* License.
*
* File: ima_main.c
- * implements the IMA hooks: ima_bprm_check, ima_file_mmap,
- * and ima_path_check.
+ * implements the IMA hooks: ima_bprm_check, ima_file_mmap,
+ * and ima_path_check.
*/
#include <linux/module.h>
#include <linux/file.h>
}
__setup("ima_hash=", hash_setup);
+struct ima_imbalance {
+ struct hlist_node node;
+ unsigned long fsmagic;
+};
+
+/*
+ * ima_limit_imbalance - emit one imbalance message per filesystem type
+ *
+ * Maintain list of filesystem types that do not measure files properly.
+ * Return false if unknown, true if known.
+ */
+static bool ima_limit_imbalance(struct file *file)
+{
+ static DEFINE_SPINLOCK(ima_imbalance_lock);
+ static HLIST_HEAD(ima_imbalance_list);
+
+ struct super_block *sb = file->f_dentry->d_sb;
+ struct ima_imbalance *entry;
+ struct hlist_node *node;
+ bool found = false;
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(entry, node, &ima_imbalance_list, node) {
+ if (entry->fsmagic == sb->s_magic) {
+ found = true;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ if (found)
+ goto out;
+
+ entry = kmalloc(sizeof(*entry), GFP_NOFS);
+ if (!entry)
+ goto out;
+ entry->fsmagic = sb->s_magic;
+ spin_lock(&ima_imbalance_lock);
+ /*
+ * we could have raced and something else might have added this fs
+ * to the list, but we don't really care
+ */
+ hlist_add_head_rcu(&entry->node, &ima_imbalance_list);
+ spin_unlock(&ima_imbalance_lock);
+ printk(KERN_INFO "IMA: unmeasured files on fsmagic: %lX\n",
+ entry->fsmagic);
+out:
+ return found;
+}
+
+/*
+ * 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++;
+}
+
+/*
+ * Decrement ima counts
+ */
+static void ima_dec_counts(struct ima_iint_cache *iint, 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;
+ }
+ }
+
+ 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",
+ __FUNCTION__, iint->readcount, iint->writecount,
+ iint->opencount);
+ dump_stack();
+ }
+}
+
/**
* ima_file_free - called on __fput()
* @file: pointer to file structure being freed
return;
mutex_lock(&iint->mutex);
- if (iint->opencount <= 0) {
- printk(KERN_INFO
- "%s: %s open/free imbalance (r:%ld w:%ld o:%ld f:%ld)\n",
- __FUNCTION__, file->f_dentry->d_name.name,
- iint->readcount, iint->writecount,
- iint->opencount, atomic_long_read(&file->f_count));
- if (!(iint->flags & IMA_IINT_DUMP_STACK)) {
- dump_stack();
- iint->flags |= IMA_IINT_DUMP_STACK;
- }
- }
- iint->opencount--;
-
- if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
- iint->readcount--;
-
- if (file->f_mode & FMODE_WRITE) {
- iint->writecount--;
- if (iint->writecount == 0) {
- if (iint->version != inode->i_version)
- iint->flags &= ~IMA_MEASURED;
- }
- }
+ ima_dec_counts(iint, inode, file);
mutex_unlock(&iint->mutex);
kref_put(&iint->refcount, iint_free);
}
{
int rc = 0;
- iint->opencount++;
- iint->readcount++;
+ ima_inc_counts(iint, file->f_mode);
rc = ima_collect_measurement(iint, file);
if (!rc)
return rc;
}
-static void ima_update_counts(struct ima_iint_cache *iint, int mask)
-{
- iint->opencount++;
- if ((mask & MAY_WRITE) || (mask == 0))
- iint->writecount++;
- else if (mask & (MAY_READ | MAY_EXEC))
- iint->readcount++;
-}
-
/**
* ima_path_check - based on policy, collect/store measurement.
* @path: contains a pointer to the path to be measured
* Always return 0 and audit dentry_open failures.
* (Return code will be based upon measurement appraisal.)
*/
-int ima_path_check(struct path *path, int mask, int update_counts)
+int ima_path_check(struct path *path, int mask)
{
struct inode *inode = path->dentry->d_inode;
struct ima_iint_cache *iint;
return 0;
mutex_lock(&iint->mutex);
- if (update_counts)
- ima_update_counts(iint, mask);
rc = ima_must_measure(iint, inode, MAY_READ, PATH_CHECK);
if (rc < 0)
}
/*
- * ima_counts_put - decrement file counts
- *
- * File counts are incremented in ima_path_check. On file open
- * error, such as ETXTBSY, decrement the counts to prevent
- * unnecessary imbalance messages.
- */
-void ima_counts_put(struct path *path, int mask)
-{
- struct inode *inode = path->dentry->d_inode;
- struct ima_iint_cache *iint;
-
- /* The inode may already have been freed, freeing the iint
- * with it. Verify the inode is not NULL before dereferencing
- * it.
- */
- if (!ima_initialized || !inode || !S_ISREG(inode->i_mode))
- return;
- iint = ima_iint_find_get(inode);
- if (!iint)
- return;
-
- mutex_lock(&iint->mutex);
- iint->opencount--;
- if ((mask & MAY_WRITE) || (mask == 0))
- iint->writecount--;
- else if (mask & (MAY_READ | MAY_EXEC))
- iint->readcount--;
- mutex_unlock(&iint->mutex);
-
- kref_put(&iint->refcount, iint_free);
-}
-
-/*
* ima_counts_get - increment file counts
*
* - for IPC shm and shmat file.
if (!iint)
return;
mutex_lock(&iint->mutex);
- iint->opencount++;
- if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
- iint->readcount++;
-
- if (file->f_mode & FMODE_WRITE)
- iint->writecount++;
+ ima_inc_counts(iint, file->f_mode);
mutex_unlock(&iint->mutex);
kref_put(&iint->refcount, iint_free);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff