[PATCH v1.2 4/5] IMA: remove IMA imbalance checking

Mimi Zohar
2010-11-02T17:09:20Z

Now that i_readcount is maintained by the VFS layer, remove the
imbalance checking in IMA. Cleans up the IMA code nicely.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
---
security/integrity/ima/ima_iint.c | 4 --
security/integrity/ima/ima_main.c | 104 ++-----------------------------------
2 files changed, 4 insertions(+), 104 deletions(-)

diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c
index 68efe3b..4ae7304 100644
--- a/security/integrity/ima/ima_iint.c
+++ b/security/integrity/ima/ima_iint.c
@@ -137,10 +137,6 @@ void ima_inode_free(struct inode *inode)
{
struct ima_iint_cache *iint;

- if (atomic_read(&inode->i_readcount))
- printk(KERN_INFO "%s: readcount: %u\n", __func__,
- atomic_read(&inode->i_readcount));
-
if (!IS_IMA(inode))
return;

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index a0626bc..2df9021 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -36,55 +36,6 @@ static int __init hash_setup(char *str)
}
__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;
-}
-
/*
* ima_rdwr_violation_check
*
@@ -131,65 +82,20 @@ out:
"open_writers");
}

-/*
- * Decrement ima counts
- */
-static void ima_dec_counts(struct inode *inode, struct file *file)
-{
- mode_t mode = file->f_mode;
-
- assert_spin_locked(&inode->i_lock);
-
- if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
- if (unlikely(atomic_read(&inode->i_readcount) == 0)) {
- if (!ima_limit_imbalance(file)) {
- printk(KERN_INFO "%s: open/free imbalance (r:%u)\n",
- __func__,
- atomic_read(&inode->i_readcount));
- dump_stack();
- }
- return;
- }
- }
-}
-
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);
-
+ mutex_lock(&iint->mutex);
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);
-}
-
/**
* ima_file_free - called on __fput()
* @file: pointer to file structure being freed
@@ -205,12 +111,10 @@ void ima_file_free(struct file *file)
return;

iint = ima_iint_find(inode);
+ if (!iint)
+ return;

- if (iint)
- ima_file_free_iint(iint, inode, file);
- else
- ima_file_free_noiint(inode, file);
-
+ ima_check_last_writer(iint, inode, file);
}

static int process_measurement(struct file *file, const unsigned char *filename,
--
1.7.2.2