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List:       linux-hams
Subject:    Re: [PATCH -next] ax25: avoid overflows in ax25_setsockopt()
From:       David Miller <davem () davemloft ! net>
Date:       2011-12-28 19:08:19
Message-ID: 20111228.140819.861154490395622829.davem () davemloft ! net
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From: Xi Wang <xi.wang@gmail.com>
Date: Tue, 27 Dec 2011 14:43:19 -0500

> Commit be639ac6 ("NET: AX.25: Check ioctl arguments to avoid overflows
> further down the road") rejects very large arguments, but doesn't
> completely fix overflows on 64-bit systems.  Consider the AX25_T2 case.
> 
> 	int opt;
> 	...
> 	if (opt < 1 || opt > ULONG_MAX / HZ) {
> 		res = -EINVAL;
> 		break;
> 	}
> 	ax25->t2 = opt * HZ;
> 
> The 32-bit multiplication opt * HZ would overflow before being assigned
> to 64-bit ax25->t2.  This patch changes "opt" to unsigned long.
> 
> Signed-off-by: Xi Wang <xi.wang@gmail.com>
> Cc: Ralf Baechle <ralf@linux-mips.org>

Applied.
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