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From: David Howells <dhowells@redhat.com>
In-Reply-To: <20100424002319.d68a3819.toshi.okajima@jp.fujitsu.com>
References: <20100424002319.d68a3819.toshi.okajima@jp.fujitsu.com> <20100423195127.48095127.toshi.okajima@jp.fujitsu.com> <20100422163755.355794e3.toshi.okajima@jp.fujitsu.com> <7894.1271931370@redhat.com> <20100423194547.3135efb8.toshi.okajima@jp.fujitsu.com> <10934.1272022437@redhat.com>
To: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Cc: dhowells@redhat.com, keyrings@linux-nfs.org, security@kernel.org,
       linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1][BUG][TAKE2] KEYRINGS: find_keyring_by_name() can gain the freed keyring
Date: Fri, 23 Apr 2010 16:52:16 +0100
Message-ID: <1790.1272037936@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 654
Lines: 15

Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> wrote:

> > Better still, atomic_inc_not_zero().  How about the attached patch?
> Your fix looks good to me. But, if usage count of the keyring is 0,
> I think it better to return -ENOKEY immediately. 

The problem with that is that someone else may have created a keyring with the
same name that you can't then reach until the dead keyring is deleted.

David
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