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Subject[RFC PATCH 10/15] IMA: clean up the IMA counts updating code
Date
We currently have a lot of duplicated code around ima file counts.  Clean
that all up.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
---
security/integrity/ima/ima.h | 1
security/integrity/ima/ima_main.c | 118 ++++++++++++++++++++++---------------
2 files changed, 70 insertions(+), 49 deletions(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 349aabc..268ef57 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -97,7 +97,6 @@ static inline unsigned long ima_hash_key(u8 *digest)

/* iint cache flags */
#define IMA_MEASURED 1
-#define IMA_IINT_DUMP_STACK 512

/* integrity data associated with an inode */
struct ima_iint_cache {
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 96fafc0..e041233 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -13,8 +13,8 @@
* 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>
@@ -35,6 +35,69 @@ static int __init hash_setup(char *str)
}
__setup("ima_hash=", hash_setup);

+/*
+ * 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++;
+}
+
+/*
+ * Update the counts given open flags instead of fmode
+ */
+static void ima_inc_counts_flags(struct ima_iint_cache *iint, int flags)
+{
+ ima_inc_counts(iint, (__force fmode_t)((flags+1) & O_ACCMODE));
+}
+
+/*
+ * Decrement ima counts
+ */
+static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
+ 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--;
+ if (iint->writecount == 0) {
+ if (iint->version != inode->i_version)
+ iint->flags &= ~IMA_MEASURED;
+ }
+ }
+
+ if ((iint->opencount < 0) ||
+ (iint->readcount < 0) ||
+ (iint->writecount < 0)) {
+ static int dumped;
+
+ if (dumped)
+ return;
+ dumped = 1;
+
+ printk(KERN_INFO "%s: open/free imbalance (r:%ld w:%ld o:%ld)\n",
+ __FUNCTION__, iint->readcount, iint->writecount,
+ iint->opencount);
+ dump_stack();
+ }
+}
+
+static void ima_dec_counts_flags(struct ima_iint_cache *iint,
+ struct inode *inode, int flags)
+{
+ ima_dec_counts(iint, inode, (__force fmode_t)((flags+1) & O_ACCMODE));
+}
+
/**
* ima_file_free - called on __fput()
* @file: pointer to file structure being freed
@@ -54,29 +117,7 @@ void ima_file_free(struct file *file)
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->f_mode);
mutex_unlock(&iint->mutex);
kref_put(&iint->refcount, iint_free);
}
@@ -116,8 +157,7 @@ static int get_path_measurement(struct ima_iint_cache *iint, struct file *file,
{
int rc = 0;

- iint->opencount++;
- iint->readcount++;
+ ima_inc_counts(iint, file->f_mode);

rc = ima_collect_measurement(iint, file);
if (!rc)
@@ -125,15 +165,6 @@ static int get_path_measurement(struct ima_iint_cache *iint, struct file *file,
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
@@ -167,7 +198,7 @@ int ima_path_check(struct path *path, int mask, int update_counts)

mutex_lock(&iint->mutex);
if (update_counts)
- ima_update_counts(iint, mask);
+ ima_inc_counts_flags(iint, mask);

rc = ima_must_measure(iint, inode, MAY_READ, PATH_CHECK);
if (rc < 0)
@@ -260,11 +291,7 @@ void ima_counts_put(struct path *path, int mask)
return;

mutex_lock(&iint->mutex);
- iint->opencount--;
- if ((mask & MAY_WRITE) || (mask == 0))
- iint->writecount--;
- else if (mask & (MAY_READ | MAY_EXEC))
- iint->readcount--;
+ ima_dec_counts_flags(iint, inode, mask);
mutex_unlock(&iint->mutex);

kref_put(&iint->refcount, iint_free);
@@ -290,12 +317,7 @@ void ima_counts_get(struct file *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);


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