Re: [patch] isdn: fix information leak

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From: Dan Carpenter <error27@gmail.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: Karsten Keil <isdn@linux-pingi.de>,
	netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] isdn: fix information leak
Date: Thu, 05 Aug 2010 10:19:38 +0000	[thread overview]
Message-ID: <20100805101938.GH9031@bicker> (raw)
In-Reply-To: <AANLkTin4jtYuaxYfxDAgST857sD2K4Q28mPcPW=xd-V3@mail.gmail.com>

On Thu, Aug 05, 2010 at 06:08:08PM +0800, Changli Gao wrote:
> On Thu, Aug 5, 2010 at 5:38 PM, Dan Carpenter <error27@gmail.com> wrote:
> > The main motivation of this patch changing strcpy() to strlcpy().
> > We strcpy() to copy a 48 byte buffers into a 49 byte buffers.  So at
> > best the last byte has leaked information, or maybe there is an
> > overflow?  Anyway, this patch closes the information leaks by zeroing
> > the memory and the calls to strlcpy() prevent overflows.
> 
> strlcpy() can handle the terminator NUL. so you don't need to zero it.

If there are no NUL chars in "rcvmsg->msg_data.byte_array" then strlcpy()
is sufficient, but if there is a NUL character then you need to zero the
memory.  The patch handles both possibilities.

regards,
dan carpenter

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WARNING: multiple messages have this Message-ID (diff)

From: Dan Carpenter <error27@gmail.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: Karsten Keil <isdn@linux-pingi.de>,
	netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] isdn: fix information leak
Date: Thu, 5 Aug 2010 12:19:38 +0200	[thread overview]
Message-ID: <20100805101938.GH9031@bicker> (raw)
In-Reply-To: <AANLkTin4jtYuaxYfxDAgST857sD2K4Q28mPcPW=xd-V3@mail.gmail.com>

On Thu, Aug 05, 2010 at 06:08:08PM +0800, Changli Gao wrote:
> On Thu, Aug 5, 2010 at 5:38 PM, Dan Carpenter <error27@gmail.com> wrote:
> > The main motivation of this patch changing strcpy() to strlcpy().
> > We strcpy() to copy a 48 byte buffers into a 49 byte buffers.  So at
> > best the last byte has leaked information, or maybe there is an
> > overflow?  Anyway, this patch closes the information leaks by zeroing
> > the memory and the calls to strlcpy() prevent overflows.
> 
> strlcpy() can handle the terminator NUL. so you don't need to zero it.

If there are no NUL chars in "rcvmsg->msg_data.byte_array" then strlcpy()
is sufficient, but if there is a NUL character then you need to zero the
memory.  The patch handles both possibilities.

regards,
dan carpenter

next prev parent reply	other threads:[~2010-08-05 10:19 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-05  9:38 [patch] isdn: fix information leak Dan Carpenter
2010-08-05  9:38 ` Dan Carpenter
2010-08-05 10:08 ` Changli Gao
2010-08-05 10:08   ` Changli Gao
2010-08-05 10:19   ` Dan Carpenter [this message]
2010-08-05 10:19     ` Dan Carpenter
2010-08-05 11:02     ` Changli Gao
2010-08-05 11:02       ` Changli Gao
2010-08-05 11:37       ` Dan Carpenter
2010-08-05 11:37         ` Dan Carpenter
2010-08-05 13:18         ` Changli Gao
2010-08-05 13:18           ` Changli Gao
2010-08-05 13:24           ` Changli Gao
2010-08-05 13:24             ` Changli Gao
2010-08-05 13:55           ` Dan Carpenter
2010-08-05 13:55             ` Dan Carpenter
2010-08-05 13:59             ` Changli Gao
2010-08-05 13:59               ` Changli Gao
2010-08-05 20:21 ` David Miller
2010-08-05 20:21   ` David Miller

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