linux-kernel - Re: uprobe: checking probe event include directory

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Message-ID: <20120718114522.GF5006@linux.vnet.ibm.com>
Date:	Wed, 18 Jul 2012 17:15:22 +0530
From:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:	Jovi Zhang <bookjovi@...il.com>
Cc:	Fr?d?ric Weisbecker <fweisbec@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: uprobe: checking probe event include directory

* Jovi Zhang <bookjovi@...il.com> [2012-07-18 19:38:27]:

> On Wed, Jul 18, 2012 at 7:07 PM, Srikar Dronamraju
> <srikar@...ux.vnet.ibm.com> wrote:
> > The patch looks good,
> >
> > Can you modify the description a bit. However you are free to ignore
> > these comments. After knowing your response,  I will ack the patch.
> >
> > I would probably put this as:
> >
> > The subject could be
> > tracing: Verify target file before registering a uprobe event
> >
> > Description:
> > Without this patch, we can register a uprobe event for a directory.
> > Enabling such a uprobe event would anyway fail.
> >
> > Example:
> >
> > $ echo 'p /bin:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
> >
> > However directories cannot be valid targets for uprobe.
> > Hence verify if the target is a regular file during the probe
> > registration.
> 
> Thanks srikar, your description is more clear than mine.
> 
> 
> From fd5077196038cc271e2116e1fca359a0011e1669 Mon Sep 17 00:00:00 2001
> From: Jovi Zhang <bookjovi@...il.com>
> Date: Wed, 18 Jul 2012 18:16:44 +0800
> Subject: [PATCH] tracing: Verify target file before registering a uprobe
>  event
> 
> Without this patch, we can register a uprobe event for a directory.
> Enabling such a uprobe event would anyway fail.
> 
> Example:
> $ echo 'p /bin:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
> 
> However dirctories cannot be valid targets for uprobe.
> Hence verify if the target is a regular file during the probe
> registration.
> 
> Signed-off-by: Jovi Zhang <bookjovi@...il.com>
> Reviewed-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
> ---
>  kernel/trace/trace_uprobe.c |    6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 85158fa..3b5f646 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -259,6 +259,10 @@ static int create_trace_uprobe(int argc, char **argv)
>  		goto fail_address_parse;
> 
>  	inode = igrab(path.dentry->d_inode);
> +	 if (!S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)) {
> +		ret = -EINVAL;
> +		goto fail_address_parse;
> +	}
> 
>  	argc -= 2;
>  	argv += 2;
> @@ -358,7 +362,7 @@ fail_address_parse:
>  	if (inode)
>  		iput(inode);
> 
> -	pr_info("Failed to parse address.\n");
> +	pr_info("Failed to parse address or file.\n");
> 
>  	return ret;
>  }

Looks good.

Acked-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>

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