ax25: avoid overflows in ax25_setsockopt()
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>
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index b863c18..3cd0a0d 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -545,15 +545,16 @@
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 @@
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 @@
break;
case AX25_BACKOFF:
- if (opt < 0 || opt > 2) {
+ if (opt > 2) {
res = -EINVAL;
break;
}