From: "Serge E. Hallyn" <serue@us.ibm.com>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux Containers <containers@lists.linux-foundation.org>
Subject: Re: [PATCH] devcgroup: skip superfluous checks when found the DEV_ALL elem
Date: Tue, 7 Apr 2009 21:55:05 -0500 [thread overview]
Message-ID: <20090408025505.GA28159@us.ibm.com> (raw)
In-Reply-To: <49DAE8E4.2030106@cn.fujitsu.com>
Quoting Li Zefan (lizf@cn.fujitsu.com):
> While walking through the whitelist, if the DEV_ALL item is found,
> no more check is needed.
Right, because the DEV_ALL item always has all permissions.
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
thanks,
-serge
> ---
> security/device_cgroup.c | 10 ++++++----
> 1 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/security/device_cgroup.c b/security/device_cgroup.c
> index 5fda7df..b8186ba 100644
> --- a/security/device_cgroup.c
> +++ b/security/device_cgroup.c
> @@ -490,7 +490,7 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
>
> list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
> if (wh->type & DEV_ALL)
> - goto acc_check;
> + goto found;
> if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
> continue;
> if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode))
> @@ -499,11 +499,12 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
> continue;
> if (wh->minor != ~0 && wh->minor != iminor(inode))
> continue;
> -acc_check:
> +
> if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE))
> continue;
> if ((mask & MAY_READ) && !(wh->access & ACC_READ))
> continue;
> +found:
> rcu_read_unlock();
> return 0;
> }
> @@ -527,7 +528,7 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
>
> list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
> if (wh->type & DEV_ALL)
> - goto acc_check;
> + goto found;
> if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))
> continue;
> if ((wh->type & DEV_CHAR) && !S_ISCHR(mode))
> @@ -536,9 +537,10 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
> continue;
> if (wh->minor != ~0 && wh->minor != MINOR(dev))
> continue;
> -acc_check:
> +
> if (!(wh->access & ACC_MKNOD))
> continue;
> +found:
> rcu_read_unlock();
> return 0;
> }
> --
> 1.5.4.rc3
next prev parent reply other threads:[~2009-04-08 2:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-07 5:47 [PATCH] devcgroup: skip superfluous checks when found the DEV_ALL elem Li Zefan
2009-04-08 2:55 ` Serge E. Hallyn [this message]
2009-04-10 0:06 ` Andrew Morton
2009-04-10 0:20 ` Li Zefan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20090408025505.GA28159@us.ibm.com \
--to=serue@us.ibm.com \
--cc=akpm@linux-foundation.org \
--cc=containers@lists.linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lizf@cn.fujitsu.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).