IMA: clean up the IMA counts updating code

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>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 70 insertions, 49 deletions

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 349aabc83297..268ef57b9142 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 96fafc01e2c7..e041233b4d2a 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);