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Subject[PATCH 09/11] IMA: drop refcnt from ima_iint_cache since it isn't needed
Date
Since finding a struct ima_iint_cache requires a valid struct inode, and the
struct ima_iint_cache is supposed to have the same lifetime as a struct inode
(technically they die together but don't need to be created at the same time)
we don't have to worry about the ima_iint_cache outliving or dieing before the
inode. So the refcnt isn't useful. Just get rid of it and free the structure
when the inode is freed.

Signed-off-by: Eric Paris <eapris@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---

security/integrity/ima/ima.h | 4 +---
security/integrity/ima/ima_iint.c | 38 ++++++++++++++++---------------------
security/integrity/ima/ima_main.c | 7 ++-----
3 files changed, 19 insertions(+), 30 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 27849e1..ac79032 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -107,7 +107,6 @@ struct ima_iint_cache {
unsigned char flags;
u8 digest[IMA_DIGEST_SIZE];
struct mutex mutex; /* protects: version, flags, digest */
- struct kref refcount; /* ima_iint_cache reference count */
};

/* LIM API function definitions */
@@ -125,8 +124,7 @@ void ima_template_show(struct seq_file *m, void *e,
* integrity data associated with an inode.
*/
struct ima_iint_cache *ima_iint_insert(struct inode *inode);
-struct ima_iint_cache *ima_iint_find_get(struct inode *inode);
-void iint_free(struct kref *kref);
+struct ima_iint_cache *ima_iint_find(struct inode *inode);

/* IMA policy related functions */
enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK };
diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c
index 0936a71..969a1c1 100644
--- a/security/integrity/ima/ima_iint.c
+++ b/security/integrity/ima/ima_iint.c
@@ -53,24 +53,26 @@ static struct ima_iint_cache *__ima_iint_find(struct inode *inode)
}

/*
- * ima_iint_find_get - return the iint associated with an inode
- *
- * ima_iint_find_get gets a reference to the iint. Caller must
- * remember to put the iint reference.
+ * ima_iint_find - return the iint associated with an inode
*/
-struct ima_iint_cache *ima_iint_find_get(struct inode *inode)
+struct ima_iint_cache *ima_iint_find(struct inode *inode)
{
struct ima_iint_cache *iint;

spin_lock(&ima_iint_lock);
iint = __ima_iint_find(inode);
- if (iint)
- kref_get(&iint->refcount);
spin_unlock(&ima_iint_lock);

return iint;
}

+static void iint_free(struct ima_iint_cache *iint)
+{
+ iint->version = 0;
+ iint->flags = 0UL;
+ kmem_cache_free(iint_cache, iint);
+}
+
/**
* ima_inode_alloc - allocate an iint associated with an inode
* @inode: pointer to the inode
@@ -113,19 +115,9 @@ int ima_inode_alloc(struct inode *inode)
return 0;
out_err:
spin_unlock(&ima_iint_lock);
- kref_put(&new_iint->refcount, iint_free);
- return rc;
-}
+ iint_free(new_iint);

-/* iint_free - called when the iint refcount goes to zero */
-void iint_free(struct kref *kref)
-{
- struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache,
- refcount);
- iint->version = 0;
- iint->flags = 0UL;
- kref_init(&iint->refcount);
- kmem_cache_free(iint_cache, iint);
+ return rc;
}

/**
@@ -148,8 +140,11 @@ void ima_inode_free(struct inode *inode)
if (iint)
rb_erase(&iint->rb_node, &ima_iint_tree);
spin_unlock(&ima_iint_lock);
- if (iint)
- kref_put(&iint->refcount, iint_free);
+
+ if (!iint)
+ return;
+
+ iint_free(iint);
}

static void init_once(void *foo)
@@ -160,7 +155,6 @@ static void init_once(void *foo)
iint->version = 0;
iint->flags = 0UL;
mutex_init(&iint->mutex);
- kref_init(&iint->refcount);
}

static int __init ima_iintcache_init(void)
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 5e3229c..1dccafe 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -186,8 +186,6 @@ static void ima_file_free_iint(struct ima_iint_cache *iint, struct inode *inode,

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)
@@ -213,7 +211,7 @@ void ima_file_free(struct file *file)

if (!iint_initialized || !S_ISREG(inode->i_mode))
return;
- iint = ima_iint_find_get(inode);
+ iint = ima_iint_find(inode);

if (iint)
ima_file_free_iint(iint, inode, file);
@@ -236,7 +234,7 @@ static int process_measurement(struct file *file, const unsigned char *filename,
if (rc != 0)
return rc;
retry:
- iint = ima_iint_find_get(inode);
+ iint = ima_iint_find(inode);
if (!iint) {
rc = ima_inode_alloc(inode);
if (!rc || rc == -EEXIST)
@@ -255,7 +253,6 @@ retry:
ima_store_measurement(iint, file, filename);
out:
mutex_unlock(&iint->mutex);
- kref_put(&iint->refcount, iint_free);
return rc;
}



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