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ax25: avoid overflows in ax25_setsockopt()

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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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Xi Wang 2011-12-27 09:43:19 +00:00 committed by David S. Miller
parent fa84309533
commit ba1cffe025
1 changed files with 6 additions and 5 deletions
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11
net/ax25/af_ax25.c
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@ -545,15 +545,16 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
ax25_cb *ax25;
struct net_device *dev;
char devname[IFNAMSIZ];
int opt, res = 0;
unsigned long opt;
int res = 0;
if (level != SOL_AX25)
return -ENOPROTOOPT;
if (optlen < sizeof(int))
if (optlen < sizeof(unsigned int))
return -EINVAL;
if (get_user(opt, (int __user *)optval))
if (get_user(opt, (unsigned int __user *)optval))
return -EFAULT;
lock_sock(sk);
@ -609,7 +610,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
break;
case AX25_IDLE:
if (opt < 0 || opt > ULONG_MAX / (60 * HZ)) {
if (opt > ULONG_MAX / (60 * HZ)) {
res = -EINVAL;
break;
}
@ -617,7 +618,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
break;
case AX25_BACKOFF:
if (opt < 0 || opt > 2) {
if (opt > 2) {
res = -EINVAL;
break;
}