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authorEric Paris <eparis@redhat.com>2010-10-25 14:42:05 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-26 11:37:18 -0700
commitbc7d2a3e66b40477270c3cbe3b89b47093276e7a (patch)
tree8f0198b8ad455fde11b24e32a2e32c008a5ececb /security/integrity/ima
parenta178d2027d3198b0a04517d764326ab71cd73da2 (diff)
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IMA: only allocate iint when needed
IMA always allocates an integrity structure to hold information about every inode, but only needed this structure to track the number of readers and writers currently accessing a given inode. Since that information was moved into struct inode instead of the integrity struct this patch stops allocating the integrity stucture until it is needed. Thus greatly reducing memory usage. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security/integrity/ima')
-rw-r--r--security/integrity/ima/ima_main.c94
1 files changed, 64 insertions, 30 deletions
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 2a77b14fee2..5e3229c797f 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -141,33 +141,62 @@ out:
/*
* 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;
- bool dump = false;
- BUG_ON(!mutex_is_locked(&iint->mutex));
assert_spin_locked(&inode->i_lock);
if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
- if (unlikely(inode->i_readcount == 0))
- dump = true;
+ 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 (mode & FMODE_WRITE) {
- if (atomic_read(&inode->i_writecount) <= 0)
- dump = true;
- if (atomic_read(&inode->i_writecount) == 1 &&
- iint->version != inode->i_version)
- iint->flags &= ~IMA_MEASURED;
- }
+}
- if (dump && !ima_limit_imbalance(file)) {
- printk(KERN_INFO "%s: open/free imbalance (r:%u)\n",
- __func__, inode->i_readcount);
- 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);
+
+ kref_put(&iint->refcount, iint_free);
+}
+
+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);
}
/**
@@ -175,7 +204,7 @@ static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
* @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)
{
@@ -185,17 +214,12 @@ 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);
- spin_lock(&inode->i_lock);
-
- ima_dec_counts(iint, inode, file);
+ if (iint)
+ ima_file_free_iint(iint, inode, file);
+ else
+ ima_file_free_noiint(inode, file);
- spin_unlock(&inode->i_lock);
- mutex_unlock(&iint->mutex);
- kref_put(&iint->refcount, iint_free);
}
static int process_measurement(struct file *file, const unsigned char *filename,
@@ -207,11 +231,21 @@ static int process_measurement(struct file *file, const unsigned char *filename,
if (!ima_initialized || !S_ISREG(inode->i_mode))
return 0;
+
+ rc = ima_must_measure(NULL, inode, mask, function);
+ if (rc != 0)
+ return rc;
+retry:
iint = ima_iint_find_get(inode);
- if (!iint)
- return -ENOMEM;
+ 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;