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Message-ID: <1387345370.13593.10.camel@joe-AO722>
Subject: Re: [RESEND][PATCH] scsi: esas2r: fix potential format string flaw
From: Joe Perches <joe@perches.com>
To: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org,
        Bradley Grove <linuxdrivers@attotech.com>,
        "James E.J. Bottomley" <JBottomley@parallels.com>,
        linux-scsi@vger.kernel.org
Date: Tue, 17 Dec 2013 21:42:50 -0800
In-Reply-To: <20131217182733.GA16202@www.outflux.net>
References: <20131217182733.GA16202@www.outflux.net>
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On Tue, 2013-12-17 at 10:27 -0800, Kees Cook wrote:
> This makes sure format strings cannot leak into the printk call via the
> constructed buffer.
[]
> diff --git a/drivers/scsi/esas2r/esas2r_log.c b/drivers/scsi/esas2r/esas2r_log.c
[]
> @@ -171,7 +171,7 @@ static int esas2r_log_master(const long level,
>  		if (strlen(event_buffer) < buflen)
>  			strcat(buffer, "\n");
>  
> -		printk(event_buffer);
> +		printk("%s", event_buffer);

It's probably better to remove the

		if (strlen(event_buffer) < buflen)
			strcat(buffer, "\n");

and use

	printk("%s\n", event_buffer);

so that the output is always newline terminated.