From: Joe Perches <joe@perches.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Karsten Keil <isdn@linux-pingi.de>, netdev@vger.kernel.org
Subject: Re: [bug report] buffer overflow in isdn capi
Date: Tue, 01 Apr 2014 09:25:48 -0700 [thread overview]
Message-ID: <1396369548.21529.79.camel@joe-AO722> (raw)
In-Reply-To: <20140401154830.GA16759@mwanda>
On Tue, 2014-04-01 at 18:48 +0300, Dan Carpenter wrote:
> The command_2_index() function is buggy and leads to a buffer overflow.
> Does anyone know how to fix this?
>
> drivers/isdn/capi/capiutil.c
> 403 static unsigned command_2_index(unsigned c, unsigned sc)
These arguments should be u8 as well.
> 404 {
> 405 if (c & 0x80)
> 406 c = 0x9 + (c & 0x0f);
> 407 else if (c <= 0x0f);
> 408 else if (c == 0x41)
> 409 c = 0x9 + 0x1;
> 410 else if (c == 0xff)
> 411 c = 0x00;
> 412 return (sc & 3) * (0x9 + 0x9) + c;
> 413 }
>
> Imagine that we input c = 0x7f and sc = 0x3. Then 3 * 18 + 127 = 181
> and we return 181.
>
> The other thing that stands out to me is that the last condition
> "(c == 0xff)" is never true because then the first condition
> "(c & 0x80)" would have been true already.
next prev parent reply other threads:[~2014-04-01 16:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-01 15:48 [bug report] buffer overflow in isdn capi Dan Carpenter
2014-04-01 16:25 ` Joe Perches [this message]
2014-04-02 16:46 ` Karsten Keil
2014-06-02 22:48 ` Tilman Schmidt
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