rc;
+ bool send_tomtou = false, send_writers = false;
- if (!iint_initialized || !S_ISREG(inode->i_mode))
+ if (!S_ISREG(inode->i_mode))
return;
- iint = ima_iint_find_get(inode);
- if (!iint)
- return;
- mutex_lock(&iint->mutex);
+
+ spin_lock(&inode->i_lock);
+
if (!ima_initialized)
goto out;
- rc = ima_must_measure(iint, inode, MAY_READ, FILE_CHECK);
- if (rc < 0)
- goto out;
if (mode & FMODE_WRITE) {
- ima_read_write_check(TOMTOU, iint, inode, dentry->d_name.name);
+ if (inode->i_readcount && IS_IMA(inode))
+ send_tomtou = true;
goto out;
}
- ima_read_write_check(OPEN_WRITERS, iint, inode, dentry->d_name.name);
+
+ rc = ima_must_measure(NULL, inode, MAY_READ, FILE_CHECK);
+ if (rc < 0)
+ goto out;
+
+ if (atomic_read(&inode->i_writecount) > 0)
+ send_writers = true;
out:
- ima_inc_counts(iint, file->f_mode);
- mutex_unlock(&iint->mutex);
+ /* remember the vfs deals with i_writecount */
+ if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+ inode->i_readcount++;
- kref_put(&iint->refcount, iint_free);
+ spin_unlock(&inode->i_lock);
+
+ if (send_tomtou)
+ ima_add_violation(inode, dentry->d_name.name, "invalid_pcr",
+ "ToMToU");
+ if (send_writers)
+ ima_add_violation(inode, dentry->d_name.name, "invalid_pcr",
+ "open_writers");
}
/*
* Decrement ima counts
*/
-static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
- struct file *file)
+static void ima_dec_counts(struct inode *inode, struct file *file)
{
mode_t mode = file->f_mode;
- BUG_ON(!mutex_is_locked(&iint->mutex));
- iint->opencount--;
- if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
- iint->readcount--;
- if (mode & FMODE_WRITE) {
- iint->writecount--;
- if (iint->writecount == 0) {
- if (iint->version != inode->i_version)
- iint->flags &= ~IMA_MEASURED;
+ assert_spin_locked(&inode->i_lock);
+
+ if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
+ if (unlikely(inode->i_readcount == 0)) {
+ if (!ima_limit_imbalance(file)) {
+ printk(KERN_INFO "%s: open/free imbalance (r:%u)\n",
+ __func__, inode->i_readcount);
+ dump_stack();
+ }
+ return;
}
+ inode->i_readcount--;
}
+}
- if (((iint->opencount < 0) ||
- (iint->readcount < 0) ||
- (iint->writecount < 0)) &&
- !ima_limit_imbalance(file)) {
- printk(KERN_INFO "%s: open/free imbalance (r:%ld w:%ld o:%ld)\n",
- __func__, iint->readcount, iint->writecount,
- iint->opencount);
- dump_stack();
- }
+static void ima_check_last_writer(struct ima_iint_cache *iint,
+ struct inode *inode,
+ struct file *file)
+{
+ mode_t mode = file->f_mode;
+
+ BUG_ON(!mutex_is_locked(&iint->mutex));
+ assert_spin_locked(&inode->i_lock);
+
+ if (mode & FMODE_WRITE &&
+ atomic_read(&inode->i_writecount) == 1 &&
+ iint->version != inode->i_version)
+ iint->flags &= ~IMA_MEASURED;
+}
+
+static void ima_file_free_iint(struct ima_iint_cache *iint, struct inode *inode,
+ struct file *file)
+{
+ mutex_lock(&iint->mutex);
+ spin_lock(&inode->i_lock);
+
+ ima_dec_counts(inode, file);
+ ima_check_last_writer(iint, inode, file);
+
+ spin_unlock(&inode->i_lock);
+ mutex_unlock(&iint->mutex);
+}
+
+static void ima_file_free_noiint(struct inode *inode, struct file *file)
+{
+ spin_lock(&inode->i_lock);
+
+ ima_dec_counts(inode, file);
+
+ spin_unlock(&inode->i_lock);
}
/**
* @file: pointer to file structure being freed
*
* Flag files that changed, based on i_version;
- * and decrement the iint readcount/writecount.
+ * and decrement the i_readcount.
*/
void ima_file_free(struct file *file)
{
if (!iint_initialized || !S_ISREG(inode->i_mode))
return;
- iint = ima_iint_find_get(inode);
- if (!iint)
- return;
- mutex_lock(&iint->mutex);
- ima_dec_counts(iint, inode, file);
- mutex_unlock(&iint->mutex);
- kref_put(&iint->refcount, iint_free);
+ iint = ima_iint_find(inode);
+
+ if (iint)
+ ima_file_free_iint(iint, inode, file);
+ else
+ ima_file_free_noiint(inode, file);
+
}
static int process_measurement(struct file *file, const unsigned char *filename,
if (!ima_initialized || !S_ISREG(inode->i_mode))
return 0;
- iint = ima_iint_find_get(inode);
- if (!iint)
- return -ENOMEM;
+
+ rc = ima_must_measure(NULL, inode, mask, function);
+ if (rc != 0)
+ return rc;
+retry:
+ iint = ima_iint_find(inode);
+ if (!iint) {
+ rc = ima_inode_alloc(inode);
+ if (!rc || rc == -EEXIST)
+ goto retry;
+ return rc;
+ }
mutex_lock(&iint->mutex);
+
rc = ima_must_measure(iint, inode, mask, function);
if (rc != 0)
goto out;
ima_store_measurement(iint, file, filename);
out:
mutex_unlock(&iint->mutex);
- kref_put(&iint->refcount, iint_free);
return rc;
}
git://bbs.cooldavid.org / net-next-2.6.git / blobdiff