linux-kernel - Re: [PATCH 6/6] Integrity: IMA file free imbalance

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Message-ID: <20090202234702.GD18452@hallyn.com>
Date:	Mon, 2 Feb 2009 17:47:02 -0600
From:	"Serge E. Hallyn" <serge@...lyn.com>
To:	Mimi Zohar <zohar@...ux.vnet.ibm.com>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	James Morris <jmorris@...ei.org>,
	Christoph Hellwig <hch@...radead.org>,
	Dave Hansen <dave@...ux.vnet.ibm.com>,
	"<David Safford" <safford@...son.ibm.com>,
	Serge Hallyn <serue@...ibm.com>, Mimi Zohar <zohar@...ibm.com>
Subject: Re: [PATCH 6/6] Integrity: IMA file free imbalance

Quoting Mimi Zohar (zohar@...ux.vnet.ibm.com):
> The number of calls to ima_path_check()/ima_file_free()
> should be balanced.  An extra call to fput(), indicates
> the file could have been accessed without first being
> measured.
> 
> Although f_count is incremented/decremented in places other
> than fget/fput, like fget_light/fput_light and get_file, the
> current task must already hold a file refcnt.  The call to
> __fput() is delayed until the refcnt becomes 0, resulting
> in ima_file_free() flagging any changes.
> 
> - add hook to increment opencount for IPC shared memory(SYSV)
>   and shmat files
> 
> Signed-off-by: Mimi Zohar <zohar@...ibm.com>

...

> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c

...

> +static void opencount_get(struct file *file)
> +{
> +	struct inode *inode = file->f_dentry->d_inode;
> +	struct ima_iint_cache *iint;
> +
> +	if (!ima_initialized || !S_ISREG(inode->i_mode))
> +		return;
> +	iint = ima_iint_find_insert_get(inode);
> +	mutex_lock(&iint->mutex);
> +	if (iint)

Hey, I think you've got those two lines above mixed
up a bit :)

Very neat, though.

Acked-by: Serge Hallyn <serue@...ibm.com>

once that's fixed up.

thanks,
-serge
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