integrity: add ima_counts_put (updated)

This patch fixes an imbalance message as reported by J.R. Okajima.
The IMA file counters are incremented in ima_path_check. If the
actual open fails, such as ETXTBSY, decrement the counters to
prevent unnecessary imbalance messages.

Reported-by: J.R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 28 insertions, 1 deletions

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 6f611874d10e..101c512564ec 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -238,7 +238,34 @@ out:
 }
 
 /*
- * ima_opens_get - increment file counts
+ * 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;
+
+        if (!ima_initialized || !S_ISREG(inode->i_mode))
+                return;
+        iint = ima_iint_find_insert_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);
+}
+
+/*
+ * ima_counts_get - increment file counts
  *
  * - for IPC shm and shmat file.
  * - for nfsd exported files.