Re: [PATCH] IMA: remove read permissions on the ima policy file

From: James Morris
Date: Thu May 14 2009 - 20:41:50 EST


On Tue, 12 May 2009, Eric Paris wrote:

> 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@xxxxxxxxxx>

Applied to
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6#next

> ---
>
> security/integrity/ima/ima_fs.c | 6 +++++-
> 1 files changed, 5 insertions(+), 1 deletions(-)
>
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index 510186f..2a829da 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 @@ static atomic_t policy_opencount = ATOMIC_INIT(1);
> */
> 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 @@ int ima_fs_init(void)
> 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))
>

--
James Morris
<jmorris@xxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/