IMA: maintain i_readcount in the VFS layer
ima_counts_get() updated the readcount and invalidated the PCR,
as necessary. Only update the i_readcount in the VFS layer.
Move the PCR invalidation checks to ima_file_check(), where it
belongs.
Maintaining the i_readcount in the VFS layer, will allow other
subsystems to use i_readcount.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Eric Paris <eparis@redhat.com>
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 6e8cb93..69b4856 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -86,17 +86,16 @@
}
/*
- * ima_counts_get - increment file counts
+ * ima_rdwr_violation_check
*
- * Maintain read/write counters for all files, but only
- * invalidate the PCR for measured files:
+ * Only invalidate the PCR for measured files:
* - Opening a file for write when already open for read,
* results in a time of measure, time of use (ToMToU) error.
* - Opening a file for read when already open for write,
* could result in a file measurement error.
*
*/
-void ima_counts_get(struct file *file)
+static void ima_rdwr_violation_check(struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
@@ -104,13 +103,10 @@
int rc;
bool send_tomtou = false, send_writers = false;
- if (!S_ISREG(inode->i_mode))
+ if (!S_ISREG(inode->i_mode) || !ima_initialized)
return;
- spin_lock(&inode->i_lock);
-
- if (!ima_initialized)
- goto out;
+ mutex_lock(&inode->i_mutex); /* file metadata: permissions, xattr */
if (mode & FMODE_WRITE) {
if (atomic_read(&inode->i_readcount) && IS_IMA(inode))
@@ -125,11 +121,7 @@
if (atomic_read(&inode->i_writecount) > 0)
send_writers = true;
out:
- /* remember the vfs deals with i_writecount */
- if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
- atomic_inc(&inode->i_readcount);
-
- spin_unlock(&inode->i_lock);
+ mutex_unlock(&inode->i_mutex);
if (send_tomtou)
ima_add_violation(inode, dentry->d_name.name, "invalid_pcr",
@@ -158,7 +150,6 @@
}
return;
}
- atomic_dec(&inode->i_readcount);
}
}
@@ -203,8 +194,7 @@
* ima_file_free - called on __fput()
* @file: pointer to file structure being freed
*
- * Flag files that changed, based on i_version;
- * and decrement the i_readcount.
+ * Flag files that changed, based on i_version
*/
void ima_file_free(struct file *file)
{
@@ -318,6 +308,7 @@
{
int rc;
+ ima_rdwr_violation_check(file);
rc = process_measurement(file, file->f_dentry->d_name.name,
mask & (MAY_READ | MAY_WRITE | MAY_EXEC),
FILE_CHECK);