Commit 2c50b964 authored Jun 13, 2014 by Dmitry Kasatkin Committed by Mimi Zohar Jul 17, 2014

ima: remove unnecessary i_mutex locking from ima_rdwr_violation_check()

Before 2.6.39 inode->i_readcount was maintained by IMA. It was not atomic
and protected using spinlock. For 2.6.39, i_readcount was converted to
atomic and maintaining was moved VFS layer. Spinlock for some unclear
reason was replaced by i_mutex.

After analyzing the code, we came to conclusion that i_mutex locking is
unnecessary, especially when an IMA policy has not been defined.

This patch removes i_mutex locking from ima_rdwr_violation_check().

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

parent b6b8a371

security/integrity/ima/ima_main.c

+0 −4

Original line number	Diff line number	Diff line
		@@ -88,8 +88,6 @@ static void ima_rdwr_violation_check(struct file *file)
		if (!S_ISREG(inode->i_mode) \|\| !ima_initialized)
		return;

		mutex_lock(&inode->i_mutex); /* file metadata: permissions, xattr */

		if (mode & FMODE_WRITE) {
		if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
		struct integrity_iint_cache *iint;
		@@ -104,8 +102,6 @@ static void ima_rdwr_violation_check(struct file *file)
		send_writers = true;
		}

		mutex_unlock(&inode->i_mutex);

		if (!send_tomtou && !send_writers)
		return;