IMA: remove read permissions on the ima policy file
The IMA policy file does not implement read. Trying to just open/read/close
the file will load a blank policy and you cannot then change the policy
without a reboot. This removes the read permission from the file so one must
at least be attempting to write...
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index ffbe259..3305a96 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -15,6 +15,7 @@
* implemenents security file system for reporting
* current measurement list and IMA statistics
*/
+#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/rculist.h>
@@ -283,6 +284,9 @@
*/
int ima_open_policy(struct inode * inode, struct file * filp)
{
+ /* No point in being allowed to open it if you aren't going to write */
+ if (!(filp->f_flags & O_WRONLY))
+ return -EACCES;
if (atomic_dec_and_test(&policy_opencount))
return 0;
return -EBUSY;
@@ -349,7 +353,7 @@
goto out;
ima_policy = securityfs_create_file("policy",
- S_IRUSR | S_IRGRP | S_IWUSR,
+ S_IWUSR,
ima_dir, NULL,
&ima_measure_policy_ops);
if (IS_ERR(ima_policy))
